[PATCH 0/5] ChromeOS Embedded Controller LED driver

[PATCH 0/5] ChromeOS Embedded Controller LED driver

[Thomas Weißschuh]

Add a LED driver that supports the LED devices exposed by the
ChromeOS Embedded Controller.

Patch 1-3 add a utility function to the led subsystem.
Patch 4 introduces the actual driver.
Patch 5 registers the driver through the cros_ec mfd devices.

Currently the driver introduces some non-standard LED functions.
(See "cros_ec_led_functions")

Tested on a Framework 13 AMD, Firmware 3.05.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
Thomas Weißschuh (5):
      leds: introduce led_color_name function
      leds: multicolor: use led_color_name function
      leds: unexport led_colors array
      leds: add ChromeOS EC driver
      mfd: cros_ec: Register LED subdevice

 MAINTAINERS                         |   5 +
 drivers/leds/Kconfig                |  15 ++
 drivers/leds/Makefile               |   1 +
 drivers/leds/led-class-multicolor.c |   2 +-
 drivers/leds/led-core.c             |  12 +-
 drivers/leds/leds-cros_ec.c         | 299 ++++++++++++++++++++++++++++++++++++
 drivers/leds/leds.h                 |   1 -
 drivers/mfd/cros_ec_dev.c           |   9 ++
 include/linux/leds.h                |  10 ++
 9 files changed, 350 insertions(+), 4 deletions(-)
---
base-commit: eb6a9339efeb6f3d2b5c86fdf2382cdc293eca2c
change-id: 20240519-cros_ec-led-3efa24e3991e

Best regards,
-- 
Thomas Weißschuh <linux@weissschuh.net>

[PATCH 1/5] leds: introduce led_color_name function

[Thomas Weißschuh]

This is similar to the existing led_colors array but is safer to use and
usable by everyone.
Getting string representations of color ids is useful for drivers
which are handling color ids anyways, for example for the multicolor API.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 drivers/leds/led-core.c |  9 +++++++++
 include/linux/leds.h    | 10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 89c9806cc97f..04a49958458e 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -534,6 +534,15 @@ int led_compose_name(struct device *dev, struct led_init_data *init_data,
 }
 EXPORT_SYMBOL_GPL(led_compose_name);
 
+const char *led_color_name(u8 color_id)
+{
+	if (color_id >= ARRAY_SIZE(led_colors))
+		return NULL;
+
+	return led_colors[color_id];
+}
+EXPORT_SYMBOL_GPL(led_color_name);
+
 enum led_default_state led_init_default_state_get(struct fwnode_handle *fwnode)
 {
 	const char *state = NULL;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index db6b114bb3d9..0f1b955fa3f7 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -427,6 +427,16 @@ void led_sysfs_enable(struct led_classdev *led_cdev);
 int led_compose_name(struct device *dev, struct led_init_data *init_data,
 		     char *led_classdev_name);
 
+/**
+ * led_color_name - get string representation of color id
+ * @color_id: The LED_COLOR_ID_* constant
+ *
+ * Get the string name of a LED_COLOR_ID_* constant.
+ *
+ * Returns: A string constant or NULL on an invalid ID.
+ */
+const char *led_color_name(u8 color_id);
+
 /**
  * led_sysfs_is_disabled - check if LED sysfs interface is disabled
  * @led_cdev: the LED to query

-- 
2.45.1

Re: [PATCH 1/5] leds: introduce led_color_name function

[Lee Jones]

It would save me a lot of work if you could follow the conventions of
the subsystem when drafting subjects.

`git log --online -- <subsystem>` is your friend.

> This is similar to the existing led_colors array but is safer to use and
> usable by everyone.

Place spaces between paragraphs or don't line-break at all please.

