[PATCH v8 0/9] Turris Omnia MCU driver

[PATCH v8 0/9] Turris Omnia MCU driver

[Marek Behún]

Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,

this is v8 of the series adding Turris Omnia MCU driver.

This series depends on the immutable branch between LEDs and locking,
introducing devm_mutex_init(), see the PR
  https://lore.kernel.org/linux-leds/20240412084616.GR2399047@google.com/

See also cover letters for v1, v2, v3, v4, v5, v6 and v7:
  https://patchwork.kernel.org/project/linux-soc/cover/20230823161012.6986-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20230919103815.16818-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20231023143130.11602-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20231026161803.16750-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240323164359.21642-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240418121116.22184-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240424173809.7214-1-kabel@kernel.org/

Changes since v7:
- fixed wrong $id path in DT binding (patch 1)
- removed resource managed IRQ mapping disposal, which is not needed, as
  pointed out by Andy (patches 6, 7)
- added some more #includes (for linux/device.h, linux/interrupt.h,
  linux/hw_random.h) (patches 3, 6, 7)
- dropped the Fixes tags from the DT changes (patches 8, 9), with an
  explanation of this added into the commit message of patch 8, as
  suggested by Andrew

Marek Behún (9):
  dt-bindings: firmware: add cznic,turris-omnia-mcu binding
  platform: cznic: Add preliminary support for Turris Omnia MCU
  platform: cznic: turris-omnia-mcu: Add support for MCU connected GPIOs
  platform: cznic: turris-omnia-mcu: Add support for poweroff and wakeup
  platform: cznic: turris-omnia-mcu: Add support for MCU watchdog
  platform: cznic: turris-omnia-mcu: Add support for MCU provided TRNG
  platform: cznic: turris-omnia-mcu: Add support for digital message
    signing via debugfs
  ARM: dts: turris-omnia: Add MCU system-controller node
  ARM: dts: turris-omnia: Add GPIO key node for front button

 .../ABI/testing/debugfs-turris-omnia-mcu      |   13 +
 .../sysfs-bus-i2c-devices-turris-omnia-mcu    |  126 ++
 .../firmware/cznic,turris-omnia-mcu.yaml      |   86 ++
 MAINTAINERS                                   |    5 +
 .../dts/marvell/armada-385-turris-omnia.dts   |   35 +-
 drivers/platform/Kconfig                      |    2 +
 drivers/platform/Makefile                     |    1 +
 drivers/platform/cznic/Kconfig                |   51 +
 drivers/platform/cznic/Makefile               |    9 +
 .../platform/cznic/turris-omnia-mcu-base.c    |  439 +++++++
 .../platform/cznic/turris-omnia-mcu-debugfs.c |  207 ++++
 .../platform/cznic/turris-omnia-mcu-gpio.c    | 1048 +++++++++++++++++
 .../cznic/turris-omnia-mcu-sys-off-wakeup.c   |  258 ++++
 .../platform/cznic/turris-omnia-mcu-trng.c    |  101 ++
 .../cznic/turris-omnia-mcu-watchdog.c         |  123 ++
 drivers/platform/cznic/turris-omnia-mcu.h     |  188 +++
 include/linux/turris-omnia-mcu-interface.h    |  249 ++++
 17 files changed, 2940 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/debugfs-turris-omnia-mcu
 create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
 create mode 100644 Documentation/devicetree/bindings/firmware/cznic,turris-omnia-mcu.yaml
 create mode 100644 drivers/platform/cznic/Kconfig
 create mode 100644 drivers/platform/cznic/Makefile
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-base.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-debugfs.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-gpio.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-trng.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-watchdog.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu.h
 create mode 100644 include/linux/turris-omnia-mcu-interface.h

-- 
2.43.2

[PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

Add the basic skeleton for a new platform driver for the microcontroller
found on the Turris Omnia board.

Signed-off-by: Marek Behún <kabel@kernel.org>
---
 .../sysfs-bus-i2c-devices-turris-omnia-mcu    |  81 ++++
 MAINTAINERS                                   |   3 +
 drivers/platform/Kconfig                      |   2 +
 drivers/platform/Makefile                     |   1 +
 drivers/platform/cznic/Kconfig                |  26 ++
 drivers/platform/cznic/Makefile               |   4 +
 .../platform/cznic/turris-omnia-mcu-base.c    | 376 ++++++++++++++++++
 drivers/platform/cznic/turris-omnia-mcu.h     |  50 +++
 include/linux/turris-omnia-mcu-interface.h    | 249 ++++++++++++
 9 files changed, 792 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
 create mode 100644 drivers/platform/cznic/Kconfig
 create mode 100644 drivers/platform/cznic/Makefile
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-base.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu.h
 create mode 100644 include/linux/turris-omnia-mcu-interface.h

diff --git a/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
new file mode 100644
index 000000000000..ff5e7cb00206
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
@@ -0,0 +1,81 @@
+What:		/sys/bus/i2c/devices/<mcu_device>/board_revision
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains board revision number.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %u.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/first_mac_address
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains device first MAC address. Each Turris Omnia is
+		allocated 3 MAC addresses. The two additional addresses are
+		computed from the first one by incrementing it.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %pM.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_features
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Newer versions of the microcontroller firmware report the
+		features they support. These can be read from this file. If the
+		MCU firmware is too old, this file reads 0x0.
+
+		Format: 0x%x.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_version_hash_application
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the version hash (commit hash) of the application
+		part of the microcontroller firmware.
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_version_hash_bootloader
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the version hash (commit hash) of the bootloader
+		part of the microcontroller firmware.
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/mcu_type
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the microcontroller type (STM32, GD32, MKL).
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/reset_selector
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the selected factory reset level, determined by
+		how long the rear reset button was held by the user during board
+		reset.
+
+		Format: %i.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/serial_number
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the 64 bit long board serial number in hexadecimal
+		format.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %016X.
diff --git a/MAINTAINERS b/MAINTAINERS
index 359ed2cadfc4..2aa178a9d53e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2139,6 +2139,7 @@ M:	Marek Behún <kabel@kernel.org>
 S:	Maintained
 W:	https://www.turris.cz/
 F:	Documentation/ABI/testing/debugfs-moxtet
+F:	Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
 F:	Documentation/ABI/testing/sysfs-bus-moxtet-devices
 F:	Documentation/ABI/testing/sysfs-firmware-turris-mox-rwtm
 F:	Documentation/devicetree/bindings/bus/moxtet.txt
@@ -2152,10 +2153,12 @@ F:	drivers/firmware/turris-mox-rwtm.c
 F:	drivers/gpio/gpio-moxtet.c
 F:	drivers/leds/leds-turris-omnia.c
 F:	drivers/mailbox/armada-37xx-rwtm-mailbox.c
+F:	drivers/platform/cznic/
 F:	drivers/watchdog/armada_37xx_wdt.c
 F:	include/dt-bindings/bus/moxtet.h
 F:	include/linux/armada-37xx-rwtm-mailbox.h
 F:	include/linux/moxtet.h
+F:	include/linux/turris-omnia-mcu-interface.h
 
 ARM/FARADAY FA526 PORT
 M:	Hans Ulli Kroll <ulli.kroll@googlemail.com>
diff --git a/drivers/platform/Kconfig b/drivers/platform/Kconfig
index 868b20361769..fef907a94001 100644
--- a/drivers/platform/Kconfig
+++ b/drivers/platform/Kconfig
@@ -7,6 +7,8 @@ source "drivers/platform/goldfish/Kconfig"
 
 source "drivers/platform/chrome/Kconfig"
 
+source "drivers/platform/cznic/Kconfig"
+
 source "drivers/platform/mellanox/Kconfig"
 
