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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: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Enric Balletbo i Serra 2018-03-28 19:03:25 +02:00 committed by Lee Jones
parent ac7bfb2772
commit 3157694d8c
2 changed files with 21 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/video/backlight/pwm_bl.c
View File

@ -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);

2
include/linux/pwm_backlight.h
View File

@ -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);