> Getting string representations of color ids is useful for drivers

"IDs"

> which are handling color ids anyways, for example for the multicolor API.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
>  drivers/leds/led-core.c |  9 +++++++++
>  include/linux/leds.h    | 10 ++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index 89c9806cc97f..04a49958458e 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -534,6 +534,15 @@ int led_compose_name(struct device *dev, struct led_init_data *init_data,
>  }
>  EXPORT_SYMBOL_GPL(led_compose_name);
>  
> +const char *led_color_name(u8 color_id)

led_get_color_name()

> +{
> +	if (color_id >= ARRAY_SIZE(led_colors))
> +		return NULL;
> +
> +	return led_colors[color_id];
> +}
> +EXPORT_SYMBOL_GPL(led_color_name);
> +
>  enum led_default_state led_init_default_state_get(struct fwnode_handle *fwnode)
>  {
>  	const char *state = NULL;
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index db6b114bb3d9..0f1b955fa3f7 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -427,6 +427,16 @@ void led_sysfs_enable(struct led_classdev *led_cdev);
>  int led_compose_name(struct device *dev, struct led_init_data *init_data,
>  		     char *led_classdev_name);
>  
> +/**
> + * led_color_name - get string representation of color id
> + * @color_id: The LED_COLOR_ID_* constant
> + *
> + * Get the string name of a LED_COLOR_ID_* constant.
> + *
> + * Returns: A string constant or NULL on an invalid ID.
> + */
> +const char *led_color_name(u8 color_id);


>  /**
>   * led_sysfs_is_disabled - check if LED sysfs interface is disabled
>   * @led_cdev: the LED to query
> 
> -- 
> 2.45.1
> 
> 

-- 
Lee Jones [李琼斯]

[PATCH 2/5] leds: multicolor: use led_color_name function

[Thomas Weißschuh]

led_color_name is a safer alternative to led_colors.
led-class-multicolor.c is the only external user of led_colors and its
removal allows the unexporting of the array.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 drivers/leds/led-class-multicolor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c
index ec62a4811613..34bdebcf239e 100644
--- a/drivers/leds/led-class-multicolor.c
+++ b/drivers/leds/led-class-multicolor.c
@@ -101,7 +101,7 @@ static ssize_t multi_index_show(struct device *dev,
 
 	for (i = 0; i < mcled_cdev->num_colors; i++) {
 		index = mcled_cdev->subled_info[i].color_index;
-		len += sprintf(buf + len, "%s", led_colors[index]);
+		len += sprintf(buf + len, "%s", led_color_name(index));
 		if (i < mcled_cdev->num_colors - 1)
 			len += sprintf(buf + len, " ");
 	}

-- 
2.45.1

[PATCH 3/5] leds: unexport led_colors array

[Thomas Weißschuh]

There are no external users left, make the array static.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 drivers/leds/led-core.c | 3 +--
 drivers/leds/leds.h     | 1 -
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 04a49958458e..94f8b47fc025 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -25,7 +25,7 @@ EXPORT_SYMBOL_GPL(leds_list_lock);
 LIST_HEAD(leds_list);
 EXPORT_SYMBOL_GPL(leds_list);
 
-const char * const led_colors[LED_COLOR_ID_MAX] = {
+static const char * const led_colors[LED_COLOR_ID_MAX] = {
 	[LED_COLOR_ID_WHITE] = "white",
 	[LED_COLOR_ID_RED] = "red",
 	[LED_COLOR_ID_GREEN] = "green",
@@ -42,7 +42,6 @@ const char * const led_colors[LED_COLOR_ID_MAX] = {
 	[LED_COLOR_ID_CYAN] = "cyan",
 	[LED_COLOR_ID_LIME] = "lime",
 };
-EXPORT_SYMBOL_GPL(led_colors);
 
 static int __led_set_brightness(struct led_classdev *led_cdev, unsigned int value)
 {
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index 1138e2ab82e5..d7999e7372a4 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -30,6 +30,5 @@ ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
 
 extern struct rw_semaphore leds_list_lock;
 extern struct list_head leds_list;
-extern const char * const led_colors[LED_COLOR_ID_MAX];
 
 #endif	/* __LEDS_H_INCLUDED */

-- 
2.45.1

[PATCH 4/5] leds: add ChromeOS EC driver

[Thomas Weißschuh]

The ChromeOS Embedded Controller exposes an LED control command.
Expose its functionality through the leds subsystem.

The LEDs are exposed as multicolor devices.
A hardware trigger, which is active by default, is provided to let the
EC itself take over control over the LED.

