On 17/07/17 22:28, 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-us and pwm-off-delay-us proprieties to meet the timings.Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com> --- 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 | 17 +++++++++++++++++ include/linux/pwm_backlight.h | 1 + 2 files changed, 18 insertions(+) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 909a686..528155d 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 +36,7 @@ struct pwm_bl_data { struct gpio_desc *enable_gpio; unsigned int scale; bool legacy; + unsigned int pwm_delay[2];
Two named members would be better here (eliminating the "magic" 0 and 1).
int (*notify)(struct device *, int brightness); void (*notify_after)(struct device *, @@ -56,6 +58,9 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)pwm_enable(pb->pwm); + if (pb->pwm_delay[0])+ usleep_range(pb->pwm_delay[0], pb->pwm_delay[0] * 2); + if (pb->enable_gpio) gpiod_set_value_cansleep(pb->enable_gpio, 1);@@ -70,6 +75,9 @@ 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_delay[1])+ usleep_range(pb->pwm_delay[1], pb->pwm_delay[1] * 2); + pwm_config(pb->pwm, 0, pb->period); pwm_disable(pb->pwm);@@ -175,6 +183,14 @@ 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-us", + &data->pwm_delay[0]); + of_property_read_u32(node, "pwm-off-delay-us", &data->pwm_delay[1]); + data->enable_gpio = -EINVAL; return 0; } @@ -273,6 +289,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->exit = data->exit; pb->dev = &pdev->dev; pb->enabled = false; + memcpy(pb->pwm_delay, data->pwm_delay, sizeof(pb->pwm_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..bf37131 100644 --- a/include/linux/pwm_backlight.h +++ b/include/linux/pwm_backlight.h @@ -13,6 +13,7 @@ struct platform_pwm_backlight_data { unsigned int lth_brightness; unsigned int pwm_period_ns; unsigned int *levels; + unsigned int pwm_delay[2]; /* TODO remove once all users are switched to gpiod_* API */ int enable_gpio; int (*init)(struct device *dev);
