[PATCH v3 0/8] mfd / platform: cros_ec: move cros_ec sysfs attributes to its own drivers.

[PATCH v3 0/8] mfd / platform: cros_ec: move cros_ec sysfs attributes to its own drivers.

[Enric Balletbo i Serra]

Hi,

This is quick respin of the previous version because I introduced a
build problem between patch 3 and 6 due a wrong squash on my side. Sorry
about that. I also take this opportunity to do some few cleanups.

This is another patchset to try to cleanup a bit more the crossed
references for cros-ec driver between the MFD and the platform/chrome
subsystems.

The purpose of these patches is get rid of the different cros-ec attributes
from mfd/cros_ec_dev to its own sub-driver in platform/chrome. cros_ec_dev
continues instantiating the sub-devices but the sysfs attributes are owned
by the platform driver.E.g. The lightbar driver should own his sysfs
attributes and be instantiated only if the Embedded Controller has a
lightbar.

The patchset also adds the documentation of the sysfs attributes.

Most of the patches touches mfd subsystem and platform/chrome so I'd
suggest go all using and inmutable branch.

Waiting for your feedback. Best regards,
 Enric

Changes in v3:
- Removed cros_ec_remove from include file.
- Removed unneded check for ec_dev.
- Fixed build error as reported by the kbuild test robot.
- Do not print ec_platform name as is with dev_err is enough.

Changes in v2:
- Use devm only for the cros-ec core.
- Removed the two exported functions to attach/detach to the cros_class.
- Create the attributes directly instead of use the attach/detach callbacks.
- Add a "default MFD_CROS_EC_CHARDEV" in Kconfig for this.
- Removed the checks for missing debug_info, are not needed now.
- Removed a comment that no longer applies.
- Removed unnecessary IS_ENABLED.
- Removed dev_err message telling that VBC is found.
- Use dev_warn instead of dev_err as the error is ignored.
- Removed ec_with_lightbar variable.
- Fix WARN when unloading. This is new in these series.

Enric Balletbo i Serra (8):
  mfd / platform: cros_ec: use devm_mfd_add_devices.
  mfd / platform: cros_ec: move lightbar attributes to its own driver.
  mfd / platform: cros_ec: move vbc attributes to its own driver.
  mfd / platform: cros_ec: move debugfs attributes to its own driver.
  mfd / platform: cros_ec: move device sysfs attributes to its own
    driver.
  mfd / platform: cros_ec: instantiate only if th EC has a VBC NVRAM.
  platform/chrome: cros_ec_lightbar: instantiate only if the EC has a
    lightbar.
  mfd: cros_ec: add a dev_release empty method.

 .../ABI/testing/sysfs-class-chromeos          |  32 +++++
 ...sfs-class-chromeos-driver-cros-ec-lightbar |  74 ++++++++++
 .../sysfs-class-chromeos-driver-cros-ec-vbc   |   6 +
 drivers/mfd/Kconfig                           |   1 -
 drivers/mfd/cros_ec.c                         |  14 +-
 drivers/mfd/cros_ec_dev.c                     |  93 +++++--------
 drivers/mfd/cros_ec_dev.h                     |   6 -
 drivers/platform/chrome/Kconfig               |  45 ++++++-
 drivers/platform/chrome/Makefile              |   7 +-
 drivers/platform/chrome/cros_ec_debugfs.c     |  62 ++++++---
 drivers/platform/chrome/cros_ec_i2c.c         |  10 --
 drivers/platform/chrome/cros_ec_lightbar.c    | 126 ++++++++++++------
 drivers/platform/chrome/cros_ec_lpc.c         |   4 -
 drivers/platform/chrome/cros_ec_spi.c         |  11 --
 drivers/platform/chrome/cros_ec_sysfs.c       |  36 ++++-
 drivers/platform/chrome/cros_ec_vbc.c         |  59 +++++---
 include/linux/mfd/cros_ec.h                   |  21 ---
 17 files changed, 400 insertions(+), 207 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
 create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
 create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc

-- 
2.19.1

[PATCH v3 1/8] mfd / platform: cros_ec: use devm_mfd_add_devices.

[Enric Balletbo i Serra]

Use devm_mfd_add_devices() for adding cros-ec core MFD child devices. This
reduces the need of remove callback from platform/chrome for removing the
MFD child devices.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3:
- Removed cros_ec_remove from include file.

Changes in v2:
- Use devm only for the cros-ec core.

 drivers/mfd/cros_ec.c                 | 14 +++-----------
 drivers/mfd/cros_ec_dev.c             |  1 +
 drivers/platform/chrome/cros_ec_i2c.c | 10 ----------
 drivers/platform/chrome/cros_ec_lpc.c |  4 ----
 drivers/platform/chrome/cros_ec_spi.c | 11 -----------
 include/linux/mfd/cros_ec.h           | 10 ----------
 6 files changed, 4 insertions(+), 46 deletions(-)

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index fe6f83766144..6acfe036d522 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -129,8 +129,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		}
 	}
 
-	err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell, 1,
-			      NULL, ec_dev->irq, NULL);
+	err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell,
+				   1, NULL, ec_dev->irq, NULL);
 	if (err) {
 		dev_err(dev,
 			"Failed to register Embedded Controller subdevice %d\n",
@@ -147,7 +147,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		 * - the EC is responsive at init time (it is not true for a
 		 *   sensor hub.
 		 */
-		err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
+		err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
 				      &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
 		if (err) {
 			dev_err(dev,
@@ -181,14 +181,6 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 }
 EXPORT_SYMBOL(cros_ec_register);
 
-int cros_ec_remove(struct cros_ec_device *ec_dev)
-{
-	mfd_remove_devices(ec_dev->dev);
-
-	return 0;
-}
-EXPORT_SYMBOL(cros_ec_remove);
-
 #ifdef CONFIG_PM_SLEEP
 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 {
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 8f9d6964173e..ff788d3e6d5f 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -493,6 +493,7 @@ static int ec_device_remove(struct platform_device *pdev)
 
 	cros_ec_debugfs_remove(ec);
 
+	mfd_remove_devices(ec->dev);
 	cdev_del(&ec->cdev);
 	device_unregister(&ec->class_dev);
 	return 0;
diff --git a/drivers/platform/chrome/cros_ec_i2c.c b/drivers/platform/chrome/cros_ec_i2c.c
index ef9b4763356f..9a009eaa4ada 100644
--- a/drivers/platform/chrome/cros_ec_i2c.c
+++ b/drivers/platform/chrome/cros_ec_i2c.c
@@ -317,15 +317,6 @@ static int cros_ec_i2c_probe(struct i2c_client *client,
 	return 0;
 }
 
-static int cros_ec_i2c_remove(struct i2c_client *client)
-{
-	struct cros_ec_device *ec_dev = i2c_get_clientdata(client);
-
-	cros_ec_remove(ec_dev);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM_SLEEP
 static int cros_ec_i2c_suspend(struct device *dev)
 {
@@ -376,7 +367,6 @@ static struct i2c_driver cros_ec_driver = {
 		.pm	= &cros_ec_i2c_pm_ops,
 	},
 	.probe		= cros_ec_i2c_probe,
-	.remove		= cros_ec_i2c_remove,
 	.id_table	= cros_ec_i2c_id,
 };
 
diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index e1b75775cd4a..14684a56e40f 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -327,7 +327,6 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 
 static int cros_ec_lpc_remove(struct platform_device *pdev)
 {
-	struct cros_ec_device *ec_dev;
 	struct acpi_device *adev;
 
 	adev = ACPI_COMPANION(&pdev->dev);
@@ -335,9 +334,6 @@ static int cros_ec_lpc_remove(struct platform_device *pdev)
 		acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
 					   cros_ec_lpc_acpi_notify);
 
-	ec_dev = platform_get_drvdata(pdev);
-	cros_ec_remove(ec_dev);
-
 	return 0;
 }
 
diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
index 2060d1483043..6cfbc2835beb 100644
--- a/drivers/platform/chrome/cros_ec_spi.c
+++ b/drivers/platform/chrome/cros_ec_spi.c
@@ -685,16 +685,6 @@ static int cros_ec_spi_probe(struct spi_device *spi)
 	return 0;
 }
 
-static int cros_ec_spi_remove(struct spi_device *spi)
-{
-	struct cros_ec_device *ec_dev;
-
-	ec_dev = spi_get_drvdata(spi);
-	cros_ec_remove(ec_dev);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM_SLEEP
 static int cros_ec_spi_suspend(struct device *dev)
 {
@@ -733,7 +723,6 @@ static struct spi_driver cros_ec_driver_spi = {
 		.pm	= &cros_ec_spi_pm_ops,
 	},
 	.probe		= cros_ec_spi_probe,
-	.remove		= cros_ec_spi_remove,
 	.id_table	= cros_ec_spi_id,
 };
 
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index e44e3ec8a9c7..706dd724de52 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -281,16 +281,6 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 			    struct cros_ec_command *msg);
 
-/**
- * cros_ec_remove() - Remove a ChromeOS EC.
- * @ec_dev: Device to register.
- *
- * Call this to deregister a ChromeOS EC, then clean up any private data.
- *
- * Return: 0 on success or negative error code.
- */
-int cros_ec_remove(struct cros_ec_device *ec_dev);
-
 /**
  * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
  * @ec_dev: Device to register.
-- 
2.19.1

[PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Enric Balletbo i Serra]

The entire way how cros sysfs attibutes are created is broken.
cros_ec_lightbar should be its own driver and its attributes should be
associated with a lightbar driver not the mfd driver. In order to retain
the path, the lightbar attributes are attached to the cros_class.

The patch also adds the sysfs documentation.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3:
- Removed unneded check for ec_dev.

Changes in v2:
- Removed the two exported functions to attach/detach to the cros_class.
- Use dev_warn instead of dev_err when adding the lightbar.

 ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
 drivers/mfd/cros_ec_dev.c                     | 24 ++---
 drivers/mfd/cros_ec_dev.h                     |  6 --
 drivers/platform/chrome/Kconfig               | 10 ++
 drivers/platform/chrome/Makefile              |  3 +-
 drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
 include/linux/mfd/cros_ec.h                   |  1 -
 7 files changed, 172 insertions(+), 41 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar

diff --git a/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
new file mode 100644
index 000000000000..4893fd2e956f
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
@@ -0,0 +1,74 @@
+What:		/sys/class/chromeos/<cros-ec>/lightbar/brightness
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Writing to this file adjusts the overall brightness of
+		the lightbar, separate from any color intensity. The
+		valid range is 0 (off) to 255 (maximum brightness).
+
+What:		/sys/class/chromeos/<cros-ec>/lightbar/interval_msec
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		The lightbar is controlled by an embedded controller (EC),
+		which also manages the keyboard, battery charging, fans,
+		and other system hardware. To prevent unprivileged users
+		from interfering with the other EC functions, the rate at
+		which the lightbar control files can be read or written is
+		limited.
+
+		Reading this file will return the number of milliseconds
+		that must elapse between accessing any of the lightbar
+		functions through this interface. Going faster will simply
+		block until the necessary interval has lapsed. The interval
+		applies uniformly to all accesses of any kind by any user.
+
+What:		/sys/class/chromeos/<cros-ec>/lightbar/led_rgb
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		This allows you to control each LED segment. If the
+		lightbar is already running one of the automatic
+		sequences, you probably won’t see anything change because
+		your color setting will be almost immediately replaced.
+		To get useful results, you should stop the lightbar
+		sequence first.
+
+		The values written to this file are sets of four integers,
+		indicating LED, RED, GREEN, BLUE. The LED number is 0 to 3
+		to select a single segment, or 4 to set all four segments
+		to the same value at once. The RED, GREEN, and BLUE
+		numbers should be in the range 0 (off) to 255 (maximum).
+		You can update more than one segment at a time by writing
+		more than one set of four integers.
+
+What:		/sys/class/chromeos/<cros-ec>/lightbar/program
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		This allows you to upload and run custom lightbar sequences.
+
+What:		/sys/class/chromeos/<cros-ec>/lightbar/sequence
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		The Pixel lightbar has a number of built-in sequences
+		that it displays under various conditions, such as at
+		power on, shut down, or while running. Reading from this
+		file displays the current sequence that the lightbar is
+		displaying. Writing to this file allows you to change the
+		sequence.
+
+What:		/sys/class/chromeos/<cros-ec>/lightbar/userspace_control
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		This allows you to take the control of the lightbar. This
+		prevents the kernel from going through its normal
+		sequences.
+
+What:		/sys/class/chromeos/<cros-ec>/lightbar/version
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Show the information about the lightbar version.
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index ff788d3e6d5f..614f888c9d6d 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -36,7 +36,6 @@ static int ec_major;
 
 static const struct attribute_group *cros_ec_groups[] = {
 	&cros_ec_attr_group,
-	&cros_ec_lightbar_attr_group,
 	&cros_ec_vbc_attr_group,
 	NULL,
 };
@@ -390,6 +389,10 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
 	{ .name = "cros-usbpd-charger" }
 };
 
+static const struct mfd_cell cros_ec_platform_cells[] = {
+	{ .name = "cros-ec-lightbar" },
+};
+
 static int ec_device_probe(struct platform_device *pdev)
 {
 	int retval = -ENOMEM;
@@ -464,9 +467,6 @@ static int ec_device_probe(struct platform_device *pdev)
 				retval);
 	}
 
-	/* Take control of the lightbar from the EC. */
-	lb_manual_suspend_ctrl(ec, 1);
-
 	/* We can now add the sysfs class, we know which parameter to show */
 	retval = cdev_device_add(&ec->cdev, &ec->class_dev);
 	if (retval) {
@@ -474,6 +474,15 @@ static int ec_device_probe(struct platform_device *pdev)
 		goto failed;
 	}
 
+	retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
+				 cros_ec_platform_cells,
+				 ARRAY_SIZE(cros_ec_platform_cells),
+				 NULL, 0, NULL);
+	if (retval)
+		dev_warn(ec->dev,
+			 "failed to add cros-ec platform devices: %d\n",
+			 retval);
+
 	if (cros_ec_debugfs_init(ec))
 		dev_warn(dev, "failed to create debugfs directory\n");
 
@@ -488,9 +497,6 @@ static int ec_device_remove(struct platform_device *pdev)
 {
 	struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 
-	/* Let the EC take over the lightbar again. */
-	lb_manual_suspend_ctrl(ec, 0);
-
 	cros_ec_debugfs_remove(ec);
 
 	mfd_remove_devices(ec->dev);
@@ -519,8 +525,6 @@ static __maybe_unused int ec_device_suspend(struct device *dev)
 
 	cros_ec_debugfs_suspend(ec);
 
-	lb_suspend(ec);
-
 	return 0;
 }
 
@@ -530,8 +534,6 @@ static __maybe_unused int ec_device_resume(struct device *dev)
 
 	cros_ec_debugfs_resume(ec);
 
-	lb_resume(ec);
-
 	return 0;
 }
 
diff --git a/drivers/mfd/cros_ec_dev.h b/drivers/mfd/cros_ec_dev.h
index 978d836a0248..ec750433455a 100644
--- a/drivers/mfd/cros_ec_dev.h
+++ b/drivers/mfd/cros_ec_dev.h
@@ -44,10 +44,4 @@ struct cros_ec_readmem {
 #define CROS_EC_DEV_IOCXCMD   _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
 #define CROS_EC_DEV_IOCRDMEM  _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)
 
-/* Lightbar utilities */
-extern bool ec_has_lightbar(struct cros_ec_dev *ec);
-extern int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable);
-extern int lb_suspend(struct cros_ec_dev *ec);
-extern int lb_resume(struct cros_ec_dev *ec);
-
 #endif /* _CROS_EC_DEV_H_ */
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 16b1615958aa..05bcefbe1926 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -111,4 +111,14 @@ config CROS_KBD_LED_BACKLIGHT
 	  To compile this driver as a module, choose M here: the
 	  module will be called cros_kbd_led_backlight.
 
+config CROS_EC_LIGHTBAR
+	tristate "Chromebook Pixel's lightbar support"
+	depends on MFD_CROS_EC_CHARDEV
+	help
+	  This option exposes the Chromebook Pixel's lightbar to
+	  userspace.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_lightbar.
+
 endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index cd591bf872bb..3c29a4b405d5 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -3,7 +3,7 @@
 obj-$(CONFIG_CHROMEOS_LAPTOP)		+= chromeos_laptop.o
 obj-$(CONFIG_CHROMEOS_PSTORE)		+= chromeos_pstore.o
 obj-$(CONFIG_CHROMEOS_TBMC)		+= chromeos_tbmc.o
-cros_ec_ctl-objs			:= cros_ec_sysfs.o cros_ec_lightbar.o \
+cros_ec_ctl-objs			:= cros_ec_sysfs.o \
 					   cros_ec_vbc.o cros_ec_debugfs.o
 obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
@@ -13,3 +13,4 @@ cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)	+= cros_ec_lpc_mec.o
 obj-$(CONFIG_CROS_EC_LPC)		+= cros_ec_lpcs.o
 obj-$(CONFIG_CROS_EC_PROTO)		+= cros_ec_proto.o
 obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.o
+obj-$(CONFIG_CROS_EC_LIGHTBAR)		+= cros_ec_lightbar.o
diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
index 68193bb53383..80eed6317570 100644
--- a/drivers/platform/chrome/cros_ec_lightbar.c
+++ b/drivers/platform/chrome/cros_ec_lightbar.c
@@ -33,6 +33,8 @@
 #include <linux/uaccess.h>
 #include <linux/slab.h>
 
+#define DRV_NAME "cros-ec-lightbar"
+
 /* Rate-limit the lightbar interface to prevent DoS. */
 static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
 
@@ -373,7 +375,7 @@ static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd)
 	return ret;
 }
 
-int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
+static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
 {
 	struct ec_params_lightbar *param;
 	struct cros_ec_command *msg;
@@ -408,25 +410,6 @@ int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
 
 	return ret;
 }
-EXPORT_SYMBOL(lb_manual_suspend_ctrl);
-
-int lb_suspend(struct cros_ec_dev *ec)
-{
-	if (userspace_control || ec != ec_with_lightbar)
-		return 0;
-
-	return lb_send_empty_cmd(ec, LIGHTBAR_CMD_SUSPEND);
-}
-EXPORT_SYMBOL(lb_suspend);
-
-int lb_resume(struct cros_ec_dev *ec)
-{
-	if (userspace_control || ec != ec_with_lightbar)
-		return 0;
-
-	return lb_send_empty_cmd(ec, LIGHTBAR_CMD_RESUME);
-}
-EXPORT_SYMBOL(lb_resume);
 
 static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
@@ -584,7 +567,7 @@ static struct attribute *__lb_cmds_attrs[] = {
 	NULL,
 };
 
-bool ec_has_lightbar(struct cros_ec_dev *ec)
+static bool ec_has_lightbar(struct cros_ec_dev *ec)
 {
 	return !!get_lightbar_version(ec, NULL, NULL);
 }
@@ -616,4 +599,72 @@ struct attribute_group cros_ec_lightbar_attr_group = {
 	.attrs = __lb_cmds_attrs,
 	.is_visible = cros_ec_lightbar_attrs_are_visible,
 };
-EXPORT_SYMBOL(cros_ec_lightbar_attr_group);
+
+static int cros_ec_lightbar_probe(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+	struct device *dev = &pd->dev;
+	int ret;
+
+	/* Take control of the lightbar from the EC. */
+	lb_manual_suspend_ctrl(ec_dev, 1);
+
+	ret = sysfs_create_group(&ec_dev->class_dev.kobj,
+				 &cros_ec_lightbar_attr_group);
+	if (ret < 0)
+		dev_err(dev, "failed to create %s attributes. err=%d\n",
+			cros_ec_lightbar_attr_group.name, ret);
+
+	return ret;
+}
+
+static int cros_ec_lightbar_remove(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+
+	sysfs_remove_group(&ec_dev->class_dev.kobj,
+			   &cros_ec_lightbar_attr_group);
+
+	/* Let the EC take over the lightbar again. */
+	lb_manual_suspend_ctrl(ec_dev, 0);
+
+	return 0;
+}
+
+static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
+
+	if (userspace_control || ec_dev != ec_with_lightbar)
+		return 0;
+
+	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
+}
+
+static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
+
+	if (userspace_control || ec_dev != ec_with_lightbar)
+		return 0;
+
+	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
+}
+
+static SIMPLE_DEV_PM_OPS(cros_ec_lightbar_pm_ops,
+			 cros_ec_lightbar_suspend, cros_ec_lightbar_resume);
+
+static struct platform_driver cros_ec_lightbar_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.pm = &cros_ec_lightbar_pm_ops,
+	},
+	.probe = cros_ec_lightbar_probe,
+	.remove = cros_ec_lightbar_remove,
+};
+
+module_platform_driver(cros_ec_lightbar_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Expose the Chromebook Pixel's lightbar to userspace");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 706dd724de52..b6beba3031ba 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -325,7 +325,6 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
 
 /* sysfs stuff */
 extern struct attribute_group cros_ec_attr_group;
-extern struct attribute_group cros_ec_lightbar_attr_group;
 extern struct attribute_group cros_ec_vbc_attr_group;
 
 /* debugfs stuff */
-- 
2.19.1

[PATCH v3 3/8] mfd / platform: cros_ec: move vbc attributes to its own driver.

[Enric Balletbo i Serra]

The entire way how cros sysfs attibutes are created is broken.
cros_ec_vbc should be its own driver and its attributes should be
associated with a vbc driver not the mfd driver. In order to retain
the path, the vbc attributes are attached to the cros_class.

The patch also adds the sysfs documentation.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3:
- Fixed build error as reported by the kbuild test robot.

Changes in v2:
- Removed unneeded check of ec_dev.

 .../sysfs-class-chromeos-driver-cros-ec-vbc   |  6 +++
 drivers/mfd/cros_ec_dev.c                     |  2 +-
 drivers/platform/chrome/Kconfig               | 10 +++++
 drivers/platform/chrome/Makefile              |  3 +-
 drivers/platform/chrome/cros_ec_vbc.c         | 43 ++++++++++++++++++-
 include/linux/mfd/cros_ec.h                   |  1 -
 6 files changed, 61 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc

diff --git a/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc
new file mode 100644
index 000000000000..c256a2febf37
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc
@@ -0,0 +1,6 @@
+What:		/sys/class/chromeos/<cros-ec>/vbc/vboot_context
+Date:		October 2015
+KernelVersion:	4.4
+Description:
+		Read/write the verified boot context data included on a
+		small nvram space on some EC implementations.
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 614f888c9d6d..51325049690c 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -36,7 +36,6 @@ static int ec_major;
 
 static const struct attribute_group *cros_ec_groups[] = {
 	&cros_ec_attr_group,
-	&cros_ec_vbc_attr_group,
 	NULL,
 };
 
@@ -391,6 +390,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
 
 static const struct mfd_cell cros_ec_platform_cells[] = {
 	{ .name = "cros-ec-lightbar" },
+	{ .name = "cros-ec-vbc" },
 };
 
 static int ec_device_probe(struct platform_device *pdev)
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 05bcefbe1926..29bd9837d520 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -121,4 +121,14 @@ config CROS_EC_LIGHTBAR
 	  To compile this driver as a module, choose M here: the
 	  module will be called cros_ec_lightbar.
 
+config CROS_EC_VBC
+	tristate "ChromeOS EC vboot context support"
+	depends on MFD_CROS_EC_CHARDEV && OF
+	help
+	  This option exposes the ChromeOS EC vboot context nvram to
+	  userspace.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_vbc.
+
 endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 3c29a4b405d5..4081b7179df7 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -4,7 +4,7 @@ obj-$(CONFIG_CHROMEOS_LAPTOP)		+= chromeos_laptop.o
 obj-$(CONFIG_CHROMEOS_PSTORE)		+= chromeos_pstore.o
 obj-$(CONFIG_CHROMEOS_TBMC)		+= chromeos_tbmc.o
 cros_ec_ctl-objs			:= cros_ec_sysfs.o \
-					   cros_ec_vbc.o cros_ec_debugfs.o
+					   cros_ec_debugfs.o
 obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
@@ -14,3 +14,4 @@ obj-$(CONFIG_CROS_EC_LPC)		+= cros_ec_lpcs.o
 obj-$(CONFIG_CROS_EC_PROTO)		+= cros_ec_proto.o
 obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.o
 obj-$(CONFIG_CROS_EC_LIGHTBAR)		+= cros_ec_lightbar.o
+obj-$(CONFIG_CROS_EC_VBC)		+= cros_ec_vbc.o
diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c
index 5356f26bc022..da3bbf05e86f 100644
--- a/drivers/platform/chrome/cros_ec_vbc.c
+++ b/drivers/platform/chrome/cros_ec_vbc.c
@@ -22,8 +22,11 @@
 #include <linux/platform_device.h>
 #include <linux/mfd/cros_ec.h>
 #include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 
+#define DRV_NAME "cros-ec-vbc"
+
 static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
 				  struct bin_attribute *att, char *buf,
 				  loff_t pos, size_t count)
@@ -132,4 +135,42 @@ struct attribute_group cros_ec_vbc_attr_group = {
 	.bin_attrs = cros_ec_vbc_bin_attrs,
 	.is_bin_visible = cros_ec_vbc_is_visible,
 };
-EXPORT_SYMBOL(cros_ec_vbc_attr_group);
+
+static int cros_ec_vbc_probe(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+	struct device *dev = &pd->dev;
+	int ret;
+
+	ret = sysfs_create_group(&ec_dev->class_dev.kobj,
+				 &cros_ec_vbc_attr_group);
+	if (ret < 0)
+		dev_err(dev, "failed to create %s attributes. err=%d\n",
+			cros_ec_vbc_attr_group.name, ret);
+
+	return ret;
+}
+
+static int cros_ec_vbc_remove(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+
+	sysfs_remove_group(&ec_dev->class_dev.kobj,
+			   &cros_ec_vbc_attr_group);
+
+	return 0;
+}
+
+static struct platform_driver cros_ec_vbc_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.probe = cros_ec_vbc_probe,
+	.remove = cros_ec_vbc_remove,
+};
+
+module_platform_driver(cros_ec_vbc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index b6beba3031ba..bbbe416fd573 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -325,7 +325,6 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
 
 /* sysfs stuff */
 extern struct attribute_group cros_ec_attr_group;
-extern struct attribute_group cros_ec_vbc_attr_group;
 
 /* debugfs stuff */
 int cros_ec_debugfs_init(struct cros_ec_dev *ec);
-- 
2.19.1

[PATCH v3 4/8] mfd / platform: cros_ec: move debugfs attributes to its own driver.

[Enric Balletbo i Serra]

The entire way how cros debugfs attibutes are created is broken.
cros_ec_debugfs should be its own driver and its attributes should be
associated with a debugfs driver not the mfd driver.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3: None
Changes in v2:
- Add a "default MFD_CROS_EC_CHARDEV" in Kconfig for this.
- Remove the checks for missing debug_info, are not needed now.
- Remove a comment that no longer applies.

 drivers/mfd/cros_ec_dev.c                 | 41 +--------------
 drivers/platform/chrome/Kconfig           | 11 ++++
 drivers/platform/chrome/Makefile          |  4 +-
 drivers/platform/chrome/cros_ec_debugfs.c | 62 +++++++++++++++--------
 include/linux/mfd/cros_ec.h               |  6 ---
 5 files changed, 56 insertions(+), 68 deletions(-)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 51325049690c..50ba8e0fb4ec 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -389,6 +389,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
 };
 
 static const struct mfd_cell cros_ec_platform_cells[] = {
+	{ .name = "cros-ec-debugfs" },
 	{ .name = "cros-ec-lightbar" },
 	{ .name = "cros-ec-vbc" },
 };
@@ -483,9 +484,6 @@ static int ec_device_probe(struct platform_device *pdev)
 			 "failed to add cros-ec platform devices: %d\n",
 			 retval);
 
-	if (cros_ec_debugfs_init(ec))
-		dev_warn(dev, "failed to create debugfs directory\n");
-
 	return 0;
 
 failed:
@@ -497,62 +495,25 @@ static int ec_device_remove(struct platform_device *pdev)
 {
 	struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 
-	cros_ec_debugfs_remove(ec);
-
 	mfd_remove_devices(ec->dev);
 	cdev_del(&ec->cdev);
 	device_unregister(&ec->class_dev);
 	return 0;
 }
 
-static void ec_device_shutdown(struct platform_device *pdev)
-{
-	struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
-
-	/* Be sure to clear up debugfs delayed works */
-	cros_ec_debugfs_remove(ec);
-}
-
 static const struct platform_device_id cros_ec_id[] = {
 	{ DRV_NAME, 0 },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 
-static __maybe_unused int ec_device_suspend(struct device *dev)
-{
-	struct cros_ec_dev *ec = dev_get_drvdata(dev);
-
-	cros_ec_debugfs_suspend(ec);
-
-	return 0;
-}
-
-static __maybe_unused int ec_device_resume(struct device *dev)
-{
-	struct cros_ec_dev *ec = dev_get_drvdata(dev);
-
-	cros_ec_debugfs_resume(ec);
-
-	return 0;
-}
-
-static const struct dev_pm_ops cros_ec_dev_pm_ops = {
-#ifdef CONFIG_PM_SLEEP
-	.suspend = ec_device_suspend,
-	.resume = ec_device_resume,
-#endif
-};
-
 static struct platform_driver cros_ec_dev_driver = {
 	.driver = {
 		.name = DRV_NAME,
-		.pm = &cros_ec_dev_pm_ops,
 	},
 	.id_table = cros_ec_id,
 	.probe = ec_device_probe,
 	.remove = ec_device_remove,
-	.shutdown = ec_device_shutdown,
 };
 
 static int __init cros_ec_dev_init(void)
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 29bd9837d520..4e4232b47764 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -131,4 +131,15 @@ config CROS_EC_VBC
 	  To compile this driver as a module, choose M here: the
 	  module will be called cros_ec_vbc.
 
