[PATCH v3 1/2] platform: chrome: Add cros-usbpd-notify driver

[PATCH v3 1/2] platform: chrome: Add cros-usbpd-notify driver

[Prashant Malani]

From: Jon Flatley <jflat@chromium.org>

ChromiumOS uses ACPI device with HID "GOOG0003" for power delivery
related events. The existing cros-usbpd-charger driver relies on these
events without ever actually receiving them on ACPI platforms. This is
because in the ChromeOS kernel trees, the GOOG0003 device is owned by an
ACPI driver that offers firmware updates to USB-C chargers.

Introduce a new platform driver under cros-ec, the ChromeOS embedded
controller, that handles these PD events and dispatches them
appropriately over a notifier chain to all drivers that use them.

On non-ACPI platforms, the driver gets instantiated for ECs which
support the EC_FEATURE_USB_PD feature bit, and on such platforms, the
notification events will get delivered using the MKBP event handling
mechanism.

Co-Developed-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Jon Flatley <jflat@chromium.org>
Signed-off-by: Prashant Malani <pmalani@chromium.org>
---

Changes in v3 (pmalani@chromium.org):
- Renamed driver and files from "cros_ec_pd_notify" to
  "cros_usbpd_notify" to be more consistent with other naming.
- Moved the change to include cros-usbpd-notify in the charger MFD into
  a separate follow-on patch.

Changes in v2 (pmalani@chromium.org):
- Removed dependency on DT entry; instead, we will instantiate the
  driver on detecting EC_FEATURE_USB_PD for non-ACPI platforms.
- Modified the cros-ec-pd-notify device to be an mfd_cell under
  usbpdcharger for non-ACPI platforms. Altered the platform_probe() call
  to derive the cros EC structs appropriately.
- Replaced "usbpd_notify" with "pd_notify" in functions and structures.
- Addressed comments from upstream maintainer.

 drivers/platform/chrome/Kconfig               |   9 ++
 drivers/platform/chrome/Makefile              |   1 +
 drivers/platform/chrome/cros_usbpd_notify.c   | 151 ++++++++++++++++++
 .../linux/platform_data/cros_usbpd_notify.h   |  17 ++
 4 files changed, 178 insertions(+)
 create mode 100644 drivers/platform/chrome/cros_usbpd_notify.c
 create mode 100644 include/linux/platform_data/cros_usbpd_notify.h

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 5f57282a28da0..3a8a98f2fb4d1 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -226,6 +226,15 @@ config CROS_USBPD_LOGGER
 	  To compile this driver as a module, choose M here: the
 	  module will be called cros_usbpd_logger.
 
+config CROS_USBPD_NOTIFY
+	tristate "ChromeOS Type-C power delivery event notifier"
+	depends on CROS_EC
+	help
+	  If you say Y here, you get support for Type-C PD event notifications
+	  from the ChromeOS EC. On ACPI platorms this driver will bind to the
+	  GOOG0003 ACPI device, and on non-ACPI platforms this driver will get
+	  initialized on ECs which support the feature EC_FEATURE_USB_PD.
+
 source "drivers/platform/chrome/wilco_ec/Kconfig"
 
 endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index aacd5920d8a18..f6465f8ef0b5e 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -22,5 +22,6 @@ obj-$(CONFIG_CROS_EC_DEBUGFS)		+= cros_ec_debugfs.o
 obj-$(CONFIG_CROS_EC_SENSORHUB)		+= cros_ec_sensorhub.o
 obj-$(CONFIG_CROS_EC_SYSFS)		+= cros_ec_sysfs.o
 obj-$(CONFIG_CROS_USBPD_LOGGER)		+= cros_usbpd_logger.o
+obj-$(CONFIG_CROS_USBPD_NOTIFY)		+= cros_usbpd_notify.o
 