The driver is designed to be probed via the cros_ec mfd device.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 MAINTAINERS                 |   5 +
 drivers/leds/Kconfig        |  15 +++
 drivers/leds/Makefile       |   1 +
 drivers/leds/leds-cros_ec.c | 299 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 320 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 35ab336a6093..8f487c2f68cd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5097,6 +5097,11 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/sound/google,cros-ec-codec.yaml
 F:	sound/soc/codecs/cros_ec_codec.*
 
+CHROMEOS EC LED DRIVER
+M:	Thomas Weißschuh <thomas@weissschuh.net>
+S:	Maintained
+F:	drivers/leds/leds-cros_ec.c
+
 CHROMEOS EC SUBDRIVERS
 M:	Benson Leung <bleung@chromium.org>
 R:	Guenter Roeck <groeck@chromium.org>
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 05e6af88b88c..aa2fec9a34ed 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -179,6 +179,21 @@ config LEDS_CR0014114
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-cr0014114.
 
+config LEDS_CROS_EC
+	tristate "LED Support for ChromeOS EC"
+	depends on MFD_CROS_EC_DEV
+	depends on LEDS_CLASS_MULTICOLOR
+	select LEDS_TRIGGERS
+	default MFD_CROS_EC_DEV
+	help
+	  This option enables support for LEDs managed by ChromeOS ECs.
+	  All LEDs exposed by the EC are supported in multicolor mode.
+	  A hardware trigger to switch back to the automatic behaviour is
+	  provided.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-cros_ec.
+
 config LEDS_EL15203000
 	tristate "LED Support for Crane EL15203000"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index effdfc6f1e95..3491904e13f7 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_LEDS_CLEVO_MAIL)		+= leds-clevo-mail.o
 obj-$(CONFIG_LEDS_COBALT_QUBE)		+= leds-cobalt-qube.o
 obj-$(CONFIG_LEDS_COBALT_RAQ)		+= leds-cobalt-raq.o
 obj-$(CONFIG_LEDS_CPCAP)		+= leds-cpcap.o
+obj-$(CONFIG_LEDS_CROS_EC)		+= leds-cros_ec.o
 obj-$(CONFIG_LEDS_DA903X)		+= leds-da903x.o
 obj-$(CONFIG_LEDS_DA9052)		+= leds-da9052.o
 obj-$(CONFIG_LEDS_GPIO)			+= leds-gpio.o
diff --git a/drivers/leds/leds-cros_ec.c b/drivers/leds/leds-cros_ec.c
new file mode 100644
index 000000000000..f87ee9c4a29a
--- /dev/null
+++ b/drivers/leds/leds-cros_ec.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  ChromesOS EC LED Driver
+ *
+ *  Copyright (C) 2024 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#include <linux/device.h>
+#include <linux/leds.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+
+#define DRV_NAME	"cros-ec-led"
+
+static const char * const cros_ec_led_functions[] = {
+	[EC_LED_ID_BATTERY_LED]            = LED_FUNCTION_CHARGING,
+	[EC_LED_ID_POWER_LED]              = LED_FUNCTION_POWER,
+	[EC_LED_ID_ADAPTER_LED]            = "adapter",
+	[EC_LED_ID_LEFT_LED]               = "left",
+	[EC_LED_ID_RIGHT_LED]              = "right",
+	[EC_LED_ID_RECOVERY_HW_REINIT_LED] = "recovery-hw-reinit",
+	[EC_LED_ID_SYSRQ_DEBUG_LED]        = "sysrq-debug",
+};
+
+static_assert(ARRAY_SIZE(cros_ec_led_functions) == EC_LED_ID_COUNT);
+
+static const int cros_ec_led_to_linux_id[] = {
+	[EC_LED_COLOR_RED]    = LED_COLOR_ID_RED,
+	[EC_LED_COLOR_GREEN]  = LED_COLOR_ID_GREEN,
+	[EC_LED_COLOR_BLUE]   = LED_COLOR_ID_BLUE,
+	[EC_LED_COLOR_YELLOW] = LED_COLOR_ID_YELLOW,