 source "drivers/platform/olpc/Kconfig"
diff --git a/drivers/platform/Makefile b/drivers/platform/Makefile
index 41640172975a..8bf189264374 100644
--- a/drivers/platform/Makefile
+++ b/drivers/platform/Makefile
@@ -10,4 +10,5 @@ obj-$(CONFIG_MIPS)		+= mips/
 obj-$(CONFIG_OLPC_EC)		+= olpc/
 obj-$(CONFIG_GOLDFISH)		+= goldfish/
 obj-$(CONFIG_CHROME_PLATFORMS)	+= chrome/
+obj-$(CONFIG_CZNIC_PLATFORMS)	+= cznic/
 obj-$(CONFIG_SURFACE_PLATFORMS)	+= surface/
diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
new file mode 100644
index 000000000000..f8560ff9c1af
--- /dev/null
+++ b/drivers/platform/cznic/Kconfig
@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# For a description of the syntax of this configuration file,
+# see Documentation/kbuild/kconfig-language.rst.
+#
+
+menuconfig CZNIC_PLATFORMS
+	bool "Platform support for CZ.NIC's Turris hardware"
+	depends on MACH_ARMADA_38X || COMPILE_TEST
+	help
+	  Say Y here to be able to choose driver support for CZ.NIC's Turris
+	  devices. This option alone does not add any kernel code.
+
+if CZNIC_PLATFORMS
+
+config TURRIS_OMNIA_MCU
+	tristate "Turris Omnia MCU driver"
+	depends on MACH_ARMADA_38X || COMPILE_TEST
+	depends on I2C
+	help
+	  Say Y here to add support for the features implemented by the
+	  microcontroller on the CZ.NIC's Turris Omnia SOHO router.
+	  To compile this driver as a module, choose M here; the module will be
+	  called turris-omnia-mcu.
+
+endif # CZNIC_PLATFORMS
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
new file mode 100644
index 000000000000..31adca73bb94
--- /dev/null
+++ b/drivers/platform/cznic/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_TURRIS_OMNIA_MCU)	+= turris-omnia-mcu.o
+turris-omnia-mcu-y		:= turris-omnia-mcu-base.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
new file mode 100644
index 000000000000..8893c990853a
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -0,0 +1,376 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/device.h>
+#include <linux/hex.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+
+#include "turris-omnia-mcu.h"
+
+#define OMNIA_FW_VERSION_LEN		20
+#define OMNIA_FW_VERSION_HEX_LEN	(2 * OMNIA_FW_VERSION_LEN + 1)
+#define OMNIA_BOARD_INFO_LEN		16
+
+int omnia_cmd_read(const struct i2c_client *client, u8 cmd, void *reply,
+		   unsigned int len)
+{
+	struct i2c_msg msgs[2];
+	int ret;
+
+	msgs[0].addr = client->addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &cmd;
+	msgs[1].addr = client->addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = len;
+	msgs[1].buf = reply;
+
+	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return ret;
+	if (ret != ARRAY_SIZE(msgs))
+		return -EIO;
+
+	return 0;
+}
+
+static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
+				  u8 version[static OMNIA_FW_VERSION_HEX_LEN])
+{
+	u8 reply[OMNIA_FW_VERSION_LEN];
+	int err;
+
+	err = omnia_cmd_read(mcu->client,
+			     bootloader ? CMD_GET_FW_VERSION_BOOT
+					: CMD_GET_FW_VERSION_APP,
+			     reply, sizeof(reply));
+	if (err)
+		return err;
+
+	version[OMNIA_FW_VERSION_HEX_LEN - 1] = '\0';
+	bin2hex(version, reply, OMNIA_FW_VERSION_LEN);
+
+	return 0;
+}
+
+static ssize_t fw_version_hash_show(struct device *dev, char *buf,
+				    bool bootloader)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+	u8 version[OMNIA_FW_VERSION_HEX_LEN];
+	int err;
+
+	err = omnia_get_version_hash(mcu, bootloader, version);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%s\n", version);
+}
+
+static ssize_t fw_version_hash_application_show(struct device *dev,
+						struct device_attribute *a,
+						char *buf)
+{
+	return fw_version_hash_show(dev, buf, false);
+}
+static DEVICE_ATTR_RO(fw_version_hash_application);
+
+static ssize_t fw_version_hash_bootloader_show(struct device *dev,
+					       struct device_attribute *a,
+					       char *buf)
+{
+	return fw_version_hash_show(dev, buf, true);
+}
+static DEVICE_ATTR_RO(fw_version_hash_bootloader);
+
+static ssize_t fw_features_show(struct device *dev, struct device_attribute *a,
+				char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "0x%x\n", mcu->features);
+}
+static DEVICE_ATTR_RO(fw_features);
+
+static ssize_t mcu_type_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%s\n", mcu->type);
+}
+static DEVICE_ATTR_RO(mcu_type);
+
+static ssize_t reset_selector_show(struct device *dev,
+				   struct device_attribute *a, char *buf)
+{
+	int ret;
+
+	ret = omnia_cmd_read_u8(to_i2c_client(dev), CMD_GET_RESET);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", ret);
+}
+static DEVICE_ATTR_RO(reset_selector);
+
+static ssize_t serial_number_show(struct device *dev,
+				  struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%016llX\n", mcu->board_serial_number);
+}
+static DEVICE_ATTR_RO(serial_number);
+
+static ssize_t first_mac_address_show(struct device *dev,
+				      struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%pM\n", mcu->board_first_mac);
+}
+static DEVICE_ATTR_RO(first_mac_address);
+
+static ssize_t board_revision_show(struct device *dev,
+				   struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", mcu->board_revision);
+}
+static DEVICE_ATTR_RO(board_revision);
+
+static struct attribute *omnia_mcu_base_attrs[] = {
+	&dev_attr_fw_version_hash_application.attr,
+	&dev_attr_fw_version_hash_bootloader.attr,
+	&dev_attr_fw_features.attr,
+	&dev_attr_mcu_type.attr,
+	&dev_attr_reset_selector.attr,
+	&dev_attr_serial_number.attr,
+	&dev_attr_first_mac_address.attr,
+	&dev_attr_board_revision.attr,
+	NULL
+};
+
+static umode_t omnia_mcu_base_attrs_visible(struct kobject *kobj,
+					    struct attribute *a, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+	umode_t mode = a->mode;
+
+	if ((a == &dev_attr_serial_number.attr ||
+	     a == &dev_attr_first_mac_address.attr ||
+	     a == &dev_attr_board_revision.attr) &&
+	    !(mcu->features & FEAT_BOARD_INFO))
+		mode = 0;
+
+	return mode;
+}
+
+static const struct attribute_group omnia_mcu_base_group = {
+	.attrs = omnia_mcu_base_attrs,
+	.is_visible = omnia_mcu_base_attrs_visible,
+};
+
+static const struct attribute_group *omnia_mcu_groups[] = {
+	&omnia_mcu_base_group,
+	NULL
+};
+
+static void omnia_mcu_print_version_hash(struct omnia_mcu *mcu, bool bootloader)
+{
+	const char *type = bootloader ? "bootloader" : "application";
+	struct device *dev = &mcu->client->dev;
+	u8 version[OMNIA_FW_VERSION_HEX_LEN];
+	int err;
+
+	err = omnia_get_version_hash(mcu, bootloader, version);
+	if (err) {
+		dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
+			err);
+		return;
+	}
+
+	dev_info(dev, "MCU %s firmware version hash: %s\n", type, version);
+}
+
+static const char *omnia_status_to_mcu_type(uint16_t status)
+{
+	switch (status & STS_MCU_TYPE_MASK) {
+	case STS_MCU_TYPE_STM32:
+		return "STM32";
+	case STS_MCU_TYPE_GD32:
+		return "GD32";
+	case STS_MCU_TYPE_MKL:
+		return "MKL";
+	default:
+		return "unknown";
+	}
+}
+
+static void omnia_info_missing_feature(struct device *dev, const char *feature)
+{
+	dev_info(dev,
+		 "Your board's MCU firmware does not support the %s feature.\n",
+		 feature);
+}
+
+static int omnia_mcu_read_features(struct omnia_mcu *mcu)
+{
+	static const struct {
+		uint16_t mask;
+		const char *name;
+	} features[] = {
+		{ FEAT_EXT_CMDS,	   "extended control and status" },
+		{ FEAT_WDT_PING,	   "watchdog pinging" },
+		{ FEAT_LED_STATE_EXT_MASK, "peripheral LED pins reading" },
+		{ FEAT_NEW_INT_API,	   "new interrupt API" },
+		{ FEAT_POWEROFF_WAKEUP,	   "poweroff and wakeup" },
+		{ FEAT_TRNG,		   "true random number generator" },
+	};
+	struct device *dev = &mcu->client->dev;
+	bool suggest_fw_upgrade = false;
+	int status;
+
+	/* status word holds MCU type, which we need below */
+	status = omnia_cmd_read_u16(mcu->client, CMD_GET_STATUS_WORD);
+	if (status < 0)
+		return status;
+
+	/* check whether MCU firmware supports the CMD_GET_FEAUTRES command */
+	if (status & STS_FEATURES_SUPPORTED) {
+		__le32 reply;
+		int ret;
+
+		/* try read 32-bit features */
+		ret = omnia_cmd_read(mcu->client, CMD_GET_FEATURES, &reply,
+				     sizeof(reply));
+		if (ret) {
+			/* try read 16-bit features */
+			ret = omnia_cmd_read_u16(mcu->client, CMD_GET_FEATURES);
+			if (ret < 0)
+				return ret;
+
+			mcu->features = ret;
+		} else {
+			mcu->features = le32_to_cpu(reply);
+
+			if (mcu->features & FEAT_FROM_BIT_16_INVALID)
+				mcu->features &= GENMASK(15, 0);
+		}
+	} else {
+		omnia_info_missing_feature(dev, "feature reading");
+		suggest_fw_upgrade = true;
+	}
+
+	mcu->type = omnia_status_to_mcu_type(status);
+	dev_info(dev, "MCU type %s%s\n", mcu->type,
+		 (mcu->features & FEAT_PERIPH_MCU) ?
+			", with peripheral resets wired" : "");
+
+	omnia_mcu_print_version_hash(mcu, true);
+
+	if (mcu->features & FEAT_BOOTLOADER)
+		dev_warn(dev,
+			 "MCU is running bootloader firmware. Was firmware upgrade interrupted?\n");
+	else
+		omnia_mcu_print_version_hash(mcu, false);
+
+	for (unsigned int i = 0; i < ARRAY_SIZE(features); i++) {
+		if (mcu->features & features[i].mask)
+			continue;
+
+		omnia_info_missing_feature(dev, features[i].name);
+		suggest_fw_upgrade = true;
+	}
+
+	if (suggest_fw_upgrade)
+		dev_info(dev,
+			 "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
+
+	return 0;
+}
+
+static int omnia_mcu_read_board_info(struct omnia_mcu *mcu)
+{
+	u8 reply[1 + OMNIA_BOARD_INFO_LEN];
+	int err;
+
+	err = omnia_cmd_read(mcu->client, CMD_BOARD_INFO_GET, reply,
+			     sizeof(reply));
+	if (err)
+		return err;
+
+	if (reply[0] != OMNIA_BOARD_INFO_LEN)
+		return -EIO;
+
+	mcu->board_serial_number = get_unaligned_le64(&reply[1]);
+	memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);
+	mcu->board_revision = reply[15];
+
+	return 0;
+}
+