+config CROS_EC_DEBUGFS
+	tristate "Export ChromeOS EC internals in DebugFS"
+	depends on MFD_CROS_EC_CHARDEV && DEBUG_FS
+	default MFD_CROS_EC_CHARDEV
+	help
+	  This option exposes the ChromeOS EC device internals to
+	  userspace.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_debugfs.
+
 endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 4081b7179df7..12a5c4d18c17 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -3,8 +3,7 @@
 obj-$(CONFIG_CHROMEOS_LAPTOP)		+= chromeos_laptop.o
 obj-$(CONFIG_CHROMEOS_PSTORE)		+= chromeos_pstore.o
 obj-$(CONFIG_CHROMEOS_TBMC)		+= chromeos_tbmc.o
-cros_ec_ctl-objs			:= cros_ec_sysfs.o \
-					   cros_ec_debugfs.o
+cros_ec_ctl-objs			:= cros_ec_sysfs.o
 obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
@@ -15,3 +14,4 @@ obj-$(CONFIG_CROS_EC_PROTO)		+= cros_ec_proto.o
 obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.o
 obj-$(CONFIG_CROS_EC_LIGHTBAR)		+= cros_ec_lightbar.o
 obj-$(CONFIG_CROS_EC_VBC)		+= cros_ec_vbc.o
+obj-$(CONFIG_CROS_EC_DEBUGFS)		+= cros_ec_debugfs.o
diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c
index c62ee8e610a0..6cacac53dfce 100644
--- a/drivers/platform/chrome/cros_ec_debugfs.c
+++ b/drivers/platform/chrome/cros_ec_debugfs.c
@@ -23,12 +23,16 @@
 #include <linux/fs.h>
 #include <linux/mfd/cros_ec.h>
 #include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/platform_device.h>
 #include <linux/poll.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/wait.h>
 
+#define DRV_NAME "cros-ec-debugfs"
+
 #define LOG_SHIFT		14
 #define LOG_SIZE		(1 << LOG_SHIFT)
 #define LOG_POLL_SEC		10
@@ -423,8 +427,9 @@ static int cros_ec_create_pdinfo(struct cros_ec_debugfs *debug_info)
 	return 0;
 }
 
-int cros_ec_debugfs_init(struct cros_ec_dev *ec)
+static int cros_ec_debugfs_probe(struct platform_device *pd)
 {
+	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
 	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
 	const char *name = ec_platform->ec_name;
 	struct cros_ec_debugfs *debug_info;
@@ -453,40 +458,57 @@ int cros_ec_debugfs_init(struct cros_ec_dev *ec)
 
 	ec->debug_info = debug_info;
 
+	dev_set_drvdata(&pd->dev, ec);
+
 	return 0;
 
 remove_debugfs:
 	debugfs_remove_recursive(debug_info->dir);
 	return ret;
 }
-EXPORT_SYMBOL(cros_ec_debugfs_init);
 
-void cros_ec_debugfs_remove(struct cros_ec_dev *ec)
+static int cros_ec_debugfs_remove(struct platform_device *pd)
 {
-	if (!ec->debug_info)
-		return;
+	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
 
 	debugfs_remove_recursive(ec->debug_info->dir);
 	cros_ec_cleanup_console_log(ec->debug_info);
+
+	return 0;
 }
-EXPORT_SYMBOL(cros_ec_debugfs_remove);
 
-void cros_ec_debugfs_suspend(struct cros_ec_dev *ec)
+static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
 {
-	/*
-	 * cros_ec_debugfs_init() failures are non-fatal; it's also possible
-	 * that we initted things but decided that console log wasn't supported.
-	 * We'll use the same set of checks that cros_ec_debugfs_remove() +
-	 * cros_ec_cleanup_console_log() end up using to handle those cases.
-	 */
-	if (ec->debug_info && ec->debug_info->log_buffer.buf)
-		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
+	struct cros_ec_dev *ec = dev_get_drvdata(dev);
+
+	cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
+
+	return 0;
 }
-EXPORT_SYMBOL(cros_ec_debugfs_suspend);
 
-void cros_ec_debugfs_resume(struct cros_ec_dev *ec)
+static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
 {
-	if (ec->debug_info && ec->debug_info->log_buffer.buf)
-		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
+	struct cros_ec_dev *ec = dev_get_drvdata(dev);
+
+	schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
+
+	return 0;
 }
-EXPORT_SYMBOL(cros_ec_debugfs_resume);
+
+static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
+			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
+
+static struct platform_driver cros_ec_debugfs_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.pm = &cros_ec_debugfs_pm_ops,
+	},
+	.probe = cros_ec_debugfs_probe,
+	.remove = cros_ec_debugfs_remove,
+};
+
+module_platform_driver(cros_ec_debugfs_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index bbbe416fd573..3e4401e2ceea 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -326,10 +326,4 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
 /* sysfs stuff */
 extern struct attribute_group cros_ec_attr_group;
 
-/* debugfs stuff */
-int cros_ec_debugfs_init(struct cros_ec_dev *ec);
-void cros_ec_debugfs_remove(struct cros_ec_dev *ec);
-void cros_ec_debugfs_suspend(struct cros_ec_dev *ec);
-void cros_ec_debugfs_resume(struct cros_ec_dev *ec);
-
 #endif /* __LINUX_MFD_CROS_EC_H */
-- 
2.19.1

[PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Enric Balletbo i Serra]

The entire way how cros debugfs attibutes are created is broken.
cros_ec_sysfs should be its own driver and its attributes should be
associated with the sysfs driver not the mfd driver.

The patch also adds the sysfs documentation.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3:
- Do not print ec_platform name as is with dev_err is enough.

Changes in v2:
- Create the attributes directly instead of use the attach/detach callbacks.

 .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
 drivers/mfd/Kconfig                           |  1 -
 drivers/mfd/cros_ec_dev.c                     |  7 +---
 drivers/platform/chrome/Kconfig               | 14 ++++++--
 drivers/platform/chrome/Makefile              |  3 +-
 drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
 include/linux/mfd/cros_ec.h                   |  3 --
 7 files changed, 80 insertions(+), 16 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos

diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
new file mode 100644
index 000000000000..a5399c4ca82d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-chromeos
@@ -0,0 +1,32 @@
+What:		/sys/class/chromeos/<cros-ec>/flashinfo
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Show the EC flash information.
+
+What:		/sys/class/chromeos/<cros-ec>/kb_wake_angle
+Date:		March 2018
+KernelVersion:	4.17
+Description:
+		Control the keyboard wake lid angle. Values are between
+		0 and 360. This file will also show the keyboard wake lid
+		angle by querying the hardware.
+
+What:		/sys/class/chromeos/<cros-ec>/reboot
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Tell the EC to reboot in various ways. Options are:
+		"cancel": Cancel a pending reboot.
+		"ro": Jump to RO without rebooting.
+		"rw": Jump to RW without rebooting.
+		"cold": Cold reboot.
+		"disable-jump": Disable jump until next reboot.
+		"hibernate": Hibernate the EC.
+		"at-shutdown": Reboot after an AP shutdown.
+
+What:		/sys/class/chromeos/<cros-ec>/version
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Show the information about the EC software and hardware.
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 8c5dfdce4326..089ffb408918 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -214,7 +214,6 @@ config MFD_CROS_EC
 config MFD_CROS_EC_CHARDEV
         tristate "Chrome OS Embedded Controller userspace device interface"
         depends on MFD_CROS_EC
-        select CROS_EC_CTL
         ---help---
           This driver adds support to talk with the ChromeOS EC from userspace.
 
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 50ba8e0fb4ec..d9b16ce79319 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -34,15 +34,9 @@
 #define CROS_MAX_DEV 128
 static int ec_major;
 
-static const struct attribute_group *cros_ec_groups[] = {
-	&cros_ec_attr_group,
-	NULL,
-};
-
 static struct class cros_class = {
 	.owner          = THIS_MODULE,
 	.name           = "chromeos",
-	.dev_groups     = cros_ec_groups,
 };
 
 /* Basic communication */
@@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
 static const struct mfd_cell cros_ec_platform_cells[] = {
 	{ .name = "cros-ec-debugfs" },
 	{ .name = "cros-ec-lightbar" },
+	{ .name = "cros-ec-sysfs" },
 	{ .name = "cros-ec-vbc" },
 };
 
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 4e4232b47764..b709cc5173a2 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -49,9 +49,6 @@ config CHROMEOS_TBMC
 	  To compile this driver as a module, choose M here: the
 	  module will be called chromeos_tbmc.
 
-config CROS_EC_CTL
-        tristate
-
 config CROS_EC_I2C
 	tristate "ChromeOS Embedded Controller (I2C)"
 	depends on MFD_CROS_EC && I2C
@@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
 	  To compile this driver as a module, choose M here: the
 	  module will be called cros_ec_debugfs.
 
+config CROS_EC_SYSFS
+	tristate "ChromeOS EC control and information through sysfs"
+	depends on MFD_CROS_EC_CHARDEV && SYSFS
+	default y
+	help
+	  This option exposes some sysfs attributes to control and get
+	  information from ChromeOS EC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_sysfs.
+
 endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 12a5c4d18c17..fdbee501931b 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -3,8 +3,6 @@
 obj-$(CONFIG_CHROMEOS_LAPTOP)		+= chromeos_laptop.o
 obj-$(CONFIG_CHROMEOS_PSTORE)		+= chromeos_pstore.o
 obj-$(CONFIG_CHROMEOS_TBMC)		+= chromeos_tbmc.o
-cros_ec_ctl-objs			:= cros_ec_sysfs.o
-obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
 cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
@@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.o
 obj-$(CONFIG_CROS_EC_LIGHTBAR)		+= cros_ec_lightbar.o
 obj-$(CONFIG_CROS_EC_VBC)		+= cros_ec_vbc.o
 obj-$(CONFIG_CROS_EC_DEBUGFS)		+= cros_ec_debugfs.o
+obj-$(CONFIG_CROS_EC_SYSFS)		+= cros_ec_sysfs.o
diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
index f34a50121064..0ff5aa30c070 100644
--- a/drivers/platform/chrome/cros_ec_sysfs.c
+++ b/drivers/platform/chrome/cros_ec_sysfs.c
@@ -34,6 +34,8 @@
 #include <linux/types.h>
 #include <linux/uaccess.h>
 
+#define DRV_NAME "cros-ec-sysfs"
+
 /* Accessor functions */
 
 static ssize_t reboot_show(struct device *dev,
@@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
 	.attrs = __ec_attrs,
 	.is_visible = cros_ec_ctrl_visible,
 };
-EXPORT_SYMBOL(cros_ec_attr_group);
+
+static int cros_ec_sysfs_probe(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+	struct device *dev = &pd->dev;
+	int ret;
+
+	ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
+	if (ret < 0)
+		dev_err(dev, "failed to create attributes. err=%d\n", ret);
+
+	return ret;
+}
+
+static int cros_ec_sysfs_remove(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+
+	sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
+
+	return 0;
+}
+
+static struct platform_driver cros_ec_sysfs_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.probe = cros_ec_sysfs_probe,
+	.remove = cros_ec_sysfs_remove,
+};
+
+module_platform_driver(cros_ec_sysfs_driver);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("ChromeOS EC control driver");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 3e4401e2ceea..f718ad9c2132 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
  */
 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
 
-/* sysfs stuff */
-extern struct attribute_group cros_ec_attr_group;
-
 #endif /* __LINUX_MFD_CROS_EC_H */
-- 
2.19.1

[PATCH v3 6/8] mfd / platform: cros_ec: instantiate only if th EC has a VBC NVRAM.

[Enric Balletbo i Serra]

The cros-ec-vbc driver is DT-only and there is a DT property that
indicates if the EC has the VCB NVRAM, in such case instantiate the
driver but don't instantiate on the other cases.

To do this move the check code to its parent instead of play with the
attribute group visibility. This changes a bit the actual behaviour.
Before the patch if an EC doesn't have a VBC NVRAM an empty vbc folder
is created in /sys/class/chromeos/<ec device>, after the patch the empty
folder is not created, so, the folder is only created if the vbc is set.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3:
- Fixed build error as reported by kbuild test robot.

Changes in v2:
- Remove unnecessary IS_ENABLED.
- Remove dev_err message telling that VBC is found.
- Use dev_warn instead of dev_err as the error is ignored.

 drivers/mfd/cros_ec_dev.c             | 19 ++++++++++++++++++-
 drivers/platform/chrome/cros_ec_vbc.c | 16 ----------------
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index d9b16ce79319..1ba98a32715e 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -21,6 +21,7 @@
 #include <linux/mfd/core.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
+#include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/slab.h>
@@ -386,12 +387,16 @@ static const struct mfd_cell cros_ec_platform_cells[] = {
 	{ .name = "cros-ec-debugfs" },
 	{ .name = "cros-ec-lightbar" },
 	{ .name = "cros-ec-sysfs" },
-	{ .name = "cros-ec-vbc" },
+};
+
+static const struct mfd_cell cros_ec_vbc_cells[] = {
+	{ .name = "cros-ec-vbc" }
 };
 
 static int ec_device_probe(struct platform_device *pdev)
 {
 	int retval = -ENOMEM;
+	struct device_node *node;
 	struct device *dev = &pdev->dev;
 	struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 	struct cros_ec_dev *ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
@@ -479,6 +484,18 @@ static int ec_device_probe(struct platform_device *pdev)
 			 "failed to add cros-ec platform devices: %d\n",
 			 retval);
 
+	/* Check whether this EC instance has a VBC NVRAM */
+	node = ec->ec_dev->dev->of_node;
+	if (of_property_read_bool(node, "google,has-vbc-nvram")) {
+		retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
+					 cros_ec_vbc_cells,
+					 ARRAY_SIZE(cros_ec_vbc_cells),
+					 NULL, 0, NULL);
+		if (retval)
+			dev_warn(ec->dev, "failed to add VBC devices: %d\n",
+				 retval);
+	}
+
 	return 0;
 
 failed:
diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c
index da3bbf05e86f..af9bfe6f385c 100644
--- a/drivers/platform/chrome/cros_ec_vbc.c
+++ b/drivers/platform/chrome/cros_ec_vbc.c
@@ -108,21 +108,6 @@ static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
 	return data_sz;
 }
 
-static umode_t cros_ec_vbc_is_visible(struct kobject *kobj,
-				      struct bin_attribute *a, int n)
-{
-	struct device *dev = container_of(kobj, struct device, kobj);
-	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
-	struct device_node *np = ec->ec_dev->dev->of_node;
-
-	if (IS_ENABLED(CONFIG_OF) && np) {
-		if (of_property_read_bool(np, "google,has-vbc-nvram"))
-			return a->attr.mode;
-	}
-
-	return 0;
-}
-
 static BIN_ATTR_RW(vboot_context, 16);
 
 static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
@@ -133,7 +118,6 @@ static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
 struct attribute_group cros_ec_vbc_attr_group = {
 	.name = "vbc",
 	.bin_attrs = cros_ec_vbc_bin_attrs,
-	.is_bin_visible = cros_ec_vbc_is_visible,
 };
 
 static int cros_ec_vbc_probe(struct platform_device *pd)
-- 
2.19.1

[PATCH v3 7/8] platform/chrome: cros_ec_lightbar: instantiate only if the EC has a lightbar.

[Enric Balletbo i Serra]

Due to the way attribute groups visibility work, the function
cros_ec_lightbar_attrs_are_visible is called multiple times, once per
attribute, and each of these calls makes an EC transaction. For what is
worth the EC log reports multiple errors on boot when the lightbar is
not available. Instead, check if the EC has a lightbar in the probe
function and only instantiate the device.

Ideally we should have instantiate the driver only if the
EC_FEATURE_LIGHTBAR is defined, but that's not possible because that flag
is not in the very first Pixel Chromebook (Link), only on Samus. So, the
driver is instantiated by his parent always.

This patch changes a bit the actual behaviour. Before the patch if an EC
doesn't have a lightbar an empty lightbar folder is created in
/sys/class/chromeos/<ec device>, after the patch the empty folder is not
created, so, the folder is only created if the lightbar exists.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3: None
Changes in v2:
- Removed ec_with_lightbar variable.

 drivers/platform/chrome/cros_ec_lightbar.c | 37 ++++++++--------------
 1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
index 80eed6317570..6f6a4cbfc3fc 100644
--- a/drivers/platform/chrome/cros_ec_lightbar.c
+++ b/drivers/platform/chrome/cros_ec_lightbar.c
@@ -43,7 +43,6 @@ static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
  * If this is true, we won't do anything during suspend/resume.
  */
 static bool userspace_control;
-static struct cros_ec_dev *ec_with_lightbar;
 
 static ssize_t interval_msec_show(struct device *dev,
 				  struct device_attribute *attr, char *buf)
@@ -381,9 +380,6 @@ static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
 	struct cros_ec_command *msg;
 	int ret;
 
-	if (ec != ec_with_lightbar)
-		return 0;
-
 	msg = alloc_lightbar_cmd_msg(ec);
 	if (!msg)
 		return -ENOMEM;
@@ -567,37 +563,26 @@ static struct attribute *__lb_cmds_attrs[] = {
 	NULL,
 };
 
-static bool ec_has_lightbar(struct cros_ec_dev *ec)
+static bool cros_ec_has_lightbar(struct cros_ec_dev *ec_dev)
 {
-	return !!get_lightbar_version(ec, NULL, NULL);
-}
-
-static umode_t cros_ec_lightbar_attrs_are_visible(struct kobject *kobj,
-						  struct attribute *a, int n)
-{
-	struct device *dev = container_of(kobj, struct device, kobj);
-	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
-	struct platform_device *pdev = to_platform_device(ec->dev);
+	struct platform_device *pdev = to_platform_device(ec_dev->dev);
 	struct cros_ec_platform *pdata = pdev->dev.platform_data;
 	int is_cros_ec;
 
 	is_cros_ec = strcmp(pdata->ec_name, CROS_EC_DEV_NAME);
 
 	if (is_cros_ec != 0)
-		return 0;
+		return false;
 
-	/* Only instantiate this stuff if the EC has a lightbar */
-	if (ec_has_lightbar(ec)) {
-		ec_with_lightbar = ec;
-		return a->mode;
-	}
-	return 0;
+	if (!!get_lightbar_version(ec_dev, NULL, NULL))
+		return true;
+
+	return false;
 }
 
 struct attribute_group cros_ec_lightbar_attr_group = {
 	.name = "lightbar",
 	.attrs = __lb_cmds_attrs,
-	.is_visible = cros_ec_lightbar_attrs_are_visible,
 };
 
 static int cros_ec_lightbar_probe(struct platform_device *pd)
@@ -606,6 +591,10 @@ static int cros_ec_lightbar_probe(struct platform_device *pd)
 	struct device *dev = &pd->dev;
 	int ret;
 
+	/* Only instantiate this stuff if the EC has a lightbar */
+	if (!cros_ec_has_lightbar(ec_dev))
+		return -ENODEV;
+
 	/* Take control of the lightbar from the EC. */
 	lb_manual_suspend_ctrl(ec_dev, 1);
 
@@ -635,7 +624,7 @@ static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
 {
 	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
 
-	if (userspace_control || ec_dev != ec_with_lightbar)
+	if (userspace_control)
 		return 0;
 
 	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
@@ -645,7 +634,7 @@ static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
 {
 	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
 
-	if (userspace_control || ec_dev != ec_with_lightbar)
+	if (userspace_control)
 		return 0;
 
 	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
-- 
2.19.1

[PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Enric Balletbo i Serra]

Devices are required to provide a release method. This patch fixes the
following WARN():

[   47.218707] ------------[ cut here ]------------
[   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
[   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
[   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
[   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
[   47.330947] Hardware name: Google Kevin (DT)
[   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
[   47.341063] pc : device_release+0x80/0x90
[   47.345537] lr : device_release+0x80/0x90
[   47.350001] sp : ffff00000b17bc70
[   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
[   47.359629] x27: 0000000000000000 x26: 0000000000000000
[   47.365561] x25: 0000000056000000 x24: 0000000000000015
[   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
[   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
[   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
[   47.389278] x17: 0000000000000000 x16: 0000000000000000
[   47.395209] x15: 0000000000000400 x14: 0000000000000400
[   47.401131] x13: 00000000000001a7 x12: 0000000000000000
[   47.407053] x11: 0000000000000001 x10: 0000000000000960
[   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
[   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
[   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
[   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
[   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
[   47.442597] Call trace:
[   47.445324]  device_release+0x80/0x90
[   47.449414]  kobject_put+0x74/0xe8
[   47.453210]  device_unregister+0x20/0x30
[   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
[   47.463233]  platform_drv_remove+0x28/0x48
[   47.467805]  device_release_driver_internal+0x1a8/0x240
[   47.473630]  driver_detach+0x40/0x80
[   47.477609]  bus_remove_driver+0x54/0xa8
[   47.481986]  driver_unregister+0x2c/0x58
[   47.486355]  platform_driver_unregister+0x10/0x18
[   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
[   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
[   47.502689]  el0_svc_common+0x84/0xd8
[   47.506776]  el0_svc_handler+0x2c/0x80
[   47.510960]  el0_svc+0x8/0xc
[   47.514171] ---[ end trace 9087279fc8c03450 ]---

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v3: None
Changes in v2:
- Fix WARN when unloading. This is new in these series.

 drivers/mfd/cros_ec_dev.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 1ba98a32715e..cdb941c6db98 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -35,9 +35,14 @@
 #define CROS_MAX_DEV 128
 static int ec_major;
 
+static void cros_ec_dev_release(struct device *dev)
+{
+}
+
 static struct class cros_class = {
 	.owner          = THIS_MODULE,
 	.name           = "chromeos",
+	.dev_release	= cros_ec_dev_release,
 };
 
 /* Basic communication */
-- 
2.19.1

Re: [PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Guenter Roeck]

Hi Enric,

On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Devices are required to provide a release method. This patch fixes the
> following WARN():
>
> [   47.218707] ------------[ cut here ]------------
> [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
> [   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
> [   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
> [   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
> [   47.330947] Hardware name: Google Kevin (DT)
> [   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
> [   47.341063] pc : device_release+0x80/0x90
> [   47.345537] lr : device_release+0x80/0x90
> [   47.350001] sp : ffff00000b17bc70
> [   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
> [   47.359629] x27: 0000000000000000 x26: 0000000000000000
> [   47.365561] x25: 0000000056000000 x24: 0000000000000015
> [   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
> [   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
> [   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
> [   47.389278] x17: 0000000000000000 x16: 0000000000000000
> [   47.395209] x15: 0000000000000400 x14: 0000000000000400
> [   47.401131] x13: 00000000000001a7 x12: 0000000000000000
> [   47.407053] x11: 0000000000000001 x10: 0000000000000960
> [   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
> [   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
> [   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
> [   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
> [   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
> [   47.442597] Call trace:
> [   47.445324]  device_release+0x80/0x90
> [   47.449414]  kobject_put+0x74/0xe8
> [   47.453210]  device_unregister+0x20/0x30
> [   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
> [   47.463233]  platform_drv_remove+0x28/0x48
> [   47.467805]  device_release_driver_internal+0x1a8/0x240
> [   47.473630]  driver_detach+0x40/0x80
> [   47.477609]  bus_remove_driver+0x54/0xa8
> [   47.481986]  driver_unregister+0x2c/0x58
> [   47.486355]  platform_driver_unregister+0x10/0x18
> [   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
> [   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
> [   47.502689]  el0_svc_common+0x84/0xd8
> [   47.506776]  el0_svc_handler+0x2c/0x80
> [   47.510960]  el0_svc+0x8/0xc
> [   47.514171] ---[ end trace 9087279fc8c03450 ]---
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
>
> Changes in v3: None
> Changes in v2:
> - Fix WARN when unloading. This is new in these series.
>
>  drivers/mfd/cros_ec_dev.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 1ba98a32715e..cdb941c6db98 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -35,9 +35,14 @@
>  #define CROS_MAX_DEV 128
>  static int ec_major;
>
> +static void cros_ec_dev_release(struct device *dev)
> +{
> +}
> +

This tends to be a wrong solution. Problem is that object lifetime is
not necessarily tied to device lifetime. Greg KH (copied) has a much
better understanding of the problem than I do.

Guenter

>  static struct class cros_class = {
>         .owner          = THIS_MODULE,
>         .name           = "chromeos",
> +       .dev_release    = cros_ec_dev_release,
>  };
>
>  /* Basic communication */
> --
> 2.19.1
>

Re: [PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Greg Kroah-Hartman]

On Tue, Nov 27, 2018 at 09:29:38AM -0800, Guenter Roeck wrote:
> Hi Enric,
> 
> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
> >
> > Devices are required to provide a release method. This patch fixes the
> > following WARN():
> >
> > [   47.218707] ------------[ cut here ]------------
> > [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
> > [   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
> > [   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
> > [   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
> > [   47.330947] Hardware name: Google Kevin (DT)
> > [   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
> > [   47.341063] pc : device_release+0x80/0x90
> > [   47.345537] lr : device_release+0x80/0x90
> > [   47.350001] sp : ffff00000b17bc70
> > [   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
> > [   47.359629] x27: 0000000000000000 x26: 0000000000000000
> > [   47.365561] x25: 0000000056000000 x24: 0000000000000015
> > [   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
> > [   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
> > [   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
> > [   47.389278] x17: 0000000000000000 x16: 0000000000000000
> > [   47.395209] x15: 0000000000000400 x14: 0000000000000400
> > [   47.401131] x13: 00000000000001a7 x12: 0000000000000000
> > [   47.407053] x11: 0000000000000001 x10: 0000000000000960
> > [   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
> > [   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
> > [   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
> > [   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
> > [   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
> > [   47.442597] Call trace:
> > [   47.445324]  device_release+0x80/0x90
> > [   47.449414]  kobject_put+0x74/0xe8
> > [   47.453210]  device_unregister+0x20/0x30
> > [   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
> > [   47.463233]  platform_drv_remove+0x28/0x48
> > [   47.467805]  device_release_driver_internal+0x1a8/0x240
> > [   47.473630]  driver_detach+0x40/0x80
> > [   47.477609]  bus_remove_driver+0x54/0xa8
> > [   47.481986]  driver_unregister+0x2c/0x58
> > [   47.486355]  platform_driver_unregister+0x10/0x18
> > [   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
> > [   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
> > [   47.502689]  el0_svc_common+0x84/0xd8
> > [   47.506776]  el0_svc_handler+0x2c/0x80
> > [   47.510960]  el0_svc+0x8/0xc
> > [   47.514171] ---[ end trace 9087279fc8c03450 ]---
> >
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > ---
> >
> > Changes in v3: None
> > Changes in v2:
> > - Fix WARN when unloading. This is new in these series.
> >
> >  drivers/mfd/cros_ec_dev.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > index 1ba98a32715e..cdb941c6db98 100644
> > --- a/drivers/mfd/cros_ec_dev.c
> > +++ b/drivers/mfd/cros_ec_dev.c
> > @@ -35,9 +35,14 @@
> >  #define CROS_MAX_DEV 128
> >  static int ec_major;
> >
> > +static void cros_ec_dev_release(struct device *dev)
> > +{
> > +}

Yeah, as part of the in-kernel documentation, I now get to make fun of
you in public!

You did read the documentation, right?

{sigh}

Step back and think about _why_ the kernel is telling you this is not
ok, and ponder the process that came to you that resulted in, "I know,
let me trick the kernel, I know better than it!".  I didn't just put
that warning there for no good reason, I was trying to save yourself
from a major bug.  And here you go working around it, and making that
bug almost impossible to now find.

The kernel told you this, look:

> > [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.

How much more blatent and obvious can I make it in a single sentance
without it being rude?

Anyway, no, this is not what to do.  You have to actually realease the
memory you created for your device in this function.  If you do not do
that, you have a major bug.  Please fix this properly and next time, do
not ignore what the kernel is trying to tell you.

thanks,

greg k-h

Re: [PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Guenter Roeck]

Hi Greg,

On Tue, Nov 27, 2018 at 9:52 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Nov 27, 2018 at 09:29:38AM -0800, Guenter Roeck wrote:
> > Hi Enric,
> >
> > On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> > <enric.balletbo@collabora.com> wrote:
> > >
> > > Devices are required to provide a release method. This patch fixes the
> > > following WARN():
> > >
> > > [   47.218707] ------------[ cut here ]------------
> > > [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
> > > [   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
> > > [   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
> > > [   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
> > > [   47.330947] Hardware name: Google Kevin (DT)
> > > [   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
> > > [   47.341063] pc : device_release+0x80/0x90
> > > [   47.345537] lr : device_release+0x80/0x90
> > > [   47.350001] sp : ffff00000b17bc70
> > > [   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
> > > [   47.359629] x27: 0000000000000000 x26: 0000000000000000
> > > [   47.365561] x25: 0000000056000000 x24: 0000000000000015
> > > [   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
> > > [   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
> > > [   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
> > > [   47.389278] x17: 0000000000000000 x16: 0000000000000000
> > > [   47.395209] x15: 0000000000000400 x14: 0000000000000400
> > > [   47.401131] x13: 00000000000001a7 x12: 0000000000000000
> > > [   47.407053] x11: 0000000000000001 x10: 0000000000000960
> > > [   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
> > > [   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
> > > [   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
> > > [   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
> > > [   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
> > > [   47.442597] Call trace:
> > > [   47.445324]  device_release+0x80/0x90
> > > [   47.449414]  kobject_put+0x74/0xe8
> > > [   47.453210]  device_unregister+0x20/0x30
> > > [   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
> > > [   47.463233]  platform_drv_remove+0x28/0x48
> > > [   47.467805]  device_release_driver_internal+0x1a8/0x240
> > > [   47.473630]  driver_detach+0x40/0x80
> > > [   47.477609]  bus_remove_driver+0x54/0xa8
> > > [   47.481986]  driver_unregister+0x2c/0x58
> > > [   47.486355]  platform_driver_unregister+0x10/0x18
> > > [   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
> > > [   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
> > > [   47.502689]  el0_svc_common+0x84/0xd8
> > > [   47.506776]  el0_svc_handler+0x2c/0x80
> > > [   47.510960]  el0_svc+0x8/0xc
> > > [   47.514171] ---[ end trace 9087279fc8c03450 ]---
> > >
> > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > > ---
> > >
> > > Changes in v3: None
> > > Changes in v2:
> > > - Fix WARN when unloading. This is new in these series.
> > >
> > >  drivers/mfd/cros_ec_dev.c | 5 +++++
> > >  1 file changed, 5 insertions(+)
> > >
> > > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > > index 1ba98a32715e..cdb941c6db98 100644
> > > --- a/drivers/mfd/cros_ec_dev.c
> > > +++ b/drivers/mfd/cros_ec_dev.c
> > > @@ -35,9 +35,14 @@
> > >  #define CROS_MAX_DEV 128
> > >  static int ec_major;
> > >
> > > +static void cros_ec_dev_release(struct device *dev)
> > > +{
> > > +}
>
> Yeah, as part of the in-kernel documentation, I now get to make fun of
> you in public!
>
> You did read the documentation, right?
>

To be fair, the problem is difficult to understand. Maybe it is easy
for you, but that is not true for everyone, including me. Remember the
block discussion we just had ? As for the in-kernel documentation,
maybe there is a comprehensive explanation someone, one that clueless
people like me can understand, but all I found was

"If a bus driver unregisters a device, it should not immediately free
  it. It should instead wait for the driver model core to call the
  device's release method, then free the bus-specific object.
  (There may be other code that is currently referencing the device
  structure, and it would be rude to free the device while that is
  happening)"

Does that apply to mfd devices ? What other code may that be that
accesses the structure ? What else does it mean, or in other words,
what other cleanup code besides releasing the data structure needs to
reside in the release function ?

