[PATCH v6 3/5] pwm-backlight: add support for PWM delays proprieties.
From: Enric Balletbo i Serra <hidden>
Date: 2018-03-26 09:53:19
Also in:
linux-fbdev, linux-leds, linux-pwm, linux-rockchip, lkml
Subsystem:
backlight class/subsystem, framebuffer layer, the rest · Maintainers:
Lee Jones, Daniel Thompson, Jingoo Han, Helge Deller, Linus Torvalds
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-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org> Acked-by: Pavel Machek <redacted> Acked-by: Daniel Thompson <redacted> Acked-by: Jingoo Han <redacted> Acked-by: Thierry Reding <redacted> --- Changes since v5: - Add Acked-by: Thierry Reding [off-list ref] Changes since v4: - Rebased on top of mainline. - Added the acks from Pavel Machek, Daniel thompson and Jingoo Han Changes since v3: - Use two named members instead of pwm_delay[] (Daniel and Pavel) - Use msleep instead of usleep_range. (Pavel) Changes since v2: - Move the pwm/enable sequence to another patch (Thierry Reding) Changes since v1: - As suggested by Daniel Thompson - Do not assume power-on delay and power-off delay will be the same - Move the check of dt property to the parse dt function. --- drivers/video/backlight/pwm_bl.c | 19 +++++++++++++++++++ include/linux/pwm_backlight.h | 2 ++ 2 files changed, 21 insertions(+)
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);
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index e8afbd71a140..8ea265a022fd 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h@@ -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);
--
2.16.2