+static int omnia_mcu_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct omnia_mcu *mcu;
+	int err;
+
+	if (!client->irq)
+		return dev_err_probe(dev, -EINVAL, "IRQ resource not found\n");
+
+	mcu = devm_kzalloc(dev, sizeof(*mcu), GFP_KERNEL);
+	if (!mcu)
+		return -ENOMEM;
+
+	mcu->client = client;
+	i2c_set_clientdata(client, mcu);
+
+	err = omnia_mcu_read_features(mcu);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Cannot determine MCU supported features\n");
+
+	if (mcu->features & FEAT_BOARD_INFO) {
+		err = omnia_mcu_read_board_info(mcu);
+		if (err)
+			return dev_err_probe(dev, err,
+					     "Cannot read board info\n");
+	}
+
+	return 0;
+}
+
+static const struct of_device_id of_omnia_mcu_match[] = {
+	{ .compatible = "cznic,turris-omnia-mcu" },
+	{}
+};
+
+static struct i2c_driver omnia_mcu_driver = {
+	.probe		= omnia_mcu_probe,
+	.driver		= {
+		.name	= "turris-omnia-mcu",
+		.of_match_table = of_omnia_mcu_match,
+		.dev_groups = omnia_mcu_groups,
+	},
+};
+module_i2c_driver(omnia_mcu_driver);
+
+MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
+MODULE_DESCRIPTION("CZ.NIC's Turris Omnia MCU");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
new file mode 100644
index 000000000000..5b21fbca8fe1
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * CZ.NIC's Turris Omnia MCU driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#ifndef __TURRIS_OMNIA_MCU_H
+#define __TURRIS_OMNIA_MCU_H
+
+#include <linux/i2c.h>
+#include <linux/if_ether.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+struct omnia_mcu {
+	struct i2c_client *client;
+	const char *type;
+	u32 features;
+
+	/* board information */
+	u64 board_serial_number;
+	u8 board_first_mac[ETH_ALEN];
+	u8 board_revision;
+};
+
+int omnia_cmd_read(const struct i2c_client *client, u8 cmd, void *reply,
+		   unsigned int len);
+
+static inline int omnia_cmd_read_u16(const struct i2c_client *client, u8 cmd)
+{
+	__le16 reply;
+	int err;
+
+	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
+
+	return err ?: le16_to_cpu(reply);
+}
+
+static inline int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
+{
+	u8 reply;
+	int err;
+
+	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
+
+	return err ?: reply;
+}
+
+#endif /* __TURRIS_OMNIA_MCU_H */
diff --git a/include/linux/turris-omnia-mcu-interface.h b/include/linux/turris-omnia-mcu-interface.h
new file mode 100644
index 000000000000..88f8490b5897
--- /dev/null
+++ b/include/linux/turris-omnia-mcu-interface.h
@@ -0,0 +1,249 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * CZ.NIC's Turris Omnia MCU I2C interface commands definitions
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#ifndef __TURRIS_OMNIA_MCU_INTERFACE_H
+#define __TURRIS_OMNIA_MCU_INTERFACE_H
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+
+enum omnia_commands_e {
+	CMD_GET_STATUS_WORD		= 0x01, /* slave sends status word back */
+	CMD_GENERAL_CONTROL		= 0x02,
+	CMD_LED_MODE			= 0x03, /* default/user */
+	CMD_LED_STATE			= 0x04, /* LED on/off */
+	CMD_LED_COLOR			= 0x05, /* LED number + RED + GREEN + BLUE */
+	CMD_USER_VOLTAGE		= 0x06,
+	CMD_SET_BRIGHTNESS		= 0x07,
+	CMD_GET_BRIGHTNESS		= 0x08,
+	CMD_GET_RESET			= 0x09,
+	CMD_GET_FW_VERSION_APP		= 0x0A, /* 20B git hash number */
+	CMD_SET_WATCHDOG_STATE		= 0x0B, /* 0 - disable
+						 * 1 - enable / ping
+						 * after boot watchdog is started
+						 * with 2 minutes timeout
+						 */
+
+	/* CMD_WATCHDOG_STATUS		= 0x0C, not implemented anymore */
+
+	CMD_GET_WATCHDOG_STATE		= 0x0D,
+	CMD_GET_FW_VERSION_BOOT		= 0x0E, /* 20B git hash number */
+	CMD_GET_FW_CHECKSUM		= 0x0F, /* 4B length, 4B checksum */
+
+	/* available if FEATURES_SUPPORTED bit set in status word */
+	CMD_GET_FEATURES		= 0x10,
+
+	/* available if EXT_CMD bit set in features */
+	CMD_GET_EXT_STATUS_DWORD	= 0x11,
+	CMD_EXT_CONTROL			= 0x12,
+	CMD_GET_EXT_CONTROL_STATUS	= 0x13,
+
+	/* available if NEW_INT_API bit set in features */
+	CMD_GET_INT_AND_CLEAR		= 0x14,
+	CMD_GET_INT_MASK		= 0x15,
+	CMD_SET_INT_MASK		= 0x16,
+
+	/* available if FLASHING bit set in features */
+	CMD_FLASH			= 0x19,
+
+	/* available if WDT_PING bit set in features */
+	CMD_SET_WDT_TIMEOUT		= 0x20,
+	CMD_GET_WDT_TIMELEFT		= 0x21,
+
+	/* available if POWEROFF_WAKEUP bit set in features */
+	CMD_SET_WAKEUP			= 0x22,
+	CMD_GET_UPTIME_AND_WAKEUP	= 0x23,
+	CMD_POWER_OFF			= 0x24,
+
+	/* available if USB_OVC_PROT_SETTING bit set in features */
+	CMD_SET_USB_OVC_PROT		= 0x25,
+	CMD_GET_USB_OVC_PROT		= 0x26,
+
+	/* available if TRNG bit set in features */
+	CMD_TRNG_COLLECT_ENTROPY	= 0x28,
+
+	/* available if CRYPTO bit set in features */
+	CMD_CRYPTO_GET_PUBLIC_KEY	= 0x29,
+	CMD_CRYPTO_SIGN_MESSAGE		= 0x2A,
+	CMD_CRYPTO_COLLECT_SIGNATURE	= 0x2B,
+
+	/* available if BOARD_INFO it set in features */
+	CMD_BOARD_INFO_GET		= 0x2C,
+	CMD_BOARD_INFO_BURN		= 0x2D,
+
+	/* available only at address 0x2b (led-controller) */
+	/* available only if LED_GAMMA_CORRECTION bit set in features */
+	CMD_SET_GAMMA_CORRECTION	= 0x30,
+	CMD_GET_GAMMA_CORRECTION	= 0x31,
+
+	/* available only at address 0x2b (led-controller) */
+	/* available only if PER_LED_CORRECTION bit set in features */
+	/* available only if FROM_BIT_16_INVALID bit NOT set in features */
+	CMD_SET_LED_CORRECTIONS		= 0x32,
+	CMD_GET_LED_CORRECTIONS		= 0x33,
+};
+
+enum omnia_flashing_commands_e {
+	FLASH_CMD_UNLOCK		= 0x01,
+	FLASH_CMD_SIZE_AND_CSUM		= 0x02,
+	FLASH_CMD_PROGRAM		= 0x03,
+	FLASH_CMD_RESET			= 0x04,
+};
+
+enum omnia_sts_word_e {
+	STS_MCU_TYPE_MASK			= GENMASK(1, 0),
+	STS_MCU_TYPE_STM32			= 0 << 0,
+	STS_MCU_TYPE_GD32			= 1 << 0,
+	STS_MCU_TYPE_MKL			= 2 << 0,
+	STS_FEATURES_SUPPORTED			= BIT(2),
+	STS_USER_REGULATOR_NOT_SUPPORTED	= BIT(3),
+	STS_CARD_DET				= BIT(4),
+	STS_MSATA_IND				= BIT(5),
+	STS_USB30_OVC				= BIT(6),
+	STS_USB31_OVC				= BIT(7),
+	STS_USB30_PWRON				= BIT(8),
+	STS_USB31_PWRON				= BIT(9),
+	STS_ENABLE_4V5				= BIT(10),
+	STS_BUTTON_MODE				= BIT(11),
+	STS_BUTTON_PRESSED			= BIT(12),
+	STS_BUTTON_COUNTER_MASK			= GENMASK(15, 13)
+};
+
+enum omnia_ctl_byte_e {
+	CTL_LIGHT_RST		= BIT(0),
+	CTL_HARD_RST		= BIT(1),
+	/* BIT(2) is currently reserved */
+	CTL_USB30_PWRON		= BIT(3),
+	CTL_USB31_PWRON		= BIT(4),
+	CTL_ENABLE_4V5		= BIT(5),
+	CTL_BUTTON_MODE		= BIT(6),
+	CTL_BOOTLOADER		= BIT(7)
+};
+
+enum omnia_features_e {
+	FEAT_PERIPH_MCU			= BIT(0),
+	FEAT_EXT_CMDS			= BIT(1),
+	FEAT_WDT_PING			= BIT(2),
+	FEAT_LED_STATE_EXT_MASK		= GENMASK(4, 3),
+	FEAT_LED_STATE_EXT		= 1 << 3,
+	FEAT_LED_STATE_EXT_V32		= 2 << 3,
+	FEAT_LED_GAMMA_CORRECTION	= BIT(5),
+	FEAT_NEW_INT_API		= BIT(6),
+	FEAT_BOOTLOADER			= BIT(7),
+	FEAT_FLASHING			= BIT(8),
+	FEAT_NEW_MESSAGE_API		= BIT(9),
+	FEAT_BRIGHTNESS_INT		= BIT(10),
+	FEAT_POWEROFF_WAKEUP		= BIT(11),
+	FEAT_CAN_OLD_MESSAGE_API	= BIT(12),
+	FEAT_TRNG			= BIT(13),
+	FEAT_CRYPTO			= BIT(14),
+	FEAT_BOARD_INFO			= BIT(15),
+
+	/*
+	 * Orginally the features command replied only 16 bits. If more were
+	 * read, either the I2C transaction failed or 0xff bytes were sent.
+	 * Therefore to consider bits 16 - 31 valid, one bit (20) was reserved
+	 * to be zero.
+	 */
+
+	/* Bits 16 - 19 correspond to bits 0 - 3 of status word */
+	FEAT_MCU_TYPE_MASK		= GENMASK(17, 16),
+	FEAT_MCU_TYPE_STM32		= 0 << 16,
+	FEAT_MCU_TYPE_GD32		= 1 << 16,
+	FEAT_MCU_TYPE_MKL		= 2 << 16,
+	FEAT_FEATURES_SUPPORTED		= BIT(18),
+	FEAT_USER_REGULATOR_NOT_SUPPORTED = BIT(19),
+
+	/* must not be set */
+	FEAT_FROM_BIT_16_INVALID	= BIT(20),
+
+	FEAT_PER_LED_CORRECTION		= BIT(21),
+	FEAT_USB_OVC_PROT_SETTING	= BIT(22),
+};
+
+enum omnia_ext_sts_dword_e {
+	EXT_STS_SFP_nDET		= BIT(0),
+	EXT_STS_LED_STATES_MASK		= GENMASK(31, 12),
+	EXT_STS_WLAN0_MSATA_LED		= BIT(12),
+	EXT_STS_WLAN1_LED		= BIT(13),
+	EXT_STS_WLAN2_LED		= BIT(14),
+	EXT_STS_WPAN0_LED		= BIT(15),
+	EXT_STS_WPAN1_LED		= BIT(16),
+	EXT_STS_WPAN2_LED		= BIT(17),
+	EXT_STS_WAN_LED0		= BIT(18),
+	EXT_STS_WAN_LED1		= BIT(19),
+	EXT_STS_LAN0_LED0		= BIT(20),
+	EXT_STS_LAN0_LED1		= BIT(21),
+	EXT_STS_LAN1_LED0		= BIT(22),
+	EXT_STS_LAN1_LED1		= BIT(23),
+	EXT_STS_LAN2_LED0		= BIT(24),
+	EXT_STS_LAN2_LED1		= BIT(25),
+	EXT_STS_LAN3_LED0		= BIT(26),
+	EXT_STS_LAN3_LED1		= BIT(27),
+	EXT_STS_LAN4_LED0		= BIT(28),
+	EXT_STS_LAN4_LED1		= BIT(29),
+	EXT_STS_LAN5_LED0		= BIT(30),
+	EXT_STS_LAN5_LED1		= BIT(31),
+};
+
+enum omnia_ext_ctl_e {
+	EXT_CTL_nRES_MMC		= BIT(0),
+	EXT_CTL_nRES_LAN		= BIT(1),
+	EXT_CTL_nRES_PHY		= BIT(2),
+	EXT_CTL_nPERST0			= BIT(3),
+	EXT_CTL_nPERST1			= BIT(4),
+	EXT_CTL_nPERST2			= BIT(5),
+	EXT_CTL_PHY_SFP			= BIT(6),
+	EXT_CTL_PHY_SFP_AUTO		= BIT(7),
+	EXT_CTL_nVHV_CTRL		= BIT(8),
+};
+
+enum omnia_int_e {
+	INT_CARD_DET		= BIT(0),
+	INT_MSATA_IND		= BIT(1),
+	INT_USB30_OVC		= BIT(2),
+	INT_USB31_OVC		= BIT(3),
+	INT_BUTTON_PRESSED	= BIT(4),
+	INT_SFP_nDET		= BIT(5),
+	INT_BRIGHTNESS_CHANGED	= BIT(6),
+	INT_TRNG		= BIT(7),
+	INT_MESSAGE_SIGNED	= BIT(8),
+
+	INT_LED_STATES_MASK	= GENMASK(31, 12),
+	INT_WLAN0_MSATA_LED	= BIT(12),
+	INT_WLAN1_LED		= BIT(13),
+	INT_WLAN2_LED		= BIT(14),
+	INT_WPAN0_LED		= BIT(15),
+	INT_WPAN1_LED		= BIT(16),
+	INT_WPAN2_LED		= BIT(17),
+	INT_WAN_LED0		= BIT(18),
+	INT_WAN_LED1		= BIT(19),
+	INT_LAN0_LED0		= BIT(20),
+	INT_LAN0_LED1		= BIT(21),
+	INT_LAN1_LED0		= BIT(22),
+	INT_LAN1_LED1		= BIT(23),
+	INT_LAN2_LED0		= BIT(24),
+	INT_LAN2_LED1		= BIT(25),
+	INT_LAN3_LED0		= BIT(26),
+	INT_LAN3_LED1		= BIT(27),
+	INT_LAN4_LED0		= BIT(28),
+	INT_LAN4_LED1		= BIT(29),
+	INT_LAN5_LED0		= BIT(30),
+	INT_LAN5_LED1		= BIT(31),
+};
+
+enum omnia_cmd_poweroff_e {
+	CMD_POWER_OFF_POWERON_BUTTON	= BIT(0),
+	CMD_POWER_OFF_MAGIC		= 0xdead,
+};
+
+enum cmd_usb_ovc_prot_e {
+	CMD_xET_USB_OVC_PROT_PORT_MASK	= GENMASK(3, 0),
+	CMD_xET_USB_OVC_PROT_ENABLE	= BIT(4),
+};
+
+#endif /* __TURRIS_OMNIA_MCU_INTERFACE_H */
-- 
2.43.2