+	[EC_LED_COLOR_WHITE]  = LED_COLOR_ID_WHITE,
+	[EC_LED_COLOR_AMBER]  = LED_COLOR_ID_AMBER,
+};
+
+static_assert(ARRAY_SIZE(cros_ec_led_to_linux_id) == EC_LED_COLOR_COUNT);
+
+static const int cros_ec_linux_to_ec_id[] = {
+	[LED_COLOR_ID_RED]    = EC_LED_COLOR_RED,
+	[LED_COLOR_ID_GREEN]  = EC_LED_COLOR_GREEN,
+	[LED_COLOR_ID_BLUE]   = EC_LED_COLOR_BLUE,
+	[LED_COLOR_ID_YELLOW] = EC_LED_COLOR_YELLOW,
+	[LED_COLOR_ID_WHITE]  = EC_LED_COLOR_WHITE,
+	[LED_COLOR_ID_AMBER]  = EC_LED_COLOR_AMBER,
+};
+
+struct cros_ec_led_priv {
+	struct led_classdev_mc led_mc_cdev;
+	struct cros_ec_device *cros_ec;
+	enum ec_led_id led_id;
+};
+
+static inline struct cros_ec_led_priv *cros_ec_led_cdev_to_priv(struct led_classdev *led_cdev)
+{
+	return container_of(lcdev_to_mccdev(led_cdev), struct cros_ec_led_priv, led_mc_cdev);
+}
+
+union cros_ec_led_cmd_data {
+	struct ec_params_led_control req;
+	struct ec_response_led_control resp;
+} __packed;
+
+static int cros_ec_led_send_cmd(struct cros_ec_device *cros_ec,
+				union cros_ec_led_cmd_data *arg)
+{
+	int ret;
+	struct {
+		struct cros_ec_command msg;
+		union cros_ec_led_cmd_data data;
+	} __packed buf = {
+		.msg = {
+			.version = 1,
+			.command = EC_CMD_LED_CONTROL,
+			.insize  = sizeof(arg->resp),
+			.outsize = sizeof(arg->req),
+		},
+		.data.req = arg->req
+	};
+
+	ret = cros_ec_cmd_xfer_status(cros_ec, &buf.msg);
+	if (ret < 0)
+		return ret;
+
+	arg->resp = buf.data.resp;
+
+	return 0;
+}
+
+static int cros_ec_led_trigger_activate(struct led_classdev *led_cdev)
+{
+	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
+	union cros_ec_led_cmd_data arg = { };
+
+	arg.req.led_id = priv->led_id;
+	arg.req.flags = EC_LED_FLAGS_AUTO;
+
+	return cros_ec_led_send_cmd(priv->cros_ec, &arg);
+}
+
+static struct led_hw_trigger_type cros_ec_led_trigger_type;
+
+static struct led_trigger cros_ec_led_trigger = {
+	.name = "cros_ec-auto",
+	.trigger_type = &cros_ec_led_trigger_type,
+	.activate = cros_ec_led_trigger_activate,
+};
+
+static int cros_ec_led_brightness_set_blocking(struct led_classdev *led_cdev,
+					       enum led_brightness brightness)
+{
+	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
+	union cros_ec_led_cmd_data arg = { };
+	enum ec_led_colors led_color;
+	struct mc_subled *subled;
+	size_t i;
+
+	led_mc_calc_color_components(&priv->led_mc_cdev, brightness);
+
+	arg.req.led_id = priv->led_id;
+
+	for (i = 0; i < priv->led_mc_cdev.num_colors; i++) {
+		subled = &priv->led_mc_cdev.subled_info[i];
+		led_color = cros_ec_linux_to_ec_id[subled->color_index];
+		arg.req.brightness[led_color] = subled->brightness;
+	}
+
+	return cros_ec_led_send_cmd(priv->cros_ec, &arg);
+}
+
+static int cros_ec_led_count_subleds(struct device *dev,
+				     struct ec_response_led_control *resp,
+				     unsigned int *max_brightness)
+{
+	unsigned int range, common_range = 0;
+	int num_subleds = 0;
+	size_t i;
+
+	for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
+		range = resp->brightness_range[i];
+
+		if (!range)
+			continue;
+
+		num_subleds++;
+
+		if (!common_range)
+			common_range = range;
+
+		if (common_range != range) {
+			/* The multicolor LED API expects a uniform max_brightness */
+			dev_warn(dev, "Inconsistent LED brightness values\n");
+			return -EINVAL;
+		}
+	}
+
+	if (!num_subleds)
+		return -EINVAL;
+
+	*max_brightness = common_range;
+	return num_subleds;
+}
+
+static const char *cros_ec_led_color_name(struct led_classdev_mc *led_mc_cdev)
+{
+	int color;
+
+	if (led_mc_cdev->num_colors == 1)
+		color = led_mc_cdev->subled_info[0].color_index;
+	else if (led_mc_cdev->led_cdev.max_brightness == 1)
+		color = LED_COLOR_ID_MULTI;
+	else
+		color = LED_COLOR_ID_RGB;
+
+	return led_color_name(color);
+}
+
+static int cros_ec_led_probe_led(struct device *dev, struct cros_ec_device *cros_ec,
+				 enum ec_led_id id)
+{
+	union cros_ec_led_cmd_data arg = { };
+	struct cros_ec_led_priv *priv;
+	struct led_classdev *led_cdev;
+	struct mc_subled *subleds;
+	int ret, num_subleds;
+	size_t i, subled;
+
+	arg.req.led_id = id;
+	arg.req.flags = EC_LED_FLAGS_QUERY;
+	ret = cros_ec_led_send_cmd(cros_ec, &arg);
+	/* Unknown LED, skip */
+	if (ret == -EINVAL)
+		return 0;
+	if (ret == -EOPNOTSUPP)
+		return -ENODEV;
+	if (ret < 0)
+		return ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	num_subleds = cros_ec_led_count_subleds(dev, &arg.resp,
+						&priv->led_mc_cdev.led_cdev.max_brightness);
+	if (num_subleds < 0)
+		return num_subleds;
+
+	priv->cros_ec = cros_ec;
+	priv->led_id = id;
+
+	subleds = devm_kcalloc(dev, num_subleds, sizeof(*subleds), GFP_KERNEL);
+	if (!subleds)
+		return -ENOMEM;
+
+	subled = 0;
+	for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
+		if (!arg.resp.brightness_range[i])
+			continue;
+
+		subleds[subled].color_index = cros_ec_led_to_linux_id[i];
+		subleds[subled].intensity = 100;
+		subled++;
+	}
+
+	priv->led_mc_cdev.subled_info = subleds;
+	priv->led_mc_cdev.num_colors = num_subleds;
+
+	led_cdev = &priv->led_mc_cdev.led_cdev;
+	led_cdev->brightness_set_blocking = cros_ec_led_brightness_set_blocking;
+	led_cdev->trigger_type = &cros_ec_led_trigger_type;
+	led_cdev->hw_control_trigger = cros_ec_led_trigger.name;
+
+	led_cdev->name = devm_kasprintf(dev, GFP_KERNEL, "cros_ec:%s:%s",
+					cros_ec_led_color_name(&priv->led_mc_cdev),
+					cros_ec_led_functions[id]);
+	if (!led_cdev->name)
+		return -ENOMEM;
+
+	return devm_led_classdev_multicolor_register(dev, &priv->led_mc_cdev);
+}
+
+static int cros_ec_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
+	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
+	size_t i;
+	int ret;
+
+	for (i = 0; i < EC_LED_ID_COUNT; i++) {
+		ret = cros_ec_led_probe_led(dev, cros_ec, i);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static const struct platform_device_id cros_ec_led_id[] = {
+	{ DRV_NAME, 0 },
+	{ }
+};
+
+static struct platform_driver cros_ec_led_driver = {
+	.driver.name	= DRV_NAME,
+	.probe		= cros_ec_led_probe,
+	.id_table	= cros_ec_led_id,
+};
+
+static int __init cros_ec_led_init(void)
+{
+	int ret;
+
+	ret = led_trigger_register(&cros_ec_led_trigger);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&cros_ec_led_driver);
+	if (ret)
+		led_trigger_unregister(&cros_ec_led_trigger);
+
+	return ret;
+};
+module_init(cros_ec_led_init);
+
+static void __exit cros_ec_led_exit(void)
+{
+	platform_driver_unregister(&cros_ec_led_driver);
+	led_trigger_unregister(&cros_ec_led_trigger);
+};
+module_exit(cros_ec_led_exit);
+
+MODULE_DEVICE_TABLE(platform, cros_ec_led_id);
+MODULE_DESCRIPTION("ChromeOS EC LED Driver");
+MODULE_AUTHOR("Thomas Weißschuh <linux@weissschuh.net");
+MODULE_LICENSE("GPL");

-- 
2.45.1

Re: [PATCH 4/5] leds: add ChromeOS EC driver

[Tzung-Bi Shih]

On Mon, May 20, 2024 at 12:00:32PM +0200, Thomas Weißschuh wrote:
> diff --git a/drivers/leds/leds-cros_ec.c b/drivers/leds/leds-cros_ec.c
[...]
> + *  ChromesOS EC LED Driver

s/ChromesOS/ChromeOS/.

> +static int cros_ec_led_trigger_activate(struct led_classdev *led_cdev)
> +{
> +	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
> +	union cros_ec_led_cmd_data arg = { };

To be neat, { } -> {}.

> +static int cros_ec_led_brightness_set_blocking(struct led_classdev *led_cdev,
> +					       enum led_brightness brightness)
> +{
> +	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
> +	union cros_ec_led_cmd_data arg = { };

Ditto.

> +static int cros_ec_led_count_subleds(struct device *dev,
> +				     struct ec_response_led_control *resp,
> +				     unsigned int *max_brightness)
> +{
> +	unsigned int range, common_range = 0;
> +	int num_subleds = 0;
> +	size_t i;
> +
> +	for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
> +		range = resp->brightness_range[i];
> +
> +		if (!range)
> +			continue;
> +
> +		num_subleds++;
> +
> +		if (!common_range)
> +			common_range = range;
> +
> +		if (common_range != range) {
> +			/* The multicolor LED API expects a uniform max_brightness */
> +			dev_warn(dev, "Inconsistent LED brightness values\n");
> +			return -EINVAL;
> +		}

What if the array is [0, 1, 1]?

> +static int cros_ec_led_probe_led(struct device *dev, struct cros_ec_device *cros_ec,
> +				 enum ec_led_id id)
> +{
> +	union cros_ec_led_cmd_data arg = { };

Ditto.

> +static int cros_ec_led_probe(struct platform_device *pdev)
> +{
[...]
> +	int ret;
> +
> +	for (i = 0; i < EC_LED_ID_COUNT; i++) {
> +		ret = cros_ec_led_probe_led(dev, cros_ec, i);
> +		if (ret)
> +			break;
> +	}
> +
> +	return ret;

`ret` should be initialized in case EC_LED_ID_COUNT would be somehow 0.

> +static int __init cros_ec_led_init(void)
> +{
> +	int ret;
> +
> +	ret = led_trigger_register(&cros_ec_led_trigger);
> +	if (ret)
> +		return ret;
> +
> +	ret = platform_driver_register(&cros_ec_led_driver);
> +	if (ret)
> +		led_trigger_unregister(&cros_ec_led_trigger);
> +
> +	return ret;
> +};
> +module_init(cros_ec_led_init);
> +
> +static void __exit cros_ec_led_exit(void)
> +{
> +	platform_driver_unregister(&cros_ec_led_driver);
> +	led_trigger_unregister(&cros_ec_led_trigger);
> +};
> +module_exit(cros_ec_led_exit);

I wonder it could use module_led_trigger() and module_platform_driver().

Re: [PATCH 4/5] leds: add ChromeOS EC driver

[Thomas Weißschuh]

On 2024-05-28 05:09:29+0000, Tzung-Bi Shih wrote:
> On Mon, May 20, 2024 at 12:00:32PM +0200, Thomas Weißschuh wrote:
> > diff --git a/drivers/leds/leds-cros_ec.c b/drivers/leds/leds-cros_ec.c
> [...]
> > + *  ChromesOS EC LED Driver
> 
> s/ChromesOS/ChromeOS/.

Ack.

> > +static int cros_ec_led_trigger_activate(struct led_classdev *led_cdev)
> > +{
> > +	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
> > +	union cros_ec_led_cmd_data arg = { };
> 
> To be neat, { } -> {}.

Ack.
 
> > +static int cros_ec_led_brightness_set_blocking(struct led_classdev *led_cdev,
> > +					       enum led_brightness brightness)
> > +{
> > +	struct cros_ec_led_priv *priv = cros_ec_led_cdev_to_priv(led_cdev);
> > +	union cros_ec_led_cmd_data arg = { };
> 
> Ditto.
> 
> > +static int cros_ec_led_count_subleds(struct device *dev,
> > +				     struct ec_response_led_control *resp,
> > +				     unsigned int *max_brightness)
> > +{
> > +	unsigned int range, common_range = 0;
> > +	int num_subleds = 0;
> > +	size_t i;
> > +
> > +	for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
> > +		range = resp->brightness_range[i];
> > +
> > +		if (!range)
> > +			continue;
> > +
> > +		num_subleds++;
> > +
> > +		if (!common_range)
> > +			common_range = range;
> > +
> > +		if (common_range != range) {
> > +			/* The multicolor LED API expects a uniform max_brightness */
> > +			dev_warn(dev, "Inconsistent LED brightness values\n");
> > +			return -EINVAL;
> > +		}
> 
> What if the array is [0, 1, 1]?

The "0" will be skipped by 

if (!range)
	continue;

And the two "1" will pass the check.

> 
> > +static int cros_ec_led_probe_led(struct device *dev, struct cros_ec_device *cros_ec,
> > +				 enum ec_led_id id)
> > +{
> > +	union cros_ec_led_cmd_data arg = { };
> 
> Ditto.
> 
> > +static int cros_ec_led_probe(struct platform_device *pdev)
> > +{
> [...]
> > +	int ret;
> > +
> > +	for (i = 0; i < EC_LED_ID_COUNT; i++) {
> > +		ret = cros_ec_led_probe_led(dev, cros_ec, i);
> > +		if (ret)
> > +			break;
> > +	}
> > +
> > +	return ret;
> 
> `ret` should be initialized in case EC_LED_ID_COUNT would be somehow 0.

As that's a constant define, this should never happen.
But after thinking about it, it seems a bit clearer.
The compiler should figure out that it's redundant anyways.

> > +static int __init cros_ec_led_init(void)
> > +{
> > +	int ret;
> > +
> > +	ret = led_trigger_register(&cros_ec_led_trigger);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = platform_driver_register(&cros_ec_led_driver);
> > +	if (ret)
> > +		led_trigger_unregister(&cros_ec_led_trigger);
> > +
> > +	return ret;
> > +};
> > +module_init(cros_ec_led_init);
> > +
> > +static void __exit cros_ec_led_exit(void)
> > +{
> > +	platform_driver_unregister(&cros_ec_led_driver);
> > +	led_trigger_unregister(&cros_ec_led_trigger);
> > +};
> > +module_exit(cros_ec_led_exit);
> 
> I wonder it could use module_led_trigger() and module_platform_driver().

This won't compile as the macros generate various duplicate symbols.

Also the order is important, so I think the explicit logic is clearer.


Thomas

Re: [PATCH 4/5] leds: add ChromeOS EC driver

[Tzung-Bi Shih]

On Tue, May 28, 2024 at 07:25:07AM +0200, Thomas Weißschuh wrote:
> On 2024-05-28 05:09:29+0000, Tzung-Bi Shih wrote:
> > On Mon, May 20, 2024 at 12:00:32PM +0200, Thomas Weißschuh wrote:
> > > +static int cros_ec_led_count_subleds(struct device *dev,
> > > +				     struct ec_response_led_control *resp,
> > > +				     unsigned int *max_brightness)
> > > +{
> > > +	unsigned int range, common_range = 0;
> > > +	int num_subleds = 0;
> > > +	size_t i;
> > > +
> > > +	for (i = 0; i < EC_LED_COLOR_COUNT; i++) {
> > > +		range = resp->brightness_range[i];
> > > +
> > > +		if (!range)
> > > +			continue;
> > > +
> > > +		num_subleds++;
> > > +
> > > +		if (!common_range)
> > > +			common_range = range;
> > > +
> > > +		if (common_range != range) {
> > > +			/* The multicolor LED API expects a uniform max_brightness */
> > > +			dev_warn(dev, "Inconsistent LED brightness values\n");
> > > +			return -EINVAL;
> > > +		}
> > 
> > What if the array is [0, 1, 1]?
> 
> The "0" will be skipped by 
> 
> if (!range)
> 	continue;
> 
> And the two "1" will pass the check.

Ack.

> > > +static int __init cros_ec_led_init(void)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = led_trigger_register(&cros_ec_led_trigger);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = platform_driver_register(&cros_ec_led_driver);
> > > +	if (ret)
> > > +		led_trigger_unregister(&cros_ec_led_trigger);
> > > +
> > > +	return ret;
> > > +};
> > > +module_init(cros_ec_led_init);
> > > +
> > > +static void __exit cros_ec_led_exit(void)
> > > +{
> > > +	platform_driver_unregister(&cros_ec_led_driver);
> > > +	led_trigger_unregister(&cros_ec_led_trigger);
> > > +};
> > > +module_exit(cros_ec_led_exit);
> > 
> > I wonder it could use module_led_trigger() and module_platform_driver().
> 
> This won't compile as the macros generate various duplicate symbols.
> 
> Also the order is important, so I think the explicit logic is clearer.

I'm not sure if it is feasible by separating the trigger part to
drivers/leds/trigger/ and specify it in `default_trigger`.

Re: [PATCH 4/5] leds: add ChromeOS EC driver

[Thomas Weißschuh]

On 2024-05-28 07:15:07+0000, Tzung-Bi Shih wrote:
> On Tue, May 28, 2024 at 07:25:07AM +0200, Thomas Weißschuh wrote:
> > On 2024-05-28 05:09:29+0000, Tzung-Bi Shih wrote:
> > > On Mon, May 20, 2024 at 12:00:32PM +0200, Thomas Weißschuh wrote:
> > > > +static int __init cros_ec_led_init(void)
> > > > +{
> > > > +	int ret;
> > > > +
> > > > +	ret = led_trigger_register(&cros_ec_led_trigger);
> > > > +	if (ret)
> > > > +		return ret;
> > > > +
> > > > +	ret = platform_driver_register(&cros_ec_led_driver);
> > > > +	if (ret)
> > > > +		led_trigger_unregister(&cros_ec_led_trigger);
> > > > +
> > > > +	return ret;
> > > > +};
> > > > +module_init(cros_ec_led_init);
> > > > +
> > > > +static void __exit cros_ec_led_exit(void)
> > > > +{
> > > > +	platform_driver_unregister(&cros_ec_led_driver);
> > > > +	led_trigger_unregister(&cros_ec_led_trigger);
> > > > +};
> > > > +module_exit(cros_ec_led_exit);
> > > 
> > > I wonder it could use module_led_trigger() and module_platform_driver().
> > 
> > This won't compile as the macros generate various duplicate symbols.
> > 
> > Also the order is important, so I think the explicit logic is clearer.
> 
> I'm not sure if it is feasible by separating the trigger part to
> drivers/leds/trigger/ and specify it in `default_trigger`.

I don't think so.

The trigger is a private one and can only ever used with those LEDs.
(through cros_ec_led_trigger_type)

If we want to split it out we would need to export at least
cros_ec_led_trigger_type, cros_ec_led_cdev_to_priv,
cros_ec_led_cmd_arg_data, cros_ec_led_priv and more from leds-cros_ec to
the trigger.

[PATCH 5/5] mfd: cros_ec: Register LED subdevice

[Thomas Weißschuh]

Add ChromeOS EC-based LED control as EC subdevice.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 drivers/mfd/cros_ec_dev.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index a52d59cc2b1e..d8cf1c5ce5a1 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -99,6 +99,10 @@ static const struct mfd_cell cros_ec_wdt_cells[] = {
 	{ .name = "cros-ec-wdt", }
 };
 
+static const struct mfd_cell cros_ec_led_cells[] = {
+	{ .name = "cros-ec-led", }
+};
+
 static const struct cros_feature_to_cells cros_subdevices[] = {
 	{
 		.id		= EC_FEATURE_CEC,
@@ -125,6 +129,11 @@ static const struct cros_feature_to_cells cros_subdevices[] = {
 		.mfd_cells	= cros_ec_wdt_cells,
 		.num_cells	= ARRAY_SIZE(cros_ec_wdt_cells),
 	},
+	{
+		.id		= EC_FEATURE_LED,
+		.mfd_cells	= cros_ec_led_cells,
+		.num_cells	= ARRAY_SIZE(cros_ec_led_cells),
+	},
 };
 
 static const struct mfd_cell cros_ec_platform_cells[] = {

-- 
2.45.1