Sure, it would be easy to use kzalloc() instead of devm_kzalloc(), and
to release the memory in the class release function, but does that
actually _fix_ the problem ? Is dummy_sysfs_dev_release() in the
extcon core buggy, or is there a reason why the dummy function works
there ? I for my part have no idea whatsoever, and, sorry, the
documentation doesn't really help me to find out.

Guenter

> {sigh}
>
> Step back and think about _why_ the kernel is telling you this is not
> ok, and ponder the process that came to you that resulted in, "I know,
> let me trick the kernel, I know better than it!".  I didn't just put
> that warning there for no good reason, I was trying to save yourself
> from a major bug.  And here you go working around it, and making that
> bug almost impossible to now find.
>
> The kernel told you this, look:
>
> > > [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
>
> How much more blatent and obvious can I make it in a single sentance
> without it being rude?
>
> Anyway, no, this is not what to do.  You have to actually realease the
> memory you created for your device in this function.  If you do not do
> that, you have a major bug.  Please fix this properly and next time, do
> not ignore what the kernel is trying to tell you.
>
> thanks,
>
> greg k-h

Re: [PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Greg Kroah-Hartman]

On Wed, Nov 28, 2018 at 05:17:22PM -0800, Guenter Roeck wrote:
> Hi Greg,
> 
> On Tue, Nov 27, 2018 at 9:52 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Tue, Nov 27, 2018 at 09:29:38AM -0800, Guenter Roeck wrote:
> > > Hi Enric,
> > >
> > > On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> > > <enric.balletbo@collabora.com> wrote:
> > > >
> > > > Devices are required to provide a release method. This patch fixes the
> > > > following WARN():
> > > >
> > > > [   47.218707] ------------[ cut here ]------------
> > > > [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
> > > > [   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
> > > > [   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
> > > > [   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
> > > > [   47.330947] Hardware name: Google Kevin (DT)
> > > > [   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
> > > > [   47.341063] pc : device_release+0x80/0x90
> > > > [   47.345537] lr : device_release+0x80/0x90
> > > > [   47.350001] sp : ffff00000b17bc70
> > > > [   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
> > > > [   47.359629] x27: 0000000000000000 x26: 0000000000000000
> > > > [   47.365561] x25: 0000000056000000 x24: 0000000000000015
> > > > [   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
> > > > [   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
> > > > [   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
> > > > [   47.389278] x17: 0000000000000000 x16: 0000000000000000
> > > > [   47.395209] x15: 0000000000000400 x14: 0000000000000400
> > > > [   47.401131] x13: 00000000000001a7 x12: 0000000000000000
> > > > [   47.407053] x11: 0000000000000001 x10: 0000000000000960
> > > > [   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
> > > > [   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
> > > > [   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
> > > > [   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
> > > > [   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
> > > > [   47.442597] Call trace:
> > > > [   47.445324]  device_release+0x80/0x90
> > > > [   47.449414]  kobject_put+0x74/0xe8
> > > > [   47.453210]  device_unregister+0x20/0x30
> > > > [   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
> > > > [   47.463233]  platform_drv_remove+0x28/0x48
> > > > [   47.467805]  device_release_driver_internal+0x1a8/0x240
> > > > [   47.473630]  driver_detach+0x40/0x80
> > > > [   47.477609]  bus_remove_driver+0x54/0xa8
> > > > [   47.481986]  driver_unregister+0x2c/0x58
> > > > [   47.486355]  platform_driver_unregister+0x10/0x18
> > > > [   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
> > > > [   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
> > > > [   47.502689]  el0_svc_common+0x84/0xd8
> > > > [   47.506776]  el0_svc_handler+0x2c/0x80
> > > > [   47.510960]  el0_svc+0x8/0xc
> > > > [   47.514171] ---[ end trace 9087279fc8c03450 ]---
> > > >
> > > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > > > ---
> > > >
> > > > Changes in v3: None
> > > > Changes in v2:
> > > > - Fix WARN when unloading. This is new in these series.
> > > >
> > > >  drivers/mfd/cros_ec_dev.c | 5 +++++
> > > >  1 file changed, 5 insertions(+)
> > > >
> > > > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > > > index 1ba98a32715e..cdb941c6db98 100644
> > > > --- a/drivers/mfd/cros_ec_dev.c
> > > > +++ b/drivers/mfd/cros_ec_dev.c
> > > > @@ -35,9 +35,14 @@
> > > >  #define CROS_MAX_DEV 128
> > > >  static int ec_major;
> > > >
> > > > +static void cros_ec_dev_release(struct device *dev)
> > > > +{
> > > > +}
> >
> > Yeah, as part of the in-kernel documentation, I now get to make fun of
> > you in public!
> >
> > You did read the documentation, right?
> >
> 
> To be fair, the problem is difficult to understand. Maybe it is easy
> for you, but that is not true for everyone, including me. Remember the
> block discussion we just had ? As for the in-kernel documentation,
> maybe there is a comprehensive explanation someone, one that clueless
> people like me can understand, but all I found was
> 
> "If a bus driver unregisters a device, it should not immediately free
>   it. It should instead wait for the driver model core to call the
>   device's release method, then free the bus-specific object.
>   (There may be other code that is currently referencing the device
>   structure, and it would be rude to free the device while that is
>   happening)"
> 
> Does that apply to mfd devices ? What other code may that be that
> accesses the structure ? What else does it mean, or in other words,
> what other cleanup code besides releasing the data structure needs to
> reside in the release function ?

To quote Documentation/kobject.txt:
	One important point cannot be overstated: every kobject must
	have a release() method, and the kobject must persist (in a
	consistent state) until that method is called. If these
	constraints are not met, the code is flawed.  Note that the
	kernel will warn you if you forget to provide a release()
	method.  Do not try to get rid of this warning by providing an
	"empty" release function; you will be mocked mercilessly by the
	kobject maintainer if you attempt this.

The fact that you couldn't even find this means that it probably is in
the wrong place, but then, where is the "right" place for where everyone
can see it?  Should I refer to this file in the kernel error message?

That file also should answer your other questions about lifetime rules
of kobjects, which is really the same thing as 'struct device' here.  If
not, please let me know and I can fix it up.

thanks,

greg k-h

Re: [PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Enric Balletbo i Serra]

Hi,

On 29/11/18 8:55, Greg Kroah-Hartman wrote:
> On Wed, Nov 28, 2018 at 05:17:22PM -0800, Guenter Roeck wrote:
>> Hi Greg,
>>
>> On Tue, Nov 27, 2018 at 9:52 AM Greg Kroah-Hartman
>> <gregkh@linuxfoundation.org> wrote:
>>>
>>> On Tue, Nov 27, 2018 at 09:29:38AM -0800, Guenter Roeck wrote:
>>>> Hi Enric,
>>>>
>>>> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
>>>> <enric.balletbo@collabora.com> wrote:
>>>>>
>>>>> Devices are required to provide a release method. This patch fixes the
>>>>> following WARN():
>>>>>
>>>>> [   47.218707] ------------[ cut here ]------------
>>>>> [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
>>>>> [   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
>>>>> [   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
>>>>> [   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
>>>>> [   47.330947] Hardware name: Google Kevin (DT)
>>>>> [   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
>>>>> [   47.341063] pc : device_release+0x80/0x90
>>>>> [   47.345537] lr : device_release+0x80/0x90
>>>>> [   47.350001] sp : ffff00000b17bc70
>>>>> [   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
>>>>> [   47.359629] x27: 0000000000000000 x26: 0000000000000000
>>>>> [   47.365561] x25: 0000000056000000 x24: 0000000000000015
>>>>> [   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
>>>>> [   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
>>>>> [   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
>>>>> [   47.389278] x17: 0000000000000000 x16: 0000000000000000
>>>>> [   47.395209] x15: 0000000000000400 x14: 0000000000000400
>>>>> [   47.401131] x13: 00000000000001a7 x12: 0000000000000000
>>>>> [   47.407053] x11: 0000000000000001 x10: 0000000000000960
>>>>> [   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
>>>>> [   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
>>>>> [   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
>>>>> [   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
>>>>> [   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
>>>>> [   47.442597] Call trace:
>>>>> [   47.445324]  device_release+0x80/0x90
>>>>> [   47.449414]  kobject_put+0x74/0xe8
>>>>> [   47.453210]  device_unregister+0x20/0x30
>>>>> [   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
>>>>> [   47.463233]  platform_drv_remove+0x28/0x48
>>>>> [   47.467805]  device_release_driver_internal+0x1a8/0x240
>>>>> [   47.473630]  driver_detach+0x40/0x80
>>>>> [   47.477609]  bus_remove_driver+0x54/0xa8
>>>>> [   47.481986]  driver_unregister+0x2c/0x58
>>>>> [   47.486355]  platform_driver_unregister+0x10/0x18
>>>>> [   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
>>>>> [   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
>>>>> [   47.502689]  el0_svc_common+0x84/0xd8
>>>>> [   47.506776]  el0_svc_handler+0x2c/0x80
>>>>> [   47.510960]  el0_svc+0x8/0xc
>>>>> [   47.514171] ---[ end trace 9087279fc8c03450 ]---
>>>>>
>>>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>>>>> ---
>>>>>
>>>>> Changes in v3: None
>>>>> Changes in v2:
>>>>> - Fix WARN when unloading. This is new in these series.
>>>>>
>>>>>  drivers/mfd/cros_ec_dev.c | 5 +++++
>>>>>  1 file changed, 5 insertions(+)
>>>>>
>>>>> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
>>>>> index 1ba98a32715e..cdb941c6db98 100644
>>>>> --- a/drivers/mfd/cros_ec_dev.c
>>>>> +++ b/drivers/mfd/cros_ec_dev.c
>>>>> @@ -35,9 +35,14 @@
>>>>>  #define CROS_MAX_DEV 128
>>>>>  static int ec_major;
>>>>>
>>>>> +static void cros_ec_dev_release(struct device *dev)
>>>>> +{
>>>>> +}
>>>
>>> Yeah, as part of the in-kernel documentation, I now get to make fun of
>>> you in public!
>>>
>>> You did read the documentation, right?
>>>
>>
>> To be fair, the problem is difficult to understand. Maybe it is easy
>> for you, but that is not true for everyone, including me. Remember the
>> block discussion we just had ? As for the in-kernel documentation,
>> maybe there is a comprehensive explanation someone, one that clueless
>> people like me can understand, but all I found was
>>
>> "If a bus driver unregisters a device, it should not immediately free
>>   it. It should instead wait for the driver model core to call the
>>   device's release method, then free the bus-specific object.
>>   (There may be other code that is currently referencing the device
>>   structure, and it would be rude to free the device while that is
>>   happening)"
>>
>> Does that apply to mfd devices ? What other code may that be that
>> accesses the structure ? What else does it mean, or in other words,
>> what other cleanup code besides releasing the data structure needs to
>> reside in the release function ?
> 

I think that this can be one of those cases where using device managed
allocations is not right. If so we only need to revert commit

3aa2177e4787 ("mfd: cros_ec: Use devm_kzalloc for private data")

I think that the problem might be a dereference when a file operation call
happens if accesses to the device but the struct is already freed, so the
allocated structure should be freed after the last release call because you
can't guarantee is _not_ used before that. In this case class_dev is embedded to
the struct so I guess that the only resource we need to free is the cros_ec
device struct. I can be wrong, I didn't continue the research.

This is what Guenter make me think when he said "object lifetime", then I read
the Greg's answer. I felt bad and I just abandoned that task and switch to
another one. There were still open questions in my mind but I was not so
motivated to solve it.

Before send the patch I looked at the code and I saw that there are different
places where an "empty" release function is used. If this is never allowed,
maybe we can create a cocci script to catch these cases, I started this script
(thanks Peter for helping me). Only detects two places, but the script is not
complete as should also take in consideration when the release function is
assigned in a function (usually people does this) instead of assigning the
function directly in the struct. I'll be happy to help on this if people think
will be useful.


@r1@
identifier I, s, func;
@@
struct I s = { ..., .dev_release = func, ...};

@r2@
identifier r1.func;
position p1;
@@
func@p1(...){}

@script:python@
fn << r1.func;
p1 << r2.p1;
@@

print ("%s:%s empty release function at lines %s" % (p1[0].file,fn,p1[0].line))

Thanks
 Enric

> To quote Documentation/kobject.txt:
> 	One important point cannot be overstated: every kobject must
> 	have a release() method, and the kobject must persist (in a
> 	consistent state) until that method is called. If these
> 	constraints are not met, the code is flawed.  Note that the
> 	kernel will warn you if you forget to provide a release()
> 	method.  Do not try to get rid of this warning by providing an
> 	"empty" release function; you will be mocked mercilessly by the
> 	kobject maintainer if you attempt this.
> 
> The fact that you couldn't even find this means that it probably is in
> the wrong place, but then, where is the "right" place for where everyone
> can see it?  Should I refer to this file in the kernel error message?
> 
> That file also should answer your other questions about lifetime rules
> of kobjects, which is really the same thing as 'struct device' here.  If
> not, please let me know and I can fix it up.
> 
> thanks,
> 
> greg k-h
> 

Re: [PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Guenter Roeck]

On Thu, Nov 29, 2018 at 2:11 PM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Hi,
>
> On 29/11/18 8:55, Greg Kroah-Hartman wrote:
> > On Wed, Nov 28, 2018 at 05:17:22PM -0800, Guenter Roeck wrote:
> >> Hi Greg,
> >>
> >> On Tue, Nov 27, 2018 at 9:52 AM Greg Kroah-Hartman
> >> <gregkh@linuxfoundation.org> wrote:
> >>>
> >>> On Tue, Nov 27, 2018 at 09:29:38AM -0800, Guenter Roeck wrote:
> >>>> Hi Enric,
> >>>>
> >>>> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> >>>> <enric.balletbo@collabora.com> wrote:
> >>>>>
> >>>>> Devices are required to provide a release method. This patch fixes the
> >>>>> following WARN():
> >>>>>
> >>>>> [   47.218707] ------------[ cut here ]------------
> >>>>> [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
> >>>>> [   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
> >>>>> [   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
> >>>>> [   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
> >>>>> [   47.330947] Hardware name: Google Kevin (DT)
> >>>>> [   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
> >>>>> [   47.341063] pc : device_release+0x80/0x90
> >>>>> [   47.345537] lr : device_release+0x80/0x90
> >>>>> [   47.350001] sp : ffff00000b17bc70
> >>>>> [   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
> >>>>> [   47.359629] x27: 0000000000000000 x26: 0000000000000000
> >>>>> [   47.365561] x25: 0000000056000000 x24: 0000000000000015
> >>>>> [   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
> >>>>> [   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
> >>>>> [   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
> >>>>> [   47.389278] x17: 0000000000000000 x16: 0000000000000000
> >>>>> [   47.395209] x15: 0000000000000400 x14: 0000000000000400
> >>>>> [   47.401131] x13: 00000000000001a7 x12: 0000000000000000
> >>>>> [   47.407053] x11: 0000000000000001 x10: 0000000000000960
> >>>>> [   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
> >>>>> [   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
> >>>>> [   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
> >>>>> [   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
> >>>>> [   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
> >>>>> [   47.442597] Call trace:
> >>>>> [   47.445324]  device_release+0x80/0x90
> >>>>> [   47.449414]  kobject_put+0x74/0xe8
> >>>>> [   47.453210]  device_unregister+0x20/0x30
> >>>>> [   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
> >>>>> [   47.463233]  platform_drv_remove+0x28/0x48
> >>>>> [   47.467805]  device_release_driver_internal+0x1a8/0x240
> >>>>> [   47.473630]  driver_detach+0x40/0x80
> >>>>> [   47.477609]  bus_remove_driver+0x54/0xa8
> >>>>> [   47.481986]  driver_unregister+0x2c/0x58
> >>>>> [   47.486355]  platform_driver_unregister+0x10/0x18
> >>>>> [   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
> >>>>> [   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
> >>>>> [   47.502689]  el0_svc_common+0x84/0xd8
> >>>>> [   47.506776]  el0_svc_handler+0x2c/0x80
> >>>>> [   47.510960]  el0_svc+0x8/0xc
> >>>>> [   47.514171] ---[ end trace 9087279fc8c03450 ]---
> >>>>>
> >>>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >>>>> ---
> >>>>>
> >>>>> Changes in v3: None
> >>>>> Changes in v2:
> >>>>> - Fix WARN when unloading. This is new in these series.
> >>>>>
> >>>>>  drivers/mfd/cros_ec_dev.c | 5 +++++
> >>>>>  1 file changed, 5 insertions(+)
> >>>>>
> >>>>> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> >>>>> index 1ba98a32715e..cdb941c6db98 100644
> >>>>> --- a/drivers/mfd/cros_ec_dev.c
> >>>>> +++ b/drivers/mfd/cros_ec_dev.c
> >>>>> @@ -35,9 +35,14 @@
> >>>>>  #define CROS_MAX_DEV 128
> >>>>>  static int ec_major;
> >>>>>
> >>>>> +static void cros_ec_dev_release(struct device *dev)
> >>>>> +{
> >>>>> +}
> >>>
> >>> Yeah, as part of the in-kernel documentation, I now get to make fun of
> >>> you in public!
> >>>
> >>> You did read the documentation, right?
> >>>
> >>
> >> To be fair, the problem is difficult to understand. Maybe it is easy
> >> for you, but that is not true for everyone, including me. Remember the
> >> block discussion we just had ? As for the in-kernel documentation,
> >> maybe there is a comprehensive explanation someone, one that clueless
> >> people like me can understand, but all I found was
> >>
> >> "If a bus driver unregisters a device, it should not immediately free
> >>   it. It should instead wait for the driver model core to call the
> >>   device's release method, then free the bus-specific object.
> >>   (There may be other code that is currently referencing the device
> >>   structure, and it would be rude to free the device while that is
> >>   happening)"
> >>
> >> Does that apply to mfd devices ? What other code may that be that
> >> accesses the structure ? What else does it mean, or in other words,
> >> what other cleanup code besides releasing the data structure needs to
> >> reside in the release function ?
> >
>
> I think that this can be one of those cases where using device managed
> allocations is not right. If so we only need to revert commit
>
> 3aa2177e4787 ("mfd: cros_ec: Use devm_kzalloc for private data")
>

Hmm, yes, that patch looks problematic.

> I think that the problem might be a dereference when a file operation call
> happens if accesses to the device but the struct is already freed, so the
> allocated structure should be freed after the last release call because you
> can't guarantee is _not_ used before that. In this case class_dev is embedded to
> the struct so I guess that the only resource we need to free is the cros_ec
> device struct. I can be wrong, I didn't continue the research.
>
> This is what Guenter make me think when he said "object lifetime", then I read
> the Greg's answer. I felt bad and I just abandoned that task and switch to
> another one. There were still open questions in my mind but I was not so
> motivated to solve it.
>
> Before send the patch I looked at the code and I saw that there are different
> places where an "empty" release function is used. If this is never allowed,
> maybe we can create a cocci script to catch these cases, I started this script
> (thanks Peter for helping me). Only detects two places, but the script is not
> complete as should also take in consideration when the release function is
> assigned in a function (usually people does this) instead of assigning the
> function directly in the struct. I'll be happy to help on this if people think
> will be useful.

I think it would be useful. It should also detect empty device release
functions, such as the one you tried to introduce here.

Thanks,
Guenter

>
>
> @r1@
> identifier I, s, func;
> @@
> struct I s = { ..., .dev_release = func, ...};
>
> @r2@
> identifier r1.func;
> position p1;
> @@
> func@p1(...){}
>
> @script:python@
> fn << r1.func;
> p1 << r2.p1;
> @@
>
> print ("%s:%s empty release function at lines %s" % (p1[0].file,fn,p1[0].line))
>
> Thanks
>  Enric
>
> > To quote Documentation/kobject.txt:
> >       One important point cannot be overstated: every kobject must
> >       have a release() method, and the kobject must persist (in a
> >       consistent state) until that method is called. If these
> >       constraints are not met, the code is flawed.  Note that the
> >       kernel will warn you if you forget to provide a release()
> >       method.  Do not try to get rid of this warning by providing an
> >       "empty" release function; you will be mocked mercilessly by the
> >       kobject maintainer if you attempt this.
> >
> > The fact that you couldn't even find this means that it probably is in
> > the wrong place, but then, where is the "right" place for where everyone
> > can see it?  Should I refer to this file in the kernel error message?
> >
> > That file also should answer your other questions about lifetime rules
> > of kobjects, which is really the same thing as 'struct device' here.  If
> > not, please let me know and I can fix it up.
> >
> > thanks,
> >
> > greg k-h
> >

Re: [PATCH v3 1/8] mfd / platform: cros_ec: use devm_mfd_add_devices.

[Guenter Roeck]

On Tue, Nov 27, 2018 at 4:18 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Use devm_mfd_add_devices() for adding cros-ec core MFD child devices. This
> reduces the need of remove callback from platform/chrome for removing the
> MFD child devices.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Reviewed-by: Guenter Roeck <groeck@chromium.org>

> ---
>
> Changes in v3:
> - Removed cros_ec_remove from include file.
>
> Changes in v2:
> - Use devm only for the cros-ec core.
>
>  drivers/mfd/cros_ec.c                 | 14 +++-----------
>  drivers/mfd/cros_ec_dev.c             |  1 +
>  drivers/platform/chrome/cros_ec_i2c.c | 10 ----------
>  drivers/platform/chrome/cros_ec_lpc.c |  4 ----
>  drivers/platform/chrome/cros_ec_spi.c | 11 -----------
>  include/linux/mfd/cros_ec.h           | 10 ----------
>  6 files changed, 4 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index fe6f83766144..6acfe036d522 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -129,8 +129,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>                 }
>         }
>
> -       err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell, 1,
> -                             NULL, ec_dev->irq, NULL);
> +       err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell,
> +                                  1, NULL, ec_dev->irq, NULL);
>         if (err) {
>                 dev_err(dev,
>                         "Failed to register Embedded Controller subdevice %d\n",
> @@ -147,7 +147,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>                  * - the EC is responsive at init time (it is not true for a
>                  *   sensor hub.
>                  */
> -               err = mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
> +               err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
>                                       &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
>                 if (err) {
>                         dev_err(dev,
> @@ -181,14 +181,6 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>  }
>  EXPORT_SYMBOL(cros_ec_register);
>
> -int cros_ec_remove(struct cros_ec_device *ec_dev)
> -{
> -       mfd_remove_devices(ec_dev->dev);
> -
> -       return 0;
> -}
> -EXPORT_SYMBOL(cros_ec_remove);
> -
>  #ifdef CONFIG_PM_SLEEP
>  int cros_ec_suspend(struct cros_ec_device *ec_dev)
>  {
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 8f9d6964173e..ff788d3e6d5f 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -493,6 +493,7 @@ static int ec_device_remove(struct platform_device *pdev)
>
>         cros_ec_debugfs_remove(ec);
>
> +       mfd_remove_devices(ec->dev);
>         cdev_del(&ec->cdev);
>         device_unregister(&ec->class_dev);
>         return 0;
> diff --git a/drivers/platform/chrome/cros_ec_i2c.c b/drivers/platform/chrome/cros_ec_i2c.c
> index ef9b4763356f..9a009eaa4ada 100644
> --- a/drivers/platform/chrome/cros_ec_i2c.c
> +++ b/drivers/platform/chrome/cros_ec_i2c.c
> @@ -317,15 +317,6 @@ static int cros_ec_i2c_probe(struct i2c_client *client,
>         return 0;
>  }
>
> -static int cros_ec_i2c_remove(struct i2c_client *client)
> -{
> -       struct cros_ec_device *ec_dev = i2c_get_clientdata(client);
> -
> -       cros_ec_remove(ec_dev);
> -
> -       return 0;
> -}
> -
>  #ifdef CONFIG_PM_SLEEP
>  static int cros_ec_i2c_suspend(struct device *dev)
>  {
> @@ -376,7 +367,6 @@ static struct i2c_driver cros_ec_driver = {
>                 .pm     = &cros_ec_i2c_pm_ops,
>         },
>         .probe          = cros_ec_i2c_probe,
> -       .remove         = cros_ec_i2c_remove,
>         .id_table       = cros_ec_i2c_id,
>  };
>
> diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
> index e1b75775cd4a..14684a56e40f 100644
> --- a/drivers/platform/chrome/cros_ec_lpc.c
> +++ b/drivers/platform/chrome/cros_ec_lpc.c
> @@ -327,7 +327,6 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
>
>  static int cros_ec_lpc_remove(struct platform_device *pdev)
>  {
> -       struct cros_ec_device *ec_dev;
>         struct acpi_device *adev;
>
>         adev = ACPI_COMPANION(&pdev->dev);
> @@ -335,9 +334,6 @@ static int cros_ec_lpc_remove(struct platform_device *pdev)
>                 acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
>                                            cros_ec_lpc_acpi_notify);
>
> -       ec_dev = platform_get_drvdata(pdev);
> -       cros_ec_remove(ec_dev);
> -
>         return 0;
>  }
>
> diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
> index 2060d1483043..6cfbc2835beb 100644
> --- a/drivers/platform/chrome/cros_ec_spi.c
> +++ b/drivers/platform/chrome/cros_ec_spi.c
> @@ -685,16 +685,6 @@ static int cros_ec_spi_probe(struct spi_device *spi)
>         return 0;
>  }
>
> -static int cros_ec_spi_remove(struct spi_device *spi)
> -{
> -       struct cros_ec_device *ec_dev;
> -
> -       ec_dev = spi_get_drvdata(spi);
> -       cros_ec_remove(ec_dev);
> -
> -       return 0;
> -}
> -
>  #ifdef CONFIG_PM_SLEEP
>  static int cros_ec_spi_suspend(struct device *dev)
>  {
> @@ -733,7 +723,6 @@ static struct spi_driver cros_ec_driver_spi = {
>                 .pm     = &cros_ec_spi_pm_ops,
>         },
>         .probe          = cros_ec_spi_probe,
> -       .remove         = cros_ec_spi_remove,
>         .id_table       = cros_ec_spi_id,
>  };
>
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index e44e3ec8a9c7..706dd724de52 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -281,16 +281,6 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
>  int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
>                             struct cros_ec_command *msg);
>
> -/**
> - * cros_ec_remove() - Remove a ChromeOS EC.
> - * @ec_dev: Device to register.
> - *
> - * Call this to deregister a ChromeOS EC, then clean up any private data.
> - *
> - * Return: 0 on success or negative error code.
> - */
> -int cros_ec_remove(struct cros_ec_device *ec_dev);
> -
>  /**
>   * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
>   * @ec_dev: Device to register.
> --
> 2.19.1
>

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Guenter Roeck]

On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> The entire way how cros sysfs attibutes are created is broken.
> cros_ec_lightbar should be its own driver and its attributes should be
> associated with a lightbar driver not the mfd driver. In order to retain
> the path, the lightbar attributes are attached to the cros_class.
>
> The patch also adds the sysfs documentation.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Reviewed-by: Guenter Roeck <groeck@chromium.org>