[PATCH v8 4/9] platform: cznic: turris-omnia-mcu: Add support for poweroff and wakeup

[Marek Behún]

Add support for true board poweroff (MCU can disable all unnecessary
voltage regulators) and wakeup at a specified time, implemented via a
RTC driver so that the rtcwake utility can be used to configure it.

Signed-off-by: Marek Behún <kabel@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 .../sysfs-bus-i2c-devices-turris-omnia-mcu    |  16 ++
 drivers/platform/cznic/Kconfig                |   4 +
 drivers/platform/cznic/Makefile               |   1 +
 .../platform/cznic/turris-omnia-mcu-base.c    |   5 +
 .../cznic/turris-omnia-mcu-sys-off-wakeup.c   | 258 ++++++++++++++++++
 drivers/platform/cznic/turris-omnia-mcu.h     |  20 ++
 6 files changed, 304 insertions(+)
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c

diff --git a/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
index b27b60d00c87..564119849388 100644
--- a/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
+++ b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
@@ -38,6 +38,22 @@ Description:	(RW) The front button on the Turris Omnia router can be
 
 		Format: %s.
 
+What:		/sys/bus/i2c/devices/<mcu_device>/front_button_poweron
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RW) Newer versions of the microcontroller firmware of the
+		Turris Omnia router support powering off the router into true
+		low power mode. The router can be powered on by pressing the
+		front button.
+
+		This file configures whether front button power on is enabled.
+
+		This file is present only if the power off feature is supported
+		by the firmware.
+
+		Format: %i.
+
 What:		/sys/bus/i2c/devices/<mcu_device>/fw_features
 Date:		July 2024
 KernelVersion:	6.10
diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
index 3a8c3edcd7e6..0a752aa654fa 100644
--- a/drivers/platform/cznic/Kconfig
+++ b/drivers/platform/cznic/Kconfig
@@ -19,10 +19,14 @@ config TURRIS_OMNIA_MCU
 	depends on I2C
 	select GPIOLIB
 	select GPIOLIB_IRQCHIP
+	select RTC_CLASS
 	help
 	  Say Y here to add support for the features implemented by the
 	  microcontroller on the CZ.NIC's Turris Omnia SOHO router.
 	  The features include:
+	  - board poweroff into true low power mode (with voltage regulators
+	    disabled) and the ability to configure wake up from this mode (via
+	    rtcwake)
 	  - GPIO pins
 	    - to get front button press events (the front button can be
 	      configured either to generate press events to the CPU or to change
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
index 53fd8f1777a3..a185ef882e44 100644
--- a/drivers/platform/cznic/Makefile
+++ b/drivers/platform/cznic/Makefile
@@ -3,3 +3,4 @@
 obj-$(CONFIG_TURRIS_OMNIA_MCU)	+= turris-omnia-mcu.o
 turris-omnia-mcu-y		:= turris-omnia-mcu-base.o
 turris-omnia-mcu-y		+= turris-omnia-mcu-gpio.o
+turris-omnia-mcu-y		+= turris-omnia-mcu-sys-off-wakeup.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
index 708b084cb5da..697ace090bda 100644
--- a/drivers/platform/cznic/turris-omnia-mcu-base.c
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -195,6 +195,7 @@ static const struct attribute_group omnia_mcu_base_group = {
 static const struct attribute_group *omnia_mcu_groups[] = {
 	&omnia_mcu_base_group,
 	&omnia_mcu_gpio_group,
+	&omnia_mcu_poweroff_group,
 	NULL
 };
 
@@ -360,6 +361,10 @@ static int omnia_mcu_probe(struct i2c_client *client)
 					     "Cannot read board info\n");
 	}
 
+	err = omnia_mcu_register_sys_off_and_wakeup(mcu);
+	if (err)
+		return err;
+
 	return omnia_mcu_register_gpiochip(mcu);
 }
 
diff --git a/drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c b/drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c
new file mode 100644
index 000000000000..fbd1b4cd7011
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU system off and RTC wakeup driver
+ *
+ * This is not a true RTC driver (in the sense that it does not provide a
+ * real-time clock), rather the MCU implements a wakeup from powered off state
+ * at a specified time relative to MCU boot, and we expose this feature via RTC
+ * alarm, so that it can be used via the rtcwake command, which is the standard
+ * Linux command for this.
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#include <linux/crc32.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/reboot.h>
+#include <linux/rtc.h>
+#include <linux/sysfs.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+
+#include "turris-omnia-mcu.h"
+
+static int omnia_get_uptime_wakeup(const struct i2c_client *client, u32 *uptime,
+				   u32 *wakeup)
+{
+	__le32 reply[2];
+	int err;
+
+	err = omnia_cmd_read(client, CMD_GET_UPTIME_AND_WAKEUP, reply,
+			     sizeof(reply));
+	if (err)
+		return err;
+
+	if (uptime)
+		*uptime = le32_to_cpu(reply[0]);
+
+	if (wakeup)
+		*wakeup = le32_to_cpu(reply[1]);
+
+	return 0;
+}
+
+static int omnia_read_time(struct device *dev, struct rtc_time *tm)
+{
+	u32 uptime;
+	int err;
+
+	err = omnia_get_uptime_wakeup(to_i2c_client(dev), &uptime, NULL);
+	if (err)
+		return err;
+
+	rtc_time64_to_tm(uptime, tm);
+
+	return 0;
+}
+
+static int omnia_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct omnia_mcu *mcu = i2c_get_clientdata(client);
+	u32 wakeup;
+	int err;
+
+	err = omnia_get_uptime_wakeup(client, NULL, &wakeup);
+	if (err)
+		return err;
+
+	alrm->enabled = !!wakeup;
+	rtc_time64_to_tm(wakeup ?: mcu->rtc_alarm, &alrm->time);
+
+	return 0;
+}
+
+static int omnia_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct omnia_mcu *mcu = i2c_get_clientdata(client);
+
+	mcu->rtc_alarm = rtc_tm_to_time64(&alrm->time);
+
+	if (alrm->enabled)
+		return omnia_cmd_write_u32(client, CMD_SET_WAKEUP,
+					   mcu->rtc_alarm);
+
+	return 0;
+}
+
+static int omnia_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct omnia_mcu *mcu = i2c_get_clientdata(client);
+
+	return omnia_cmd_write_u32(client, CMD_SET_WAKEUP,
+				   enabled ? mcu->rtc_alarm : 0);
+}
+
+static const struct rtc_class_ops omnia_rtc_ops = {
+	.read_time		= omnia_read_time,
+	.read_alarm		= omnia_read_alarm,
+	.set_alarm		= omnia_set_alarm,
+	.alarm_irq_enable	= omnia_alarm_irq_enable,
+};
+
+static int omnia_power_off(struct sys_off_data *data)
+{
+	struct omnia_mcu *mcu = data->cb_data;
+	__be32 tmp;
+	u8 cmd[9];
+	u16 arg;
+	int err;
+
+	if (mcu->front_button_poweron)
+		arg = CMD_POWER_OFF_POWERON_BUTTON;
+	else
+		arg = 0;
+
+	cmd[0] = CMD_POWER_OFF;
+	put_unaligned_le16(CMD_POWER_OFF_MAGIC, &cmd[1]);
+	put_unaligned_le16(arg, &cmd[3]);
+
+	/*
+	 * Although all values from and to MCU are passed in little-endian, the
+	 * MCU's CRC unit uses big-endian CRC32 polynomial (0x04c11db7), so we
+	 * need to use crc32_be() here.
+	 */
+	tmp = cpu_to_be32(get_unaligned_le32(&cmd[1]));
+	put_unaligned_le32(crc32_be(0xffffffff, (void *)&tmp, sizeof(tmp)),
+			   &cmd[5]);
+
+	err = omnia_cmd_write(mcu->client, cmd, sizeof(cmd));
+	if (err)
+		dev_err(&mcu->client->dev,
+			"Unable to send the poweroff command: %d\n", err);
+
+	return NOTIFY_DONE;
+}
+
+static int omnia_restart(struct sys_off_data *data)
+{
+	struct omnia_mcu *mcu = data->cb_data;
+	u8 cmd[3];
+	int err;
+
+	cmd[0] = CMD_GENERAL_CONTROL;
+
+	if (reboot_mode == REBOOT_HARD)
+		cmd[1] = cmd[2] = CTL_HARD_RST;
+	else
+		cmd[1] = cmd[2] = CTL_LIGHT_RST;
+
+	err = omnia_cmd_write(mcu->client, cmd, sizeof(cmd));
+	if (err)
+		dev_err(&mcu->client->dev,
+			"Unable to send the restart command: %d\n", err);
+
+	/*
+	 * MCU needs a little bit to process the I2C command, otherwise it will
+	 * do a light reset based on SOC SYSRES_OUT pin.
+	 */
+	mdelay(1);
+
+	return NOTIFY_DONE;
+}
+
+static ssize_t front_button_poweron_show(struct device *dev,
+					 struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", mcu->front_button_poweron);
+}
+
+static ssize_t front_button_poweron_store(struct device *dev,
+					  struct device_attribute *a,
+					  const char *buf, size_t count)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+	bool val;
+	int err;
+
+	err = kstrtobool(buf, &val);
+	if (err)
+		return err;
+
+	mcu->front_button_poweron = val;
+
+	return count;
+}
+static DEVICE_ATTR_RW(front_button_poweron);
+
+static struct attribute *omnia_mcu_poweroff_attrs[] = {
+	&dev_attr_front_button_poweron.attr,
+	NULL
+};
+
+static umode_t poweroff_attrs_visible(struct kobject *kobj, struct attribute *a,
+				      int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	if (mcu->features & FEAT_POWEROFF_WAKEUP)
+		return a->mode;
+
+	return 0;
+}
+
+const struct attribute_group omnia_mcu_poweroff_group = {
+	.attrs = omnia_mcu_poweroff_attrs,
+	.is_visible = poweroff_attrs_visible,
+};
+
+int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu)
+{
+	struct device *dev = &mcu->client->dev;
+	int err;
+
+	/* MCU restart is always available */
+	err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART,
+					    SYS_OFF_PRIO_FIRMWARE,
+					    omnia_restart, mcu);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Cannot register system restart handler\n");
+
+	/*
+	 * Poweroff and wakeup are available only if POWEROFF_WAKEUP feature is
+	 * present.
+	 */
+	if (!(mcu->features & FEAT_POWEROFF_WAKEUP))
+		return 0;
+
+	err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_POWER_OFF,
+					    SYS_OFF_PRIO_FIRMWARE,
+					    omnia_power_off, mcu);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Cannot register system power off handler\n");
+
+	mcu->rtcdev = devm_rtc_allocate_device(dev);
+	if (IS_ERR(mcu->rtcdev))
+		return dev_err_probe(dev, PTR_ERR(mcu->rtcdev),
+				     "Cannot allocate RTC device\n");
+
+	mcu->rtcdev->ops = &omnia_rtc_ops;
+	mcu->rtcdev->range_max = U32_MAX;
+	set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, mcu->rtcdev->features);
+
+	err = devm_rtc_register_device(mcu->rtcdev);
+	if (err)
+		return dev_err_probe(dev, err, "Cannot register RTC device\n");
+
+	mcu->front_button_poweron = true;
+
+	return 0;
+}
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
index e8d9bf1c8fdc..6179a4f2069e 100644
--- a/drivers/platform/cznic/turris-omnia-mcu.h
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -12,9 +12,11 @@
 #include <linux/gpio/driver.h>
 #include <linux/if_ether.h>
 #include <linux/mutex.h>
+#include <linux/rtc.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
 #include <asm/byteorder.h>
+#include <asm/unaligned.h>
 
