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Commit 3157694d authored by Enric Balletbo i Serra's avatar Enric Balletbo i Serra Committed by Lee Jones
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pwm-backlight: Add support for PWM delays proprieties. 



Some panels (i.e. N116BGE-L41), in their power sequence specifications,
request a delay between set the PWM signal and enable the backlight and
between clear the PWM signal and disable the backlight. Add support for
the new post-pwm-on-delay-ms and pwm-off-delay-ms proprieties to meet
the timings.

Signed-off-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Acked-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: default avatarJingoo Han <jingoohan1@gmail.com>
Acked-by: default avatarThierry Reding <thierry.reding@gmail.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent ac7bfb27

drivers/video/backlight/pwm_bl.c

+19 −0
Original line number Diff line number Diff line
@@ -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>
@@ -35,6 +36,8 @@ struct pwm_bl_data { 
	struct gpio_desc	*enable_gpio;

	unsigned int		scale;

	bool			legacy;

	unsigned int		post_pwm_on_delay;

	unsigned int		pwm_off_delay;

	int			(*notify)(struct device *,

					  int brightness);

	void			(*notify_after)(struct device *,
@@ -56,6 +59,9 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) 


	pwm_enable(pb->pwm);



	if (pb->post_pwm_on_delay)

		msleep(pb->post_pwm_on_delay);



	if (pb->enable_gpio)

		gpiod_set_value_cansleep(pb->enable_gpio, 1);
@@ -70,6 +76,9 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) 
	if (pb->enable_gpio)

		gpiod_set_value_cansleep(pb->enable_gpio, 0);



	if (pb->pwm_off_delay)

		msleep(pb->pwm_off_delay);



	pwm_config(pb->pwm, 0, pb->period);

	pwm_disable(pb->pwm);
@@ -178,6 +187,14 @@ static int pwm_backlight_parse_dt(struct device *dev, 
		data->max_brightness--;

	}



	/*

	 * These values are optional and set as 0 by default, the out values

	 * are modified only if a valid u32 value can be decoded.

	 */

	of_property_read_u32(node, "post-pwm-on-delay-ms",

			     &data->post_pwm_on_delay);

	of_property_read_u32(node, "pwm-off-delay-ms", &data->pwm_off_delay);



	data->enable_gpio = -EINVAL;

	return 0;

}
@@ -276,6 +293,8 @@ static int pwm_backlight_probe(struct platform_device *pdev) 
	pb->exit = data->exit;

	pb->dev = &pdev->dev;

	pb->enabled = false;

	pb->post_pwm_on_delay = data->post_pwm_on_delay;

	pb->pwm_off_delay = data->pwm_off_delay;



	pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",

						  GPIOD_ASIS);

include/linux/pwm_backlight.h

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ struct platform_pwm_backlight_data { 
	unsigned int lth_brightness;

	unsigned int pwm_period_ns;

	unsigned int *levels;

	unsigned int post_pwm_on_delay;

	unsigned int pwm_off_delay;

	/* TODO remove once all users are switched to gpiod_* API */

	int enable_gpio;

	int (*init)(struct device *dev);