On Sat, 24 Jun 2023, 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. > > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx> > --- > drivers/leds/rgb/Kconfig | 12 ++ > drivers/leds/rgb/Makefile | 1 + > drivers/leds/rgb/leds-group-multicolor.c | 165 +++++++++++++++++++++++ > 3 files changed, 178 insertions(+) > create mode 100644 drivers/leds/rgb/leds-group-multicolor.c Reviewed-by: Lee Jones <lee@xxxxxxxxxx> > 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..df3e41a6272b > --- /dev/null > +++ b/drivers/leds/rgb/leds-group-multicolor.c > @@ -0,0 +1,165 @@ > +// 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 <jjhiblot@xxxxxxxxxxxxxxx> > + */ > + > +#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; > + > + 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 monochromatic LED sysfs interface read-only */ > + mutex_lock(&led_cdev->led_access); > + led_sysfs_disable(led_cdev); > + mutex_unlock(&led_cdev->led_access); > + > + /* Restore sysfs access when the multicolor LED is released */ > + 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 <jjhiblot@xxxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("LEDs group multicolor driver"); > +MODULE_LICENSE("GPL"); > +MODULE_ALIAS("platform:leds-group-multicolor"); > -- > 2.34.1 > -- Lee Jones [李琼斯]