From: huang lin <[email protected]> Some panel backlight (i.e. N116BGE-L41), in their power sequence specifications, request a delay between PWM signal and the backlight enable signal, so use the pwm-delay-us property to meet the timing.
Signed-off-by: huang lin <[email protected]> Signed-off-by: Enric Balletbo i Serra <[email protected]> --- drivers/video/backlight/pwm_bl.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 002f1ce..c5c4ef0 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -10,6 +10,7 @@ * published by the Free Software Foundation. */ +#include <linux/delay.h> #include <linux/gpio/consumer.h> #include <linux/gpio.h> #include <linux/module.h> @@ -30,6 +31,7 @@ struct pwm_bl_data { unsigned int period; unsigned int lth_brightness; unsigned int *levels; + unsigned int pwm_delay; bool enabled; struct regulator *power_supply; struct gpio_desc *enable_gpio; @@ -54,10 +56,14 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) if (err < 0) dev_err(pb->dev, "failed to enable power supply\n"); + pwm_enable(pb->pwm); + + if (pb->pwm_delay) + usleep_range(pb->pwm_delay, pb->pwm_delay + 2000); + if (pb->enable_gpio) gpiod_set_value_cansleep(pb->enable_gpio, 1); - pwm_enable(pb->pwm); pb->enabled = true; } @@ -66,12 +72,15 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) if (!pb->enabled) return; - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); - if (pb->enable_gpio) gpiod_set_value_cansleep(pb->enable_gpio, 0); + if (pb->pwm_delay) + usleep_range(pb->pwm_delay, pb->pwm_delay + 2000); + + pwm_config(pb->pwm, 0, pb->period); + pwm_disable(pb->pwm); + regulator_disable(pb->power_supply); pb->enabled = false; } @@ -273,6 +282,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->dev = &pdev->dev; pb->enabled = false; + of_property_read_u32(pdev->dev.of_node, "pwm-delay-us", &pb->pwm_delay); pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", GPIOD_ASIS); if (IS_ERR(pb->enable_gpio)) { -- 2.9.3
