Resending this series as the v11 didn't apply cleanly.
The patch adding devm_krealloc_array() has been dropped because this function is now available.
Below is the original cover-letter.
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 v10->v11:
- updated commit logs of patch 2 and 3
- Improved comments
changes v9->v10:
- updated comments and kconfig description
- renamed all 'led_mcg_xxx' into 'leds_gmc_xxx'
changes v8->v9:
- rebased on top of lee-leds/for-leds-next
- updated kernel version and date for /sys/class/leds/<led>/color in
Documentation/ABI/testing/sysfs-class-led
- dropped patch "leds: class: simplify the implementation of
devm_of_led_get()" because __devm_led_get() is now used by
devm_led_get()
changes v7->v8:
- consistently use "LEDs group multicolor" throughout the code.
- rename some variables with more explicit names.
- improve comments.
- use the 100-characters per line limit.
changes v6->v7:
- in led_mcg_probe() increment the counter at the end of the loop for
clarity.
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 (4):
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 | 46 +++++
drivers/leds/rgb/Kconfig | 12 ++
drivers/leds/rgb/Makefile | 1 +
drivers/leds/rgb/leds-group-multicolor.c | 169 ++++++++++++++++++
include/linux/leds.h | 3 +
7 files changed, 304 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
create mode 100644 drivers/leds/rgb/leds-group-multicolor.c
--
2.34.1
Store the color of the LED so that it is not lost after the LED's
name has been composed. This color information can then be exposed to
the user space or used by the LED consumer.
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
---
Documentation/ABI/testing/sysfs-class-led | 9 +++++++++
drivers/leds/led-class.c | 21 +++++++++++++++++++++
include/linux/leds.h | 1 +
3 files changed, 31 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 2e24ac3bd7ef..b2ff0012c0f2 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 (e.g: "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 78068b06d009..4bcbd46ec75a 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -76,6 +76,19 @@ 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 +103,7 @@ 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,
};
@@ -486,6 +500,10 @@ int led_classdev_register_ext(struct device *parent,
fwnode_property_read_u32(init_data->fwnode,
"max-brightness",
&led_cdev->max_brightness);
+
+ 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;
@@ -495,6 +513,9 @@ 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 8740b4e47f88..aa16dc2a8230 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
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>;
+ };
+
+...
--
2.34.1
Grouping multiple monochrome LEDs into a multicolor LED device has a few
benefits over handling the group in user-space:
- The state of the LEDs relative to each other is consistent. In other
words, if 2 threads competes to set the LED to green and red, the
end-result cannot be black or yellow.
- The multicolor LED as a whole can be driven through the sysfs LED
interface.
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
Reviewed-by: Lee Jones <[email protected]>
---
drivers/leds/rgb/Kconfig | 12 ++
drivers/leds/rgb/Makefile | 1 +
drivers/leds/rgb/leds-group-multicolor.c | 169 +++++++++++++++++++++++
3 files changed, 182 insertions(+)
create mode 100644 drivers/leds/rgb/leds-group-multicolor.c
diff --git a/drivers/leds/rgb/Kconfig b/drivers/leds/rgb/Kconfig
index 360c8679c6e2..183bccc06cf3 100644
--- a/drivers/leds/rgb/Kconfig
+++ b/drivers/leds/rgb/Kconfig
@@ -2,6 +2,18 @@
if LEDS_CLASS_MULTICOLOR
+config LEDS_GROUP_MULTICOLOR
+ tristate "LEDs group multi-color support"
+ depends on OF || COMPILE_TEST
+ help
+ This option enables support for monochrome LEDs that are grouped
+ into multicolor LEDs which is useful in the case where LEDs of
+ different colors are physically grouped in a single multi-color LED
+ and driven by a controller that doesn't have multi-color support.
+
+ To compile this driver as a module, choose M here: the module
+ will be called leds-group-multicolor.
