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SubjectRe: [PATCH v4 3/5] pwm-backlight: add support for PWM delays proprieties.
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On 21/07/17 11:48, Enric Balletbo i Serra wrote:
> 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: Daniel Thompson <daniel.thompson@linaro.org>


> ---
> 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 909a686..6cf6109 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);
>
> @@ -175,6 +184,14 @@ 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;
> }
> @@ -273,6 +290,8 @@ 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 efdd922..62f59c4 100644
> --- a/include/linux/pwm_backlight.h
> +++ b/include/linux/pwm_backlight.h
> @@ -13,6 +13,8 @@ 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);
>

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