 struct omnia_mcu {
 	struct i2c_client *client;
@@ -34,6 +36,11 @@ struct omnia_mcu {
 	struct delayed_work button_release_emul_work;
 	u16 last_status;
 	bool button_pressed_emul;
+
+	/* RTC device for configuring wake-up */
+	struct rtc_device *rtcdev;
+	u32 rtc_alarm;
+	bool front_button_poweron;
 };
 
 int omnia_cmd_write_read(const struct i2c_client *client,
@@ -46,6 +53,17 @@ static inline int omnia_cmd_write(const struct i2c_client *client, void *cmd,
 	return omnia_cmd_write_read(client, cmd, len, NULL, 0);
 }
 
+static inline int omnia_cmd_write_u32(const struct i2c_client *client, u8 cmd,
+				      u32 val)
+{
+	u8 buf[5];
+
+	buf[0] = cmd;
+	put_unaligned_le32(val, &buf[1]);
+
+	return omnia_cmd_write(client, buf, sizeof(buf));
+}
+
 static inline int omnia_cmd_read(const struct i2c_client *client, u8 cmd,
 				 void *reply, unsigned int len)
 {
@@ -107,7 +125,9 @@ static inline int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
 }
 
 extern const struct attribute_group omnia_mcu_gpio_group;
+extern const struct attribute_group omnia_mcu_poweroff_group;
 
 int omnia_mcu_register_gpiochip(struct omnia_mcu *mcu);
+int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu);
 
 #endif /* __TURRIS_OMNIA_MCU_H */
-- 
2.43.2

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Andy Shevchenko]

On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
>
> Add the basic skeleton for a new platform driver for the microcontroller
> found on the Turris Omnia board.

...

> +What:          /sys/bus/i2c/devices/<mcu_device>/serial_number
> +Date:          July 2024
> +KernelVersion: 6.10
> +Contact:       Marek Behún <kabel@kernel.org>
> +Description:   (RO) Contains the 64 bit long board serial number in hexadecimal

64 bit long --> 64-bit

> +               format.
> +
> +               Only available if board information is burned in the MCU (older
> +               revisions have board information burned in the ATSHA204-A chip).
> +
> +               Format: %016X.

It's strange to use capitalized hexadecimal here and not in other
files, but maybe it's something special about "serial number"? Dunno.

...

> +menuconfig CZNIC_PLATFORMS
> +       bool "Platform support for CZ.NIC's Turris hardware"

> +       depends on MACH_ARMADA_38X || COMPILE_TEST

This...

> +       help
> +         Say Y here to be able to choose driver support for CZ.NIC's Turris
> +         devices. This option alone does not add any kernel code.
> +
> +if CZNIC_PLATFORMS
> +
> +config TURRIS_OMNIA_MCU
> +       tristate "Turris Omnia MCU driver"

> +       depends on MACH_ARMADA_38X || COMPILE_TEST

...or this dependency is redundant. I think one would expect that
these platforms will not be always based on the same platform, hence I
would drop the former and leave the latter. But you should know better
than me.

> +       depends on I2C
> +       help
> +         Say Y here to add support for the features implemented by the
> +         microcontroller on the CZ.NIC's Turris Omnia SOHO router.
> +         To compile this driver as a module, choose M here; the module will be
> +         called turris-omnia-mcu.

...

> +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])

Interesting format of the last parameter. Does it make any difference
to the compiler if you use u8 *version?

> +{
> +       u8 reply[OMNIA_FW_VERSION_LEN];
> +       int err;
> +
> +       err = omnia_cmd_read(mcu->client,
> +                            bootloader ? CMD_GET_FW_VERSION_BOOT
> +                                       : CMD_GET_FW_VERSION_APP,
> +                            reply, sizeof(reply));
> +       if (err)
> +               return err;

> +       version[OMNIA_FW_VERSION_HEX_LEN - 1] = '\0';
> +       bin2hex(version, reply, OMNIA_FW_VERSION_LEN);

Hmm... I would rather use returned value

char *p;

p = bin2hex(...);
*p = '\0';

return 0;

> +       return 0;
> +}

...

> +static umode_t omnia_mcu_base_attrs_visible(struct kobject *kobj,
> +                                           struct attribute *a, int n)
> +{
> +       struct device *dev = kobj_to_dev(kobj);
> +       struct omnia_mcu *mcu = dev_get_drvdata(dev);

> +       umode_t mode = a->mode;

Do you need this?

> +       if ((a == &dev_attr_serial_number.attr ||
> +            a == &dev_attr_first_mac_address.attr ||
> +            a == &dev_attr_board_revision.attr) &&
> +           !(mcu->features & FEAT_BOARD_INFO))

> +               mode = 0;

return 0; ?

> +       return mode;

return a->mode; ?

> +}

...

> +static void omnia_mcu_print_version_hash(struct omnia_mcu *mcu, bool bootloader)
> +{
> +       const char *type = bootloader ? "bootloader" : "application";
> +       struct device *dev = &mcu->client->dev;
> +       u8 version[OMNIA_FW_VERSION_HEX_LEN];
> +       int err;
> +
> +       err = omnia_get_version_hash(mcu, bootloader, version);
> +       if (err) {
> +               dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
> +                       err);

One  line?

> +               return;
> +       }
> +
> +       dev_info(dev, "MCU %s firmware version hash: %s\n", type, version);
> +}

...

> +static const char *omnia_status_to_mcu_type(uint16_t status)

Why out of a sudden uint16_t instead of u16?

> +{
> +       switch (status & STS_MCU_TYPE_MASK) {
> +       case STS_MCU_TYPE_STM32:
> +               return "STM32";
> +       case STS_MCU_TYPE_GD32:
> +               return "GD32";
> +       case STS_MCU_TYPE_MKL:
> +               return "MKL";
> +       default:
> +               return "unknown";
> +       }
> +}

...

> +       static const struct {
> +               uint16_t mask;

Ditto.

> +               const char *name;
> +       } features[] = {
> +               { FEAT_EXT_CMDS,           "extended control and status" },
> +               { FEAT_WDT_PING,           "watchdog pinging" },
> +               { FEAT_LED_STATE_EXT_MASK, "peripheral LED pins reading" },
> +               { FEAT_NEW_INT_API,        "new interrupt API" },
> +               { FEAT_POWEROFF_WAKEUP,    "poweroff and wakeup" },
> +               { FEAT_TRNG,               "true random number generator" },
> +       };

...

> +               omnia_info_missing_feature(dev, "feature reading");

Tautology. Read the final message. I believe you wanted to pass just
"reading" here.

...

> +       memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);

There is an API ether_copy_addr() or so, don't remember by heart.
You also need an include for ETH_ALEN definition.

...

> +#include <linux/i2c.h>

No users of this, you may replace with

struct i2c_client;

Am I right?

...

> +       CMD_GET_FW_VERSION_BOOT         = 0x0E, /* 20B git hash number */

Git

...

> +       /* available only at address 0x2b (led-controller) */

LED-controller

...

> +enum omnia_ctl_byte_e {
> +       CTL_LIGHT_RST           = BIT(0),
> +       CTL_HARD_RST            = BIT(1),
> +       /* BIT(2) is currently reserved */
> +       CTL_USB30_PWRON         = BIT(3),
> +       CTL_USB31_PWRON         = BIT(4),
> +       CTL_ENABLE_4V5          = BIT(5),
> +       CTL_BUTTON_MODE         = BIT(6),
> +       CTL_BOOTLOADER          = BIT(7)

Keep trailing comma as it might be extended (theoretically). And you
do the similar in other enums anyway.

> +};

--
With Best Regards,
Andy Shevchenko

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

On Tue, 30 Apr 2024 15:53:51 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
> >
> > Add the basic skeleton for a new platform driver for the microcontroller
> > found on the Turris Omnia board.  
> 
> ...
> 
> > +What:          /sys/bus/i2c/devices/<mcu_device>/serial_number
> > +Date:          July 2024
> > +KernelVersion: 6.10
> > +Contact:       Marek Behún <kabel@kernel.org>
> > +Description:   (RO) Contains the 64 bit long board serial number in hexadecimal  
> 
> 64 bit long --> 64-bit

ok

> 
> > +               format.
> > +
> > +               Only available if board information is burned in the MCU (older
> > +               revisions have board information burned in the ATSHA204-A chip).
> > +
> > +               Format: %016X.  
> 
> It's strange to use capitalized hexadecimal here and not in other
> files, but maybe it's something special about "serial number"? Dunno.

Yes, the serial number is printed with captial hex letters.

> > +menuconfig CZNIC_PLATFORMS
> > +       bool "Platform support for CZ.NIC's Turris hardware"  
> 
> > +       depends on MACH_ARMADA_38X || COMPILE_TEST  
> 
> This...
> 
> > +       help
> > +         Say Y here to be able to choose driver support for CZ.NIC's Turris
> > +         devices. This option alone does not add any kernel code.
> > +
> > +if CZNIC_PLATFORMS
> > +
> > +config TURRIS_OMNIA_MCU
> > +       tristate "Turris Omnia MCU driver"  
> 
> > +       depends on MACH_ARMADA_38X || COMPILE_TEST  
> 
> ...or this dependency is redundant. I think one would expect that
> these platforms will not be always based on the same platform, hence I
> would drop the former and leave the latter. But you should know better
> than me.

ok

> 
> > +       depends on I2C
> > +       help
> > +         Say Y here to add support for the features implemented by the
> > +         microcontroller on the CZ.NIC's Turris Omnia SOHO router.
> > +         To compile this driver as a module, choose M here; the module will be
> > +         called turris-omnia-mcu.  
> 
> ...
> 
> > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])  
> 
> Interesting format of the last parameter. Does it make any difference
> to the compiler if you use u8 *version?