+
config LEDS_PWM_MULTICOLOR
tristate "PWM driven multi-color LED Support"
depends on PWM
diff --git a/drivers/leds/rgb/Makefile b/drivers/leds/rgb/Makefile
index 8c01daf63f61..c11cc56384e7 100644
--- a/drivers/leds/rgb/Makefile
+++ b/drivers/leds/rgb/Makefile
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_LEDS_GROUP_MULTICOLOR) += leds-group-multicolor.o
obj-$(CONFIG_LEDS_PWM_MULTICOLOR) += leds-pwm-multicolor.o
obj-$(CONFIG_LEDS_QCOM_LPG) += leds-qcom-lpg.o
obj-$(CONFIG_LEDS_MT6370_RGB) += leds-mt6370-rgb.o
diff --git a/drivers/leds/rgb/leds-group-multicolor.c b/drivers/leds/rgb/leds-group-multicolor.c
new file mode 100644
index 000000000000..39f58be32af5
--- /dev/null
+++ b/drivers/leds/rgb/leds-group-multicolor.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Multi-color LED built with monochromatic LED devices
+ *
+ * This driver groups several monochromatic LED devices in a single multicolor LED device.
+ *
+ * Compared to handling this grouping in user-space, the benefits are:
+ * - The state of the monochromatic LED relative to each other is always consistent.
+ * - The sysfs interface of the LEDs can be used for the group as a whole.
+ *
+ * Copyright 2023 Jean-Jacques Hiblot <[email protected]>
+ */
+
+#include <linux/err.h>
+#include <linux/leds.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+struct leds_multicolor {
+ struct led_classdev_mc mc_cdev;
+ struct led_classdev **monochromatics;
+};
+
+static int leds_gmc_set(struct led_classdev *cdev, enum led_brightness brightness)
+{
+ struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
+ struct leds_multicolor *priv = container_of(mc_cdev, struct leds_multicolor, mc_cdev);
+ const unsigned int group_max_brightness = mc_cdev->led_cdev.max_brightness;
+ int i;
+
+ for (i = 0; i < mc_cdev->num_colors; i++) {
+ struct led_classdev *mono = priv->monochromatics[i];
+ const unsigned int mono_max_brightness = mono->max_brightness;
+ unsigned int intensity = mc_cdev->subled_info[i].intensity;
+ int mono_brightness;
+
+ /*
+ * Scale the brightness according to relative intensity of the
+ * color AND the max brightness of the monochromatic LED.
+ */
+ mono_brightness = DIV_ROUND_CLOSEST(brightness * intensity * mono_max_brightness,
+ group_max_brightness * group_max_brightness);
+
+ led_set_brightness(mono, mono_brightness);
+ }
+
+ return 0;
+}
+
+static void restore_sysfs_write_access(void *data)
+{
+ struct led_classdev *led_cdev = data;
+
+ /* Restore the write acccess to the LED */
+ mutex_lock(&led_cdev->led_access);
+ led_sysfs_enable(led_cdev);
+ mutex_unlock(&led_cdev->led_access);
+}
+
+static int leds_gmc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct led_init_data init_data = {};
+ struct led_classdev *cdev;
+ struct mc_subled *subled;
+ struct leds_multicolor *priv;
+ unsigned int max_brightness = 0;
+ int i, ret, count = 0;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ for (;;) {
+ struct led_classdev *led_cdev;
+
+ led_cdev = devm_of_led_get_optional(dev, count);
+ if (IS_ERR(led_cdev))
+ return dev_err_probe(dev, PTR_ERR(led_cdev), "Unable to get LED #%d",
+ count);
+ if (!led_cdev)
+ break;
+
+ priv->monochromatics = devm_krealloc_array(dev, priv->monochromatics,
+ count + 1, sizeof(*priv->monochromatics),
+ GFP_KERNEL);
+ if (!priv->monochromatics)
+ return -ENOMEM;
+
+ priv->monochromatics[count] = led_cdev;
+
+ max_brightness = max(max_brightness, led_cdev->max_brightness);
+
+ count++;
+ }
+
+ subled = devm_kcalloc(dev, count, sizeof(*subled), GFP_KERNEL);
+ if (!subled)
+ return -ENOMEM;
+ priv->mc_cdev.subled_info = subled;
+
+ for (i = 0; i < count; i++) {
+ struct led_classdev *led_cdev = priv->monochromatics[i];
+
+ subled[i].color_index = led_cdev->color;
+
+ /* Configure the LED intensity to its maximum */
+ subled[i].intensity = max_brightness;
+ }
+
+ /* Initialise the multicolor's LED class device */
+ cdev = &priv->mc_cdev.led_cdev;
+ cdev->flags = LED_CORE_SUSPENDRESUME;
+ cdev->brightness_set_blocking = leds_gmc_set;
+ cdev->max_brightness = max_brightness;
+ cdev->color = LED_COLOR_ID_MULTI;
+ priv->mc_cdev.num_colors = count;
+
+ init_data.fwnode = dev_fwnode(dev);
+ ret = devm_led_classdev_multicolor_register_ext(dev, &priv->mc_cdev, &init_data);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to register multicolor LED for %s.\n",
+ cdev->name);
+
+ ret = leds_gmc_set(cdev, cdev->brightness);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to set LED value for %s.", cdev->name);
+
+ for (i = 0; i < count; i++) {
+ struct led_classdev *led_cdev = priv->monochromatics[i];
+
+ /*
+ * Make the individual LED sysfs interface read-only to prevent the user
+ * to change the brightness of the individual LEDs of the group.
