| Message ID | 20230624084217.3079205-6-jjhiblot@traphandler.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add a multicolor LED driver for groups of monochromatic LEDs | expand |
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@traphandler.com> > --- > 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@kernel.org> > 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@traphandler.com> > + */ > + > +#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@traphandler.com>"); > +MODULE_DESCRIPTION("LEDs group multicolor driver"); > +MODULE_LICENSE("GPL"); > +MODULE_ALIAS("platform:leds-group-multicolor"); > -- > 2.34.1 >
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@traphandler.com> + */ + +#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@traphandler.com>"); +MODULE_DESCRIPTION("LEDs group multicolor driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:leds-group-multicolor");
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@traphandler.com> --- 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