 obj-$(CONFIG_WILCO_EC)			+= wilco_ec/
diff --git a/drivers/platform/chrome/cros_usbpd_notify.c b/drivers/platform/chrome/cros_usbpd_notify.c
new file mode 100644
index 0000000000000..05a7db834d2e0
--- /dev/null
+++ b/drivers/platform/chrome/cros_usbpd_notify.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2019 Google LLC
+ *
+ * This driver serves as the receiver of cros_ec PD host events.
+ */
+
+#include <linux/acpi.h>
+#include <linux/module.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_usbpd_notify.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+
+#define DRV_NAME "cros-usbpd-notify"
+#define ACPI_DRV_NAME "GOOG0003"
+
+static BLOCKING_NOTIFIER_HEAD(cros_usbpd_notifier_list);
+
+/**
+ * cros_usbpd_register_notify - Register a notifier callback for PD events.
+ * @nb: Notifier block pointer to register
+ *
+ * On ACPI platforms this corresponds to host events on the ECPD
+ * "GOOG0003" ACPI device. On non-ACPI platforms this will filter mkbp events
+ * for USB PD events.
+ *
+ * Return: 0 on success or negative error code.
+ */
+int cros_usbpd_register_notify(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(
+			&cros_usbpd_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(cros_usbpd_register_notify);
+
+
+/**
+ * cros_usbpd_unregister_notify - Unregister notifier callback for PD events.
+ * @nb: Notifier block pointer to unregister
+ *
+ * Unregister a notifier callback that was previously registered with
+ * cros_usbpd_register_notify().
+ */
+void cros_usbpd_unregister_notify(struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&cros_usbpd_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(cros_usbpd_unregister_notify);
+
+#ifdef CONFIG_ACPI
+
+static int cros_usbpd_notify_add_acpi(struct acpi_device *adev)
+{
+	return 0;
+}
+
+static void cros_usbpd_notify_acpi(struct acpi_device *adev, u32 event)
+{
+	blocking_notifier_call_chain(&cros_usbpd_notifier_list, event, NULL);
+}
+
+static const struct acpi_device_id cros_usbpd_notify_acpi_device_ids[] = {
+	{ ACPI_DRV_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, cros_usbpd_acpi_device_ids);
+
+static struct acpi_driver cros_usbpd_notify_driver = {
+	.name = DRV_NAME,
+	.class = DRV_NAME,
+	.ids = cros_usbpd_notify_acpi_device_ids,
+	.ops = {
+		.add = cros_usbpd_notify_add_acpi,
+		.notify = cros_usbpd_notify_acpi,
+	},
+};
+module_acpi_driver(cros_usbpd_notify_driver);
+
+#else /* CONFIG_ACPI */
+
+static int cros_usbpd_notify_plat(struct notifier_block *nb,
+		unsigned long queued_during_suspend, void *data)
+{
+	struct cros_ec_device *ec_dev = (struct cros_ec_device *)data;
+	u32 host_event = cros_ec_get_host_event(ec_dev);
+
+	if (!host_event)
+		return NOTIFY_BAD;
+
+	if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU)) {
+		blocking_notifier_call_chain(&cros_usbpd_notifier_list,
+				host_event, NULL);
+		return NOTIFY_OK;
+	}
+	return NOTIFY_DONE;
+}
+
+static int cros_usbpd_notify_probe_plat(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
+	struct notifier_block *nb;
+	int ret;
+
+	nb = devm_kzalloc(dev, sizeof(*nb), GFP_KERNEL);
+	if (!nb)
+		return -ENOMEM;
+
+	nb->notifier_call = cros_usbpd_notify_plat;
+	dev_set_drvdata(dev, nb);
+
+	ret = blocking_notifier_chain_register(&ecdev->ec_dev->event_notifier,
+						nb);
+	if (ret < 0) {
+		dev_err(dev, "Failed to register notifier\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int cros_usbpd_notify_remove_plat(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cros_ec_dev *ecdev = dev_get_drvdata(dev->parent);
+	struct notifier_block *nb =
+		(struct notifier_block *)dev_get_drvdata(dev);
+
+	blocking_notifier_chain_unregister(&ecdev->ec_dev->event_notifier,
+			nb);
+
+	return 0;
+}
+
+static struct platform_driver cros_usbpd_notify_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.probe = cros_usbpd_notify_probe_plat,
+	.remove = cros_usbpd_notify_remove_plat,
+};
+module_platform_driver(cros_usbpd_notify_driver);
+
+#endif /* CONFIG_ACPI */
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ChromeOS power delivery notifier device");
+MODULE_AUTHOR("Jon Flatley <jflat@chromium.org>");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/platform_data/cros_usbpd_notify.h b/include/linux/platform_data/cros_usbpd_notify.h
new file mode 100644
index 0000000000000..cd7c7bebf18da
--- /dev/null
+++ b/include/linux/platform_data/cros_usbpd_notify.h
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ChromeOS EC Power Delivery Notifier Driver
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef __LINUX_PLATFORM_DATA_CROS_USBPD_NOTIFY_H
+#define __LINUX_PLATFORM_DATA_CROS_USBPD_NOTIFY_H
+
+#include <linux/notifier.h>
+
+int cros_usbpd_register_notify(struct notifier_block *nb);
+
+void cros_usbpd_unregister_notify(struct notifier_block *nb);
+
+#endif  /* __LINUX_PLATFORM_DATA_CROS_USBPD_NOTIFY_H */
-- 
2.24.1.735.g03f4e72817-goog

