From bb64206276db15f1d6e115febb262c9830628625 Mon Sep 17 00:00:00 2001 From: LI Qingwu Date: Mon, 17 Nov 2025 05:45:09 +0000 Subject: [PATCH] leds: pwm: Add optional GPIO enable pin support Add support for optional GPIO-based enable pin control to PWM LED driver. Some PWM LED driver chips like TPS92380 and LT3743 require a separate enable signal in addition to PWM control. Implement support for such GPIO control through the "enable-gpios" device tree property, activating the pin when LED brightness is non-zero and deactivating it when off. Tested on i.MX8MP EVK with TPS92380 LED driver chip Signed-off-by: LI Qingwu Link: https://patch.msgid.link/20251117054511.730246-2-Qing-wu.Li@leica-geosystems.com.cn Signed-off-by: Lee Jones --- drivers/leds/leds-pwm.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c index c73134e7b951..dac96d91e6bf 100644 --- a/drivers/leds/leds-pwm.c +++ b/drivers/leds/leds-pwm.c @@ -9,6 +9,7 @@ * based on leds-gpio.c by Raphael Assenat */ +#include #include #include #include @@ -26,6 +27,7 @@ struct led_pwm { }; struct led_pwm_data { + struct gpio_desc *enable_gpio; struct led_classdev cdev; struct pwm_device *pwm; struct pwm_state pwmstate; @@ -51,6 +53,8 @@ static int led_pwm_set(struct led_classdev *led_cdev, if (led_dat->active_low) duty = led_dat->pwmstate.period - duty; + gpiod_set_value_cansleep(led_dat->enable_gpio, !!brightness); + led_dat->pwmstate.duty_cycle = duty; /* * Disabling a PWM doesn't guarantee that it emits the inactive level. @@ -132,6 +136,21 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, break; } + /* + * Claim the GPIO as GPIOD_ASIS and set the value + * later on to honor the different default states + */ + led_data->enable_gpio = devm_fwnode_gpiod_get(dev, fwnode, "enable", GPIOD_ASIS, NULL); + if (IS_ERR(led_data->enable_gpio)) { + if (PTR_ERR(led_data->enable_gpio) == -ENOENT) + /* Enable GPIO is optional */ + led_data->enable_gpio = NULL; + else + return PTR_ERR(led_data->enable_gpio); + } + + gpiod_direction_output(led_data->enable_gpio, !!led_data->cdev.brightness); + ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data); if (ret) { dev_err(dev, "failed to register PWM led for %s: %d\n", -- 2.47.3