> ---
>
> Changes in v3:
> - Removed unneded check for ec_dev.
>
> Changes in v2:
> - Removed the two exported functions to attach/detach to the cros_class.
> - Use dev_warn instead of dev_err when adding the lightbar.
>
>  ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
>  drivers/mfd/cros_ec_dev.c                     | 24 ++---
>  drivers/mfd/cros_ec_dev.h                     |  6 --
>  drivers/platform/chrome/Kconfig               | 10 ++
>  drivers/platform/chrome/Makefile              |  3 +-
>  drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
>  include/linux/mfd/cros_ec.h                   |  1 -
>  7 files changed, 172 insertions(+), 41 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
>
> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
> new file mode 100644
> index 000000000000..4893fd2e956f
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
> @@ -0,0 +1,74 @@
> +What:          /sys/class/chromeos/<cros-ec>/lightbar/brightness
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               Writing to this file adjusts the overall brightness of
> +               the lightbar, separate from any color intensity. The
> +               valid range is 0 (off) to 255 (maximum brightness).
> +
> +What:          /sys/class/chromeos/<cros-ec>/lightbar/interval_msec
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               The lightbar is controlled by an embedded controller (EC),
> +               which also manages the keyboard, battery charging, fans,
> +               and other system hardware. To prevent unprivileged users
> +               from interfering with the other EC functions, the rate at
> +               which the lightbar control files can be read or written is
> +               limited.
> +
> +               Reading this file will return the number of milliseconds
> +               that must elapse between accessing any of the lightbar
> +               functions through this interface. Going faster will simply
> +               block until the necessary interval has lapsed. The interval
> +               applies uniformly to all accesses of any kind by any user.
> +
> +What:          /sys/class/chromeos/<cros-ec>/lightbar/led_rgb
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               This allows you to control each LED segment. If the
> +               lightbar is already running one of the automatic
> +               sequences, you probably won’t see anything change because
> +               your color setting will be almost immediately replaced.
> +               To get useful results, you should stop the lightbar
> +               sequence first.
> +
> +               The values written to this file are sets of four integers,
> +               indicating LED, RED, GREEN, BLUE. The LED number is 0 to 3
> +               to select a single segment, or 4 to set all four segments
> +               to the same value at once. The RED, GREEN, and BLUE
> +               numbers should be in the range 0 (off) to 255 (maximum).
> +               You can update more than one segment at a time by writing
> +               more than one set of four integers.
> +
> +What:          /sys/class/chromeos/<cros-ec>/lightbar/program
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               This allows you to upload and run custom lightbar sequences.
> +
> +What:          /sys/class/chromeos/<cros-ec>/lightbar/sequence
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               The Pixel lightbar has a number of built-in sequences
> +               that it displays under various conditions, such as at
> +               power on, shut down, or while running. Reading from this
> +               file displays the current sequence that the lightbar is
> +               displaying. Writing to this file allows you to change the
> +               sequence.
> +
> +What:          /sys/class/chromeos/<cros-ec>/lightbar/userspace_control
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               This allows you to take the control of the lightbar. This
> +               prevents the kernel from going through its normal
> +               sequences.
> +
> +What:          /sys/class/chromeos/<cros-ec>/lightbar/version
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               Show the information about the lightbar version.
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index ff788d3e6d5f..614f888c9d6d 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -36,7 +36,6 @@ static int ec_major;
>
>  static const struct attribute_group *cros_ec_groups[] = {
>         &cros_ec_attr_group,
> -       &cros_ec_lightbar_attr_group,
>         &cros_ec_vbc_attr_group,
>         NULL,
>  };
> @@ -390,6 +389,10 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
>         { .name = "cros-usbpd-charger" }
>  };
>
> +static const struct mfd_cell cros_ec_platform_cells[] = {
> +       { .name = "cros-ec-lightbar" },
> +};
> +
>  static int ec_device_probe(struct platform_device *pdev)
>  {
>         int retval = -ENOMEM;
> @@ -464,9 +467,6 @@ static int ec_device_probe(struct platform_device *pdev)
>                                 retval);
>         }
>
> -       /* Take control of the lightbar from the EC. */
> -       lb_manual_suspend_ctrl(ec, 1);
> -
>         /* We can now add the sysfs class, we know which parameter to show */
>         retval = cdev_device_add(&ec->cdev, &ec->class_dev);
>         if (retval) {
> @@ -474,6 +474,15 @@ static int ec_device_probe(struct platform_device *pdev)
>                 goto failed;
>         }
>
> +       retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> +                                cros_ec_platform_cells,
> +                                ARRAY_SIZE(cros_ec_platform_cells),
> +                                NULL, 0, NULL);
> +       if (retval)
> +               dev_warn(ec->dev,
> +                        "failed to add cros-ec platform devices: %d\n",
> +                        retval);
> +
>         if (cros_ec_debugfs_init(ec))
>                 dev_warn(dev, "failed to create debugfs directory\n");
>
> @@ -488,9 +497,6 @@ static int ec_device_remove(struct platform_device *pdev)
>  {
>         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
>
> -       /* Let the EC take over the lightbar again. */
> -       lb_manual_suspend_ctrl(ec, 0);
> -
>         cros_ec_debugfs_remove(ec);
>
>         mfd_remove_devices(ec->dev);
> @@ -519,8 +525,6 @@ static __maybe_unused int ec_device_suspend(struct device *dev)
>
>         cros_ec_debugfs_suspend(ec);
>
> -       lb_suspend(ec);
> -
>         return 0;
>  }
>
> @@ -530,8 +534,6 @@ static __maybe_unused int ec_device_resume(struct device *dev)
>
>         cros_ec_debugfs_resume(ec);
>
> -       lb_resume(ec);
> -
>         return 0;
>  }
>
> diff --git a/drivers/mfd/cros_ec_dev.h b/drivers/mfd/cros_ec_dev.h
> index 978d836a0248..ec750433455a 100644
> --- a/drivers/mfd/cros_ec_dev.h
> +++ b/drivers/mfd/cros_ec_dev.h
> @@ -44,10 +44,4 @@ struct cros_ec_readmem {
>  #define CROS_EC_DEV_IOCXCMD   _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
>  #define CROS_EC_DEV_IOCRDMEM  _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)
>
> -/* Lightbar utilities */
> -extern bool ec_has_lightbar(struct cros_ec_dev *ec);
> -extern int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable);
> -extern int lb_suspend(struct cros_ec_dev *ec);
> -extern int lb_resume(struct cros_ec_dev *ec);
> -
>  #endif /* _CROS_EC_DEV_H_ */
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 16b1615958aa..05bcefbe1926 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -111,4 +111,14 @@ config CROS_KBD_LED_BACKLIGHT
>           To compile this driver as a module, choose M here: the
>           module will be called cros_kbd_led_backlight.
>
> +config CROS_EC_LIGHTBAR
> +       tristate "Chromebook Pixel's lightbar support"
> +       depends on MFD_CROS_EC_CHARDEV
> +       help
> +         This option exposes the Chromebook Pixel's lightbar to
> +         userspace.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called cros_ec_lightbar.
> +
>  endif # CHROMEOS_PLATFORMS
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index cd591bf872bb..3c29a4b405d5 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -3,7 +3,7 @@
>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> -cros_ec_ctl-objs                       := cros_ec_sysfs.o cros_ec_lightbar.o \
> +cros_ec_ctl-objs                       := cros_ec_sysfs.o \
>                                            cros_ec_vbc.o cros_ec_debugfs.o
>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> @@ -13,3 +13,4 @@ cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)        += cros_ec_lpc_mec.o
>  obj-$(CONFIG_CROS_EC_LPC)              += cros_ec_lpcs.o
>  obj-$(CONFIG_CROS_EC_PROTO)            += cros_ec_proto.o
>  obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)   += cros_kbd_led_backlight.o
> +obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
> diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
> index 68193bb53383..80eed6317570 100644
> --- a/drivers/platform/chrome/cros_ec_lightbar.c
> +++ b/drivers/platform/chrome/cros_ec_lightbar.c
> @@ -33,6 +33,8 @@
>  #include <linux/uaccess.h>
>  #include <linux/slab.h>
>
> +#define DRV_NAME "cros-ec-lightbar"
> +
>  /* Rate-limit the lightbar interface to prevent DoS. */
>  static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
>
> @@ -373,7 +375,7 @@ static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd)
>         return ret;
>  }
>
> -int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
> +static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
>  {
>         struct ec_params_lightbar *param;
>         struct cros_ec_command *msg;
> @@ -408,25 +410,6 @@ int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
>
>         return ret;
>  }
> -EXPORT_SYMBOL(lb_manual_suspend_ctrl);
> -
> -int lb_suspend(struct cros_ec_dev *ec)
> -{
> -       if (userspace_control || ec != ec_with_lightbar)
> -               return 0;
> -
> -       return lb_send_empty_cmd(ec, LIGHTBAR_CMD_SUSPEND);
> -}
> -EXPORT_SYMBOL(lb_suspend);
> -
> -int lb_resume(struct cros_ec_dev *ec)
> -{
> -       if (userspace_control || ec != ec_with_lightbar)
> -               return 0;
> -
> -       return lb_send_empty_cmd(ec, LIGHTBAR_CMD_RESUME);
> -}
> -EXPORT_SYMBOL(lb_resume);
>
>  static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
>                               const char *buf, size_t count)
> @@ -584,7 +567,7 @@ static struct attribute *__lb_cmds_attrs[] = {
>         NULL,
>  };
>
> -bool ec_has_lightbar(struct cros_ec_dev *ec)
> +static bool ec_has_lightbar(struct cros_ec_dev *ec)
>  {
>         return !!get_lightbar_version(ec, NULL, NULL);
>  }
> @@ -616,4 +599,72 @@ struct attribute_group cros_ec_lightbar_attr_group = {
>         .attrs = __lb_cmds_attrs,
>         .is_visible = cros_ec_lightbar_attrs_are_visible,
>  };
> -EXPORT_SYMBOL(cros_ec_lightbar_attr_group);
> +
> +static int cros_ec_lightbar_probe(struct platform_device *pd)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> +       struct device *dev = &pd->dev;
> +       int ret;
> +
> +       /* Take control of the lightbar from the EC. */
> +       lb_manual_suspend_ctrl(ec_dev, 1);
> +
> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj,
> +                                &cros_ec_lightbar_attr_group);
> +       if (ret < 0)
> +               dev_err(dev, "failed to create %s attributes. err=%d\n",
> +                       cros_ec_lightbar_attr_group.name, ret);
> +
> +       return ret;
> +}
> +
> +static int cros_ec_lightbar_remove(struct platform_device *pd)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> +
> +       sysfs_remove_group(&ec_dev->class_dev.kobj,
> +                          &cros_ec_lightbar_attr_group);
> +
> +       /* Let the EC take over the lightbar again. */
> +       lb_manual_suspend_ctrl(ec_dev, 0);
> +
> +       return 0;
> +}
> +
> +static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
> +
> +       if (userspace_control || ec_dev != ec_with_lightbar)
> +               return 0;
> +
> +       return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
> +}
> +
> +static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
> +
> +       if (userspace_control || ec_dev != ec_with_lightbar)
> +               return 0;
> +
> +       return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(cros_ec_lightbar_pm_ops,
> +                        cros_ec_lightbar_suspend, cros_ec_lightbar_resume);
> +
> +static struct platform_driver cros_ec_lightbar_driver = {
> +       .driver = {
> +               .name = DRV_NAME,
> +               .pm = &cros_ec_lightbar_pm_ops,
> +       },
> +       .probe = cros_ec_lightbar_probe,
> +       .remove = cros_ec_lightbar_remove,
> +};
> +
> +module_platform_driver(cros_ec_lightbar_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Expose the Chromebook Pixel's lightbar to userspace");
> +MODULE_ALIAS("platform:" DRV_NAME);
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 706dd724de52..b6beba3031ba 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -325,7 +325,6 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
>
>  /* sysfs stuff */
>  extern struct attribute_group cros_ec_attr_group;
> -extern struct attribute_group cros_ec_lightbar_attr_group;
>  extern struct attribute_group cros_ec_vbc_attr_group;
>
>  /* debugfs stuff */
> --
> 2.19.1
>

Re: [PATCH v3 3/8] mfd / platform: cros_ec: move vbc attributes to its own driver.

[Guenter Roeck]

On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> The entire way how cros sysfs attibutes are created is broken.
> cros_ec_vbc should be its own driver and its attributes should be
> associated with a vbc driver not the mfd driver. In order to retain
> the path, the vbc attributes are attached to the cros_class.
>
> The patch also adds the sysfs documentation.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Reviewed-by: Guenter Roeck <groeck@chromium.org>

> ---
>
> Changes in v3:
> - Fixed build error as reported by the kbuild test robot.
>
> Changes in v2:
> - Removed unneeded check of ec_dev.
>
>  .../sysfs-class-chromeos-driver-cros-ec-vbc   |  6 +++
>  drivers/mfd/cros_ec_dev.c                     |  2 +-
>  drivers/platform/chrome/Kconfig               | 10 +++++
>  drivers/platform/chrome/Makefile              |  3 +-
>  drivers/platform/chrome/cros_ec_vbc.c         | 43 ++++++++++++++++++-
>  include/linux/mfd/cros_ec.h                   |  1 -
>  6 files changed, 61 insertions(+), 4 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc
>
> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc
> new file mode 100644
> index 000000000000..c256a2febf37
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc
> @@ -0,0 +1,6 @@
> +What:          /sys/class/chromeos/<cros-ec>/vbc/vboot_context
> +Date:          October 2015
> +KernelVersion: 4.4
> +Description:
> +               Read/write the verified boot context data included on a
> +               small nvram space on some EC implementations.
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 614f888c9d6d..51325049690c 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -36,7 +36,6 @@ static int ec_major;
>
>  static const struct attribute_group *cros_ec_groups[] = {
>         &cros_ec_attr_group,
> -       &cros_ec_vbc_attr_group,
>         NULL,
>  };
>
> @@ -391,6 +390,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
>
>  static const struct mfd_cell cros_ec_platform_cells[] = {
>         { .name = "cros-ec-lightbar" },
> +       { .name = "cros-ec-vbc" },
>  };
>
>  static int ec_device_probe(struct platform_device *pdev)
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 05bcefbe1926..29bd9837d520 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -121,4 +121,14 @@ config CROS_EC_LIGHTBAR
>           To compile this driver as a module, choose M here: the
>           module will be called cros_ec_lightbar.
>
> +config CROS_EC_VBC
> +       tristate "ChromeOS EC vboot context support"
> +       depends on MFD_CROS_EC_CHARDEV && OF
> +       help
> +         This option exposes the ChromeOS EC vboot context nvram to
> +         userspace.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called cros_ec_vbc.
> +
>  endif # CHROMEOS_PLATFORMS
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index 3c29a4b405d5..4081b7179df7 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -4,7 +4,7 @@ obj-$(CONFIG_CHROMEOS_LAPTOP)           += chromeos_laptop.o
>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
>  cros_ec_ctl-objs                       := cros_ec_sysfs.o \
> -                                          cros_ec_vbc.o cros_ec_debugfs.o
> +                                          cros_ec_debugfs.o
>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> @@ -14,3 +14,4 @@ obj-$(CONFIG_CROS_EC_LPC)             += cros_ec_lpcs.o
>  obj-$(CONFIG_CROS_EC_PROTO)            += cros_ec_proto.o
>  obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)   += cros_kbd_led_backlight.o
>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
> +obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
> diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c
> index 5356f26bc022..da3bbf05e86f 100644
> --- a/drivers/platform/chrome/cros_ec_vbc.c
> +++ b/drivers/platform/chrome/cros_ec_vbc.c
> @@ -22,8 +22,11 @@
>  #include <linux/platform_device.h>
>  #include <linux/mfd/cros_ec.h>
>  #include <linux/mfd/cros_ec_commands.h>
> +#include <linux/module.h>
>  #include <linux/slab.h>
>
> +#define DRV_NAME "cros-ec-vbc"
> +
>  static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
>                                   struct bin_attribute *att, char *buf,
>                                   loff_t pos, size_t count)
> @@ -132,4 +135,42 @@ struct attribute_group cros_ec_vbc_attr_group = {
>         .bin_attrs = cros_ec_vbc_bin_attrs,
>         .is_bin_visible = cros_ec_vbc_is_visible,
>  };
> -EXPORT_SYMBOL(cros_ec_vbc_attr_group);
> +
> +static int cros_ec_vbc_probe(struct platform_device *pd)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> +       struct device *dev = &pd->dev;
> +       int ret;
> +
> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj,
> +                                &cros_ec_vbc_attr_group);
> +       if (ret < 0)
> +               dev_err(dev, "failed to create %s attributes. err=%d\n",
> +                       cros_ec_vbc_attr_group.name, ret);
> +
> +       return ret;
> +}
> +
> +static int cros_ec_vbc_remove(struct platform_device *pd)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> +
> +       sysfs_remove_group(&ec_dev->class_dev.kobj,
> +                          &cros_ec_vbc_attr_group);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver cros_ec_vbc_driver = {
> +       .driver = {
> +               .name = DRV_NAME,
> +       },
> +       .probe = cros_ec_vbc_probe,
> +       .remove = cros_ec_vbc_remove,
> +};
> +
> +module_platform_driver(cros_ec_vbc_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
> +MODULE_ALIAS("platform:" DRV_NAME);
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index b6beba3031ba..bbbe416fd573 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -325,7 +325,6 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
>
>  /* sysfs stuff */
>  extern struct attribute_group cros_ec_attr_group;
> -extern struct attribute_group cros_ec_vbc_attr_group;
>
>  /* debugfs stuff */
>  int cros_ec_debugfs_init(struct cros_ec_dev *ec);
> --
> 2.19.1
>

Re: [PATCH v3 8/8] mfd: cros_ec: add a dev_release empty method.

[Greg Kroah-Hartman]

On Thu, Nov 29, 2018 at 11:11:16PM +0100, Enric Balletbo i Serra wrote:
> Hi,
> 
> On 29/11/18 8:55, Greg Kroah-Hartman wrote:
> > On Wed, Nov 28, 2018 at 05:17:22PM -0800, Guenter Roeck wrote:
> >> Hi Greg,
> >>
> >> On Tue, Nov 27, 2018 at 9:52 AM Greg Kroah-Hartman
> >> <gregkh@linuxfoundation.org> wrote:
> >>>
> >>> On Tue, Nov 27, 2018 at 09:29:38AM -0800, Guenter Roeck wrote:
> >>>> Hi Enric,
> >>>>
> >>>> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> >>>> <enric.balletbo@collabora.com> wrote:
> >>>>>
> >>>>> Devices are required to provide a release method. This patch fixes the
> >>>>> following WARN():
> >>>>>
> >>>>> [   47.218707] ------------[ cut here ]------------
> >>>>> [   47.223901] Device 'cros_ec' does not have a release() function, it is broken and must be fixed.
> >>>>> [   47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 device_release+0x80/0x90
> >>>>> [   47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth ecdh_generic [...]
> >>>>> [   47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29
> >>>>> [   47.330947] Hardware name: Google Kevin (DT)
> >>>>> [   47.335714] pstate: 40000005 (nZcv daif -PAN -UAO)
> >>>>> [   47.341063] pc : device_release+0x80/0x90
> >>>>> [   47.345537] lr : device_release+0x80/0x90
> >>>>> [   47.350001] sp : ffff00000b17bc70
> >>>>> [   47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80
> >>>>> [   47.359629] x27: 0000000000000000 x26: 0000000000000000
> >>>>> [   47.365561] x25: 0000000056000000 x24: 0000000000000015
> >>>>> [   47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0
> >>>>> [   47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028
> >>>>> [   47.383346] x19: ffff8000edd13018 x18: 0000000000000095
> >>>>> [   47.389278] x17: 0000000000000000 x16: 0000000000000000
> >>>>> [   47.395209] x15: 0000000000000400 x14: 0000000000000400
> >>>>> [   47.401131] x13: 00000000000001a7 x12: 0000000000000000
> >>>>> [   47.407053] x11: 0000000000000001 x10: 0000000000000960
> >>>>> [   47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440
> >>>>> [   47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8
> >>>>> [   47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000
> >>>>> [   47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80
> >>>>> [   47.436674] x1 : 37d859939c964800 x0 : 0000000000000000
> >>>>> [   47.442597] Call trace:
> >>>>> [   47.445324]  device_release+0x80/0x90
> >>>>> [   47.449414]  kobject_put+0x74/0xe8
> >>>>> [   47.453210]  device_unregister+0x20/0x30
> >>>>> [   47.457592]  ec_device_remove+0x34/0x48 [cros_ec_dev]
> >>>>> [   47.463233]  platform_drv_remove+0x28/0x48
> >>>>> [   47.467805]  device_release_driver_internal+0x1a8/0x240
> >>>>> [   47.473630]  driver_detach+0x40/0x80
> >>>>> [   47.477609]  bus_remove_driver+0x54/0xa8
> >>>>> [   47.481986]  driver_unregister+0x2c/0x58
> >>>>> [   47.486355]  platform_driver_unregister+0x10/0x18
> >>>>> [   47.491599]  cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev]
> >>>>> [   47.497338]  __arm64_sys_delete_module+0x16c/0x1f8
> >>>>> [   47.502689]  el0_svc_common+0x84/0xd8
> >>>>> [   47.506776]  el0_svc_handler+0x2c/0x80
> >>>>> [   47.510960]  el0_svc+0x8/0xc
> >>>>> [   47.514171] ---[ end trace 9087279fc8c03450 ]---
> >>>>>
> >>>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >>>>> ---
> >>>>>
> >>>>> Changes in v3: None
> >>>>> Changes in v2:
> >>>>> - Fix WARN when unloading. This is new in these series.
> >>>>>
> >>>>>  drivers/mfd/cros_ec_dev.c | 5 +++++
> >>>>>  1 file changed, 5 insertions(+)
> >>>>>
> >>>>> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> >>>>> index 1ba98a32715e..cdb941c6db98 100644
> >>>>> --- a/drivers/mfd/cros_ec_dev.c
> >>>>> +++ b/drivers/mfd/cros_ec_dev.c
> >>>>> @@ -35,9 +35,14 @@
> >>>>>  #define CROS_MAX_DEV 128
> >>>>>  static int ec_major;
> >>>>>
> >>>>> +static void cros_ec_dev_release(struct device *dev)
> >>>>> +{
> >>>>> +}
> >>>
> >>> Yeah, as part of the in-kernel documentation, I now get to make fun of
> >>> you in public!
> >>>
> >>> You did read the documentation, right?
> >>>
> >>
> >> To be fair, the problem is difficult to understand. Maybe it is easy
> >> for you, but that is not true for everyone, including me. Remember the
> >> block discussion we just had ? As for the in-kernel documentation,
> >> maybe there is a comprehensive explanation someone, one that clueless
> >> people like me can understand, but all I found was
> >>
> >> "If a bus driver unregisters a device, it should not immediately free
> >>   it. It should instead wait for the driver model core to call the
> >>   device's release method, then free the bus-specific object.
> >>   (There may be other code that is currently referencing the device
> >>   structure, and it would be rude to free the device while that is
> >>   happening)"
> >>
> >> Does that apply to mfd devices ? What other code may that be that
> >> accesses the structure ? What else does it mean, or in other words,
> >> what other cleanup code besides releasing the data structure needs to
> >> reside in the release function ?
> > 
> 
> I think that this can be one of those cases where using device managed
> allocations is not right. If so we only need to revert commit
> 
> 3aa2177e4787 ("mfd: cros_ec: Use devm_kzalloc for private data")

Yes, that patch is not correct.

> I think that the problem might be a dereference when a file operation call
> happens if accesses to the device but the struct is already freed, so the
> allocated structure should be freed after the last release call because you
> can't guarantee is _not_ used before that. In this case class_dev is embedded to
> the struct so I guess that the only resource we need to free is the cros_ec
> device struct. I can be wrong, I didn't continue the research.

If a class_dev is embedded in a structure then that class_dev is the
thing that controls the lifetime of that structure and you have to have
a release function for it, otherwise it is broken.

> This is what Guenter make me think when he said "object lifetime", then I read
> the Greg's answer. I felt bad and I just abandoned that task and switch to
> another one. There were still open questions in my mind but I was not so
> motivated to solve it.

Don't feel bad, it's not a simple problem, but hopefully the
documentation we have should explain it all.  If not, please let me
know.

> Before send the patch I looked at the code and I saw that there are different
> places where an "empty" release function is used.

There are?  Please let me know, we used to have a patch in linux-next
that would catch these at runtime with some fun x86-special checks but I
think it got lost a few years ago.

> If this is never allowed, maybe we can create a cocci script to catch
> these cases, I started this script (thanks Peter for helping me). Only
> detects two places, but the script is not complete as should also take
> in consideration when the release function is assigned in a function
> (usually people does this) instead of assigning the function directly
> in the struct. I'll be happy to help on this if people think will be
> useful.

Yes it is useful, as those should never be allowed.  I know some release
functions were never getting hit as no one even cleaned up the
structures, so people were not seeing the kernel warnings at runtime, so
static checking might be the only way to solve this.

thanks,

greg k-h

Re: [PATCH v3 1/8] mfd / platform: cros_ec: use devm_mfd_add_devices.

[Lee Jones]

On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:

> Use devm_mfd_add_devices() for adding cros-ec core MFD child devices. This
> reduces the need of remove callback from platform/chrome for removing the
> MFD child devices.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> 
> Changes in v3:
> - Removed cros_ec_remove from include file.
> 
> Changes in v2:
> - Use devm only for the cros-ec core.
> 
>  drivers/mfd/cros_ec.c                 | 14 +++-----------
>  drivers/mfd/cros_ec_dev.c             |  1 +
>  drivers/platform/chrome/cros_ec_i2c.c | 10 ----------
>  drivers/platform/chrome/cros_ec_lpc.c |  4 ----
>  drivers/platform/chrome/cros_ec_spi.c | 11 -----------
>  include/linux/mfd/cros_ec.h           | 10 ----------
>  6 files changed, 4 insertions(+), 46 deletions(-)

Nice patch.

Just one question:

[...]

> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 8f9d6964173e..ff788d3e6d5f 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -493,6 +493,7 @@ static int ec_device_remove(struct platform_device *pdev)
>  
>  	cros_ec_debugfs_remove(ec);
>  
> +	mfd_remove_devices(ec->dev);

Why is this still required?

>  	cdev_del(&ec->cdev);
>  	device_unregister(&ec->class_dev);
>  	return 0;

[...]

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Lee Jones]

On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:

> The entire way how cros sysfs attibutes are created is broken.
> cros_ec_lightbar should be its own driver and its attributes should be
> associated with a lightbar driver not the mfd driver. In order to retain
> the path, the lightbar attributes are attached to the cros_class.

I'm not exactly clear on what a lightbar is, but shouldn't it live in
the appropriate subsystem.  Like LED for example?

> The patch also adds the sysfs documentation.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> 
> Changes in v3:
> - Removed unneded check for ec_dev.
> 
> Changes in v2:
> - Removed the two exported functions to attach/detach to the cros_class.
> - Use dev_warn instead of dev_err when adding the lightbar.
> 
>  ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
>  drivers/mfd/cros_ec_dev.c                     | 24 ++---
>  drivers/mfd/cros_ec_dev.h                     |  6 --
>  drivers/platform/chrome/Kconfig               | 10 ++
>  drivers/platform/chrome/Makefile              |  3 +-
>  drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
>  include/linux/mfd/cros_ec.h                   |  1 -
>  7 files changed, 172 insertions(+), 41 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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Re: [PATCH v3 3/8] mfd / platform: cros_ec: move vbc attributes to its own driver.

[Lee Jones]

On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:

> The entire way how cros sysfs attibutes are created is broken.
> cros_ec_vbc should be its own driver and its attributes should be
> associated with a vbc driver not the mfd driver. In order to retain
> the path, the vbc attributes are attached to the cros_class.
> 
> The patch also adds the sysfs documentation.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> 
> Changes in v3:
> - Fixed build error as reported by the kbuild test robot.
> 
> Changes in v2:
> - Removed unneeded check of ec_dev.
> 
>  .../sysfs-class-chromeos-driver-cros-ec-vbc   |  6 +++
>  drivers/mfd/cros_ec_dev.c                     |  2 +-
>  drivers/platform/chrome/Kconfig               | 10 +++++
>  drivers/platform/chrome/Makefile              |  3 +-
>  drivers/platform/chrome/cros_ec_vbc.c         | 43 ++++++++++++++++++-
>  include/linux/mfd/cros_ec.h                   |  1 -
>  6 files changed, 61 insertions(+), 4 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-vbc

Patch looks fine, so long as drivers/platform is the right place for
this driver to reside.  No better subsystems for it?

For my own reference:
  Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 4/8] mfd / platform: cros_ec: move debugfs attributes to its own driver.

[Lee Jones]

On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:

> The entire way how cros debugfs attibutes are created is broken.
> cros_ec_debugfs should be its own driver and its attributes should be
> associated with a debugfs driver not the mfd driver.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> 
> Changes in v3: None
> Changes in v2:
> - Add a "default MFD_CROS_EC_CHARDEV" in Kconfig for this.
> - Remove the checks for missing debug_info, are not needed now.
> - Remove a comment that no longer applies.
> 
>  drivers/platform/chrome/Kconfig           | 11 ++++
>  drivers/platform/chrome/Makefile          |  4 +-
>  drivers/platform/chrome/cros_ec_debugfs.c | 62 +++++++++++++++--------

>  drivers/mfd/cros_ec_dev.c                 | 41 +--------------
>  include/linux/mfd/cros_ec.h               |  6 ---

For my own reference:
  Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Lee Jones]

On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:

> The entire way how cros debugfs attibutes are created is broken.
> cros_ec_sysfs should be its own driver and its attributes should be
> associated with the sysfs driver not the mfd driver.
> 
> The patch also adds the sysfs documentation.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> 
> Changes in v3:
> - Do not print ec_platform name as is with dev_err is enough.
> 
> Changes in v2:
> - Create the attributes directly instead of use the attach/detach callbacks.
> 
>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
>  drivers/platform/chrome/Kconfig               | 14 ++++++--
>  drivers/platform/chrome/Makefile              |  3 +-
>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-

>  drivers/mfd/Kconfig                           |  1 -
>  drivers/mfd/cros_ec_dev.c                     |  7 +---
>  include/linux/mfd/cros_ec.h                   |  3 --

For my own reference:
  Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 6/8] mfd / platform: cros_ec: instantiate only if th EC has a VBC NVRAM.

[Lee Jones]

On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:

> The cros-ec-vbc driver is DT-only and there is a DT property that
> indicates if the EC has the VCB NVRAM, in such case instantiate the
> driver but don't instantiate on the other cases.
> 
> To do this move the check code to its parent instead of play with the
> attribute group visibility. This changes a bit the actual behaviour.
> Before the patch if an EC doesn't have a VBC NVRAM an empty vbc folder
> is created in /sys/class/chromeos/<ec device>, after the patch the empty
> folder is not created, so, the folder is only created if the vbc is set.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> 
> Changes in v3:
> - Fixed build error as reported by kbuild test robot.
> 
> Changes in v2:
> - Remove unnecessary IS_ENABLED.
> - Remove dev_err message telling that VBC is found.
> - Use dev_warn instead of dev_err as the error is ignored.
> 
>  drivers/mfd/cros_ec_dev.c             | 19 ++++++++++++++++++-

For my own reference:
  Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>

>  drivers/platform/chrome/cros_ec_vbc.c | 16 ----------------

Isn't there anywhere better for this to reside?

>  2 files changed, 18 insertions(+), 17 deletions(-)

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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Re: [PATCH v3 1/8] mfd / platform: cros_ec: use devm_mfd_add_devices.

[Enric Balletbo i Serra]

Hi Lee,

On 3/12/18 11:32, Lee Jones wrote:
> On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
> 
>> Use devm_mfd_add_devices() for adding cros-ec core MFD child devices. This
>> reduces the need of remove callback from platform/chrome for removing the
>> MFD child devices.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> ---
>>
>> Changes in v3:
>> - Removed cros_ec_remove from include file.
>>
>> Changes in v2:
>> - Use devm only for the cros-ec core.
>>
>>  drivers/mfd/cros_ec.c                 | 14 +++-----------
>>  drivers/mfd/cros_ec_dev.c             |  1 +
>>  drivers/platform/chrome/cros_ec_i2c.c | 10 ----------
>>  drivers/platform/chrome/cros_ec_lpc.c |  4 ----
>>  drivers/platform/chrome/cros_ec_spi.c | 11 -----------
>>  include/linux/mfd/cros_ec.h           | 10 ----------
>>  6 files changed, 4 insertions(+), 46 deletions(-)
> 
> Nice patch.
> 
> Just one question:
> 
> [...]
> 
>> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
>> index 8f9d6964173e..ff788d3e6d5f 100644
>> --- a/drivers/mfd/cros_ec_dev.c
>> +++ b/drivers/mfd/cros_ec_dev.c
>> @@ -493,6 +493,7 @@ static int ec_device_remove(struct platform_device *pdev)
>>  
>>  	cros_ec_debugfs_remove(ec);
>>  
>> +	mfd_remove_devices(ec->dev);
> 
> Why is this still required?
> 

Hmm, maybe that line shouldn't be here as is not really related to this patch,
it's more a fix for the cros_ec_dev to remove those cells that are registered
with mfd_add_devices.

Actually what we have is cros_ec that instantiates one or two cros_ec_dev
(depends on the platform) and cros_ec_dev instantiating different subdrivers.
The purpose of the patch was use the device managed resource for the cros_ec
driver, I did not touch the cros_ec_dev driver

>>  	cdev_del(&ec->cdev);
>>  	device_unregister(&ec->class_dev);
>>  	return 0;
> 
> [...]
> 

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Enric Balletbo i Serra]

Hi Lee,

On 3/12/18 11:36, Lee Jones wrote:
> On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
> 
>> The entire way how cros sysfs attibutes are created is broken.
>> cros_ec_lightbar should be its own driver and its attributes should be
>> associated with a lightbar driver not the mfd driver. In order to retain
>> the path, the lightbar attributes are attached to the cros_class.
> 
> I'm not exactly clear on what a lightbar is, but shouldn't it live in
> the appropriate subsystem.  Like LED for example?
> 

The lightbar is a four-color indicator available on some Chromebook, but the
fact that can you can program this lightbar with different sequences, including
user defined sequences makes the device a bit special and very chrome platform
specific. The same happens with the VBC driver.

Other subdevices like, rtc, keyboard, usbpd charger,etc. are already in their
subsystems.

