Some HW design implement multicolor LEDs with several monochromatic LEDs.
Grouping the monochromatic LEDs allows to configure them in sync and use
the triggers.
The PWM multicolor LED driver implements such grouping but only for
PWM-based LEDs. As this feature is also desirable for the other types of
LEDs, this series implements it for any kind of LED device.
changes v5->v6:
- restore sysfs access to the leds when the device is removed
changes v4->v5:
- Use "depends on COMPILE_TEST || OF" in Kconfig to indicate that OF
is a functional requirement, not just a requirement for the
compilation.
- in led_mcg_probe() check if devm_of_led_get_optional() returns an
error before testing for the end of the list.
- use sysfs_emit() instead of sprintf() in color_show().
- some grammar fixes in the comments and the commit logs.
changes v2->v3, only minor changes:
- rephrased the Kconfig descritpion
- make the sysfs interface of underlying LEDs read-only only if the probe
is successful.
- sanitize the header files
- removed the useless call to dev_set_drvdata()
- use dev_fwnode() to get the fwnode to the device.
changes v1->v2:
- Followed Rob Herrings's suggestion to make the dt binding much simpler.
- Added a patch to store the color property of a LED in its class
structure (struct led_classdev).
Jean-Jacques Hiblot (6):
devres: provide devm_krealloc_array()
leds: class: simplify the implementation of devm_of_led_get()
leds: provide devm_of_led_get_optional()
leds: class: store the color index in struct led_classdev
dt-bindings: leds: Add binding for a multicolor group of LEDs
leds: Add a multicolor LED driver to group monochromatic LEDs
Documentation/ABI/testing/sysfs-class-led | 9 +
.../bindings/leds/leds-group-multicolor.yaml | 64 +++++++
drivers/leds/led-class.c | 65 +++++--
drivers/leds/rgb/Kconfig | 10 ++
drivers/leds/rgb/Makefile | 1 +
drivers/leds/rgb/leds-group-multicolor.c | 168 ++++++++++++++++++
include/linux/device.h | 13 ++
include/linux/leds.h | 3 +
8 files changed, 319 insertions(+), 14 deletions(-)
create mode 100644 Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
create mode 100644 drivers/leds/rgb/leds-group-multicolor.c
--
2.25.1
Use the devm_add_action_or_reset() helper.
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
---
drivers/leds/led-class.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 6a8ea94834fa..2c0d979d0c8a 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -258,11 +258,9 @@ void led_put(struct led_classdev *led_cdev)
}
EXPORT_SYMBOL_GPL(led_put);
-static void devm_led_release(struct device *dev, void *res)
+static void devm_led_release(void *cdev)
{
- struct led_classdev **p = res;
-
- led_put(*p);
+ led_put(cdev);
}
/**
@@ -280,7 +278,7 @@ struct led_classdev *__must_check devm_of_led_get(struct device *dev,
int index)
{
struct led_classdev *led;
- struct led_classdev **dr;
+ int ret;
if (!dev)
return ERR_PTR(-EINVAL);
@@ -289,15 +287,9 @@ struct led_classdev *__must_check devm_of_led_get(struct device *dev,
if (IS_ERR(led))
return led;
- dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
- GFP_KERNEL);
- if (!dr) {
- led_put(led);
- return ERR_PTR(-ENOMEM);
- }
-
- *dr = led;
- devres_add(dev, dr);
+ ret = devm_add_action_or_reset(dev, devm_led_release, led);
+ if (ret)
+ return ERR_PTR(ret);
return led;
}
--
2.25.1
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 <[email protected]>
---
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..e3ae9111b70d 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: October 2022
+KernelVersion: 6.1
+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").
+
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 9cddcd908bce..4432e85a5fc6 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -74,6 +74,18 @@ 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[] = {
@@ -88,6 +100,7 @@ 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,
};
@@ -375,6 +388,10 @@ 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;
@@ -384,6 +401,9 @@ 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 41df18f42d00..9d38cb90331d 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -71,6 +71,7 @@ struct led_classdev {
const char *name;
unsigned int brightness;
unsigned int max_brightness;
+ unsigned int color;
int flags;
/* Lower 16 bits reflect status */
--
2.25.1
This version of devm_of_led_get() doesn't fail if a LED is not found.