+ */
+ mutex_lock(&led_cdev->led_access);
+ led_sysfs_disable(led_cdev);
+ mutex_unlock(&led_cdev->led_access);
+
+ /* Restore the write access to the LED sysfs when the group is destroyed */
+ devm_add_action_or_reset(dev, restore_sysfs_write_access, led_cdev);
+ }
+
+ return 0;
+}
+
+static const struct of_device_id of_leds_group_multicolor_match[] = {
+ { .compatible = "leds-group-multicolor" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_leds_group_multicolor_match);
+
+static struct platform_driver leds_group_multicolor_driver = {
+ .probe = leds_gmc_probe,
+ .driver = {
+ .name = "leds_group_multicolor",
+ .of_match_table = of_leds_group_multicolor_match,
+ }
+};
+module_platform_driver(leds_group_multicolor_driver);
+
+MODULE_AUTHOR("Jean-Jacques Hiblot <[email protected]>");
+MODULE_DESCRIPTION("LEDs group multicolor driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:leds-group-multicolor");
--
2.34.1
Add an optional variant of devm_of_led_get(). It behaves the same as
devm_of_led_get() except where the LED doesn't exist. In this case,
instead of returning -ENOENT, the function returns NULL.
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 4758da2b59cf..78068b06d009 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -402,6 +402,31 @@ void led_remove_lookup(struct led_lookup_data *led_lookup)
}
EXPORT_SYMBOL_GPL(led_remove_lookup);
+/**
+ * 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 7d428100b42b..8740b4e47f88 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -313,6 +313,8 @@ 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
--
2.34.1
On Fri, 28 Jul 2023 17:37:31 +0200, Jean-Jacques Hiblot wrote:
> Grouping multiple monochrome LEDs into a multicolor LED device has a few
> benefits over handling the group in user-space:
> - The state of the LEDs relative to each other is consistent. In other
> words, if 2 threads competes to set the LED to green and red, the
> end-result cannot be black or yellow.
> - The multicolor LED as a whole can be driven through the sysfs LED
> interface.
>
> [...]
Applied, thanks!
[4/4] leds: Add a multicolor LED driver to group monochromatic LEDs
commit: 37d0849ed3927f7c4be6f5ee030730f9aa7439c0
--
Lee Jones [李琼斯]
On Fri, 28 Jul 2023 17:37:30 +0200, Jean-Jacques Hiblot wrote:
> This allows to group multiple monochromatic LEDs into a multicolor
> LED, e.g. RGB LEDs.
>
>
Applied, thanks!
[3/4] dt-bindings: leds: Add binding for a multicolor group of LEDs
commit: 099c52d9448c1ca832b4695e982221a521282b94
--
Lee Jones [李琼斯]
On Fri, 28 Jul 2023 17:37:27 +0200, Jean-Jacques Hiblot wrote:
> Resending this series as the v11 didn't apply cleanly.
> The patch adding devm_krealloc_array() has been dropped because this function is now available.
>
> Below is the original cover-letter.
>
>
>
> [...]
Applied, thanks!
[1/4] leds: provide devm_of_led_get_optional()
commit: afb48153220d35f330d0d979792920a31f7d9a81
[2/4] leds: class: store the color index in struct led_classdev
commit: c7d80059b086c4986cd994a1973ec7a5d75f8eea
[3/4] dt-bindings: leds: Add binding for a multicolor group of LEDs
commit: 099c52d9448c1ca832b4695e982221a521282b94
[4/4] leds: Add a multicolor LED driver to group monochromatic LEDs
commit: 37d0849ed3927f7c4be6f5ee030730f9aa7439c0
--
Lee Jones [李琼斯]