>> The patch also adds the sysfs documentation.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> ---
>>
>> Changes in v3:
>> - Removed unneded check for ec_dev.
>>
>> Changes in v2:
>> - Removed the two exported functions to attach/detach to the cros_class.
>> - Use dev_warn instead of dev_err when adding the lightbar.
>>
>>  ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
>>  drivers/mfd/cros_ec_dev.c                     | 24 ++---
>>  drivers/mfd/cros_ec_dev.h                     |  6 --
>>  drivers/platform/chrome/Kconfig               | 10 ++
>>  drivers/platform/chrome/Makefile              |  3 +-
>>  drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
>>  include/linux/mfd/cros_ec.h                   |  1 -
>>  7 files changed, 172 insertions(+), 41 deletions(-)
>>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
> 

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Lee Jones]

On Mon, 03 Dec 2018, Enric Balletbo i Serra wrote:
> On 3/12/18 11:36, Lee Jones wrote:
> > On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
> > 
> >> The entire way how cros sysfs attibutes are created is broken.
> >> cros_ec_lightbar should be its own driver and its attributes should be
> >> associated with a lightbar driver not the mfd driver. In order to retain
> >> the path, the lightbar attributes are attached to the cros_class.
> > 
> > I'm not exactly clear on what a lightbar is, but shouldn't it live in
> > the appropriate subsystem.  Like LED for example?
> > 
> 
> The lightbar is a four-color indicator available on some Chromebook, but the
> fact that can you can program this lightbar with different sequences, including
> user defined sequences makes the device a bit special and very chrome platform
> specific. The same happens with the VBC driver.

Being Chrome specific doesn't necessarily mean that these drivers
shouldn't reside in a proper subsystem.  A lot of drivers in the
kernel are only relevant to very specific hardware/platforms.

IMHO code in drivers/platform should pertain only to the core platform
itself.  Any drivers for leaf hardware/functionality should be split
out into the subsystems, however niche you think they are.

I also understand the convenience factor of not having to go through
a !Google Maintainer, but this is not a loophole I'm prepared to
support. ;)

> Other subdevices like, rtc, keyboard, usbpd charger,etc. are already in their
> subsystems.
> 
> >> The patch also adds the sysfs documentation.
> >>
> >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >> ---
> >>
> >> Changes in v3:
> >> - Removed unneded check for ec_dev.
> >>
> >> Changes in v2:
> >> - Removed the two exported functions to attach/detach to the cros_class.
> >> - Use dev_warn instead of dev_err when adding the lightbar.
> >>
> >>  ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
> >>  drivers/mfd/cros_ec_dev.c                     | 24 ++---
> >>  drivers/mfd/cros_ec_dev.h                     |  6 --
> >>  drivers/platform/chrome/Kconfig               | 10 ++
> >>  drivers/platform/chrome/Makefile              |  3 +-
> >>  drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
> >>  include/linux/mfd/cros_ec.h                   |  1 -
> >>  7 files changed, 172 insertions(+), 41 deletions(-)
> >>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
> > 

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 1/8] mfd / platform: cros_ec: use devm_mfd_add_devices.

[Lee Jones]

On Mon, 03 Dec 2018, Enric Balletbo i Serra wrote:

> Hi Lee,
> 
> On 3/12/18 11:32, Lee Jones wrote:
> > On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
> > 
> >> Use devm_mfd_add_devices() for adding cros-ec core MFD child devices. This
> >> reduces the need of remove callback from platform/chrome for removing the
> >> MFD child devices.
> >>
> >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >> ---
> >>
> >> Changes in v3:
> >> - Removed cros_ec_remove from include file.
> >>
> >> Changes in v2:
> >> - Use devm only for the cros-ec core.
> >>
> >>  drivers/mfd/cros_ec.c                 | 14 +++-----------
> >>  drivers/mfd/cros_ec_dev.c             |  1 +
> >>  drivers/platform/chrome/cros_ec_i2c.c | 10 ----------
> >>  drivers/platform/chrome/cros_ec_lpc.c |  4 ----
> >>  drivers/platform/chrome/cros_ec_spi.c | 11 -----------
> >>  include/linux/mfd/cros_ec.h           | 10 ----------
> >>  6 files changed, 4 insertions(+), 46 deletions(-)
> > 
> > Nice patch.
> > 
> > Just one question:
> > 
> > [...]
> > 
> >> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> >> index 8f9d6964173e..ff788d3e6d5f 100644
> >> --- a/drivers/mfd/cros_ec_dev.c
> >> +++ b/drivers/mfd/cros_ec_dev.c
> >> @@ -493,6 +493,7 @@ static int ec_device_remove(struct platform_device *pdev)
> >>  
> >>  	cros_ec_debugfs_remove(ec);
> >>  
> >> +	mfd_remove_devices(ec->dev);
> > 
> > Why is this still required?
> > 
> 
> Hmm, maybe that line shouldn't be here as is not really related to this patch,
> it's more a fix for the cros_ec_dev to remove those cells that are registered
> with mfd_add_devices.
> 
> Actually what we have is cros_ec that instantiates one or two cros_ec_dev
> (depends on the platform) and cros_ec_dev instantiating different subdrivers.
> The purpose of the patch was use the device managed resource for the cros_ec
> driver, I did not touch the cros_ec_dev driver

Also, if you are using managed devices, you shouldn't need to call
mfd_remove_devices() at all, since it will be called for you when the
device is torn down, right?

> >>  	cdev_del(&ec->cdev);
> >>  	device_unregister(&ec->class_dev);
> >>  	return 0;
> > 
> > [...]
> > 

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Enric Balletbo i Serra]

Hi Lee,

On 4/12/18 10:21, Lee Jones wrote:
> On Mon, 03 Dec 2018, Enric Balletbo i Serra wrote:
>> On 3/12/18 11:36, Lee Jones wrote:
>>> On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
>>>
>>>> The entire way how cros sysfs attibutes are created is broken.
>>>> cros_ec_lightbar should be its own driver and its attributes should be
>>>> associated with a lightbar driver not the mfd driver. In order to retain
>>>> the path, the lightbar attributes are attached to the cros_class.
>>>
>>> I'm not exactly clear on what a lightbar is, but shouldn't it live in
>>> the appropriate subsystem.  Like LED for example?
>>>
>>
>> The lightbar is a four-color indicator available on some Chromebook, but the
>> fact that can you can program this lightbar with different sequences, including
>> user defined sequences makes the device a bit special and very chrome platform
>> specific. The same happens with the VBC driver.
> 
> Being Chrome specific doesn't necessarily mean that these drivers
> shouldn't reside in a proper subsystem.  A lot of drivers in the
> kernel are only relevant to very specific hardware/platforms.
> 

Agree, and we try to put these drivers in their subsystem when we think it is
appropriate (we have in rtc, power, iio, keyboard, etc.)

> IMHO code in drivers/platform should pertain only to the core platform
> itself.  Any drivers for leaf hardware/functionality should be split
> out into the subsystems, however niche you think they are.
> 

To be honest, I don't have a hard opinion yet on if the drivers/platform should
pertain only to the core platform itself.

The cros_ec_lightbar.c file already exists in drivers/platform, the patch just
converts it to a kernel module (only adds few lines). The main purpose of the se
patches was have cros-ec mfd code and their subdrivers separated instead of
having crossed calls.

I don't mind to move to another subsystem (I need to discuss with the chromium
guys and I am still not sure if LED fits very well in this case, I can look in
more detail) but shouldn't be this a follow up patch?

I am also worried on how this could affect the current user interface. Well,
something to look, right.

Thanks,
 Enric


> I also understand the convenience factor of not having to go through
> a !Google Maintainer, but this is not a loophole I'm prepared to
> support. ;)
> 
>> Other subdevices like, rtc, keyboard, usbpd charger,etc. are already in their
>> subsystems.
>>
>>>> The patch also adds the sysfs documentation.
>>>>
>>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>>>> ---
>>>>
>>>> Changes in v3:
>>>> - Removed unneded check for ec_dev.
>>>>
>>>> Changes in v2:
>>>> - Removed the two exported functions to attach/detach to the cros_class.
>>>> - Use dev_warn instead of dev_err when adding the lightbar.
>>>>
>>>>  ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
>>>>  drivers/mfd/cros_ec_dev.c                     | 24 ++---
>>>>  drivers/mfd/cros_ec_dev.h                     |  6 --
>>>>  drivers/platform/chrome/Kconfig               | 10 ++
>>>>  drivers/platform/chrome/Makefile              |  3 +-
>>>>  drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
>>>>  include/linux/mfd/cros_ec.h                   |  1 -
>>>>  7 files changed, 172 insertions(+), 41 deletions(-)
>>>>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
>>>
> 

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Guenter Roeck]

On Tue, Dec 4, 2018 at 3:52 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Hi Lee,
>
> On 4/12/18 10:21, Lee Jones wrote:
> > On Mon, 03 Dec 2018, Enric Balletbo i Serra wrote:
> >> On 3/12/18 11:36, Lee Jones wrote:
> >>> On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
> >>>
> >>>> The entire way how cros sysfs attibutes are created is broken.
> >>>> cros_ec_lightbar should be its own driver and its attributes should be
> >>>> associated with a lightbar driver not the mfd driver. In order to retain
> >>>> the path, the lightbar attributes are attached to the cros_class.
> >>>
> >>> I'm not exactly clear on what a lightbar is, but shouldn't it live in
> >>> the appropriate subsystem.  Like LED for example?
> >>>
> >>
> >> The lightbar is a four-color indicator available on some Chromebook, but the
> >> fact that can you can program this lightbar with different sequences, including
> >> user defined sequences makes the device a bit special and very chrome platform
> >> specific. The same happens with the VBC driver.
> >
> > Being Chrome specific doesn't necessarily mean that these drivers
> > shouldn't reside in a proper subsystem.  A lot of drivers in the
> > kernel are only relevant to very specific hardware/platforms.
> >
>
> Agree, and we try to put these drivers in their subsystem when we think it is
> appropriate (we have in rtc, power, iio, keyboard, etc.)
>
> > IMHO code in drivers/platform should pertain only to the core platform
> > itself.  Any drivers for leaf hardware/functionality should be split
> > out into the subsystems, however niche you think they are.
> >
>
> To be honest, I don't have a hard opinion yet on if the drivers/platform should
> pertain only to the core platform itself.
>
> The cros_ec_lightbar.c file already exists in drivers/platform, the patch just
> converts it to a kernel module (only adds few lines). The main purpose of the se
> patches was have cros-ec mfd code and their subdrivers separated instead of
> having crossed calls.
>
> I don't mind to move to another subsystem (I need to discuss with the chromium
> guys and I am still not sure if LED fits very well in this case, I can look in
> more detail) but shouldn't be this a follow up patch?
>

Separate patch, please, if anything.

I would not know which subsystem to move this to, though, and moving
it to misc just for the sake of it would seem odd, since this most
definitely _is_ platform related code. What is platform for if not for
platform specific code ?

> I am also worried on how this could affect the current user interface. Well,
> something to look, right.
>

No ABI changes, please.

Guenter

> Thanks,
>  Enric
>
>
> > I also understand the convenience factor of not having to go through
> > a !Google Maintainer, but this is not a loophole I'm prepared to
> > support. ;)
> >
> >> Other subdevices like, rtc, keyboard, usbpd charger,etc. are already in their
> >> subsystems.
> >>
> >>>> The patch also adds the sysfs documentation.
> >>>>
> >>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >>>> ---
> >>>>
> >>>> Changes in v3:
> >>>> - Removed unneded check for ec_dev.
> >>>>
> >>>> Changes in v2:
> >>>> - Removed the two exported functions to attach/detach to the cros_class.
> >>>> - Use dev_warn instead of dev_err when adding the lightbar.
> >>>>
> >>>>  ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
> >>>>  drivers/mfd/cros_ec_dev.c                     | 24 ++---
> >>>>  drivers/mfd/cros_ec_dev.h                     |  6 --
> >>>>  drivers/platform/chrome/Kconfig               | 10 ++
> >>>>  drivers/platform/chrome/Makefile              |  3 +-
> >>>>  drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
> >>>>  include/linux/mfd/cros_ec.h                   |  1 -
> >>>>  7 files changed, 172 insertions(+), 41 deletions(-)
> >>>>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
> >>>
> >

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Lee Jones]

On Tue, 04 Dec 2018, Enric Balletbo i Serra wrote:
> On 4/12/18 10:21, Lee Jones wrote:
> > On Mon, 03 Dec 2018, Enric Balletbo i Serra wrote:
> >> On 3/12/18 11:36, Lee Jones wrote:
> >>> On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
> >>>
> >>>> The entire way how cros sysfs attibutes are created is broken.
> >>>> cros_ec_lightbar should be its own driver and its attributes should be
> >>>> associated with a lightbar driver not the mfd driver. In order to retain
> >>>> the path, the lightbar attributes are attached to the cros_class.
> >>>
> >>> I'm not exactly clear on what a lightbar is, but shouldn't it live in
> >>> the appropriate subsystem.  Like LED for example?
> >>>
> >>
> >> The lightbar is a four-color indicator available on some Chromebook, but the
> >> fact that can you can program this lightbar with different sequences, including
> >> user defined sequences makes the device a bit special and very chrome platform
> >> specific. The same happens with the VBC driver.
> > 
> > Being Chrome specific doesn't necessarily mean that these drivers
> > shouldn't reside in a proper subsystem.  A lot of drivers in the
> > kernel are only relevant to very specific hardware/platforms.
> 
> Agree, and we try to put these drivers in their subsystem when we think it is
> appropriate (we have in rtc, power, iio, keyboard, etc.)

Right.  I can see that.  This is good.

> > IMHO code in drivers/platform should pertain only to the core platform
> > itself.  Any drivers for leaf hardware/functionality should be split
> > out into the subsystems, however niche you think they are.
> 
> To be honest, I don't have a hard opinion yet on if the drivers/platform should
> pertain only to the core platform itself.
> 
> The cros_ec_lightbar.c file already exists in drivers/platform, the patch just
> converts it to a kernel module (only adds few lines). The main purpose of the se
> patches was have cros-ec mfd code and their subdrivers separated instead of
> having crossed calls.

Right.  I have no intention of blocking *this* patch.  All we're doing
here is highlighting potential issues I see.

> I don't mind to move to another subsystem (I need to discuss with the chromium
> guys

Wonderful.  That's exactly what I wanted to hear.

> and I am still not sure if LED fits very well in this case, I can look in
> more detail)

Sure.

> but shouldn't be this a follow up patch?

Absolutely.

> I am also worried on how this could affect the current user interface. Well,
> something to look, right.

Right.

Thanks again for looking into this.  I will re-review your patch, this
time *not* taking the location of the driver into consideration.

> > I also understand the convenience factor of not having to go through
> > a !Google Maintainer, but this is not a loophole I'm prepared to
> > support. ;)
> > 
> >> Other subdevices like, rtc, keyboard, usbpd charger,etc. are already in their
> >> subsystems.
> >>
> >>>> The patch also adds the sysfs documentation.
> >>>>
> >>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >>>> ---
> >>>>
> >>>> Changes in v3:
> >>>> - Removed unneded check for ec_dev.
> >>>>
> >>>> Changes in v2:
> >>>> - Removed the two exported functions to attach/detach to the cros_class.
> >>>> - Use dev_warn instead of dev_err when adding the lightbar.
> >>>>
> >>>>  ...sfs-class-chromeos-driver-cros-ec-lightbar | 74 +++++++++++++++
> >>>>  drivers/mfd/cros_ec_dev.c                     | 24 ++---
> >>>>  drivers/mfd/cros_ec_dev.h                     |  6 --
> >>>>  drivers/platform/chrome/Kconfig               | 10 ++
> >>>>  drivers/platform/chrome/Makefile              |  3 +-
> >>>>  drivers/platform/chrome/cros_ec_lightbar.c    | 95 ++++++++++++++-----
> >>>>  include/linux/mfd/cros_ec.h                   |  1 -
> >>>>  7 files changed, 172 insertions(+), 41 deletions(-)
> >>>>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos-driver-cros-ec-lightbar
> >>>
> > 

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 2/8] mfd / platform: cros_ec: move lightbar attributes to its own driver.

[Lee Jones]

On Tue, 04 Dec 2018, Guenter Roeck wrote:
> On Tue, Dec 4, 2018 at 3:52 AM Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
> > On 4/12/18 10:21, Lee Jones wrote:
> > > On Mon, 03 Dec 2018, Enric Balletbo i Serra wrote:
> > >> On 3/12/18 11:36, Lee Jones wrote:
> > >>> On Tue, 27 Nov 2018, Enric Balletbo i Serra wrote:
> > >>>
> > >>>> The entire way how cros sysfs attibutes are created is broken.
> > >>>> cros_ec_lightbar should be its own driver and its attributes should be
> > >>>> associated with a lightbar driver not the mfd driver. In order to retain
> > >>>> the path, the lightbar attributes are attached to the cros_class.
> > >>>
> > >>> I'm not exactly clear on what a lightbar is, but shouldn't it live in
> > >>> the appropriate subsystem.  Like LED for example?
> > >>>
> > >>
> > >> The lightbar is a four-color indicator available on some Chromebook, but the
> > >> fact that can you can program this lightbar with different sequences, including
> > >> user defined sequences makes the device a bit special and very chrome platform
> > >> specific. The same happens with the VBC driver.
> > >
> > > Being Chrome specific doesn't necessarily mean that these drivers
> > > shouldn't reside in a proper subsystem.  A lot of drivers in the
> > > kernel are only relevant to very specific hardware/platforms.
> >
> > Agree, and we try to put these drivers in their subsystem when we think it is
> > appropriate (we have in rtc, power, iio, keyboard, etc.)
> >
> > > IMHO code in drivers/platform should pertain only to the core platform
> > > itself.  Any drivers for leaf hardware/functionality should be split
> > > out into the subsystems, however niche you think they are.
> > >
> >
> > To be honest, I don't have a hard opinion yet on if the drivers/platform should
> > pertain only to the core platform itself.
> >
> > The cros_ec_lightbar.c file already exists in drivers/platform, the patch just
> > converts it to a kernel module (only adds few lines). The main purpose of the se
> > patches was have cros-ec mfd code and their subdrivers separated instead of
> > having crossed calls.
> >
> > I don't mind to move to another subsystem (I need to discuss with the chromium
> > guys and I am still not sure if LED fits very well in this case, I can look in
> > more detail) but shouldn't be this a follow up patch?
> 
> Separate patch, please, if anything.

Agreed.

> I would not know which subsystem to move this to, though, and moving
> it to misc just for the sake of it would seem odd, since this most
> definitely _is_ platform related code. What is platform for if not for
> platform specific code ?

"platform" has very broad and varying meanings in Computer Science
nomenclature.  Unfortunately, it can be used to describe quite a lot
of different aspects of the (I wanted to say platform then) hardware.

All drivers are 'platform' device drivers, that's why we have the
platform_device_*/platform_driver_* API.  Saying that "platform
specific code" should live in */platform reminds me of the
arch/*/<platform> days when similar arguments were put forward with
respect to jamming all "platform specific code" into arch/*.  A great
deal of effort was put in to relocate it all into the proper
subsystems.

What I see here is the backslide into the same mind-set.

My guess is that defining what 'platform' means in the context of
drivers/platform is not going to be straight forward, however; I have
always seen it as a place to put *core* platform code, perhaps an API
akin to the one used for the EC in the Chromium context is a good
example.  Drivers required to control peripherals that, for instance,
operate a set of LEDs, I would not consider core platform code.

In my mind, *any* and *all* leaf and peripheral drivers should be
relocated into a proper subsystem.  Even if that is drivers/misc.

> > I am also worried on how this could affect the current user interface. Well,
> > something to look, right.
> 
> No ABI changes, please.

Without seeing the way in which a user controls this stuff, it's
difficult to comment, but a change in subsystem usually means a shift
in control.  Particularly if that control is operated via SYSFS.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 4/8] mfd / platform: cros_ec: move debugfs attributes to its own driver.

[Guenter Roeck]

On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> The entire way how cros debugfs attibutes are created is broken.
> cros_ec_debugfs should be its own driver and its attributes should be
> associated with a debugfs driver not the mfd driver.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Reviewed-by: Guenter Roeck <groeck@chromium.org>

> ---
>
> Changes in v3: None
> Changes in v2:
> - Add a "default MFD_CROS_EC_CHARDEV" in Kconfig for this.
> - Remove the checks for missing debug_info, are not needed now.
> - Remove a comment that no longer applies.
>
>  drivers/mfd/cros_ec_dev.c                 | 41 +--------------
>  drivers/platform/chrome/Kconfig           | 11 ++++
>  drivers/platform/chrome/Makefile          |  4 +-
>  drivers/platform/chrome/cros_ec_debugfs.c | 62 +++++++++++++++--------
>  include/linux/mfd/cros_ec.h               |  6 ---
>  5 files changed, 56 insertions(+), 68 deletions(-)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 51325049690c..50ba8e0fb4ec 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -389,6 +389,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
>  };
>
>  static const struct mfd_cell cros_ec_platform_cells[] = {
> +       { .name = "cros-ec-debugfs" },
>         { .name = "cros-ec-lightbar" },
>         { .name = "cros-ec-vbc" },
>  };
> @@ -483,9 +484,6 @@ static int ec_device_probe(struct platform_device *pdev)
>                          "failed to add cros-ec platform devices: %d\n",
>                          retval);
>
> -       if (cros_ec_debugfs_init(ec))
> -               dev_warn(dev, "failed to create debugfs directory\n");
> -
>         return 0;
>
>  failed:
> @@ -497,62 +495,25 @@ static int ec_device_remove(struct platform_device *pdev)
>  {
>         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
>
> -       cros_ec_debugfs_remove(ec);
> -
>         mfd_remove_devices(ec->dev);
>         cdev_del(&ec->cdev);
>         device_unregister(&ec->class_dev);
>         return 0;
>  }
>
> -static void ec_device_shutdown(struct platform_device *pdev)
> -{
> -       struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
> -
> -       /* Be sure to clear up debugfs delayed works */
> -       cros_ec_debugfs_remove(ec);
> -}
> -
>  static const struct platform_device_id cros_ec_id[] = {
>         { DRV_NAME, 0 },
>         { /* sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(platform, cros_ec_id);
>
> -static __maybe_unused int ec_device_suspend(struct device *dev)
> -{
> -       struct cros_ec_dev *ec = dev_get_drvdata(dev);
> -
> -       cros_ec_debugfs_suspend(ec);
> -
> -       return 0;
> -}
> -
> -static __maybe_unused int ec_device_resume(struct device *dev)
> -{
> -       struct cros_ec_dev *ec = dev_get_drvdata(dev);
> -
> -       cros_ec_debugfs_resume(ec);
> -
> -       return 0;
> -}
> -
> -static const struct dev_pm_ops cros_ec_dev_pm_ops = {
> -#ifdef CONFIG_PM_SLEEP
> -       .suspend = ec_device_suspend,
> -       .resume = ec_device_resume,
> -#endif
> -};
> -
>  static struct platform_driver cros_ec_dev_driver = {
>         .driver = {
>                 .name = DRV_NAME,
> -               .pm = &cros_ec_dev_pm_ops,
>         },
>         .id_table = cros_ec_id,
>         .probe = ec_device_probe,
>         .remove = ec_device_remove,
> -       .shutdown = ec_device_shutdown,
>  };
>
>  static int __init cros_ec_dev_init(void)
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 29bd9837d520..4e4232b47764 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -131,4 +131,15 @@ config CROS_EC_VBC
>           To compile this driver as a module, choose M here: the
>           module will be called cros_ec_vbc.
>
> +config CROS_EC_DEBUGFS
> +       tristate "Export ChromeOS EC internals in DebugFS"
> +       depends on MFD_CROS_EC_CHARDEV && DEBUG_FS
> +       default MFD_CROS_EC_CHARDEV
> +       help
> +         This option exposes the ChromeOS EC device internals to
> +         userspace.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called cros_ec_debugfs.
> +
>  endif # CHROMEOS_PLATFORMS
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index 4081b7179df7..12a5c4d18c17 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -3,8 +3,7 @@
>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> -cros_ec_ctl-objs                       := cros_ec_sysfs.o \
> -                                          cros_ec_debugfs.o
> +cros_ec_ctl-objs                       := cros_ec_sysfs.o
>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> @@ -15,3 +14,4 @@ obj-$(CONFIG_CROS_EC_PROTO)           += cros_ec_proto.o
>  obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)   += cros_kbd_led_backlight.o
>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
> +obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
> diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c
> index c62ee8e610a0..6cacac53dfce 100644
> --- a/drivers/platform/chrome/cros_ec_debugfs.c
> +++ b/drivers/platform/chrome/cros_ec_debugfs.c
> @@ -23,12 +23,16 @@
>  #include <linux/fs.h>
>  #include <linux/mfd/cros_ec.h>
>  #include <linux/mfd/cros_ec_commands.h>
> +#include <linux/module.h>
>  #include <linux/mutex.h>
> +#include <linux/platform_device.h>
>  #include <linux/poll.h>
>  #include <linux/sched.h>
>  #include <linux/slab.h>
>  #include <linux/wait.h>
>
> +#define DRV_NAME "cros-ec-debugfs"
> +
>  #define LOG_SHIFT              14
>  #define LOG_SIZE               (1 << LOG_SHIFT)
>  #define LOG_POLL_SEC           10
> @@ -423,8 +427,9 @@ static int cros_ec_create_pdinfo(struct cros_ec_debugfs *debug_info)
>         return 0;
>  }
>
> -int cros_ec_debugfs_init(struct cros_ec_dev *ec)
> +static int cros_ec_debugfs_probe(struct platform_device *pd)
>  {
> +       struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
>         struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
>         const char *name = ec_platform->ec_name;
>         struct cros_ec_debugfs *debug_info;
> @@ -453,40 +458,57 @@ int cros_ec_debugfs_init(struct cros_ec_dev *ec)
>
>         ec->debug_info = debug_info;
>
> +       dev_set_drvdata(&pd->dev, ec);
> +
>         return 0;
>
>  remove_debugfs:
>         debugfs_remove_recursive(debug_info->dir);
>         return ret;
>  }
> -EXPORT_SYMBOL(cros_ec_debugfs_init);
>
> -void cros_ec_debugfs_remove(struct cros_ec_dev *ec)
> +static int cros_ec_debugfs_remove(struct platform_device *pd)
>  {
> -       if (!ec->debug_info)
> -               return;
> +       struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
>
>         debugfs_remove_recursive(ec->debug_info->dir);
>         cros_ec_cleanup_console_log(ec->debug_info);
> +
> +       return 0;
>  }
> -EXPORT_SYMBOL(cros_ec_debugfs_remove);
>
> -void cros_ec_debugfs_suspend(struct cros_ec_dev *ec)
> +static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
>  {
> -       /*
> -        * cros_ec_debugfs_init() failures are non-fatal; it's also possible
> -        * that we initted things but decided that console log wasn't supported.
> -        * We'll use the same set of checks that cros_ec_debugfs_remove() +
> -        * cros_ec_cleanup_console_log() end up using to handle those cases.
> -        */
> -       if (ec->debug_info && ec->debug_info->log_buffer.buf)
> -               cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
> +       struct cros_ec_dev *ec = dev_get_drvdata(dev);
> +
> +       cancel_delayed_work_sync(&ec->debug_info->log_poll_work);
> +
> +       return 0;
>  }
> -EXPORT_SYMBOL(cros_ec_debugfs_suspend);
>
> -void cros_ec_debugfs_resume(struct cros_ec_dev *ec)
> +static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
>  {
> -       if (ec->debug_info && ec->debug_info->log_buffer.buf)
> -               schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
> +       struct cros_ec_dev *ec = dev_get_drvdata(dev);
> +
> +       schedule_delayed_work(&ec->debug_info->log_poll_work, 0);
> +
> +       return 0;
>  }
> -EXPORT_SYMBOL(cros_ec_debugfs_resume);
> +
> +static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
> +                        cros_ec_debugfs_suspend, cros_ec_debugfs_resume);
> +
> +static struct platform_driver cros_ec_debugfs_driver = {
> +       .driver = {
> +               .name = DRV_NAME,
> +               .pm = &cros_ec_debugfs_pm_ops,
> +       },
> +       .probe = cros_ec_debugfs_probe,
> +       .remove = cros_ec_debugfs_remove,
> +};
> +
> +module_platform_driver(cros_ec_debugfs_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
> +MODULE_ALIAS("platform:" DRV_NAME);
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index bbbe416fd573..3e4401e2ceea 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -326,10 +326,4 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
>  /* sysfs stuff */
>  extern struct attribute_group cros_ec_attr_group;
>
> -/* debugfs stuff */
> -int cros_ec_debugfs_init(struct cros_ec_dev *ec);
> -void cros_ec_debugfs_remove(struct cros_ec_dev *ec);
> -void cros_ec_debugfs_suspend(struct cros_ec_dev *ec);
> -void cros_ec_debugfs_resume(struct cros_ec_dev *ec);
> -
>  #endif /* __LINUX_MFD_CROS_EC_H */
> --
> 2.19.1
>

Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Guenter Roeck]

On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> The entire way how cros debugfs attibutes are created is broken.
> cros_ec_sysfs should be its own driver and its attributes should be
> associated with the sysfs driver not the mfd driver.
>
> The patch also adds the sysfs documentation.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
>
> Changes in v3:
> - Do not print ec_platform name as is with dev_err is enough.
>
> Changes in v2:
> - Create the attributes directly instead of use the attach/detach callbacks.
>
>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
>  drivers/mfd/Kconfig                           |  1 -
>  drivers/mfd/cros_ec_dev.c                     |  7 +---
>  drivers/platform/chrome/Kconfig               | 14 ++++++--
>  drivers/platform/chrome/Makefile              |  3 +-
>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
>  include/linux/mfd/cros_ec.h                   |  3 --
>  7 files changed, 80 insertions(+), 16 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
>
> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
> new file mode 100644
> index 000000000000..a5399c4ca82d
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
> @@ -0,0 +1,32 @@
> +What:          /sys/class/chromeos/<cros-ec>/flashinfo

Why "<cros-ec>" and not "cros_ec" ?

> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               Show the EC flash information.
> +
> +What:          /sys/class/chromeos/<cros-ec>/kb_wake_angle
> +Date:          March 2018
> +KernelVersion: 4.17
> +Description:
> +               Control the keyboard wake lid angle. Values are between
> +               0 and 360. This file will also show the keyboard wake lid
> +               angle by querying the hardware.
> +
> +What:          /sys/class/chromeos/<cros-ec>/reboot
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               Tell the EC to reboot in various ways. Options are:
> +               "cancel": Cancel a pending reboot.
> +               "ro": Jump to RO without rebooting.
> +               "rw": Jump to RW without rebooting.
> +               "cold": Cold reboot.
> +               "disable-jump": Disable jump until next reboot.
> +               "hibernate": Hibernate the EC.
> +               "at-shutdown": Reboot after an AP shutdown.
> +
> +What:          /sys/class/chromeos/<cros-ec>/version
> +Date:          August 2015
> +KernelVersion: 4.2
> +Description:
> +               Show the information about the EC software and hardware.
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 8c5dfdce4326..089ffb408918 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -214,7 +214,6 @@ config MFD_CROS_EC
>  config MFD_CROS_EC_CHARDEV
>          tristate "Chrome OS Embedded Controller userspace device interface"
>          depends on MFD_CROS_EC
> -        select CROS_EC_CTL
>          ---help---
>            This driver adds support to talk with the ChromeOS EC from userspace.
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 50ba8e0fb4ec..d9b16ce79319 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -34,15 +34,9 @@
>  #define CROS_MAX_DEV 128
>  static int ec_major;
>
> -static const struct attribute_group *cros_ec_groups[] = {
> -       &cros_ec_attr_group,
> -       NULL,
> -};
> -
>  static struct class cros_class = {
>         .owner          = THIS_MODULE,
>         .name           = "chromeos",
> -       .dev_groups     = cros_ec_groups,
>  };
>
>  /* Basic communication */
> @@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
>  static const struct mfd_cell cros_ec_platform_cells[] = {
>         { .name = "cros-ec-debugfs" },
>         { .name = "cros-ec-lightbar" },
> +       { .name = "cros-ec-sysfs" },
>         { .name = "cros-ec-vbc" },
>  };
>
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 4e4232b47764..b709cc5173a2 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -49,9 +49,6 @@ config CHROMEOS_TBMC
>           To compile this driver as a module, choose M here: the
>           module will be called chromeos_tbmc.
>
> -config CROS_EC_CTL
> -        tristate
> -
>  config CROS_EC_I2C
>         tristate "ChromeOS Embedded Controller (I2C)"
>         depends on MFD_CROS_EC && I2C
> @@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
>           To compile this driver as a module, choose M here: the
>           module will be called cros_ec_debugfs.
>
> +config CROS_EC_SYSFS
> +       tristate "ChromeOS EC control and information through sysfs"
> +       depends on MFD_CROS_EC_CHARDEV && SYSFS
> +       default y

In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
set to m if MFD_CROS_EC_CHARDEV=m.
Not sure what is better here, but for consistency I would prefer
"default MFD_CROS_EC_CHARDEV" (or default y
in the entire series).

> +       help
> +         This option exposes some sysfs attributes to control and get
> +         information from ChromeOS EC.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called cros_ec_sysfs.
> +
>  endif # CHROMEOS_PLATFORMS
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index 12a5c4d18c17..fdbee501931b 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -3,8 +3,6 @@
>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> -cros_ec_ctl-objs                       := cros_ec_sysfs.o
> -obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
> @@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)  += cros_kbd_led_backlight.o
>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
>  obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
> +obj-$(CONFIG_CROS_EC_SYSFS)            += cros_ec_sysfs.o
> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
> index f34a50121064..0ff5aa30c070 100644
> --- a/drivers/platform/chrome/cros_ec_sysfs.c
> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
> @@ -34,6 +34,8 @@
>  #include <linux/types.h>
>  #include <linux/uaccess.h>
>
> +#define DRV_NAME "cros-ec-sysfs"
> +
>  /* Accessor functions */
>
>  static ssize_t reboot_show(struct device *dev,
> @@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
>         .attrs = __ec_attrs,
>         .is_visible = cros_ec_ctrl_visible,
>  };
> -EXPORT_SYMBOL(cros_ec_attr_group);
> +
> +static int cros_ec_sysfs_probe(struct platform_device *pd)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> +       struct device *dev = &pd->dev;
> +       int ret;
> +
> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> +       if (ret < 0)
> +               dev_err(dev, "failed to create attributes. err=%d\n", ret);
> +
> +       return ret;
> +}
> +
> +static int cros_ec_sysfs_remove(struct platform_device *pd)
> +{
> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> +
> +       sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver cros_ec_sysfs_driver = {
> +       .driver = {
> +               .name = DRV_NAME,
> +       },
> +       .probe = cros_ec_sysfs_probe,
> +       .remove = cros_ec_sysfs_remove,
> +};
> +
> +module_platform_driver(cros_ec_sysfs_driver);
>
>  MODULE_LICENSE("GPL");
>  MODULE_DESCRIPTION("ChromeOS EC control driver");
> +MODULE_ALIAS("platform:" DRV_NAME);
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 3e4401e2ceea..f718ad9c2132 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
>   */
>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
>
> -/* sysfs stuff */
> -extern struct attribute_group cros_ec_attr_group;
> -
>  #endif /* __LINUX_MFD_CROS_EC_H */
> --
> 2.19.1
>

Re: [PATCH v3 6/8] mfd / platform: cros_ec: instantiate only if th EC has a VBC NVRAM.

[Guenter Roeck]

On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> The cros-ec-vbc driver is DT-only and there is a DT property that
> indicates if the EC has the VCB NVRAM, in such case instantiate the
> driver but don't instantiate on the other cases.
>
> To do this move the check code to its parent instead of play with the
> attribute group visibility. This changes a bit the actual behaviour.
> Before the patch if an EC doesn't have a VBC NVRAM an empty vbc folder
> is created in /sys/class/chromeos/<ec device>, after the patch the empty
> folder is not created, so, the folder is only created if the vbc is set.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Reviewed-by: Guenter Roeck <groeck@chromium.org>

> ---
>
> Changes in v3:
> - Fixed build error as reported by kbuild test robot.
>
> Changes in v2:
> - Remove unnecessary IS_ENABLED.
> - Remove dev_err message telling that VBC is found.
> - Use dev_warn instead of dev_err as the error is ignored.
>
>  drivers/mfd/cros_ec_dev.c             | 19 ++++++++++++++++++-
>  drivers/platform/chrome/cros_ec_vbc.c | 16 ----------------
>  2 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index d9b16ce79319..1ba98a32715e 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -21,6 +21,7 @@
>  #include <linux/mfd/core.h>
>  #include <linux/module.h>
>  #include <linux/mod_devicetable.h>
> +#include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm.h>
>  #include <linux/slab.h>
> @@ -386,12 +387,16 @@ static const struct mfd_cell cros_ec_platform_cells[] = {
>         { .name = "cros-ec-debugfs" },
>         { .name = "cros-ec-lightbar" },
>         { .name = "cros-ec-sysfs" },
> -       { .name = "cros-ec-vbc" },
> +};
> +
> +static const struct mfd_cell cros_ec_vbc_cells[] = {
> +       { .name = "cros-ec-vbc" }
>  };
>
>  static int ec_device_probe(struct platform_device *pdev)
>  {
>         int retval = -ENOMEM;
> +       struct device_node *node;
>         struct device *dev = &pdev->dev;
>         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
>         struct cros_ec_dev *ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
> @@ -479,6 +484,18 @@ static int ec_device_probe(struct platform_device *pdev)
>                          "failed to add cros-ec platform devices: %d\n",
>                          retval);
>
> +       /* Check whether this EC instance has a VBC NVRAM */
> +       node = ec->ec_dev->dev->of_node;
> +       if (of_property_read_bool(node, "google,has-vbc-nvram")) {
> +               retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> +                                        cros_ec_vbc_cells,
> +                                        ARRAY_SIZE(cros_ec_vbc_cells),
> +                                        NULL, 0, NULL);
> +               if (retval)
> +                       dev_warn(ec->dev, "failed to add VBC devices: %d\n",
> +                                retval);
> +       }
> +
>         return 0;
>
>  failed:
> diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c
> index da3bbf05e86f..af9bfe6f385c 100644
> --- a/drivers/platform/chrome/cros_ec_vbc.c
> +++ b/drivers/platform/chrome/cros_ec_vbc.c
> @@ -108,21 +108,6 @@ static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
>         return data_sz;
>  }
>
> -static umode_t cros_ec_vbc_is_visible(struct kobject *kobj,
> -                                     struct bin_attribute *a, int n)
> -{
> -       struct device *dev = container_of(kobj, struct device, kobj);
> -       struct cros_ec_dev *ec = to_cros_ec_dev(dev);
> -       struct device_node *np = ec->ec_dev->dev->of_node;
> -
> -       if (IS_ENABLED(CONFIG_OF) && np) {
> -               if (of_property_read_bool(np, "google,has-vbc-nvram"))
> -                       return a->attr.mode;
> -       }
> -
> -       return 0;
> -}
> -
>  static BIN_ATTR_RW(vboot_context, 16);
>
>  static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
> @@ -133,7 +118,6 @@ static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
>  struct attribute_group cros_ec_vbc_attr_group = {
>         .name = "vbc",
>         .bin_attrs = cros_ec_vbc_bin_attrs,
> -       .is_bin_visible = cros_ec_vbc_is_visible,
>  };
>
>  static int cros_ec_vbc_probe(struct platform_device *pd)
> --
> 2.19.1
>

Re: [PATCH v3 7/8] platform/chrome: cros_ec_lightbar: instantiate only if the EC has a lightbar.

[Guenter Roeck]

On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Due to the way attribute groups visibility work, the function
> cros_ec_lightbar_attrs_are_visible is called multiple times, once per
> attribute, and each of these calls makes an EC transaction. For what is
> worth the EC log reports multiple errors on boot when the lightbar is
> not available. Instead, check if the EC has a lightbar in the probe
> function and only instantiate the device.
>
> Ideally we should have instantiate the driver only if the
> EC_FEATURE_LIGHTBAR is defined, but that's not possible because that flag
> is not in the very first Pixel Chromebook (Link), only on Samus. So, the
> driver is instantiated by his parent always.
>
> This patch changes a bit the actual behaviour. Before the patch if an EC
> doesn't have a lightbar an empty lightbar folder is created in
> /sys/class/chromeos/<ec device>, after the patch the empty folder is not
> created, so, the folder is only created if the lightbar exists.
>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Nitpicks, otherwise

Reviewed-by: Guenter Roeck <groeck@chromium.org>

> ---
>
> Changes in v3: None
> Changes in v2:
> - Removed ec_with_lightbar variable.
>
>  drivers/platform/chrome/cros_ec_lightbar.c | 37 ++++++++--------------
>  1 file changed, 13 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
> index 80eed6317570..6f6a4cbfc3fc 100644
> --- a/drivers/platform/chrome/cros_ec_lightbar.c
> +++ b/drivers/platform/chrome/cros_ec_lightbar.c
> @@ -43,7 +43,6 @@ static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
>   * If this is true, we won't do anything during suspend/resume.
>   */
>  static bool userspace_control;
> -static struct cros_ec_dev *ec_with_lightbar;
>
>  static ssize_t interval_msec_show(struct device *dev,
>                                   struct device_attribute *attr, char *buf)
> @@ -381,9 +380,6 @@ static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
>         struct cros_ec_command *msg;
>         int ret;
>
> -       if (ec != ec_with_lightbar)
> -               return 0;
> -
>         msg = alloc_lightbar_cmd_msg(ec);
>         if (!msg)
>                 return -ENOMEM;
> @@ -567,37 +563,26 @@ static struct attribute *__lb_cmds_attrs[] = {
>         NULL,
>  };
>
> -static bool ec_has_lightbar(struct cros_ec_dev *ec)
> +static bool cros_ec_has_lightbar(struct cros_ec_dev *ec_dev)
>  {
> -       return !!get_lightbar_version(ec, NULL, NULL);
> -}
> -
> -static umode_t cros_ec_lightbar_attrs_are_visible(struct kobject *kobj,
> -                                                 struct attribute *a, int n)
> -{
> -       struct device *dev = container_of(kobj, struct device, kobj);
> -       struct cros_ec_dev *ec = to_cros_ec_dev(dev);
> -       struct platform_device *pdev = to_platform_device(ec->dev);
> +       struct platform_device *pdev = to_platform_device(ec_dev->dev);
>         struct cros_ec_platform *pdata = pdev->dev.platform_data;
>         int is_cros_ec;
>
>         is_cros_ec = strcmp(pdata->ec_name, CROS_EC_DEV_NAME);
>
>         if (is_cros_ec != 0)
> -               return 0;
> +               return false;
>
FWIW, is_cros_ec is really unnecessary here, though I guess that might
be a different patch.

> -       /* Only instantiate this stuff if the EC has a lightbar */
> -       if (ec_has_lightbar(ec)) {
> -               ec_with_lightbar = ec;
> -               return a->mode;
> -       }
> -       return 0;
> +       if (!!get_lightbar_version(ec_dev, NULL, NULL))
> +               return true;
> +
> +       return false;

Why not just the following ?
            return !!get_lightbar_version(ec_dev, NULL, NULL);
or even
            return !strcmp(pdata->ec_name, CROS_EC_DEV_NAME) &&
                      !!get_lightbar_version(ec_dev, NULL, NULL);

>  }
>
>  struct attribute_group cros_ec_lightbar_attr_group = {
>         .name = "lightbar",
>         .attrs = __lb_cmds_attrs,
> -       .is_visible = cros_ec_lightbar_attrs_are_visible,
>  };
>
>  static int cros_ec_lightbar_probe(struct platform_device *pd)
> @@ -606,6 +591,10 @@ static int cros_ec_lightbar_probe(struct platform_device *pd)
>         struct device *dev = &pd->dev;
>         int ret;
>
> +       /* Only instantiate this stuff if the EC has a lightbar */
> +       if (!cros_ec_has_lightbar(ec_dev))
> +               return -ENODEV;
> +
>         /* Take control of the lightbar from the EC. */
>         lb_manual_suspend_ctrl(ec_dev, 1);
>
> @@ -635,7 +624,7 @@ static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
>  {
>         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
>
> -       if (userspace_control || ec_dev != ec_with_lightbar)
> +       if (userspace_control)
>                 return 0;
>
>         return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
> @@ -645,7 +634,7 @@ static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
>  {
>         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
>
> -       if (userspace_control || ec_dev != ec_with_lightbar)
> +       if (userspace_control)
>                 return 0;
>
>         return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
> --
> 2.19.1
>

Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Enric Balletbo i Serra]

Hi Guenter,

On 10/12/18 19:13, Guenter Roeck wrote:
> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
>>
>> The entire way how cros debugfs attibutes are created is broken.
>> cros_ec_sysfs should be its own driver and its attributes should be
>> associated with the sysfs driver not the mfd driver.
>>
>> The patch also adds the sysfs documentation.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> ---
>>
>> Changes in v3:
>> - Do not print ec_platform name as is with dev_err is enough.
>>
>> Changes in v2:
>> - Create the attributes directly instead of use the attach/detach callbacks.
>>
>>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
>>  drivers/mfd/Kconfig                           |  1 -
>>  drivers/mfd/cros_ec_dev.c                     |  7 +---
>>  drivers/platform/chrome/Kconfig               | 14 ++++++--
>>  drivers/platform/chrome/Makefile              |  3 +-
>>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
>>  include/linux/mfd/cros_ec.h                   |  3 --
>>  7 files changed, 80 insertions(+), 16 deletions(-)
>>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
>>
>> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
>> new file mode 100644
>> index 000000000000..a5399c4ca82d
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
>> @@ -0,0 +1,32 @@
>> +What:          /sys/class/chromeos/<cros-ec>/flashinfo
> 
> Why "<cros-ec>" and not "cros_ec" ?
> 

Maybe will be more clear if I use <cros-ec-name>?

Actually <cros-ec-name> can be cros_ec or cros_pd. I put between <> to indicate
that is not the literal name.

>> +Date:          August 2015
>> +KernelVersion: 4.2
>> +Description:
>> +               Show the EC flash information.
>> +
>> +What:          /sys/class/chromeos/<cros-ec>/kb_wake_angle
>> +Date:          March 2018
>> +KernelVersion: 4.17
>> +Description:
>> +               Control the keyboard wake lid angle. Values are between
>> +               0 and 360. This file will also show the keyboard wake lid
>> +               angle by querying the hardware.
>> +
>> +What:          /sys/class/chromeos/<cros-ec>/reboot
>> +Date:          August 2015
>> +KernelVersion: 4.2
>> +Description:
>> +               Tell the EC to reboot in various ways. Options are:
>> +               "cancel": Cancel a pending reboot.
>> +               "ro": Jump to RO without rebooting.
>> +               "rw": Jump to RW without rebooting.
>> +               "cold": Cold reboot.
>> +               "disable-jump": Disable jump until next reboot.
>> +               "hibernate": Hibernate the EC.
>> +               "at-shutdown": Reboot after an AP shutdown.
>> +
>> +What:          /sys/class/chromeos/<cros-ec>/version
>> +Date:          August 2015
>> +KernelVersion: 4.2
>> +Description:
>> +               Show the information about the EC software and hardware.
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index 8c5dfdce4326..089ffb408918 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -214,7 +214,6 @@ config MFD_CROS_EC
>>  config MFD_CROS_EC_CHARDEV
>>          tristate "Chrome OS Embedded Controller userspace device interface"
>>          depends on MFD_CROS_EC
>> -        select CROS_EC_CTL
>>          ---help---
>>            This driver adds support to talk with the ChromeOS EC from userspace.
>>
>> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
>> index 50ba8e0fb4ec..d9b16ce79319 100644
>> --- a/drivers/mfd/cros_ec_dev.c
>> +++ b/drivers/mfd/cros_ec_dev.c
>> @@ -34,15 +34,9 @@
>>  #define CROS_MAX_DEV 128
>>  static int ec_major;
>>
>> -static const struct attribute_group *cros_ec_groups[] = {
>> -       &cros_ec_attr_group,
>> -       NULL,
>> -};
>> -
>>  static struct class cros_class = {
>>         .owner          = THIS_MODULE,
>>         .name           = "chromeos",
>> -       .dev_groups     = cros_ec_groups,
>>  };
>>
>>  /* Basic communication */
>> @@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
>>  static const struct mfd_cell cros_ec_platform_cells[] = {
>>         { .name = "cros-ec-debugfs" },
>>         { .name = "cros-ec-lightbar" },
>> +       { .name = "cros-ec-sysfs" },
>>         { .name = "cros-ec-vbc" },
>>  };
>>
>> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
>> index 4e4232b47764..b709cc5173a2 100644
>> --- a/drivers/platform/chrome/Kconfig
>> +++ b/drivers/platform/chrome/Kconfig
>> @@ -49,9 +49,6 @@ config CHROMEOS_TBMC
>>           To compile this driver as a module, choose M here: the
>>           module will be called chromeos_tbmc.
>>
>> -config CROS_EC_CTL
>> -        tristate
>> -
>>  config CROS_EC_I2C
>>         tristate "ChromeOS Embedded Controller (I2C)"
>>         depends on MFD_CROS_EC && I2C
>> @@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
>>           To compile this driver as a module, choose M here: the
>>           module will be called cros_ec_debugfs.
>>
>> +config CROS_EC_SYSFS
>> +       tristate "ChromeOS EC control and information through sysfs"
>> +       depends on MFD_CROS_EC_CHARDEV && SYSFS
>> +       default y
> 
> In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
> set to m if MFD_CROS_EC_CHARDEV=m.
> Not sure what is better here, but for consistency I would prefer
> "default MFD_CROS_EC_CHARDEV" (or default y
> in the entire series).
> 

Right, makes sense that if the MFD_CROS_EC_CHARDEV is selected set also those by
default. Will prepare a new version with that small change.

>> +       help
>> +         This option exposes some sysfs attributes to control and get
>> +         information from ChromeOS EC.
>> +
>> +         To compile this driver as a module, choose M here: the
>> +         module will be called cros_ec_sysfs.
>> +
>>  endif # CHROMEOS_PLATFORMS
>> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
>> index 12a5c4d18c17..fdbee501931b 100644
>> --- a/drivers/platform/chrome/Makefile
>> +++ b/drivers/platform/chrome/Makefile
>> @@ -3,8 +3,6 @@
>>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
>>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
>>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
>> -cros_ec_ctl-objs                       := cros_ec_sysfs.o
>> -obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
>>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
>>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
>> @@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)  += cros_kbd_led_backlight.o
>>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
>>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
>>  obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
>> +obj-$(CONFIG_CROS_EC_SYSFS)            += cros_ec_sysfs.o
>> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
>> index f34a50121064..0ff5aa30c070 100644
>> --- a/drivers/platform/chrome/cros_ec_sysfs.c
>> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
>> @@ -34,6 +34,8 @@
>>  #include <linux/types.h>
>>  #include <linux/uaccess.h>
>>
>> +#define DRV_NAME "cros-ec-sysfs"
>> +
>>  /* Accessor functions */
>>
>>  static ssize_t reboot_show(struct device *dev,
>> @@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
>>         .attrs = __ec_attrs,
>>         .is_visible = cros_ec_ctrl_visible,
>>  };
>> -EXPORT_SYMBOL(cros_ec_attr_group);
>> +
>> +static int cros_ec_sysfs_probe(struct platform_device *pd)
>> +{
>> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
>> +       struct device *dev = &pd->dev;
>> +       int ret;
>> +
>> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
>> +       if (ret < 0)
>> +               dev_err(dev, "failed to create attributes. err=%d\n", ret);
>> +
>> +       return ret;
>> +}
>> +
>> +static int cros_ec_sysfs_remove(struct platform_device *pd)
>> +{
>> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
>> +
>> +       sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
>> +
>> +       return 0;
>> +}
>> +
>> +static struct platform_driver cros_ec_sysfs_driver = {
>> +       .driver = {
>> +               .name = DRV_NAME,
>> +       },
>> +       .probe = cros_ec_sysfs_probe,
>> +       .remove = cros_ec_sysfs_remove,
>> +};
>> +
>> +module_platform_driver(cros_ec_sysfs_driver);
>>
>>  MODULE_LICENSE("GPL");
>>  MODULE_DESCRIPTION("ChromeOS EC control driver");
>> +MODULE_ALIAS("platform:" DRV_NAME);
>> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
>> index 3e4401e2ceea..f718ad9c2132 100644
>> --- a/include/linux/mfd/cros_ec.h
>> +++ b/include/linux/mfd/cros_ec.h
>> @@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
>>   */
>>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
>>
>> -/* sysfs stuff */
>> -extern struct attribute_group cros_ec_attr_group;
>> -
>>  #endif /* __LINUX_MFD_CROS_EC_H */
>> --
>> 2.19.1
>>
> 

Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Guenter Roeck]

On Mon, Dec 10, 2018 at 10:22 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Hi Guenter,
>
> On 10/12/18 19:13, Guenter Roeck wrote:
> > On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> > <enric.balletbo@collabora.com> wrote:
> >>
> >> The entire way how cros debugfs attibutes are created is broken.
> >> cros_ec_sysfs should be its own driver and its attributes should be
> >> associated with the sysfs driver not the mfd driver.
> >>
> >> The patch also adds the sysfs documentation.
> >>
> >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> >> ---
> >>
> >> Changes in v3:
> >> - Do not print ec_platform name as is with dev_err is enough.
> >>
> >> Changes in v2:
> >> - Create the attributes directly instead of use the attach/detach callbacks.
> >>
> >>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
> >>  drivers/mfd/Kconfig                           |  1 -
> >>  drivers/mfd/cros_ec_dev.c                     |  7 +---
> >>  drivers/platform/chrome/Kconfig               | 14 ++++++--
> >>  drivers/platform/chrome/Makefile              |  3 +-
> >>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
> >>  include/linux/mfd/cros_ec.h                   |  3 --
> >>  7 files changed, 80 insertions(+), 16 deletions(-)
> >>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
> >>
> >> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
> >> new file mode 100644
> >> index 000000000000..a5399c4ca82d
> >> --- /dev/null
> >> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
> >> @@ -0,0 +1,32 @@
> >> +What:          /sys/class/chromeos/<cros-ec>/flashinfo
> >
> > Why "<cros-ec>" and not "cros_ec" ?
> >
>
> Maybe will be more clear if I use <cros-ec-name>?
>
> Actually <cros-ec-name> can be cros_ec or cros_pd. I put between <> to indicate
> that is not the literal name.
>
Should that be mentioned somewhere ? Readers of this document won't
know what it stands for.

Thanks,
Guenter

> >> +Date:          August 2015
> >> +KernelVersion: 4.2
> >> +Description:
> >> +               Show the EC flash information.
> >> +
> >> +What:          /sys/class/chromeos/<cros-ec>/kb_wake_angle
> >> +Date:          March 2018
> >> +KernelVersion: 4.17
> >> +Description:
> >> +               Control the keyboard wake lid angle. Values are between
> >> +               0 and 360. This file will also show the keyboard wake lid
> >> +               angle by querying the hardware.
> >> +
> >> +What:          /sys/class/chromeos/<cros-ec>/reboot
> >> +Date:          August 2015
> >> +KernelVersion: 4.2
> >> +Description:
> >> +               Tell the EC to reboot in various ways. Options are:
> >> +               "cancel": Cancel a pending reboot.
> >> +               "ro": Jump to RO without rebooting.
> >> +               "rw": Jump to RW without rebooting.
> >> +               "cold": Cold reboot.
> >> +               "disable-jump": Disable jump until next reboot.
> >> +               "hibernate": Hibernate the EC.
> >> +               "at-shutdown": Reboot after an AP shutdown.
> >> +
> >> +What:          /sys/class/chromeos/<cros-ec>/version
> >> +Date:          August 2015
> >> +KernelVersion: 4.2
> >> +Description:
> >> +               Show the information about the EC software and hardware.
> >> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> >> index 8c5dfdce4326..089ffb408918 100644
> >> --- a/drivers/mfd/Kconfig
> >> +++ b/drivers/mfd/Kconfig
> >> @@ -214,7 +214,6 @@ config MFD_CROS_EC
> >>  config MFD_CROS_EC_CHARDEV
> >>          tristate "Chrome OS Embedded Controller userspace device interface"
> >>          depends on MFD_CROS_EC
> >> -        select CROS_EC_CTL
> >>          ---help---
> >>            This driver adds support to talk with the ChromeOS EC from userspace.
> >>
> >> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> >> index 50ba8e0fb4ec..d9b16ce79319 100644
> >> --- a/drivers/mfd/cros_ec_dev.c
> >> +++ b/drivers/mfd/cros_ec_dev.c
> >> @@ -34,15 +34,9 @@
> >>  #define CROS_MAX_DEV 128
> >>  static int ec_major;
> >>
> >> -static const struct attribute_group *cros_ec_groups[] = {
> >> -       &cros_ec_attr_group,
> >> -       NULL,
> >> -};
> >> -
> >>  static struct class cros_class = {
> >>         .owner          = THIS_MODULE,
> >>         .name           = "chromeos",
> >> -       .dev_groups     = cros_ec_groups,
> >>  };
> >>
> >>  /* Basic communication */
> >> @@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
> >>  static const struct mfd_cell cros_ec_platform_cells[] = {
> >>         { .name = "cros-ec-debugfs" },
> >>         { .name = "cros-ec-lightbar" },
> >> +       { .name = "cros-ec-sysfs" },
> >>         { .name = "cros-ec-vbc" },
> >>  };
> >>
> >> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> >> index 4e4232b47764..b709cc5173a2 100644
> >> --- a/drivers/platform/chrome/Kconfig
> >> +++ b/drivers/platform/chrome/Kconfig
> >> @@ -49,9 +49,6 @@ config CHROMEOS_TBMC
> >>           To compile this driver as a module, choose M here: the
> >>           module will be called chromeos_tbmc.
> >>
> >> -config CROS_EC_CTL
> >> -        tristate
> >> -
> >>  config CROS_EC_I2C
> >>         tristate "ChromeOS Embedded Controller (I2C)"
> >>         depends on MFD_CROS_EC && I2C
> >> @@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
> >>           To compile this driver as a module, choose M here: the
> >>           module will be called cros_ec_debugfs.
> >>
> >> +config CROS_EC_SYSFS
> >> +       tristate "ChromeOS EC control and information through sysfs"
> >> +       depends on MFD_CROS_EC_CHARDEV && SYSFS
> >> +       default y
> >
> > In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
> > set to m if MFD_CROS_EC_CHARDEV=m.
> > Not sure what is better here, but for consistency I would prefer
> > "default MFD_CROS_EC_CHARDEV" (or default y
> > in the entire series).
> >
>
> Right, makes sense that if the MFD_CROS_EC_CHARDEV is selected set also those by
> default. Will prepare a new version with that small change.
>
> >> +       help
> >> +         This option exposes some sysfs attributes to control and get
> >> +         information from ChromeOS EC.
> >> +
> >> +         To compile this driver as a module, choose M here: the
> >> +         module will be called cros_ec_sysfs.
> >> +
> >>  endif # CHROMEOS_PLATFORMS
> >> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> >> index 12a5c4d18c17..fdbee501931b 100644
> >> --- a/drivers/platform/chrome/Makefile
> >> +++ b/drivers/platform/chrome/Makefile
> >> @@ -3,8 +3,6 @@
> >>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
> >>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
> >>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> >> -cros_ec_ctl-objs                       := cros_ec_sysfs.o
> >> -obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> >>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> >>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> >>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
> >> @@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)  += cros_kbd_led_backlight.o
> >>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
> >>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
> >>  obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
> >> +obj-$(CONFIG_CROS_EC_SYSFS)            += cros_ec_sysfs.o
> >> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
> >> index f34a50121064..0ff5aa30c070 100644
> >> --- a/drivers/platform/chrome/cros_ec_sysfs.c
> >> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
> >> @@ -34,6 +34,8 @@
> >>  #include <linux/types.h>
> >>  #include <linux/uaccess.h>
> >>
> >> +#define DRV_NAME "cros-ec-sysfs"
> >> +
> >>  /* Accessor functions */
> >>
> >>  static ssize_t reboot_show(struct device *dev,
> >> @@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
> >>         .attrs = __ec_attrs,
> >>         .is_visible = cros_ec_ctrl_visible,
> >>  };
> >> -EXPORT_SYMBOL(cros_ec_attr_group);
> >> +
> >> +static int cros_ec_sysfs_probe(struct platform_device *pd)
> >> +{
> >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> >> +       struct device *dev = &pd->dev;
> >> +       int ret;
> >> +
> >> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> >> +       if (ret < 0)
> >> +               dev_err(dev, "failed to create attributes. err=%d\n", ret);
> >> +
> >> +       return ret;
> >> +}
> >> +
> >> +static int cros_ec_sysfs_remove(struct platform_device *pd)
> >> +{
> >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> >> +
> >> +       sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> >> +
> >> +       return 0;
> >> +}
> >> +
> >> +static struct platform_driver cros_ec_sysfs_driver = {
> >> +       .driver = {
> >> +               .name = DRV_NAME,
> >> +       },
> >> +       .probe = cros_ec_sysfs_probe,
> >> +       .remove = cros_ec_sysfs_remove,
> >> +};
> >> +
> >> +module_platform_driver(cros_ec_sysfs_driver);
> >>
> >>  MODULE_LICENSE("GPL");
> >>  MODULE_DESCRIPTION("ChromeOS EC control driver");
> >> +MODULE_ALIAS("platform:" DRV_NAME);
> >> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> >> index 3e4401e2ceea..f718ad9c2132 100644
> >> --- a/include/linux/mfd/cros_ec.h
> >> +++ b/include/linux/mfd/cros_ec.h
> >> @@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
> >>   */
> >>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
> >>
> >> -/* sysfs stuff */
> >> -extern struct attribute_group cros_ec_attr_group;
> >> -
> >>  #endif /* __LINUX_MFD_CROS_EC_H */
> >> --
> >> 2.19.1
> >>
> >

Re: [PATCH v3 6/8] mfd / platform: cros_ec: instantiate only if th EC has a VBC NVRAM.