The compiler will warn if an array with not enough space is passed as
argument.

> 
> > +{
> > +       u8 reply[OMNIA_FW_VERSION_LEN];
> > +       int err;
> > +
> > +       err = omnia_cmd_read(mcu->client,
> > +                            bootloader ? CMD_GET_FW_VERSION_BOOT
> > +                                       : CMD_GET_FW_VERSION_APP,
> > +                            reply, sizeof(reply));
> > +       if (err)
> > +               return err;  
> 
> > +       version[OMNIA_FW_VERSION_HEX_LEN - 1] = '\0';
> > +       bin2hex(version, reply, OMNIA_FW_VERSION_LEN);  
> 
> Hmm... I would rather use returned value
> 
> char *p;
> 
> p = bin2hex(...);
> *p = '\0';
> 
> return 0;

OK. I guess

  *bin2hex(version, reply, OMNIA_FW_VERSION_LEN) = '\0';

would be too crazy, right?

> 
> > +       return 0;
> > +}  
> 
> ...
> 
> > +static umode_t omnia_mcu_base_attrs_visible(struct kobject *kobj,
> > +                                           struct attribute *a, int n)
> > +{
> > +       struct device *dev = kobj_to_dev(kobj);
> > +       struct omnia_mcu *mcu = dev_get_drvdata(dev);  
> 
> > +       umode_t mode = a->mode;  
> 
> Do you need this?
> 
> > +       if ((a == &dev_attr_serial_number.attr ||
> > +            a == &dev_attr_first_mac_address.attr ||
> > +            a == &dev_attr_board_revision.attr) &&
> > +           !(mcu->features & FEAT_BOARD_INFO))  
> 
> > +               mode = 0;  
> 
> return 0; ?
> 
> > +       return mode;  
> 
> return a->mode; ?

ok

> 
> > +}  
> 
> ...
> 
> > +static void omnia_mcu_print_version_hash(struct omnia_mcu *mcu, bool bootloader)
> > +{
> > +       const char *type = bootloader ? "bootloader" : "application";
> > +       struct device *dev = &mcu->client->dev;
> > +       u8 version[OMNIA_FW_VERSION_HEX_LEN];
> > +       int err;
> > +
> > +       err = omnia_get_version_hash(mcu, bootloader, version);
> > +       if (err) {
> > +               dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
> > +                       err);  
> 
> One  line?

I'd like to keep this driver to 80 columns.

> 
> > +               return;
> > +       }
> > +
> > +       dev_info(dev, "MCU %s firmware version hash: %s\n", type, version);
> > +}  
> 
> ...
> 
> > +static const char *omnia_status_to_mcu_type(uint16_t status)  
> 
> Why out of a sudden uint16_t instead of u16?

This was a mistake, thanks.

> > +{
> > +       switch (status & STS_MCU_TYPE_MASK) {
> > +       case STS_MCU_TYPE_STM32:
> > +               return "STM32";
> > +       case STS_MCU_TYPE_GD32:
> > +               return "GD32";
> > +       case STS_MCU_TYPE_MKL:
> > +               return "MKL";
> > +       default:
> > +               return "unknown";
> > +       }
> > +}  
> 
> ...
> 
> > +       static const struct {
> > +               uint16_t mask;  
> 
> Ditto.
> 
> > +               const char *name;
> > +       } features[] = {
> > +               { FEAT_EXT_CMDS,           "extended control and status" },
> > +               { FEAT_WDT_PING,           "watchdog pinging" },
> > +               { FEAT_LED_STATE_EXT_MASK, "peripheral LED pins reading" },
> > +               { FEAT_NEW_INT_API,        "new interrupt API" },
> > +               { FEAT_POWEROFF_WAKEUP,    "poweroff and wakeup" },
> > +               { FEAT_TRNG,               "true random number generator" },
> > +       };  
> 
> ...
> 
> > +               omnia_info_missing_feature(dev, "feature reading");  
> 
> Tautology. Read the final message. I believe you wanted to pass just
> "reading" here.

No, I actually wanted it to print
  Your board's MCU firmware does not support the feature reading
  feature.
as in the feature "feature reading" is not supported.
I guess I could change it to
  Your board's MCU firmware does not support the feature reading.
but that would complicate the code: either I would need to add
" feature" suffix to all the features[].name, or duplicate the
info string from the omnia_info_missing_feature() function.

> ...
> 
> > +       memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);  
> 
> There is an API ether_copy_addr() or so, don't remember by heart.
> You also need an include for ETH_ALEN definition.

Doc for ether_addr_copy says:
  Please note: dst & src must both be aligned to u16.
since the code does:
  u16 *a = (u16 *)dst;
  const u16 *b = (const u16 *)src;

  a[0] = b[0];
  a[1] = b[1];
  a[2] = b[2]

Since I am copying from &reply[9], which is not u16-aligned, this won't
work.

> ...
> 
> > +#include <linux/i2c.h>  
> 
> No users of this, you may replace with
> 
> struct i2c_client;
> 
> Am I right?

OK.

> 
> ...
> 
> > +       CMD_GET_FW_VERSION_BOOT         = 0x0E, /* 20B git hash
> > number */  
> 
> Git

OK.

> ...
> 
> > +       /* available only at address 0x2b (led-controller) */  
> 
> LED-controller

OK

> 
> ...
> 
> > +enum omnia_ctl_byte_e {
> > +       CTL_LIGHT_RST           = BIT(0),
> > +       CTL_HARD_RST            = BIT(1),
> > +       /* BIT(2) is currently reserved */
> > +       CTL_USB30_PWRON         = BIT(3),
> > +       CTL_USB31_PWRON         = BIT(4),
> > +       CTL_ENABLE_4V5          = BIT(5),
> > +       CTL_BUTTON_MODE         = BIT(6),
> > +       CTL_BOOTLOADER          = BIT(7)  
> 
> Keep trailing comma as it might be extended (theoretically). And you
> do the similar in other enums anyway.

ctl_byt is 8-bit, so this enum really can't be extended. In fact I need
to drop the last comma from omnia_ext_sts_dword_e and omnia_int_e.

Thanks, Andy.

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Dan Carpenter]

On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > +{
> > > +       u8 reply[OMNIA_FW_VERSION_LEN];
> > > +       int err;
> > > +
> > > +       err = omnia_cmd_read(mcu->client,
> > > +                            bootloader ? CMD_GET_FW_VERSION_BOOT
> > > +                                       : CMD_GET_FW_VERSION_APP,
> > > +                            reply, sizeof(reply));
> > > +       if (err)
> > > +               return err;  
> > 
> > > +       version[OMNIA_FW_VERSION_HEX_LEN - 1] = '\0';
> > > +       bin2hex(version, reply, OMNIA_FW_VERSION_LEN);  
> > 
> > Hmm... I would rather use returned value
> > 
> > char *p;
> > 
> > p = bin2hex(...);
> > *p = '\0';
> > 
> > return 0;
> 
> OK. I guess
> 
>   *bin2hex(version, reply, OMNIA_FW_VERSION_LEN) = '\0';
> 
> would be too crazy, right?

Indeed.  Please don't do that.  0_0

regards,
dan carpenter

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Andy Shevchenko]

On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> On Tue, 30 Apr 2024 15:53:51 +0300
> Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:

...

> > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > 
> > Interesting format of the last parameter. Does it make any difference
> > to the compiler if you use u8 *version?
> 
> The compiler will warn if an array with not enough space is passed as
> argument.

Really?

> > > +{
> > > +       u8 reply[OMNIA_FW_VERSION_LEN];
> > > +       int err;
> > > +
> > > +       err = omnia_cmd_read(mcu->client,
> > > +                            bootloader ? CMD_GET_FW_VERSION_BOOT
> > > +                                       : CMD_GET_FW_VERSION_APP,
> > > +                            reply, sizeof(reply));
> > > +       if (err)
> > > +               return err;  
> > 
> > > +       version[OMNIA_FW_VERSION_HEX_LEN - 1] = '\0';
> > > +       bin2hex(version, reply, OMNIA_FW_VERSION_LEN);  
> > 
> > Hmm... I would rather use returned value
> > 
> > char *p;
> > 
> > p = bin2hex(...);
> > *p = '\0';
> > 
> > return 0;
> 
> OK. I guess
> 
>   *bin2hex(version, reply, OMNIA_FW_VERSION_LEN) = '\0';
> 
> would be too crazy, right?

Yes, it's not a Python :-)

> > > +       return 0;
> > > +}  

...

> > > +               dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
> > > +                       err);  
> > 
> > One  line?
> 
> I'd like to keep this driver to 80 columns.

Then better to have a logical split then?

			dev_err(dev, "Cannot read MCU %s firmware version: %d\n",
				type, err);

...

> > > +               omnia_info_missing_feature(dev, "feature reading");  
> > 
> > Tautology. Read the final message. I believe you wanted to pass just
> > "reading" here.
> 
> No, I actually wanted it to print
>   Your board's MCU firmware does not support the feature reading
>   feature.
> as in the feature "feature reading" is not supported.
> I guess I could change it to
>   Your board's MCU firmware does not support the feature reading.
> but that would complicate the code: either I would need to add
> " feature" suffix to all the features[].name, or duplicate the
> info string from the omnia_info_missing_feature() function.

From point of a mere user (as I am towards this driver) I consider
the tautology confusing.

	...the 'reading' feature

may be a good compromise.

...

> > > +       memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);  
> > 
> > There is an API ether_copy_addr() or so, don't remember by heart.
> > You also need an include for ETH_ALEN definition.
> 
> Doc for ether_addr_copy says:
>   Please note: dst & src must both be aligned to u16.
> since the code does:
>   u16 *a = (u16 *)dst;
>   const u16 *b = (const u16 *)src;
> 
>   a[0] = b[0];
>   a[1] = b[1];
>   a[2] = b[2]
> 
> Since I am copying from &reply[9], which is not u16-aligned, this won't
> work.

It would work on architectures that support misaligned accesses, but in general
you are right. Perhaps a comment on top to avoid "cleanup" patches like this?

...

> > > +enum omnia_ctl_byte_e {
> > > +       CTL_LIGHT_RST           = BIT(0),
> > > +       CTL_HARD_RST            = BIT(1),
> > > +       /* BIT(2) is currently reserved */
> > > +       CTL_USB30_PWRON         = BIT(3),
> > > +       CTL_USB31_PWRON         = BIT(4),
> > > +       CTL_ENABLE_4V5          = BIT(5),
> > > +       CTL_BUTTON_MODE         = BIT(6),
> > > +       CTL_BOOTLOADER          = BIT(7)  
> > 
> > Keep trailing comma as it might be extended (theoretically). And you
> > do the similar in other enums anyway.
> 
> ctl_byt is 8-bit, so this enum really can't be extended.

I understand that (even before writing the previous reply).

> In fact I need
> to drop the last comma from omnia_ext_sts_dword_e and omnia_int_e.

Who prevents from having in a new firmware let's say

 BIT(31) | BIT(1)

as a new value?

From Linux perspective these are not terminating lines.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 8901 bytes --]

On Tue, 30 Apr 2024, Marek Behún wrote:

> Add the basic skeleton for a new platform driver for the microcontroller
> found on the Turris Omnia board.
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>

> +	struct device *dev = &mcu->client->dev;
> +	bool suggest_fw_upgrade = false;
> +	int status;
> +
> +	/* status word holds MCU type, which we need below */
> +	status = omnia_cmd_read_u16(mcu->client, CMD_GET_STATUS_WORD);
> +	if (status < 0)
> +		return status;
> +
> +	/* check whether MCU firmware supports the CMD_GET_FEAUTRES command */

FEATURES

> +	if (status & STS_FEATURES_SUPPORTED) {
> +		__le32 reply;
> +		int ret;
> +
> +		/* try read 32-bit features */
> +		ret = omnia_cmd_read(mcu->client, CMD_GET_FEATURES, &reply,
> +				     sizeof(reply));
> +		if (ret) {
> +			/* try read 16-bit features */
> +			ret = omnia_cmd_read_u16(mcu->client, CMD_GET_FEATURES);
> +			if (ret < 0)
> +				return ret;
> +
> +			mcu->features = ret;
> +		} else {
> +			mcu->features = le32_to_cpu(reply);
> +
> +			if (mcu->features & FEAT_FROM_BIT_16_INVALID)
> +				mcu->features &= GENMASK(15, 0);
> +		}

I'm not a big fan of the inconsistency here when it comes to who handles 
the endianness, perhaps there is a good reason for that but it looks a bit 
odd to have it done in a different way for 32-bit and 16-bit.

> +	} else {
> +		omnia_info_missing_feature(dev, "feature reading");
> +		suggest_fw_upgrade = true;
> +	}
> +
> +	mcu->type = omnia_status_to_mcu_type(status);
> +	dev_info(dev, "MCU type %s%s\n", mcu->type,
> +		 (mcu->features & FEAT_PERIPH_MCU) ?
> +			", with peripheral resets wired" : "");
> +
> +	omnia_mcu_print_version_hash(mcu, true);
> +
> +	if (mcu->features & FEAT_BOOTLOADER)
> +		dev_warn(dev,
> +			 "MCU is running bootloader firmware. Was firmware upgrade interrupted?\n");
> +	else
> +		omnia_mcu_print_version_hash(mcu, false);
> +
> +	for (unsigned int i = 0; i < ARRAY_SIZE(features); i++) {
> +		if (mcu->features & features[i].mask)
> +			continue;
> +
> +		omnia_info_missing_feature(dev, features[i].name);
> +		suggest_fw_upgrade = true;
> +	}
> +
> +	if (suggest_fw_upgrade)
> +		dev_info(dev,
> +			 "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
> +
> +	return 0;
> +}

> +int omnia_cmd_read(const struct i2c_client *client, u8 cmd, void *reply,
> +		   unsigned int len);
> +
> +static inline int omnia_cmd_read_u16(const struct i2c_client *client, u8 cmd)
> +{
> +	__le16 reply;
> +	int err;
> +
> +	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
> +
> +	return err ?: le16_to_cpu(reply);
> +}
> +
> +static inline int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
> +{
> +	u8 reply;
> +	int err;
> +
> +	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
> +
> +	return err ?: reply;
> +}
> +
> +#endif /* __TURRIS_OMNIA_MCU_H */


> diff --git a/include/linux/turris-omnia-mcu-interface.h b/include/linux/turris-omnia-mcu-interface.h
> new file mode 100644
> index 000000000000..88f8490b5897
> --- /dev/null
> +++ b/include/linux/turris-omnia-mcu-interface.h
> @@ -0,0 +1,249 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * CZ.NIC's Turris Omnia MCU I2C interface commands definitions
> + *
> + * 2024 by Marek Behún <kabel@kernel.org>
> + */
> +
> +#ifndef __TURRIS_OMNIA_MCU_INTERFACE_H
> +#define __TURRIS_OMNIA_MCU_INTERFACE_H
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +
> +enum omnia_commands_e {
> +	CMD_GET_STATUS_WORD		= 0x01, /* slave sends status word back */
> +	CMD_GENERAL_CONTROL		= 0x02,
> +	CMD_LED_MODE			= 0x03, /* default/user */
> +	CMD_LED_STATE			= 0x04, /* LED on/off */
> +	CMD_LED_COLOR			= 0x05, /* LED number + RED + GREEN + BLUE */
> +	CMD_USER_VOLTAGE		= 0x06,
> +	CMD_SET_BRIGHTNESS		= 0x07,
> +	CMD_GET_BRIGHTNESS		= 0x08,
> +	CMD_GET_RESET			= 0x09,
> +	CMD_GET_FW_VERSION_APP		= 0x0A, /* 20B git hash number */
> +	CMD_SET_WATCHDOG_STATE		= 0x0B, /* 0 - disable
> +						 * 1 - enable / ping
> +						 * after boot watchdog is started
> +						 * with 2 minutes timeout
> +						 */
> +
> +	/* CMD_WATCHDOG_STATUS		= 0x0C, not implemented anymore */
> +
> +	CMD_GET_WATCHDOG_STATE		= 0x0D,
> +	CMD_GET_FW_VERSION_BOOT		= 0x0E, /* 20B git hash number */
> +	CMD_GET_FW_CHECKSUM		= 0x0F, /* 4B length, 4B checksum */
> +
> +	/* available if FEATURES_SUPPORTED bit set in status word */
> +	CMD_GET_FEATURES		= 0x10,
> +
> +	/* available if EXT_CMD bit set in features */
> +	CMD_GET_EXT_STATUS_DWORD	= 0x11,
> +	CMD_EXT_CONTROL			= 0x12,
> +	CMD_GET_EXT_CONTROL_STATUS	= 0x13,
> +
> +	/* available if NEW_INT_API bit set in features */
> +	CMD_GET_INT_AND_CLEAR		= 0x14,
> +	CMD_GET_INT_MASK		= 0x15,
> +	CMD_SET_INT_MASK		= 0x16,
> +
> +	/* available if FLASHING bit set in features */
> +	CMD_FLASH			= 0x19,
> +
> +	/* available if WDT_PING bit set in features */
> +	CMD_SET_WDT_TIMEOUT		= 0x20,
> +	CMD_GET_WDT_TIMELEFT		= 0x21,
> +
> +	/* available if POWEROFF_WAKEUP bit set in features */
> +	CMD_SET_WAKEUP			= 0x22,
> +	CMD_GET_UPTIME_AND_WAKEUP	= 0x23,
> +	CMD_POWER_OFF			= 0x24,
> +
> +	/* available if USB_OVC_PROT_SETTING bit set in features */
> +	CMD_SET_USB_OVC_PROT		= 0x25,
> +	CMD_GET_USB_OVC_PROT		= 0x26,
> +
> +	/* available if TRNG bit set in features */
> +	CMD_TRNG_COLLECT_ENTROPY	= 0x28,
> +
> +	/* available if CRYPTO bit set in features */
> +	CMD_CRYPTO_GET_PUBLIC_KEY	= 0x29,
> +	CMD_CRYPTO_SIGN_MESSAGE		= 0x2A,
> +	CMD_CRYPTO_COLLECT_SIGNATURE	= 0x2B,
> +
> +	/* available if BOARD_INFO it set in features */
> +	CMD_BOARD_INFO_GET		= 0x2C,
> +	CMD_BOARD_INFO_BURN		= 0x2D,
> +
> +	/* available only at address 0x2b (led-controller) */
> +	/* available only if LED_GAMMA_CORRECTION bit set in features */
> +	CMD_SET_GAMMA_CORRECTION	= 0x30,
> +	CMD_GET_GAMMA_CORRECTION	= 0x31,
> +
> +	/* available only at address 0x2b (led-controller) */
> +	/* available only if PER_LED_CORRECTION bit set in features */
> +	/* available only if FROM_BIT_16_INVALID bit NOT set in features */
> +	CMD_SET_LED_CORRECTIONS		= 0x32,
> +	CMD_GET_LED_CORRECTIONS		= 0x33,
> +};
> +
> +enum omnia_flashing_commands_e {
> +	FLASH_CMD_UNLOCK		= 0x01,
> +	FLASH_CMD_SIZE_AND_CSUM		= 0x02,
> +	FLASH_CMD_PROGRAM		= 0x03,
> +	FLASH_CMD_RESET			= 0x04,
> +};

I'm bit worried about many items above, they seem generic enough they 
could trigger name conflict at some point. Could these all defines be 
prefixed so there's no risk of collisions.

> +enum omnia_sts_word_e {
> +	STS_MCU_TYPE_MASK			= GENMASK(1, 0),
> +	STS_MCU_TYPE_STM32			= 0 << 0,
> +	STS_MCU_TYPE_GD32			= 1 << 0,
> +	STS_MCU_TYPE_MKL			= 2 << 0,

These are FIELD_PREP(STS_MCU_TYPE_MASK, x), although I suspect you need to 
use FIELD_PREP_CONST() in this context. If neither ends up working in this 
context, then leave it as is.

> +	STS_FEATURES_SUPPORTED			= BIT(2),
> +	STS_USER_REGULATOR_NOT_SUPPORTED	= BIT(3),
> +	STS_CARD_DET				= BIT(4),
> +	STS_MSATA_IND				= BIT(5),
> +	STS_USB30_OVC				= BIT(6),
> +	STS_USB31_OVC				= BIT(7),
> +	STS_USB30_PWRON				= BIT(8),
> +	STS_USB31_PWRON				= BIT(9),
> +	STS_ENABLE_4V5				= BIT(10),
> +	STS_BUTTON_MODE				= BIT(11),
> +	STS_BUTTON_PRESSED			= BIT(12),
> +	STS_BUTTON_COUNTER_MASK			= GENMASK(15, 13)
> +};
> +
> +enum omnia_ctl_byte_e {
> +	CTL_LIGHT_RST		= BIT(0),
> +	CTL_HARD_RST		= BIT(1),
> +	/* BIT(2) is currently reserved */
> +	CTL_USB30_PWRON		= BIT(3),
> +	CTL_USB31_PWRON		= BIT(4),
> +	CTL_ENABLE_4V5		= BIT(5),
> +	CTL_BUTTON_MODE		= BIT(6),
> +	CTL_BOOTLOADER		= BIT(7)
> +};
> +
> +enum omnia_features_e {
> +	FEAT_PERIPH_MCU			= BIT(0),
> +	FEAT_EXT_CMDS			= BIT(1),
> +	FEAT_WDT_PING			= BIT(2),
> +	FEAT_LED_STATE_EXT_MASK		= GENMASK(4, 3),
> +	FEAT_LED_STATE_EXT		= 1 << 3,
> +	FEAT_LED_STATE_EXT_V32		= 2 << 3,

Ditto.

> +	FEAT_LED_GAMMA_CORRECTION	= BIT(5),
> +	FEAT_NEW_INT_API		= BIT(6),
> +	FEAT_BOOTLOADER			= BIT(7),
> +	FEAT_FLASHING			= BIT(8),
> +	FEAT_NEW_MESSAGE_API		= BIT(9),
> +	FEAT_BRIGHTNESS_INT		= BIT(10),
> +	FEAT_POWEROFF_WAKEUP		= BIT(11),
> +	FEAT_CAN_OLD_MESSAGE_API	= BIT(12),
> +	FEAT_TRNG			= BIT(13),
> +	FEAT_CRYPTO			= BIT(14),
> +	FEAT_BOARD_INFO			= BIT(15),
> +
> +	/*
> +	 * Orginally the features command replied only 16 bits. If more were
> +	 * read, either the I2C transaction failed or 0xff bytes were sent.
> +	 * Therefore to consider bits 16 - 31 valid, one bit (20) was reserved
> +	 * to be zero.
> +	 */
> +
> +	/* Bits 16 - 19 correspond to bits 0 - 3 of status word */
> +	FEAT_MCU_TYPE_MASK		= GENMASK(17, 16),
> +	FEAT_MCU_TYPE_STM32		= 0 << 16,
> +	FEAT_MCU_TYPE_GD32		= 1 << 16,
> +	FEAT_MCU_TYPE_MKL		= 2 << 16,

Ditto.


-- 
 i.

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > On Tue, 30 Apr 2024 15:53:51 +0300
> > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
> 
> ...
> 
> > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > 
> > > Interesting format of the last parameter. Does it make any difference
> > > to the compiler if you use u8 *version?
> > 
> > The compiler will warn if an array with not enough space is passed as
> > argument.
> 
> Really?

Indeed:

  extern void a(char *x);

  static void b(char x[static 10]) {
      a(x);
  }

  void c(void) {
      char x[5] = "abcd";
      b(x);
  }

says:
  test.c: In function ‘c’:
  test.c:9:9: warning: ‘b’ accessing 10 bytes in a region of size 5 [-Wstringop-overflow=]
      9 |         b(x);
        |         ^~~~
  test.c:9:9: note: referencing argument 1 of type ‘char[10]’
  test.c:3:13: note: in a call to function ‘b’
      3 | static void b(char x[static 10]) {
        |

...

> > > > +               dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
> > > > +                       err);  
> > > 
> > > One  line?
> > 
> > I'd like to keep this driver to 80 columns.
> 
> Then better to have a logical split then?
> 
> 			dev_err(dev, "Cannot read MCU %s firmware version: %d\n",
> 				type, err);

OK

> > > > +               omnia_info_missing_feature(dev, "feature reading");  
> > > 
> > > Tautology. Read the final message. I believe you wanted to pass just
> > > "reading" here.
> > 
> > No, I actually wanted it to print
> >   Your board's MCU firmware does not support the feature reading
> >   feature.
> > as in the feature "feature reading" is not supported.
> > I guess I could change it to
> >   Your board's MCU firmware does not support the feature reading.
> > but that would complicate the code: either I would need to add
> > " feature" suffix to all the features[].name, or duplicate the
> > info string from the omnia_info_missing_feature() function.
> 
> From point of a mere user (as I am towards this driver) I consider
> the tautology confusing.
> 
> 	...the 'reading' feature
> 
> may be a good compromise.

I have rewritten it to use another dev_info:
  dev_info(dev,
           "Your board's MCU firmware does not support feature reading.\n");

> 
> ...
> 
> > > > +       memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);  
> > > 
> > > There is an API ether_copy_addr() or so, don't remember by heart.
> > > You also need an include for ETH_ALEN definition.
> > 
> > Doc for ether_addr_copy says:
> >   Please note: dst & src must both be aligned to u16.
> > since the code does:
> >   u16 *a = (u16 *)dst;
> >   const u16 *b = (const u16 *)src;
> > 
> >   a[0] = b[0];
> >   a[1] = b[1];
> >   a[2] = b[2]
> > 
> > Since I am copying from &reply[9], which is not u16-aligned, this won't
> > work.
> 
> It would work on architectures that support misaligned accesses, but in general
> you are right. Perhaps a comment on top to avoid "cleanup" patches like this?


OK
 
> > > > +enum omnia_ctl_byte_e {
> > > > +       CTL_LIGHT_RST           = BIT(0),
> > > > +       CTL_HARD_RST            = BIT(1),
> > > > +       /* BIT(2) is currently reserved */
> > > > +       CTL_USB30_PWRON         = BIT(3),
> > > > +       CTL_USB31_PWRON         = BIT(4),
> > > > +       CTL_ENABLE_4V5          = BIT(5),
> > > > +       CTL_BUTTON_MODE         = BIT(6),
> > > > +       CTL_BOOTLOADER          = BIT(7)  
> > > 
> > > Keep trailing comma as it might be extended (theoretically). And you
> > > do the similar in other enums anyway.
> > 
> > ctl_byt is 8-bit, so this enum really can't be extended.
> 
> I understand that (even before writing the previous reply).
> 
> > In fact I need
> > to drop the last comma from omnia_ext_sts_dword_e and omnia_int_e.
> 
> Who prevents from having in a new firmware let's say
> 
>  BIT(31) | BIT(1)
> 
> as a new value?
> 
> From Linux perspective these are not terminating lines.

OK

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Andy Shevchenko]

On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:

...

> > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > >
> > > > Interesting format of the last parameter. Does it make any difference
> > > > to the compiler if you use u8 *version?
> > >
> > > The compiler will warn if an array with not enough space is passed as
> > > argument.
> >
> > Really?
>
> Indeed:
>
>   extern void a(char *x);
>
>   static void b(char x[static 10]) {
>       a(x);
>   }
>
>   void c(void) {
>       char x[5] = "abcd";

>       b(x);

It's not the example I was talking about. Here should be a(x).

>   }
>
> says:
>   test.c: In function ‘c’:
>   test.c:9:9: warning: ‘b’ accessing 10 bytes in a region of size 5 [-Wstringop-overflow=]
>       9 |         b(x);
>         |         ^~~~
>   test.c:9:9: note: referencing argument 1 of type ‘char[10]’
>   test.c:3:13: note: in a call to function ‘b’
>       3 | static void b(char x[static 10]) {
>         |

...

> > > > > +               omnia_info_missing_feature(dev, "feature reading");
> > > >
> > > > Tautology. Read the final message. I believe you wanted to pass just
> > > > "reading" here.
> > >
> > > No, I actually wanted it to print
> > >   Your board's MCU firmware does not support the feature reading
> > >   feature.
> > > as in the feature "feature reading" is not supported.
> > > I guess I could change it to
> > >   Your board's MCU firmware does not support the feature reading.
> > > but that would complicate the code: either I would need to add
> > > " feature" suffix to all the features[].name, or duplicate the
> > > info string from the omnia_info_missing_feature() function.
> >
> > From point of a mere user (as I am towards this driver) I consider
> > the tautology confusing.
> >
> >       ...the 'reading' feature
> >
> > may be a good compromise.
>
> I have rewritten it to use another dev_info:
>   dev_info(dev,
>            "Your board's MCU firmware does not support feature reading.\n");

OK! As long as there are no two messages in a row for the same error.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

On Thu, May 02, 2024 at 09:47:25PM +0300, Andy Shevchenko wrote:
> On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> > On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
> 
> ...
> 
> > > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > > >
> > > > > Interesting format of the last parameter. Does it make any difference
> > > > > to the compiler if you use u8 *version?
> > > >
> > > > The compiler will warn if an array with not enough space is passed as
> > > > argument.
> > >
> > > Really?
> >
> > Indeed:
> >
> >   extern void a(char *x);
> >
> >   static void b(char x[static 10]) {
> >       a(x);
> >   }
> >
> >   void c(void) {
> >       char x[5] = "abcd";
> 
> >       b(x);
> 
> It's not the example I was talking about. Here should be a(x).

Somehow I got lost. Let's return to my function, where I have
  int omnia_get_version_hash(..., u8 version[static 40]);

and then I use this function:

  u8 version[40];
  omnia_get_version_hash(..., version);

If somehow I made a mistake and declared the version array shorter:
  u8 version[20];
  omnia_get_version_hash(..., version);
I would get a warning.

So the purpose is to get warned if the compiler can prove that there is
not enough space in the destination buffer.

Marek

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

Thanks, Ilpo, I've applied all your suggestions.

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Andy Shevchenko]

On Thu, May 2, 2024 at 10:18 PM Marek Behún <kabel@kernel.org> wrote:
> On Thu, May 02, 2024 at 09:47:25PM +0300, Andy Shevchenko wrote:
> > On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> > > On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > > > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:

...

> > > > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > > > >
> > > > > > Interesting format of the last parameter. Does it make any difference
> > > > > > to the compiler if you use u8 *version?
> > > > >
> > > > > The compiler will warn if an array with not enough space is passed as
> > > > > argument.
> > > >
> > > > Really?
> > >
> > > Indeed:
> > >
> > >   extern void a(char *x);
> > >
> > >   static void b(char x[static 10]) {
> > >       a(x);
> > >   }
> > >
> > >   void c(void) {
> > >       char x[5] = "abcd";
> >
> > >       b(x);
> >
> > It's not the example I was talking about. Here should be a(x).
>
> Somehow I got lost. Let's return to my function, where I have
>   int omnia_get_version_hash(..., u8 version[static 40]);
>
> and then I use this function:
>
>   u8 version[40];
>   omnia_get_version_hash(..., version);
>
> If somehow I made a mistake and declared the version array shorter:
>   u8 version[20];
>   omnia_get_version_hash(..., version);
> I would get a warning.

Yes. Would you get the same warning if you replace the parameter to a pointer?

> So the purpose is to get warned if the compiler can prove that there is
> not enough space in the destination buffer.


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v8 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

On Fri, May 03, 2024 at 06:59:20AM +0300, Andy Shevchenko wrote:
> On Thu, May 2, 2024 at 10:18 PM Marek Behún <kabel@kernel.org> wrote:
> > On Thu, May 02, 2024 at 09:47:25PM +0300, Andy Shevchenko wrote:
> > > On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> > > > On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > > > > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > > > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > > > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
> 
> ...
> 
> > > > > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > > > > >
> > > > > > > Interesting format of the last parameter. Does it make any difference
> > > > > > > to the compiler if you use u8 *version?
> > > > > >
> > > > > > The compiler will warn if an array with not enough space is passed as
> > > > > > argument.
> > > > >
> > > > > Really?
> > > >
> > > > Indeed:
> > > >
> > > >   extern void a(char *x);
> > > >
> > > >   static void b(char x[static 10]) {
> > > >       a(x);
> > > >   }
> > > >
> > > >   void c(void) {
> > > >       char x[5] = "abcd";
> > >
> > > >       b(x);
> > >
> > > It's not the example I was talking about. Here should be a(x).
> >
> > Somehow I got lost. Let's return to my function, where I have
> >   int omnia_get_version_hash(..., u8 version[static 40]);
> >
> > and then I use this function:
> >
> >   u8 version[40];
> >   omnia_get_version_hash(..., version);
> >
> > If somehow I made a mistake and declared the version array shorter:
> >   u8 version[20];
> >   omnia_get_version_hash(..., version);
> > I would get a warning.
> 
> Yes. Would you get the same warning if you replace the parameter to a pointer?

If you mean instead of declaring
  u8 version[20];
if I did
  u8 *version;
  omnia_get_version_hash(..., version);
then I will get a different warning:
  version is used uninitialized

And if you mean that instead of the
  char version[static 40]
in the argument list of the function I used
  char *version,
then no, GCC spits no warning.

Marek