diff options
| author | LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn> | 2025-11-17 08:45:09 +0300 |
|---|---|---|
| committer | Lee Jones <lee@kernel.org> | 2025-11-20 15:20:21 +0300 |
| commit | bb64206276db15f1d6e115febb262c9830628625 (patch) | |
| tree | 7ecd44cc905aa1e56d574cc9760d5c813b13d690 | |
| parent | d7dca03a48e2e95b4469d3e3a1ef23065d90f98b (diff) | |
| download | linux-bb64206276db15f1d6e115febb262c9830628625.tar.xz | |
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 <Qing-wu.Li@leica-geosystems.com.cn>
Link: https://patch.msgid.link/20251117054511.730246-2-Qing-wu.Li@leica-geosystems.com.cn
Signed-off-by: Lee Jones <lee@kernel.org>
| -rw-r--r-- | drivers/leds/leds-pwm.c | 19 |
1 files changed, 19 insertions, 0 deletions
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 <raph@8d.com> */ +#include <linux/gpio/consumer.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/platform_device.h> @@ -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", |