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authorEnric Balletbo i Serra <enric.balletbo@collabora.com>2018-03-28 19:03:25 +0200
committerLee Jones <lee.jones@linaro.org>2018-04-30 10:50:44 +0100
commit3157694d8c7fed9046dece8b63434cafef21cbf6 (patch)
treefad20686e233da7d607d81292a3a9718b6784ff8 /drivers/video/backlight
parentac7bfb27729fbfe85b93b083cba7898a1c9a9d91 (diff)
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>
Diffstat (limited to 'drivers/video/backlight')
-rw-r--r--drivers/video/backlight/pwm_bl.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 698ec68bcdc9..8e3f1245f5c5 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>
@@ -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);