Instead it returns a NULL pointer.
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
---
drivers/leds/led-class.c | 25 +++++++++++++++++++++++++
include/linux/leds.h | 2 ++
2 files changed, 27 insertions(+)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 2c0d979d0c8a..9cddcd908bce 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -295,6 +295,31 @@ struct led_classdev *__must_check devm_of_led_get(struct device *dev,
}
EXPORT_SYMBOL_GPL(devm_of_led_get);
+/**
+ * devm_of_led_get_optional - Resource-managed request of an optional LED device
+ * @dev: LED consumer
+ * @index: index of the LED to obtain in the consumer
+ *
+ * The device node of the device is parsed to find the requested LED device.
+ * The LED device returned from this function is automatically released
+ * on driver detach.
+ *
+ * @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
+ * led was not found.
+ */
+struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
+ int index)
+{
+ struct led_classdev *led;
+
+ led = devm_of_led_get(dev, index);
+ if (IS_ERR(led) && PTR_ERR(led) == -ENOENT)
+ return NULL;
+
+ return led;
+}
+EXPORT_SYMBOL_GPL(devm_of_led_get_optional);
+
static int led_classdev_next_name(const char *init_name, char *name,
size_t len)
{
diff --git a/include/linux/leds.h b/include/linux/leds.h
index ba4861ec73d3..41df18f42d00 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -215,6 +215,8 @@ extern struct led_classdev *of_led_get(struct device_node *np, int index);
extern void led_put(struct led_classdev *led_cdev);
struct led_classdev *__must_check devm_of_led_get(struct device *dev,
int index);
+struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
+ int index);
/**
* led_blink_set - set blinking with software fallback
--
2.25.1
This allows to group multiple monochromatic LEDs into a multicolor
LED, e.g. RGB LEDs.
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
---
.../bindings/leds/leds-group-multicolor.yaml | 64 +++++++++++++++++++
1 file changed, 64 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
diff --git a/Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml b/Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
new file mode 100644
index 000000000000..8ed059a5a724
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/leds-group-multicolor.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Multi-color LED built with monochromatic LEDs
+
+maintainers:
+ - Jean-Jacques Hiblot <[email protected]>
+
+description: |
+ This driver combines several monochromatic LEDs into one multi-color
+ LED using the multicolor LED class.
+
+properties:
+ compatible:
+ const: leds-group-multicolor
+
+ leds:
+ description:
+ An aray of monochromatic leds
+ $ref: /schemas/types.yaml#/definitions/phandle-array
+
+required:
+ - leds
+
+allOf:
+ - $ref: leds-class-multicolor.yaml#
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ #include <dt-bindings/leds/common.h>
+
+ monochromatic-leds {
+ compatible = "gpio-leds";
+
+ led0: led-0 {
+ gpios = <&mcu_pio 0 GPIO_ACTIVE_LOW>;
+ color = <LED_COLOR_ID_RED>;
+ };
+
+ led1: led-1 {
+ gpios = <&mcu_pio 1 GPIO_ACTIVE_HIGH>;
+ color = <LED_COLOR_ID_GREEN>;
+ };
+
+ led2: led-2 {
+ gpios = <&mcu_pio 2 GPIO_ACTIVE_HIGH>;
+ color = <LED_COLOR_ID_BLUE>;
+ };
+ };
+
+ multi-led {
+ compatible = "leds-group-multicolor";
+ color = <LED_COLOR_ID_RGB>;
+ function = LED_FUNCTION_INDICATOR;
+ leds = <&led0>, <&led1>, <&led2>;
+ };
+
+...
--
2.25.1
On Thu, Nov 17, 2022 at 6:04 PM Jean-Jacques Hiblot
<[email protected]> wrote:
>
> 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.
...
> +What: /sys/class/leds/<led>/color
> +Date: October 2022
> +KernelVersion: 6.1
6.2
We missed v6.1. And I'm not sure with the current state of affairs
with LEDS subsystem maintenance we are not going to miss v6.2.
--
With Best Regards,
Andy Shevchenko