[PATCH v10 3/5] leds: class: store the color index in struct led_classdev

From: Jean-Jacques Hiblot
Date: Sat Jun 24 2023 - 05:02:22 EST


This information might be useful for more than only deriving the led's
name. And since we have this information, we can expose it in the sysfs.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-class-led | 9 +++++++++
drivers/leds/led-class.c | 20 ++++++++++++++++++++
include/linux/leds.h | 1 +
3 files changed, 30 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 2e24ac3bd7ef..1509e71fcde1 100644
--- a/Documentation/ABI/testing/sysfs-class-led
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -59,6 +59,15 @@ Description:
brightness. Reading this file when no hw brightness change
event has happened will return an ENODATA error.

+What: /sys/class/leds/<led>/color
+Date: June 2023
+KernelVersion: 6.5
+Description:
+ Color of the led.
+
+ This is a read-only file. Reading this file returns the color
+ of the led as a string (ex: "red", "green", "multicolor").
+
What: /sys/class/leds/<led>/trigger
Date: March 2006
KernelVersion: 2.6.17
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index eb1a8494dc5b..6cca21b227dd 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -76,6 +76,18 @@ static ssize_t max_brightness_show(struct device *dev,
}
static DEVICE_ATTR_RO(max_brightness);

+static ssize_t color_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const char *color_text = "invalid";
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+ if (led_cdev->color < LED_COLOR_ID_MAX)
+ color_text = led_colors[led_cdev->color];
+ return sysfs_emit(buf, "%s\n", color_text);
+}
+static DEVICE_ATTR_RO(color);
+
#ifdef CONFIG_LEDS_TRIGGERS
static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
static struct bin_attribute *led_trigger_bin_attrs[] = {
@@ -90,6 +102,7 @@ static const struct attribute_group led_trigger_group = {
static struct attribute *led_class_attrs[] = {
&dev_attr_brightness.attr,
&dev_attr_max_brightness.attr,
+ &dev_attr_color.attr,
NULL,
};

@@ -482,6 +495,10 @@ int led_classdev_register_ext(struct device *parent,
if (fwnode_property_present(init_data->fwnode,
"retain-state-shutdown"))
led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
+
+ if (fwnode_property_present(init_data->fwnode, "color"))
+ fwnode_property_read_u32(init_data->fwnode, "color",
+ &led_cdev->color);
}
} else {
proposed_name = led_cdev->name;
@@ -491,6 +508,9 @@ int led_classdev_register_ext(struct device *parent,
if (ret < 0)
return ret;

+ if (led_cdev->color >= LED_COLOR_ID_MAX)
+ dev_warn(parent, "LED %s color identifier out of range\n", final_name);
+
mutex_init(&led_cdev->led_access);
mutex_lock(&led_cdev->led_access);
led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 95311c70d95c..487d00dac4de 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -100,6 +100,7 @@ struct led_classdev {
const char *name;
unsigned int brightness;
unsigned int max_brightness;
+ unsigned int color;
int flags;

/* Lower 16 bits reflect status */
--
2.34.1