[Guenter Roeck]

On Mon, Dec 10, 2018 at 10:15 AM Guenter Roeck <groeck@google.com> wrote:
>
> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
> >
> > The cros-ec-vbc driver is DT-only and there is a DT property that
> > indicates if the EC has the VCB NVRAM, in such case instantiate the
> > driver but don't instantiate on the other cases.
> >
> > To do this move the check code to its parent instead of play with the
> > attribute group visibility. This changes a bit the actual behaviour.
> > Before the patch if an EC doesn't have a VBC NVRAM an empty vbc folder
> > is created in /sys/class/chromeos/<ec device>, after the patch the empty
> > folder is not created, so, the folder is only created if the vbc is set.
> >
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>
> Reviewed-by: Guenter Roeck <groeck@chromium.org>
>
Forgot to mention: It would be nice if the subject would mention what
is only instantiated if there is a VBC NVRAM, and there is a typo (th
instead of the).

Guenter

> > ---
> >
> > Changes in v3:
> > - Fixed build error as reported by kbuild test robot.
> >
> > Changes in v2:
> > - Remove unnecessary IS_ENABLED.
> > - Remove dev_err message telling that VBC is found.
> > - Use dev_warn instead of dev_err as the error is ignored.
> >
> >  drivers/mfd/cros_ec_dev.c             | 19 ++++++++++++++++++-
> >  drivers/platform/chrome/cros_ec_vbc.c | 16 ----------------
> >  2 files changed, 18 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > index d9b16ce79319..1ba98a32715e 100644
> > --- a/drivers/mfd/cros_ec_dev.c
> > +++ b/drivers/mfd/cros_ec_dev.c
> > @@ -21,6 +21,7 @@
> >  #include <linux/mfd/core.h>
> >  #include <linux/module.h>
> >  #include <linux/mod_devicetable.h>
> > +#include <linux/of_platform.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/pm.h>
> >  #include <linux/slab.h>
> > @@ -386,12 +387,16 @@ static const struct mfd_cell cros_ec_platform_cells[] = {
> >         { .name = "cros-ec-debugfs" },
> >         { .name = "cros-ec-lightbar" },
> >         { .name = "cros-ec-sysfs" },
> > -       { .name = "cros-ec-vbc" },
> > +};
> > +
> > +static const struct mfd_cell cros_ec_vbc_cells[] = {
> > +       { .name = "cros-ec-vbc" }
> >  };
> >
> >  static int ec_device_probe(struct platform_device *pdev)
> >  {
> >         int retval = -ENOMEM;
> > +       struct device_node *node;
> >         struct device *dev = &pdev->dev;
> >         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
> >         struct cros_ec_dev *ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
> > @@ -479,6 +484,18 @@ static int ec_device_probe(struct platform_device *pdev)
> >                          "failed to add cros-ec platform devices: %d\n",
> >                          retval);
> >
> > +       /* Check whether this EC instance has a VBC NVRAM */
> > +       node = ec->ec_dev->dev->of_node;
> > +       if (of_property_read_bool(node, "google,has-vbc-nvram")) {
> > +               retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> > +                                        cros_ec_vbc_cells,
> > +                                        ARRAY_SIZE(cros_ec_vbc_cells),
> > +                                        NULL, 0, NULL);
> > +               if (retval)
> > +                       dev_warn(ec->dev, "failed to add VBC devices: %d\n",
> > +                                retval);
> > +       }
> > +
> >         return 0;
> >
> >  failed:
> > diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c
> > index da3bbf05e86f..af9bfe6f385c 100644
> > --- a/drivers/platform/chrome/cros_ec_vbc.c
> > +++ b/drivers/platform/chrome/cros_ec_vbc.c
> > @@ -108,21 +108,6 @@ static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
> >         return data_sz;
> >  }
> >
> > -static umode_t cros_ec_vbc_is_visible(struct kobject *kobj,
> > -                                     struct bin_attribute *a, int n)
> > -{
> > -       struct device *dev = container_of(kobj, struct device, kobj);
> > -       struct cros_ec_dev *ec = to_cros_ec_dev(dev);
> > -       struct device_node *np = ec->ec_dev->dev->of_node;
> > -
> > -       if (IS_ENABLED(CONFIG_OF) && np) {
> > -               if (of_property_read_bool(np, "google,has-vbc-nvram"))
> > -                       return a->attr.mode;
> > -       }
> > -
> > -       return 0;
> > -}
> > -
> >  static BIN_ATTR_RW(vboot_context, 16);
> >
> >  static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
> > @@ -133,7 +118,6 @@ static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
> >  struct attribute_group cros_ec_vbc_attr_group = {
> >         .name = "vbc",
> >         .bin_attrs = cros_ec_vbc_bin_attrs,
> > -       .is_bin_visible = cros_ec_vbc_is_visible,
> >  };
> >
> >  static int cros_ec_vbc_probe(struct platform_device *pd)
> > --
> > 2.19.1
> >

Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Enric Balletbo Serra]

Missatge de Guenter Roeck <groeck@google.com> del dia dl., 10 de des.
2018 a les 19:34:
>
> On Mon, Dec 10, 2018 at 10:22 AM Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
> >
> > Hi Guenter,
> >
> > On 10/12/18 19:13, Guenter Roeck wrote:
> > > On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> > > <enric.balletbo@collabora.com> wrote:
> > >>
> > >> The entire way how cros debugfs attibutes are created is broken.
> > >> cros_ec_sysfs should be its own driver and its attributes should be
> > >> associated with the sysfs driver not the mfd driver.
> > >>
> > >> The patch also adds the sysfs documentation.
> > >>
> > >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > >> ---
> > >>
> > >> Changes in v3:
> > >> - Do not print ec_platform name as is with dev_err is enough.
> > >>
> > >> Changes in v2:
> > >> - Create the attributes directly instead of use the attach/detach callbacks.
> > >>
> > >>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
> > >>  drivers/mfd/Kconfig                           |  1 -
> > >>  drivers/mfd/cros_ec_dev.c                     |  7 +---
> > >>  drivers/platform/chrome/Kconfig               | 14 ++++++--
> > >>  drivers/platform/chrome/Makefile              |  3 +-
> > >>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
> > >>  include/linux/mfd/cros_ec.h                   |  3 --
> > >>  7 files changed, 80 insertions(+), 16 deletions(-)
> > >>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
> > >>
> > >> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
> > >> new file mode 100644
> > >> index 000000000000..a5399c4ca82d
> > >> --- /dev/null
> > >> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
> > >> @@ -0,0 +1,32 @@
> > >> +What:          /sys/class/chromeos/<cros-ec>/flashinfo
> > >
> > > Why "<cros-ec>" and not "cros_ec" ?
> > >
> >
> > Maybe will be more clear if I use <cros-ec-name>?
> >
> > Actually <cros-ec-name> can be cros_ec or cros_pd. I put between <> to indicate
> > that is not the literal name.
> >
> Should that be mentioned somewhere ? Readers of this document won't
> know what it stands for.
>

I assumed that <something> is the standard de facto, although I don't
see that documented anywhere. If you do a grep it is extensively used.
I.e:

stable/sysfs-class-infiniband:199:What:
/sys/class/infiniband/<device-name>/ports/<port-num>/hw_counters/lifespan
testing/sysfs-class-power:3:What:
/sys/class/power_supply/<supply_name>/manufacturer
... and many others

Maybe add a new entry at the beginning?

What:          /sys/class/chromeos/<cros-ec-name>
...
Description:
              The cros-ec device name, i.e. cros_ec or cros_pd.

> Thanks,
> Guenter
>
> > >> +Date:          August 2015
> > >> +KernelVersion: 4.2
> > >> +Description:
> > >> +               Show the EC flash information.
> > >> +
> > >> +What:          /sys/class/chromeos/<cros-ec>/kb_wake_angle
> > >> +Date:          March 2018
> > >> +KernelVersion: 4.17
> > >> +Description:
> > >> +               Control the keyboard wake lid angle. Values are between
> > >> +               0 and 360. This file will also show the keyboard wake lid
> > >> +               angle by querying the hardware.
> > >> +
> > >> +What:          /sys/class/chromeos/<cros-ec>/reboot
> > >> +Date:          August 2015
> > >> +KernelVersion: 4.2
> > >> +Description:
> > >> +               Tell the EC to reboot in various ways. Options are:
> > >> +               "cancel": Cancel a pending reboot.
> > >> +               "ro": Jump to RO without rebooting.
> > >> +               "rw": Jump to RW without rebooting.
> > >> +               "cold": Cold reboot.
> > >> +               "disable-jump": Disable jump until next reboot.
> > >> +               "hibernate": Hibernate the EC.
> > >> +               "at-shutdown": Reboot after an AP shutdown.
> > >> +
> > >> +What:          /sys/class/chromeos/<cros-ec>/version
> > >> +Date:          August 2015
> > >> +KernelVersion: 4.2
> > >> +Description:
> > >> +               Show the information about the EC software and hardware.
> > >> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > >> index 8c5dfdce4326..089ffb408918 100644
> > >> --- a/drivers/mfd/Kconfig
> > >> +++ b/drivers/mfd/Kconfig
> > >> @@ -214,7 +214,6 @@ config MFD_CROS_EC
> > >>  config MFD_CROS_EC_CHARDEV
> > >>          tristate "Chrome OS Embedded Controller userspace device interface"
> > >>          depends on MFD_CROS_EC
> > >> -        select CROS_EC_CTL
> > >>          ---help---
> > >>            This driver adds support to talk with the ChromeOS EC from userspace.
> > >>
> > >> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > >> index 50ba8e0fb4ec..d9b16ce79319 100644
> > >> --- a/drivers/mfd/cros_ec_dev.c
> > >> +++ b/drivers/mfd/cros_ec_dev.c
> > >> @@ -34,15 +34,9 @@
> > >>  #define CROS_MAX_DEV 128
> > >>  static int ec_major;
> > >>
> > >> -static const struct attribute_group *cros_ec_groups[] = {
> > >> -       &cros_ec_attr_group,
> > >> -       NULL,
> > >> -};
> > >> -
> > >>  static struct class cros_class = {
> > >>         .owner          = THIS_MODULE,
> > >>         .name           = "chromeos",
> > >> -       .dev_groups     = cros_ec_groups,
> > >>  };
> > >>
> > >>  /* Basic communication */
> > >> @@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
> > >>  static const struct mfd_cell cros_ec_platform_cells[] = {
> > >>         { .name = "cros-ec-debugfs" },
> > >>         { .name = "cros-ec-lightbar" },
> > >> +       { .name = "cros-ec-sysfs" },
> > >>         { .name = "cros-ec-vbc" },
> > >>  };
> > >>
> > >> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> > >> index 4e4232b47764..b709cc5173a2 100644
> > >> --- a/drivers/platform/chrome/Kconfig
> > >> +++ b/drivers/platform/chrome/Kconfig
> > >> @@ -49,9 +49,6 @@ config CHROMEOS_TBMC
> > >>           To compile this driver as a module, choose M here: the
> > >>           module will be called chromeos_tbmc.
> > >>
> > >> -config CROS_EC_CTL
> > >> -        tristate
> > >> -
> > >>  config CROS_EC_I2C
> > >>         tristate "ChromeOS Embedded Controller (I2C)"
> > >>         depends on MFD_CROS_EC && I2C
> > >> @@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
> > >>           To compile this driver as a module, choose M here: the
> > >>           module will be called cros_ec_debugfs.
> > >>
> > >> +config CROS_EC_SYSFS
> > >> +       tristate "ChromeOS EC control and information through sysfs"
> > >> +       depends on MFD_CROS_EC_CHARDEV && SYSFS
> > >> +       default y
> > >
> > > In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
> > > set to m if MFD_CROS_EC_CHARDEV=m.
> > > Not sure what is better here, but for consistency I would prefer
> > > "default MFD_CROS_EC_CHARDEV" (or default y
> > > in the entire series).
> > >
> >
> > Right, makes sense that if the MFD_CROS_EC_CHARDEV is selected set also those by
> > default. Will prepare a new version with that small change.
> >
> > >> +       help
> > >> +         This option exposes some sysfs attributes to control and get
> > >> +         information from ChromeOS EC.
> > >> +
> > >> +         To compile this driver as a module, choose M here: the
> > >> +         module will be called cros_ec_sysfs.
> > >> +
> > >>  endif # CHROMEOS_PLATFORMS
> > >> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > >> index 12a5c4d18c17..fdbee501931b 100644
> > >> --- a/drivers/platform/chrome/Makefile
> > >> +++ b/drivers/platform/chrome/Makefile
> > >> @@ -3,8 +3,6 @@
> > >>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
> > >>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
> > >>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> > >> -cros_ec_ctl-objs                       := cros_ec_sysfs.o
> > >> -obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> > >>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> > >>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> > >>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
> > >> @@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)  += cros_kbd_led_backlight.o
> > >>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
> > >>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
> > >>  obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
> > >> +obj-$(CONFIG_CROS_EC_SYSFS)            += cros_ec_sysfs.o
> > >> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
> > >> index f34a50121064..0ff5aa30c070 100644
> > >> --- a/drivers/platform/chrome/cros_ec_sysfs.c
> > >> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
> > >> @@ -34,6 +34,8 @@
> > >>  #include <linux/types.h>
> > >>  #include <linux/uaccess.h>
> > >>
> > >> +#define DRV_NAME "cros-ec-sysfs"
> > >> +
> > >>  /* Accessor functions */
> > >>
> > >>  static ssize_t reboot_show(struct device *dev,
> > >> @@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
> > >>         .attrs = __ec_attrs,
> > >>         .is_visible = cros_ec_ctrl_visible,
> > >>  };
> > >> -EXPORT_SYMBOL(cros_ec_attr_group);
> > >> +
> > >> +static int cros_ec_sysfs_probe(struct platform_device *pd)
> > >> +{
> > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > >> +       struct device *dev = &pd->dev;
> > >> +       int ret;
> > >> +
> > >> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > >> +       if (ret < 0)
> > >> +               dev_err(dev, "failed to create attributes. err=%d\n", ret);
> > >> +
> > >> +       return ret;
> > >> +}
> > >> +
> > >> +static int cros_ec_sysfs_remove(struct platform_device *pd)
> > >> +{
> > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > >> +
> > >> +       sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > >> +
> > >> +       return 0;
> > >> +}
> > >> +
> > >> +static struct platform_driver cros_ec_sysfs_driver = {
> > >> +       .driver = {
> > >> +               .name = DRV_NAME,
> > >> +       },
> > >> +       .probe = cros_ec_sysfs_probe,
> > >> +       .remove = cros_ec_sysfs_remove,
> > >> +};
> > >> +
> > >> +module_platform_driver(cros_ec_sysfs_driver);
> > >>
> > >>  MODULE_LICENSE("GPL");
> > >>  MODULE_DESCRIPTION("ChromeOS EC control driver");
> > >> +MODULE_ALIAS("platform:" DRV_NAME);
> > >> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> > >> index 3e4401e2ceea..f718ad9c2132 100644
> > >> --- a/include/linux/mfd/cros_ec.h
> > >> +++ b/include/linux/mfd/cros_ec.h
> > >> @@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
> > >>   */
> > >>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
> > >>
> > >> -/* sysfs stuff */
> > >> -extern struct attribute_group cros_ec_attr_group;
> > >> -
> > >>  #endif /* __LINUX_MFD_CROS_EC_H */
> > >> --
> > >> 2.19.1
> > >>
> > >

Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Guenter Roeck]

On Mon, Dec 10, 2018 at 1:27 PM Enric Balletbo Serra
<eballetbo@gmail.com> wrote:
>
> Missatge de Guenter Roeck <groeck@google.com> del dia dl., 10 de des.
> 2018 a les 19:34:
> >
> > On Mon, Dec 10, 2018 at 10:22 AM Enric Balletbo i Serra
> > <enric.balletbo@collabora.com> wrote:
> > >
> > > Hi Guenter,
> > >
> > > On 10/12/18 19:13, Guenter Roeck wrote:
> > > > On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> > > > <enric.balletbo@collabora.com> wrote:
> > > >>
> > > >> The entire way how cros debugfs attibutes are created is broken.
> > > >> cros_ec_sysfs should be its own driver and its attributes should be
> > > >> associated with the sysfs driver not the mfd driver.
> > > >>
> > > >> The patch also adds the sysfs documentation.
> > > >>
> > > >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > > >> ---
> > > >>
> > > >> Changes in v3:
> > > >> - Do not print ec_platform name as is with dev_err is enough.
> > > >>
> > > >> Changes in v2:
> > > >> - Create the attributes directly instead of use the attach/detach callbacks.
> > > >>
> > > >>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
> > > >>  drivers/mfd/Kconfig                           |  1 -
> > > >>  drivers/mfd/cros_ec_dev.c                     |  7 +---
> > > >>  drivers/platform/chrome/Kconfig               | 14 ++++++--
> > > >>  drivers/platform/chrome/Makefile              |  3 +-
> > > >>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
> > > >>  include/linux/mfd/cros_ec.h                   |  3 --
> > > >>  7 files changed, 80 insertions(+), 16 deletions(-)
> > > >>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
> > > >>
> > > >> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
> > > >> new file mode 100644
> > > >> index 000000000000..a5399c4ca82d
> > > >> --- /dev/null
> > > >> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
> > > >> @@ -0,0 +1,32 @@
> > > >> +What:          /sys/class/chromeos/<cros-ec>/flashinfo
> > > >
> > > > Why "<cros-ec>" and not "cros_ec" ?
> > > >
> > >
> > > Maybe will be more clear if I use <cros-ec-name>?
> > >
> > > Actually <cros-ec-name> can be cros_ec or cros_pd. I put between <> to indicate
> > > that is not the literal name.
> > >
> > Should that be mentioned somewhere ? Readers of this document won't
> > know what it stands for.
> >
>
> I assumed that <something> is the standard de facto, although I don't
> see that documented anywhere. If you do a grep it is extensively used.
> I.e:
>
> stable/sysfs-class-infiniband:199:What:
> /sys/class/infiniband/<device-name>/ports/<port-num>/hw_counters/lifespan
> testing/sysfs-class-power:3:What:
> /sys/class/power_supply/<supply_name>/manufacturer
> ... and many others
>
That makes sense if the name is determined by the driver, and there
are many drivers and no fixed name(s). Here we have exactly two
possible names.

> Maybe add a new entry at the beginning?
>
> What:          /sys/class/chromeos/<cros-ec-name>
> ...
> Description:
>               The cros-ec device name, i.e. cros_ec or cros_pd.
>
How about {cros_ec,cros_pd} instead of <cros-ec> ?
I see that used a few times where the names are well defined.

Thanks,
Guenter

> > Thanks,
> > Guenter
> >
> > > >> +Date:          August 2015
> > > >> +KernelVersion: 4.2
> > > >> +Description:
> > > >> +               Show the EC flash information.
> > > >> +
> > > >> +What:          /sys/class/chromeos/<cros-ec>/kb_wake_angle
> > > >> +Date:          March 2018
> > > >> +KernelVersion: 4.17
> > > >> +Description:
> > > >> +               Control the keyboard wake lid angle. Values are between
> > > >> +               0 and 360. This file will also show the keyboard wake lid
> > > >> +               angle by querying the hardware.
> > > >> +
> > > >> +What:          /sys/class/chromeos/<cros-ec>/reboot
> > > >> +Date:          August 2015
> > > >> +KernelVersion: 4.2
> > > >> +Description:
> > > >> +               Tell the EC to reboot in various ways. Options are:
> > > >> +               "cancel": Cancel a pending reboot.
> > > >> +               "ro": Jump to RO without rebooting.
> > > >> +               "rw": Jump to RW without rebooting.
> > > >> +               "cold": Cold reboot.
> > > >> +               "disable-jump": Disable jump until next reboot.
> > > >> +               "hibernate": Hibernate the EC.
> > > >> +               "at-shutdown": Reboot after an AP shutdown.
> > > >> +
> > > >> +What:          /sys/class/chromeos/<cros-ec>/version
> > > >> +Date:          August 2015
> > > >> +KernelVersion: 4.2
> > > >> +Description:
> > > >> +               Show the information about the EC software and hardware.
> > > >> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > >> index 8c5dfdce4326..089ffb408918 100644
> > > >> --- a/drivers/mfd/Kconfig
> > > >> +++ b/drivers/mfd/Kconfig
> > > >> @@ -214,7 +214,6 @@ config MFD_CROS_EC
> > > >>  config MFD_CROS_EC_CHARDEV
> > > >>          tristate "Chrome OS Embedded Controller userspace device interface"
> > > >>          depends on MFD_CROS_EC
> > > >> -        select CROS_EC_CTL
> > > >>          ---help---
> > > >>            This driver adds support to talk with the ChromeOS EC from userspace.
> > > >>
> > > >> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > > >> index 50ba8e0fb4ec..d9b16ce79319 100644
> > > >> --- a/drivers/mfd/cros_ec_dev.c
> > > >> +++ b/drivers/mfd/cros_ec_dev.c
> > > >> @@ -34,15 +34,9 @@
> > > >>  #define CROS_MAX_DEV 128
> > > >>  static int ec_major;
> > > >>
> > > >> -static const struct attribute_group *cros_ec_groups[] = {
> > > >> -       &cros_ec_attr_group,
> > > >> -       NULL,
> > > >> -};
> > > >> -
> > > >>  static struct class cros_class = {
> > > >>         .owner          = THIS_MODULE,
> > > >>         .name           = "chromeos",
> > > >> -       .dev_groups     = cros_ec_groups,
> > > >>  };
> > > >>
> > > >>  /* Basic communication */
> > > >> @@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
> > > >>  static const struct mfd_cell cros_ec_platform_cells[] = {
> > > >>         { .name = "cros-ec-debugfs" },
> > > >>         { .name = "cros-ec-lightbar" },
> > > >> +       { .name = "cros-ec-sysfs" },
> > > >>         { .name = "cros-ec-vbc" },
> > > >>  };
> > > >>
> > > >> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> > > >> index 4e4232b47764..b709cc5173a2 100644
> > > >> --- a/drivers/platform/chrome/Kconfig
> > > >> +++ b/drivers/platform/chrome/Kconfig
> > > >> @@ -49,9 +49,6 @@ config CHROMEOS_TBMC
> > > >>           To compile this driver as a module, choose M here: the
> > > >>           module will be called chromeos_tbmc.
> > > >>
> > > >> -config CROS_EC_CTL
> > > >> -        tristate
> > > >> -
> > > >>  config CROS_EC_I2C
> > > >>         tristate "ChromeOS Embedded Controller (I2C)"
> > > >>         depends on MFD_CROS_EC && I2C
> > > >> @@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
> > > >>           To compile this driver as a module, choose M here: the
> > > >>           module will be called cros_ec_debugfs.
> > > >>
> > > >> +config CROS_EC_SYSFS
> > > >> +       tristate "ChromeOS EC control and information through sysfs"
> > > >> +       depends on MFD_CROS_EC_CHARDEV && SYSFS
> > > >> +       default y
> > > >
> > > > In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
> > > > set to m if MFD_CROS_EC_CHARDEV=m.
> > > > Not sure what is better here, but for consistency I would prefer
> > > > "default MFD_CROS_EC_CHARDEV" (or default y
> > > > in the entire series).
> > > >
> > >
> > > Right, makes sense that if the MFD_CROS_EC_CHARDEV is selected set also those by
> > > default. Will prepare a new version with that small change.
> > >
> > > >> +       help
> > > >> +         This option exposes some sysfs attributes to control and get
> > > >> +         information from ChromeOS EC.
> > > >> +
> > > >> +         To compile this driver as a module, choose M here: the
> > > >> +         module will be called cros_ec_sysfs.
> > > >> +
> > > >>  endif # CHROMEOS_PLATFORMS
> > > >> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > > >> index 12a5c4d18c17..fdbee501931b 100644
> > > >> --- a/drivers/platform/chrome/Makefile
> > > >> +++ b/drivers/platform/chrome/Makefile
> > > >> @@ -3,8 +3,6 @@
> > > >>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
> > > >>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
> > > >>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> > > >> -cros_ec_ctl-objs                       := cros_ec_sysfs.o
> > > >> -obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> > > >>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> > > >>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> > > >>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
> > > >> @@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)  += cros_kbd_led_backlight.o
> > > >>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
> > > >>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
> > > >>  obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
> > > >> +obj-$(CONFIG_CROS_EC_SYSFS)            += cros_ec_sysfs.o
> > > >> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
> > > >> index f34a50121064..0ff5aa30c070 100644
> > > >> --- a/drivers/platform/chrome/cros_ec_sysfs.c
> > > >> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
> > > >> @@ -34,6 +34,8 @@
> > > >>  #include <linux/types.h>
> > > >>  #include <linux/uaccess.h>
> > > >>
> > > >> +#define DRV_NAME "cros-ec-sysfs"
> > > >> +
> > > >>  /* Accessor functions */
> > > >>
> > > >>  static ssize_t reboot_show(struct device *dev,
> > > >> @@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
> > > >>         .attrs = __ec_attrs,
> > > >>         .is_visible = cros_ec_ctrl_visible,
> > > >>  };
> > > >> -EXPORT_SYMBOL(cros_ec_attr_group);
> > > >> +
> > > >> +static int cros_ec_sysfs_probe(struct platform_device *pd)
> > > >> +{
> > > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > > >> +       struct device *dev = &pd->dev;
> > > >> +       int ret;
> > > >> +
> > > >> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > > >> +       if (ret < 0)
> > > >> +               dev_err(dev, "failed to create attributes. err=%d\n", ret);
> > > >> +
> > > >> +       return ret;
> > > >> +}
> > > >> +
> > > >> +static int cros_ec_sysfs_remove(struct platform_device *pd)
> > > >> +{
> > > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > > >> +
> > > >> +       sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > > >> +
> > > >> +       return 0;
> > > >> +}
> > > >> +
> > > >> +static struct platform_driver cros_ec_sysfs_driver = {
> > > >> +       .driver = {
> > > >> +               .name = DRV_NAME,
> > > >> +       },
> > > >> +       .probe = cros_ec_sysfs_probe,
> > > >> +       .remove = cros_ec_sysfs_remove,
> > > >> +};
> > > >> +
> > > >> +module_platform_driver(cros_ec_sysfs_driver);
> > > >>
> > > >>  MODULE_LICENSE("GPL");
> > > >>  MODULE_DESCRIPTION("ChromeOS EC control driver");
> > > >> +MODULE_ALIAS("platform:" DRV_NAME);
> > > >> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> > > >> index 3e4401e2ceea..f718ad9c2132 100644
> > > >> --- a/include/linux/mfd/cros_ec.h
> > > >> +++ b/include/linux/mfd/cros_ec.h
> > > >> @@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
> > > >>   */
> > > >>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
> > > >>
> > > >> -/* sysfs stuff */
> > > >> -extern struct attribute_group cros_ec_attr_group;
> > > >> -
> > > >>  #endif /* __LINUX_MFD_CROS_EC_H */
> > > >> --
> > > >> 2.19.1
> > > >>
> > > >

Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Enric Balletbo Serra]

Missatge de Guenter Roeck <groeck@google.com> del dia dl., 10 de des.
2018 a les 22:50:
>
> On Mon, Dec 10, 2018 at 1:27 PM Enric Balletbo Serra
> <eballetbo@gmail.com> wrote:
> >
> > Missatge de Guenter Roeck <groeck@google.com> del dia dl., 10 de des.
> > 2018 a les 19:34:
> > >
> > > On Mon, Dec 10, 2018 at 10:22 AM Enric Balletbo i Serra
> > > <enric.balletbo@collabora.com> wrote:
> > > >
> > > > Hi Guenter,
> > > >
> > > > On 10/12/18 19:13, Guenter Roeck wrote:
> > > > > On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> > > > > <enric.balletbo@collabora.com> wrote:
> > > > >>
> > > > >> The entire way how cros debugfs attibutes are created is broken.
> > > > >> cros_ec_sysfs should be its own driver and its attributes should be
> > > > >> associated with the sysfs driver not the mfd driver.
> > > > >>
> > > > >> The patch also adds the sysfs documentation.
> > > > >>
> > > > >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > > > >> ---
> > > > >>
> > > > >> Changes in v3:
> > > > >> - Do not print ec_platform name as is with dev_err is enough.
> > > > >>
> > > > >> Changes in v2:
> > > > >> - Create the attributes directly instead of use the attach/detach callbacks.
> > > > >>
> > > > >>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
> > > > >>  drivers/mfd/Kconfig                           |  1 -
> > > > >>  drivers/mfd/cros_ec_dev.c                     |  7 +---
> > > > >>  drivers/platform/chrome/Kconfig               | 14 ++++++--
> > > > >>  drivers/platform/chrome/Makefile              |  3 +-
> > > > >>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
> > > > >>  include/linux/mfd/cros_ec.h                   |  3 --
> > > > >>  7 files changed, 80 insertions(+), 16 deletions(-)
> > > > >>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
> > > > >>
> > > > >> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
> > > > >> new file mode 100644
> > > > >> index 000000000000..a5399c4ca82d
> > > > >> --- /dev/null
> > > > >> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
> > > > >> @@ -0,0 +1,32 @@
> > > > >> +What:          /sys/class/chromeos/<cros-ec>/flashinfo
> > > > >
> > > > > Why "<cros-ec>" and not "cros_ec" ?
> > > > >
> > > >
> > > > Maybe will be more clear if I use <cros-ec-name>?
> > > >
> > > > Actually <cros-ec-name> can be cros_ec or cros_pd. I put between <> to indicate
> > > > that is not the literal name.
> > > >
> > > Should that be mentioned somewhere ? Readers of this document won't
> > > know what it stands for.
> > >
> >
> > I assumed that <something> is the standard de facto, although I don't
> > see that documented anywhere. If you do a grep it is extensively used.
> > I.e:
> >
> > stable/sysfs-class-infiniband:199:What:
> > /sys/class/infiniband/<device-name>/ports/<port-num>/hw_counters/lifespan
> > testing/sysfs-class-power:3:What:
> > /sys/class/power_supply/<supply_name>/manufacturer
> > ... and many others
> >
> That makes sense if the name is determined by the driver, and there
> are many drivers and no fixed name(s). Here we have exactly two
> possible names.
>

Although are not upstream yet, there aren't more possible names? If I
remember correctly there is also cros_fp (for a fingerprint) and
cros_tp (for a touchpad)? I am not sure which devices use those.