[PATCH 2/2] mfd: cros_ec: Add usbpd-notify to usbpd_charger

[Prashant Malani]

Add the cros-usbpd-notify driver as a cell for the cros_usbpd_charger
subdevice on non-ACPI platforms.

This driver allows other cros-ec devices to receive PD event
notifications from the Chrome OS Embedded Controller (EC) via a
notification chain.

Change-Id: I4c062d261fa1a504b43b0a0c0a98a661829593b9
Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/mfd/cros_ec_dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index c4b977a5dd966..1dde480f35b93 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -85,6 +85,9 @@ static const struct mfd_cell cros_ec_sensorhub_cells[] = {
 static const struct mfd_cell cros_usbpd_charger_cells[] = {
 	{ .name = "cros-usbpd-charger", },
 	{ .name = "cros-usbpd-logger", },
+#ifndef CONFIG_ACPI
+	{ .name = "cros-usbpd-notify", },
+#endif
 };
 
 static const struct cros_feature_to_cells cros_subdevices[] = {
-- 
2.24.1.735.g03f4e72817-goog

Re: [PATCH 2/2] mfd: cros_ec: Add usbpd-notify to usbpd_charger

[Benson Leung]

Hey Prashant,

On Thu, Dec 19, 2019 at 12:14 PM Prashant Malani <pmalani@chromium.org> wrote:
>
> Add the cros-usbpd-notify driver as a cell for the cros_usbpd_charger
> subdevice on non-ACPI platforms.
>
> This driver allows other cros-ec devices to receive PD event
> notifications from the Chrome OS Embedded Controller (EC) via a
> notification chain.
>
> Change-Id: I4c062d261fa1a504b43b0a0c0a98a661829593b9

Make sure to strip Gerrit's Change-Ids before sending upstream. They
don't have any meaning outside of chromiumos.

> Signed-off-by: Prashant Malani <pmalani@chromium.org>
> ---
>  drivers/mfd/cros_ec_dev.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index c4b977a5dd966..1dde480f35b93 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -85,6 +85,9 @@ static const struct mfd_cell cros_ec_sensorhub_cells[] = {
>  static const struct mfd_cell cros_usbpd_charger_cells[] = {
>         { .name = "cros-usbpd-charger", },
>         { .name = "cros-usbpd-logger", },
> +#ifndef CONFIG_ACPI
> +       { .name = "cros-usbpd-notify", },
> +#endif
>  };
>
>  static const struct cros_feature_to_cells cros_subdevices[] = {
> --
> 2.24.1.735.g03f4e72817-goog
>


-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@google.com
Chromium OS Project
bleung@chromium.org

Re: [PATCH 2/2] mfd: cros_ec: Add usbpd-notify to usbpd_charger

[Prashant Malani]

