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 (5):
devres: provide devm_krealloc_array()
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/device.h | 13 ++
include/linux/leds.h | 3 +
8 files changed, 317 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
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 6dae56b914fe..eb1a8494dc5b 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 50b2f8f153fb..95311c70d95c 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -270,6 +270,8 @@ 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
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
On Tue, 18 Jul 2023, Jean-Jacques Hiblot wrote:
> 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 (5):
> devres: provide devm_krealloc_array()
> 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/device.h | 13 ++
> include/linux/leds.h | 3 +
> 8 files changed, 317 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
> create mode 100644 drivers/leds/rgb/leds-group-multicolor.c
What base is this set sitting on top of?
It doesn't appear to want to apply to for-leds-next:
https://git.kernel.org/pub/scm/linux/kernel/git/lee/leds.git/log/?h=for-leds-next
Please rebase and submit a [RESEND].
--
Lee Jones [李琼斯]
On Tue, 18 Jul 2023 11:25:22 +0200, Jean-Jacques Hiblot wrote:
> 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.
>
> [...]
Applied, thanks!
[1/5] devres: provide devm_krealloc_array()
(no commit info)
[2/5] leds: provide devm_of_led_get_optional()
(no commit info)
[3/5] leds: class: store the color index in struct led_classdev
(no commit info)
[4/5] dt-bindings: leds: Add binding for a multicolor group of LEDs
commit: 099c52d9448c1ca832b4695e982221a521282b94
[5/5] leds: Add a multicolor LED driver to group monochromatic LEDs
(no commit info)
--
Lee Jones [李琼斯]