> > Maybe add a new entry at the beginning?
> >
> > What:          /sys/class/chromeos/<cros-ec-name>
> > ...
> > Description:
> >               The cros-ec device name, i.e. cros_ec or cros_pd.
> >
> How about {cros_ec,cros_pd} instead of <cros-ec> ?
> I see that used a few times where the names are well defined.
>

Sounds good to me if the list is fixed, if needs to increase I don't
think it will be really friendly. Or we can do this way and change if
the list grows.

Cheers,
 Enric

> Thanks,
> Guenter
>
> > > Thanks,
> > > Guenter
> > >
> > > > >> +Date:          August 2015
> > > > >> +KernelVersion: 4.2
> > > > >> +Description:
> > > > >> +               Show the EC flash information.
> > > > >> +
> > > > >> +What:          /sys/class/chromeos/<cros-ec>/kb_wake_angle
> > > > >> +Date:          March 2018
> > > > >> +KernelVersion: 4.17
> > > > >> +Description:
> > > > >> +               Control the keyboard wake lid angle. Values are between
> > > > >> +               0 and 360. This file will also show the keyboard wake lid
> > > > >> +               angle by querying the hardware.
> > > > >> +
> > > > >> +What:          /sys/class/chromeos/<cros-ec>/reboot
> > > > >> +Date:          August 2015
> > > > >> +KernelVersion: 4.2
> > > > >> +Description:
> > > > >> +               Tell the EC to reboot in various ways. Options are:
> > > > >> +               "cancel": Cancel a pending reboot.
> > > > >> +               "ro": Jump to RO without rebooting.
> > > > >> +               "rw": Jump to RW without rebooting.
> > > > >> +               "cold": Cold reboot.
> > > > >> +               "disable-jump": Disable jump until next reboot.
> > > > >> +               "hibernate": Hibernate the EC.
> > > > >> +               "at-shutdown": Reboot after an AP shutdown.
> > > > >> +
> > > > >> +What:          /sys/class/chromeos/<cros-ec>/version
> > > > >> +Date:          August 2015
> > > > >> +KernelVersion: 4.2
> > > > >> +Description:
> > > > >> +               Show the information about the EC software and hardware.
> > > > >> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > > >> index 8c5dfdce4326..089ffb408918 100644
> > > > >> --- a/drivers/mfd/Kconfig
> > > > >> +++ b/drivers/mfd/Kconfig
> > > > >> @@ -214,7 +214,6 @@ config MFD_CROS_EC
> > > > >>  config MFD_CROS_EC_CHARDEV
> > > > >>          tristate "Chrome OS Embedded Controller userspace device interface"
> > > > >>          depends on MFD_CROS_EC
> > > > >> -        select CROS_EC_CTL
> > > > >>          ---help---
> > > > >>            This driver adds support to talk with the ChromeOS EC from userspace.
> > > > >>
> > > > >> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > > > >> index 50ba8e0fb4ec..d9b16ce79319 100644
> > > > >> --- a/drivers/mfd/cros_ec_dev.c
> > > > >> +++ b/drivers/mfd/cros_ec_dev.c
> > > > >> @@ -34,15 +34,9 @@
> > > > >>  #define CROS_MAX_DEV 128
> > > > >>  static int ec_major;
> > > > >>
> > > > >> -static const struct attribute_group *cros_ec_groups[] = {
> > > > >> -       &cros_ec_attr_group,
> > > > >> -       NULL,
> > > > >> -};
> > > > >> -
> > > > >>  static struct class cros_class = {
> > > > >>         .owner          = THIS_MODULE,
> > > > >>         .name           = "chromeos",
> > > > >> -       .dev_groups     = cros_ec_groups,
> > > > >>  };
> > > > >>
> > > > >>  /* Basic communication */
> > > > >> @@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
> > > > >>  static const struct mfd_cell cros_ec_platform_cells[] = {
> > > > >>         { .name = "cros-ec-debugfs" },
> > > > >>         { .name = "cros-ec-lightbar" },
> > > > >> +       { .name = "cros-ec-sysfs" },
> > > > >>         { .name = "cros-ec-vbc" },
> > > > >>  };
> > > > >>
> > > > >> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> > > > >> index 4e4232b47764..b709cc5173a2 100644
> > > > >> --- a/drivers/platform/chrome/Kconfig
> > > > >> +++ b/drivers/platform/chrome/Kconfig
> > > > >> @@ -49,9 +49,6 @@ config CHROMEOS_TBMC
> > > > >>           To compile this driver as a module, choose M here: the
> > > > >>           module will be called chromeos_tbmc.
> > > > >>
> > > > >> -config CROS_EC_CTL
> > > > >> -        tristate
> > > > >> -
> > > > >>  config CROS_EC_I2C
> > > > >>         tristate "ChromeOS Embedded Controller (I2C)"
> > > > >>         depends on MFD_CROS_EC && I2C
> > > > >> @@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
> > > > >>           To compile this driver as a module, choose M here: the
> > > > >>           module will be called cros_ec_debugfs.
> > > > >>
> > > > >> +config CROS_EC_SYSFS
> > > > >> +       tristate "ChromeOS EC control and information through sysfs"
> > > > >> +       depends on MFD_CROS_EC_CHARDEV && SYSFS
> > > > >> +       default y
> > > > >
> > > > > In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
> > > > > set to m if MFD_CROS_EC_CHARDEV=m.
> > > > > Not sure what is better here, but for consistency I would prefer
> > > > > "default MFD_CROS_EC_CHARDEV" (or default y
> > > > > in the entire series).
> > > > >
> > > >
> > > > Right, makes sense that if the MFD_CROS_EC_CHARDEV is selected set also those by
> > > > default. Will prepare a new version with that small change.
> > > >
> > > > >> +       help
> > > > >> +         This option exposes some sysfs attributes to control and get
> > > > >> +         information from ChromeOS EC.
> > > > >> +
> > > > >> +         To compile this driver as a module, choose M here: the
> > > > >> +         module will be called cros_ec_sysfs.
> > > > >> +
> > > > >>  endif # CHROMEOS_PLATFORMS
> > > > >> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > > > >> index 12a5c4d18c17..fdbee501931b 100644
> > > > >> --- a/drivers/platform/chrome/Makefile
> > > > >> +++ b/drivers/platform/chrome/Makefile
> > > > >> @@ -3,8 +3,6 @@
> > > > >>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
> > > > >>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
> > > > >>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> > > > >> -cros_ec_ctl-objs                       := cros_ec_sysfs.o
> > > > >> -obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> > > > >>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> > > > >>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> > > > >>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
> > > > >> @@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)  += cros_kbd_led_backlight.o
> > > > >>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
> > > > >>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
> > > > >>  obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
> > > > >> +obj-$(CONFIG_CROS_EC_SYSFS)            += cros_ec_sysfs.o
> > > > >> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
> > > > >> index f34a50121064..0ff5aa30c070 100644
> > > > >> --- a/drivers/platform/chrome/cros_ec_sysfs.c
> > > > >> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
> > > > >> @@ -34,6 +34,8 @@
> > > > >>  #include <linux/types.h>
> > > > >>  #include <linux/uaccess.h>
> > > > >>
> > > > >> +#define DRV_NAME "cros-ec-sysfs"
> > > > >> +
> > > > >>  /* Accessor functions */
> > > > >>
> > > > >>  static ssize_t reboot_show(struct device *dev,
> > > > >> @@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
> > > > >>         .attrs = __ec_attrs,
> > > > >>         .is_visible = cros_ec_ctrl_visible,
> > > > >>  };
> > > > >> -EXPORT_SYMBOL(cros_ec_attr_group);
> > > > >> +
> > > > >> +static int cros_ec_sysfs_probe(struct platform_device *pd)
> > > > >> +{
> > > > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > > > >> +       struct device *dev = &pd->dev;
> > > > >> +       int ret;
> > > > >> +
> > > > >> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > > > >> +       if (ret < 0)
> > > > >> +               dev_err(dev, "failed to create attributes. err=%d\n", ret);
> > > > >> +
> > > > >> +       return ret;
> > > > >> +}
> > > > >> +
> > > > >> +static int cros_ec_sysfs_remove(struct platform_device *pd)
> > > > >> +{
> > > > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > > > >> +
> > > > >> +       sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > > > >> +
> > > > >> +       return 0;
> > > > >> +}
> > > > >> +
> > > > >> +static struct platform_driver cros_ec_sysfs_driver = {
> > > > >> +       .driver = {
> > > > >> +               .name = DRV_NAME,
> > > > >> +       },
> > > > >> +       .probe = cros_ec_sysfs_probe,
> > > > >> +       .remove = cros_ec_sysfs_remove,
> > > > >> +};
> > > > >> +
> > > > >> +module_platform_driver(cros_ec_sysfs_driver);
> > > > >>
> > > > >>  MODULE_LICENSE("GPL");
> > > > >>  MODULE_DESCRIPTION("ChromeOS EC control driver");
> > > > >> +MODULE_ALIAS("platform:" DRV_NAME);
> > > > >> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> > > > >> index 3e4401e2ceea..f718ad9c2132 100644
> > > > >> --- a/include/linux/mfd/cros_ec.h
> > > > >> +++ b/include/linux/mfd/cros_ec.h
> > > > >> @@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
> > > > >>   */
> > > > >>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
> > > > >>
> > > > >> -/* sysfs stuff */
> > > > >> -extern struct attribute_group cros_ec_attr_group;
> > > > >> -
> > > > >>  #endif /* __LINUX_MFD_CROS_EC_H */
> > > > >> --
> > > > >> 2.19.1
> > > > >>
> > > > >

Re: [PATCH v3 5/8] mfd / platform: cros_ec: move device sysfs attributes to its own driver.

[Guenter Roeck]

On Mon, Dec 10, 2018 at 2:11 PM Enric Balletbo Serra
<eballetbo@gmail.com> wrote:
>
> Missatge de Guenter Roeck <groeck@google.com> del dia dl., 10 de des.
> 2018 a les 22:50:
> >
> > On Mon, Dec 10, 2018 at 1:27 PM Enric Balletbo Serra
> > <eballetbo@gmail.com> wrote:
> > >
> > > Missatge de Guenter Roeck <groeck@google.com> del dia dl., 10 de des.
> > > 2018 a les 19:34:
> > > >
> > > > On Mon, Dec 10, 2018 at 10:22 AM Enric Balletbo i Serra
> > > > <enric.balletbo@collabora.com> wrote:
> > > > >
> > > > > Hi Guenter,
> > > > >
> > > > > On 10/12/18 19:13, Guenter Roeck wrote:
> > > > > > On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> > > > > > <enric.balletbo@collabora.com> wrote:
> > > > > >>
> > > > > >> The entire way how cros debugfs attibutes are created is broken.
> > > > > >> cros_ec_sysfs should be its own driver and its attributes should be
> > > > > >> associated with the sysfs driver not the mfd driver.
> > > > > >>
> > > > > >> The patch also adds the sysfs documentation.
> > > > > >>
> > > > > >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > > > > >> ---
> > > > > >>
> > > > > >> Changes in v3:
> > > > > >> - Do not print ec_platform name as is with dev_err is enough.
> > > > > >>
> > > > > >> Changes in v2:
> > > > > >> - Create the attributes directly instead of use the attach/detach callbacks.
> > > > > >>
> > > > > >>  .../ABI/testing/sysfs-class-chromeos          | 32 +++++++++++++++++
> > > > > >>  drivers/mfd/Kconfig                           |  1 -
> > > > > >>  drivers/mfd/cros_ec_dev.c                     |  7 +---
> > > > > >>  drivers/platform/chrome/Kconfig               | 14 ++++++--
> > > > > >>  drivers/platform/chrome/Makefile              |  3 +-
> > > > > >>  drivers/platform/chrome/cros_ec_sysfs.c       | 36 ++++++++++++++++++-
> > > > > >>  include/linux/mfd/cros_ec.h                   |  3 --
> > > > > >>  7 files changed, 80 insertions(+), 16 deletions(-)
> > > > > >>  create mode 100644 Documentation/ABI/testing/sysfs-class-chromeos
> > > > > >>
> > > > > >> diff --git a/Documentation/ABI/testing/sysfs-class-chromeos b/Documentation/ABI/testing/sysfs-class-chromeos
> > > > > >> new file mode 100644
> > > > > >> index 000000000000..a5399c4ca82d
> > > > > >> --- /dev/null
> > > > > >> +++ b/Documentation/ABI/testing/sysfs-class-chromeos
> > > > > >> @@ -0,0 +1,32 @@
> > > > > >> +What:          /sys/class/chromeos/<cros-ec>/flashinfo
> > > > > >
> > > > > > Why "<cros-ec>" and not "cros_ec" ?
> > > > > >
> > > > >
> > > > > Maybe will be more clear if I use <cros-ec-name>?
> > > > >
> > > > > Actually <cros-ec-name> can be cros_ec or cros_pd. I put between <> to indicate
> > > > > that is not the literal name.
> > > > >
> > > > Should that be mentioned somewhere ? Readers of this document won't
> > > > know what it stands for.
> > > >
> > >
> > > I assumed that <something> is the standard de facto, although I don't
> > > see that documented anywhere. If you do a grep it is extensively used.
> > > I.e:
> > >
> > > stable/sysfs-class-infiniband:199:What:
> > > /sys/class/infiniband/<device-name>/ports/<port-num>/hw_counters/lifespan
> > > testing/sysfs-class-power:3:What:
> > > /sys/class/power_supply/<supply_name>/manufacturer
> > > ... and many others
> > >
> > That makes sense if the name is determined by the driver, and there
> > are many drivers and no fixed name(s). Here we have exactly two
> > possible names.
> >
>
> Although are not upstream yet, there aren't more possible names? If I
> remember correctly there is also cros_fp (for a fingerprint) and
> cros_tp (for a touchpad)? I am not sure which devices use those.
>
Good point.

> > > Maybe add a new entry at the beginning?
> > >
> > > What:          /sys/class/chromeos/<cros-ec-name>
> > > ...
> > > Description:
> > >               The cros-ec device name, i.e. cros_ec or cros_pd.
> > >
> > How about {cros_ec,cros_pd} instead of <cros-ec> ?
> > I see that used a few times where the names are well defined.
> >
>
> Sounds good to me if the list is fixed, if needs to increase I don't
> think it will be really friendly. Or we can do this way and change if
> the list grows.
>
Also good point. Ok, let's just use <cros-ec-name> (or maybe
<ec-device-name> ?).

Thanks,
Guenter

> Cheers,
>  Enric
>
> > Thanks,
> > Guenter
> >
> > > > Thanks,
> > > > Guenter
> > > >
> > > > > >> +Date:          August 2015
> > > > > >> +KernelVersion: 4.2
> > > > > >> +Description:
> > > > > >> +               Show the EC flash information.
> > > > > >> +
> > > > > >> +What:          /sys/class/chromeos/<cros-ec>/kb_wake_angle
> > > > > >> +Date:          March 2018
> > > > > >> +KernelVersion: 4.17
> > > > > >> +Description:
> > > > > >> +               Control the keyboard wake lid angle. Values are between
> > > > > >> +               0 and 360. This file will also show the keyboard wake lid
> > > > > >> +               angle by querying the hardware.
> > > > > >> +
> > > > > >> +What:          /sys/class/chromeos/<cros-ec>/reboot
> > > > > >> +Date:          August 2015
> > > > > >> +KernelVersion: 4.2
> > > > > >> +Description:
> > > > > >> +               Tell the EC to reboot in various ways. Options are:
> > > > > >> +               "cancel": Cancel a pending reboot.
> > > > > >> +               "ro": Jump to RO without rebooting.
> > > > > >> +               "rw": Jump to RW without rebooting.
> > > > > >> +               "cold": Cold reboot.
> > > > > >> +               "disable-jump": Disable jump until next reboot.
> > > > > >> +               "hibernate": Hibernate the EC.
> > > > > >> +               "at-shutdown": Reboot after an AP shutdown.
> > > > > >> +
> > > > > >> +What:          /sys/class/chromeos/<cros-ec>/version
> > > > > >> +Date:          August 2015
> > > > > >> +KernelVersion: 4.2
> > > > > >> +Description:
> > > > > >> +               Show the information about the EC software and hardware.
> > > > > >> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > > > >> index 8c5dfdce4326..089ffb408918 100644
> > > > > >> --- a/drivers/mfd/Kconfig
> > > > > >> +++ b/drivers/mfd/Kconfig
> > > > > >> @@ -214,7 +214,6 @@ config MFD_CROS_EC
> > > > > >>  config MFD_CROS_EC_CHARDEV
> > > > > >>          tristate "Chrome OS Embedded Controller userspace device interface"
> > > > > >>          depends on MFD_CROS_EC
> > > > > >> -        select CROS_EC_CTL
> > > > > >>          ---help---
> > > > > >>            This driver adds support to talk with the ChromeOS EC from userspace.
> > > > > >>
> > > > > >> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > > > > >> index 50ba8e0fb4ec..d9b16ce79319 100644
> > > > > >> --- a/drivers/mfd/cros_ec_dev.c
> > > > > >> +++ b/drivers/mfd/cros_ec_dev.c
> > > > > >> @@ -34,15 +34,9 @@
> > > > > >>  #define CROS_MAX_DEV 128
> > > > > >>  static int ec_major;
> > > > > >>
> > > > > >> -static const struct attribute_group *cros_ec_groups[] = {
> > > > > >> -       &cros_ec_attr_group,
> > > > > >> -       NULL,
> > > > > >> -};
> > > > > >> -
> > > > > >>  static struct class cros_class = {
> > > > > >>         .owner          = THIS_MODULE,
> > > > > >>         .name           = "chromeos",
> > > > > >> -       .dev_groups     = cros_ec_groups,
> > > > > >>  };
> > > > > >>
> > > > > >>  /* Basic communication */
> > > > > >> @@ -391,6 +385,7 @@ static const struct mfd_cell cros_usbpd_charger_cells[] = {
> > > > > >>  static const struct mfd_cell cros_ec_platform_cells[] = {
> > > > > >>         { .name = "cros-ec-debugfs" },
> > > > > >>         { .name = "cros-ec-lightbar" },
> > > > > >> +       { .name = "cros-ec-sysfs" },
> > > > > >>         { .name = "cros-ec-vbc" },
> > > > > >>  };
> > > > > >>
> > > > > >> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> > > > > >> index 4e4232b47764..b709cc5173a2 100644
> > > > > >> --- a/drivers/platform/chrome/Kconfig
> > > > > >> +++ b/drivers/platform/chrome/Kconfig
> > > > > >> @@ -49,9 +49,6 @@ config CHROMEOS_TBMC
> > > > > >>           To compile this driver as a module, choose M here: the
> > > > > >>           module will be called chromeos_tbmc.
> > > > > >>
> > > > > >> -config CROS_EC_CTL
> > > > > >> -        tristate
> > > > > >> -
> > > > > >>  config CROS_EC_I2C
> > > > > >>         tristate "ChromeOS Embedded Controller (I2C)"
> > > > > >>         depends on MFD_CROS_EC && I2C
> > > > > >> @@ -142,4 +139,15 @@ config CROS_EC_DEBUGFS
> > > > > >>           To compile this driver as a module, choose M here: the
> > > > > >>           module will be called cros_ec_debugfs.
> > > > > >>
> > > > > >> +config CROS_EC_SYSFS
> > > > > >> +       tristate "ChromeOS EC control and information through sysfs"
> > > > > >> +       depends on MFD_CROS_EC_CHARDEV && SYSFS
> > > > > >> +       default y
> > > > > >
> > > > > > In practice this is limited to MFD_CROS_EC_CHARDEV, meaning it will be
> > > > > > set to m if MFD_CROS_EC_CHARDEV=m.
> > > > > > Not sure what is better here, but for consistency I would prefer
> > > > > > "default MFD_CROS_EC_CHARDEV" (or default y
> > > > > > in the entire series).
> > > > > >
> > > > >
> > > > > Right, makes sense that if the MFD_CROS_EC_CHARDEV is selected set also those by
> > > > > default. Will prepare a new version with that small change.
> > > > >
> > > > > >> +       help
> > > > > >> +         This option exposes some sysfs attributes to control and get
> > > > > >> +         information from ChromeOS EC.
> > > > > >> +
> > > > > >> +         To compile this driver as a module, choose M here: the
> > > > > >> +         module will be called cros_ec_sysfs.
> > > > > >> +
> > > > > >>  endif # CHROMEOS_PLATFORMS
> > > > > >> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > > > > >> index 12a5c4d18c17..fdbee501931b 100644
> > > > > >> --- a/drivers/platform/chrome/Makefile
> > > > > >> +++ b/drivers/platform/chrome/Makefile
> > > > > >> @@ -3,8 +3,6 @@
> > > > > >>  obj-$(CONFIG_CHROMEOS_LAPTOP)          += chromeos_laptop.o
> > > > > >>  obj-$(CONFIG_CHROMEOS_PSTORE)          += chromeos_pstore.o
> > > > > >>  obj-$(CONFIG_CHROMEOS_TBMC)            += chromeos_tbmc.o
> > > > > >> -cros_ec_ctl-objs                       := cros_ec_sysfs.o
> > > > > >> -obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> > > > > >>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> > > > > >>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> > > > > >>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
> > > > > >> @@ -15,3 +13,4 @@ obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)  += cros_kbd_led_backlight.o
> > > > > >>  obj-$(CONFIG_CROS_EC_LIGHTBAR)         += cros_ec_lightbar.o
> > > > > >>  obj-$(CONFIG_CROS_EC_VBC)              += cros_ec_vbc.o
> > > > > >>  obj-$(CONFIG_CROS_EC_DEBUGFS)          += cros_ec_debugfs.o
> > > > > >> +obj-$(CONFIG_CROS_EC_SYSFS)            += cros_ec_sysfs.o
> > > > > >> diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
> > > > > >> index f34a50121064..0ff5aa30c070 100644
> > > > > >> --- a/drivers/platform/chrome/cros_ec_sysfs.c
> > > > > >> +++ b/drivers/platform/chrome/cros_ec_sysfs.c
> > > > > >> @@ -34,6 +34,8 @@
> > > > > >>  #include <linux/types.h>
> > > > > >>  #include <linux/uaccess.h>
> > > > > >>
> > > > > >> +#define DRV_NAME "cros-ec-sysfs"
> > > > > >> +
> > > > > >>  /* Accessor functions */
> > > > > >>
> > > > > >>  static ssize_t reboot_show(struct device *dev,
> > > > > >> @@ -353,7 +355,39 @@ struct attribute_group cros_ec_attr_group = {
> > > > > >>         .attrs = __ec_attrs,
> > > > > >>         .is_visible = cros_ec_ctrl_visible,
> > > > > >>  };
> > > > > >> -EXPORT_SYMBOL(cros_ec_attr_group);
> > > > > >> +
> > > > > >> +static int cros_ec_sysfs_probe(struct platform_device *pd)
> > > > > >> +{
> > > > > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > > > > >> +       struct device *dev = &pd->dev;
> > > > > >> +       int ret;
> > > > > >> +
> > > > > >> +       ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > > > > >> +       if (ret < 0)
> > > > > >> +               dev_err(dev, "failed to create attributes. err=%d\n", ret);
> > > > > >> +
> > > > > >> +       return ret;
> > > > > >> +}
> > > > > >> +
> > > > > >> +static int cros_ec_sysfs_remove(struct platform_device *pd)
> > > > > >> +{
> > > > > >> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> > > > > >> +
> > > > > >> +       sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
> > > > > >> +
> > > > > >> +       return 0;
> > > > > >> +}
> > > > > >> +
> > > > > >> +static struct platform_driver cros_ec_sysfs_driver = {
> > > > > >> +       .driver = {
> > > > > >> +               .name = DRV_NAME,
> > > > > >> +       },
> > > > > >> +       .probe = cros_ec_sysfs_probe,
> > > > > >> +       .remove = cros_ec_sysfs_remove,
> > > > > >> +};
> > > > > >> +
> > > > > >> +module_platform_driver(cros_ec_sysfs_driver);
> > > > > >>
> > > > > >>  MODULE_LICENSE("GPL");
> > > > > >>  MODULE_DESCRIPTION("ChromeOS EC control driver");
> > > > > >> +MODULE_ALIAS("platform:" DRV_NAME);
> > > > > >> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> > > > > >> index 3e4401e2ceea..f718ad9c2132 100644
> > > > > >> --- a/include/linux/mfd/cros_ec.h
> > > > > >> +++ b/include/linux/mfd/cros_ec.h
> > > > > >> @@ -323,7 +323,4 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event);
> > > > > >>   */
> > > > > >>  u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev);
> > > > > >>
> > > > > >> -/* sysfs stuff */
> > > > > >> -extern struct attribute_group cros_ec_attr_group;
> > > > > >> -
> > > > > >>  #endif /* __LINUX_MFD_CROS_EC_H */
> > > > > >> --
> > > > > >> 2.19.1
> > > > > >>
> > > > > >

Re: [PATCH v3 7/8] platform/chrome: cros_ec_lightbar: instantiate only if the EC has a lightbar.

[Enric Balletbo i Serra]

On 10/12/18 19:20, Guenter Roeck wrote:
> On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
>>
>> Due to the way attribute groups visibility work, the function
>> cros_ec_lightbar_attrs_are_visible is called multiple times, once per
>> attribute, and each of these calls makes an EC transaction. For what is
>> worth the EC log reports multiple errors on boot when the lightbar is
>> not available. Instead, check if the EC has a lightbar in the probe
>> function and only instantiate the device.
>>
>> Ideally we should have instantiate the driver only if the
>> EC_FEATURE_LIGHTBAR is defined, but that's not possible because that flag
>> is not in the very first Pixel Chromebook (Link), only on Samus. So, the
>> driver is instantiated by his parent always.
>>
>> This patch changes a bit the actual behaviour. Before the patch if an EC
>> doesn't have a lightbar an empty lightbar folder is created in
>> /sys/class/chromeos/<ec device>, after the patch the empty folder is not
>> created, so, the folder is only created if the lightbar exists.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> 
> Nitpicks, otherwise
> 
> Reviewed-by: Guenter Roeck <groeck@chromium.org>
> 
>> ---
>>
>> Changes in v3: None
>> Changes in v2:
>> - Removed ec_with_lightbar variable.
>>
>>  drivers/platform/chrome/cros_ec_lightbar.c | 37 ++++++++--------------
>>  1 file changed, 13 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
>> index 80eed6317570..6f6a4cbfc3fc 100644
>> --- a/drivers/platform/chrome/cros_ec_lightbar.c
>> +++ b/drivers/platform/chrome/cros_ec_lightbar.c
>> @@ -43,7 +43,6 @@ static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
>>   * If this is true, we won't do anything during suspend/resume.
>>   */
>>  static bool userspace_control;
>> -static struct cros_ec_dev *ec_with_lightbar;
>>
>>  static ssize_t interval_msec_show(struct device *dev,
>>                                   struct device_attribute *attr, char *buf)
>> @@ -381,9 +380,6 @@ static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
>>         struct cros_ec_command *msg;
>>         int ret;
>>
>> -       if (ec != ec_with_lightbar)
>> -               return 0;
>> -
>>         msg = alloc_lightbar_cmd_msg(ec);
>>         if (!msg)
>>                 return -ENOMEM;
>> @@ -567,37 +563,26 @@ static struct attribute *__lb_cmds_attrs[] = {
>>         NULL,
>>  };
>>
>> -static bool ec_has_lightbar(struct cros_ec_dev *ec)
>> +static bool cros_ec_has_lightbar(struct cros_ec_dev *ec_dev)
>>  {
>> -       return !!get_lightbar_version(ec, NULL, NULL);
>> -}
>> -
>> -static umode_t cros_ec_lightbar_attrs_are_visible(struct kobject *kobj,
>> -                                                 struct attribute *a, int n)
>> -{
>> -       struct device *dev = container_of(kobj, struct device, kobj);
>> -       struct cros_ec_dev *ec = to_cros_ec_dev(dev);
>> -       struct platform_device *pdev = to_platform_device(ec->dev);
>> +       struct platform_device *pdev = to_platform_device(ec_dev->dev);
>>         struct cros_ec_platform *pdata = pdev->dev.platform_data;
>>         int is_cros_ec;
>>
>>         is_cros_ec = strcmp(pdata->ec_name, CROS_EC_DEV_NAME);
>>
>>         if (is_cros_ec != 0)
>> -               return 0;
>> +               return false;
>>
> FWIW, is_cros_ec is really unnecessary here, though I guess that might
> be a different patch.
> 
>> -       /* Only instantiate this stuff if the EC has a lightbar */
>> -       if (ec_has_lightbar(ec)) {
>> -               ec_with_lightbar = ec;
>> -               return a->mode;
>> -       }
>> -       return 0;
>> +       if (!!get_lightbar_version(ec_dev, NULL, NULL))
>> +               return true;
>> +
>> +       return false;
> 
> Why not just the following ?
>             return !!get_lightbar_version(ec_dev, NULL, NULL);
> or even
>             return !strcmp(pdata->ec_name, CROS_EC_DEV_NAME) &&
>                       !!get_lightbar_version(ec_dev, NULL, NULL);
> 

Ack, I think that we can get rid of the cros_ec_has_lightbar function then. I'll
do in next version.

Thanks,
 Enric

>>  }
>>
>>  struct attribute_group cros_ec_lightbar_attr_group = {
>>         .name = "lightbar",
>>         .attrs = __lb_cmds_attrs,
>> -       .is_visible = cros_ec_lightbar_attrs_are_visible,
>>  };
>>
>>  static int cros_ec_lightbar_probe(struct platform_device *pd)
>> @@ -606,6 +591,10 @@ static int cros_ec_lightbar_probe(struct platform_device *pd)
>>         struct device *dev = &pd->dev;
>>         int ret;
>>
>> +       /* Only instantiate this stuff if the EC has a lightbar */
>> +       if (!cros_ec_has_lightbar(ec_dev))
>> +               return -ENODEV;
>> +
>>         /* Take control of the lightbar from the EC. */
>>         lb_manual_suspend_ctrl(ec_dev, 1);
>>
>> @@ -635,7 +624,7 @@ static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
>>  {
>>         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
>>
>> -       if (userspace_control || ec_dev != ec_with_lightbar)
>> +       if (userspace_control)
>>                 return 0;
>>
>>         return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
>> @@ -645,7 +634,7 @@ static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
>>  {
>>         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev);
>>
>> -       if (userspace_control || ec_dev != ec_with_lightbar)
>> +       if (userspace_control)
>>                 return 0;
>>
>>         return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
>> --
>> 2.19.1
>>