On Thu, Dec 19, 2019 at 4:14 PM Benson Leung <bleung@chromium.org> wrote:
>
> Hey Prashant,
>
> On Thu, Dec 19, 2019 at 12:14 PM Prashant Malani <pmalani@chromium.org> wrote:
> >
> > Add the cros-usbpd-notify driver as a cell for the cros_usbpd_charger
> > subdevice on non-ACPI platforms.
> >
> > This driver allows other cros-ec devices to receive PD event
> > notifications from the Chrome OS Embedded Controller (EC) via a
> > notification chain.
> >
> > Change-Id: I4c062d261fa1a504b43b0a0c0a98a661829593b9
>
> Make sure to strip Gerrit's Change-Ids before sending upstream. They
> don't have any meaning outside of chromiumos.
Done. Thanks!
>
> > Signed-off-by: Prashant Malani <pmalani@chromium.org>
> > ---
> >  drivers/mfd/cros_ec_dev.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > index c4b977a5dd966..1dde480f35b93 100644
> > --- a/drivers/mfd/cros_ec_dev.c
> > +++ b/drivers/mfd/cros_ec_dev.c
> > @@ -85,6 +85,9 @@ static const struct mfd_cell cros_ec_sensorhub_cells[] = {
> >  static const struct mfd_cell cros_usbpd_charger_cells[] = {
> >         { .name = "cros-usbpd-charger", },
> >         { .name = "cros-usbpd-logger", },
> > +#ifndef CONFIG_ACPI
> > +       { .name = "cros-usbpd-notify", },
> > +#endif
> >  };
> >
> >  static const struct cros_feature_to_cells cros_subdevices[] = {
> > --
> > 2.24.1.735.g03f4e72817-goog
> >
>
>
> --
> Benson Leung
> Staff Software Engineer
> Chrome OS Kernel
> Google Inc.
> bleung@google.com
> Chromium OS Project
> bleung@chromium.org

Re: [PATCH 2/2] mfd: cros_ec: Add usbpd-notify to usbpd_charger

[Enric Balletbo i Serra]

Hi Prashant,

This should be [PATCH v3 2/2]. All the patches in the series should have the
same version otherwise makes difficult to follow.

Thanks,
 Enric

On 19/12/19 21:13, Prashant Malani wrote:
> Add the cros-usbpd-notify driver as a cell for the cros_usbpd_charger
> subdevice on non-ACPI platforms.
> 
> This driver allows other cros-ec devices to receive PD event
> notifications from the Chrome OS Embedded Controller (EC) via a
> notification chain.
> 
> Change-Id: I4c062d261fa1a504b43b0a0c0a98a661829593b9
> Signed-off-by: Prashant Malani <pmalani@chromium.org>
> ---
>  drivers/mfd/cros_ec_dev.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index c4b977a5dd966..1dde480f35b93 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -85,6 +85,9 @@ static const struct mfd_cell cros_ec_sensorhub_cells[] = {
>  static const struct mfd_cell cros_usbpd_charger_cells[] = {
>  	{ .name = "cros-usbpd-charger", },
>  	{ .name = "cros-usbpd-logger", },
> +#ifndef CONFIG_ACPI
> +	{ .name = "cros-usbpd-notify", },
> +#endif
>  };
>  
>  static const struct cros_feature_to_cells cros_subdevices[] = {
> 

Re: [PATCH 2/2] mfd: cros_ec: Add usbpd-notify to usbpd_charger

[Lee Jones]

On Fri, 20 Dec 2019, Enric Balletbo i Serra wrote:

> Hi Prashant,
> 
> This should be [PATCH v3 2/2]. All the patches in the series should have the
> same version otherwise makes difficult to follow.
> 
> Thanks,
>  Enric
> 
> On 19/12/19 21:13, Prashant Malani wrote:
> > Add the cros-usbpd-notify driver as a cell for the cros_usbpd_charger
> > subdevice on non-ACPI platforms.
> > 
> > This driver allows other cros-ec devices to receive PD event
> > notifications from the Chrome OS Embedded Controller (EC) via a
> > notification chain.
> > 
> > Change-Id: I4c062d261fa1a504b43b0a0c0a98a661829593b9
> > Signed-off-by: Prashant Malani <pmalani@chromium.org>
> > ---
> >  drivers/mfd/cros_ec_dev.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > index c4b977a5dd966..1dde480f35b93 100644
> > --- a/drivers/mfd/cros_ec_dev.c
> > +++ b/drivers/mfd/cros_ec_dev.c
> > @@ -85,6 +85,9 @@ static const struct mfd_cell cros_ec_sensorhub_cells[] = {
> >  static const struct mfd_cell cros_usbpd_charger_cells[] = {
> >  	{ .name = "cros-usbpd-charger", },
> >  	{ .name = "cros-usbpd-logger", },
> > +#ifndef CONFIG_ACPI
> > +	{ .name = "cros-usbpd-notify", },
> > +#endif

We don't want #iferry all over our c-files.  If you *have* to rely on
Kconfig configurations, split this out into a separate cell and use
IS_ENABLED().

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

Re: [PATCH 2/2] mfd: cros_ec: Add usbpd-notify to usbpd_charger

[Prashant Malani]

On Fri, Dec 20, 2019 at 12:55 AM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Hi Prashant,
>
> This should be [PATCH v3 2/2]. All the patches in the series should have the
> same version otherwise makes difficult to follow.
>
Noted. I was under the impression that  new patches would have
individual version numbers. I will correct this in the next version.
Thanks!

> Thanks,
>  Enric
>
> On 19/12/19 21:13, Prashant Malani wrote:
> > Add the cros-usbpd-notify driver as a cell for the cros_usbpd_charger
> > subdevice on non-ACPI platforms.
> >
> > This driver allows other cros-ec devices to receive PD event
> > notifications from the Chrome OS Embedded Controller (EC) via a
> > notification chain.
> >
> > Change-Id: I4c062d261fa1a504b43b0a0c0a98a661829593b9
> > Signed-off-by: Prashant Malani <pmalani@chromium.org>
> > ---
> >  drivers/mfd/cros_ec_dev.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > index c4b977a5dd966..1dde480f35b93 100644
> > --- a/drivers/mfd/cros_ec_dev.c
> > +++ b/drivers/mfd/cros_ec_dev.c
> > @@ -85,6 +85,9 @@ static const struct mfd_cell cros_ec_sensorhub_cells[] = {
> >  static const struct mfd_cell cros_usbpd_charger_cells[] = {
> >       { .name = "cros-usbpd-charger", },
> >       { .name = "cros-usbpd-logger", },
> > +#ifndef CONFIG_ACPI
> > +     { .name = "cros-usbpd-notify", },
> > +#endif
> >  };
> >
> >  static const struct cros_feature_to_cells cros_subdevices[] = {
> >

Re: [PATCH 2/2] mfd: cros_ec: Add usbpd-notify to usbpd_charger

[Prashant Malani]

On Fri, Dec 20, 2019 at 2:52 AM Lee Jones <lee.jones@linaro.org> wrote:
>
> On Fri, 20 Dec 2019, Enric Balletbo i Serra wrote:
>
> > Hi Prashant,
> >
> > This should be [PATCH v3 2/2]. All the patches in the series should have the
> > same version otherwise makes difficult to follow.
> >
> > Thanks,
> >  Enric
> >
> > On 19/12/19 21:13, Prashant Malani wrote:
> > > Add the cros-usbpd-notify driver as a cell for the cros_usbpd_charger
> > > subdevice on non-ACPI platforms.
> > >
> > > This driver allows other cros-ec devices to receive PD event
> > > notifications from the Chrome OS Embedded Controller (EC) via a
> > > notification chain.
> > >
> > > Change-Id: I4c062d261fa1a504b43b0a0c0a98a661829593b9
> > > Signed-off-by: Prashant Malani <pmalani@chromium.org>
> > > ---
> > >  drivers/mfd/cros_ec_dev.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > > index c4b977a5dd966..1dde480f35b93 100644
> > > --- a/drivers/mfd/cros_ec_dev.c
> > > +++ b/drivers/mfd/cros_ec_dev.c
> > > @@ -85,6 +85,9 @@ static const struct mfd_cell cros_ec_sensorhub_cells[] = {
> > >  static const struct mfd_cell cros_usbpd_charger_cells[] = {
> > >     { .name = "cros-usbpd-charger", },
> > >     { .name = "cros-usbpd-logger", },
> > > +#ifndef CONFIG_ACPI
> > > +   { .name = "cros-usbpd-notify", },
> > > +#endif
>
> We don't want #iferry all over our c-files.  If you *have* to rely on
> Kconfig configurations, split this out into a separate cell and use
> IS_ENABLED().
Done. Thanks.
>
> --
> Lee Jones [李琼斯]
> Linaro Services Technical Lead
> Linaro.org │ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog