From e6bcca0890b96a3c2c5e72169de72ba4d2b01b78 Mon Sep 17 00:00:00 2001 From: Enric Balletbo i Serra Date: Tue, 14 Aug 2018 18:50:59 +0200 Subject: [PATCH] backlight: pwm_bl: Switch to using "atomic" PWM API The "atomic" API allows us to configure PWM period and duty_cycle and enable it in one call. The patch also moves the pwm_init_state just before any use of the pwm_state struct, this fixes a potential bug where pwm_get_state can be called before pwm_init_state. Signed-off-by: Enric Balletbo i Serra Reviewed-by: Daniel Thompson Tested-by: Heiko Stuebner Signed-off-by: Lee Jones --- drivers/video/backlight/pwm_bl.c | 81 +++++++++++++++++--------------- 1 file changed, 42 insertions(+), 39 deletions(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index bdfcc0a71db1..678b27063198 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -28,10 +28,8 @@ struct pwm_bl_data { struct pwm_device *pwm; struct device *dev; - unsigned int period; unsigned int lth_brightness; unsigned int *levels; - bool enabled; struct regulator *power_supply; struct gpio_desc *enable_gpio; unsigned int scale; @@ -46,31 +44,35 @@ struct pwm_bl_data { void (*exit)(struct device *); }; -static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness) +static void pwm_backlight_power_on(struct pwm_bl_data *pb) { + struct pwm_state state; int err; - if (pb->enabled) + pwm_get_state(pb->pwm, &state); + if (state.enabled) return; err = regulator_enable(pb->power_supply); if (err < 0) dev_err(pb->dev, "failed to enable power supply\n"); - pwm_enable(pb->pwm); + state.enabled = true; + pwm_apply_state(pb->pwm, &state); if (pb->post_pwm_on_delay) msleep(pb->post_pwm_on_delay); if (pb->enable_gpio) gpiod_set_value_cansleep(pb->enable_gpio, 1); - - pb->enabled = true; } static void pwm_backlight_power_off(struct pwm_bl_data *pb) { - if (!pb->enabled) + struct pwm_state state; + + pwm_get_state(pb->pwm, &state); + if (!state.enabled) return; if (pb->enable_gpio) @@ -79,24 +81,27 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb) if (pb->pwm_off_delay) msleep(pb->pwm_off_delay); - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); + state.enabled = false; + state.duty_cycle = 0; + pwm_apply_state(pb->pwm, &state); regulator_disable(pb->power_supply); - pb->enabled = false; } static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness) { unsigned int lth = pb->lth_brightness; + struct pwm_state state; u64 duty_cycle; + pwm_get_state(pb->pwm, &state); + if (pb->levels) duty_cycle = pb->levels[brightness]; else duty_cycle = brightness; - duty_cycle *= pb->period - lth; + duty_cycle *= state.period - lth; do_div(duty_cycle, pb->scale); return duty_cycle + lth; @@ -106,7 +111,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) { struct pwm_bl_data *pb = bl_get_data(bl); int brightness = bl->props.brightness; - int duty_cycle; + struct pwm_state state; if (bl->props.power != FB_BLANK_UNBLANK || bl->props.fb_blank != FB_BLANK_UNBLANK || @@ -117,9 +122,10 @@ static int pwm_backlight_update_status(struct backlight_device *bl) brightness = pb->notify(pb->dev, brightness); if (brightness > 0) { - duty_cycle = compute_duty_cycle(pb, brightness); - pwm_config(pb->pwm, duty_cycle, pb->period); - pwm_backlight_power_on(pb, brightness); + pwm_get_state(pb->pwm, &state); + state.duty_cycle = compute_duty_cycle(pb, brightness); + pwm_apply_state(pb->pwm, &state); + pwm_backlight_power_on(pb); } else pwm_backlight_power_off(pb); @@ -447,7 +453,6 @@ static int pwm_backlight_probe(struct platform_device *pdev) struct device_node *node = pdev->dev.of_node; struct pwm_bl_data *pb; struct pwm_state state; - struct pwm_args pargs; unsigned int i; int ret; @@ -478,7 +483,6 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->check_fb = data->check_fb; 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; @@ -539,10 +543,26 @@ static int pwm_backlight_probe(struct platform_device *pdev) dev_dbg(&pdev->dev, "got pwm for backlight\n"); - if (!data->levels) { - /* Get the PWM period (in nanoseconds) */ - pwm_get_state(pb->pwm, &state); + /* Sync up PWM state. */ + pwm_init_state(pb->pwm, &state); + /* + * The DT case will set the pwm_period_ns field to 0 and store the + * period, parsed from the DT, in the PWM device. For the non-DT case, + * set the period from platform data if it has not already been set + * via the PWM lookup table. + */ + if (!state.period && (data->pwm_period_ns > 0)) + state.period = data->pwm_period_ns; + + ret = pwm_apply_state(pb->pwm, &state); + if (ret) { + dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n", + ret); + goto err_alloc; + } + + if (!data->levels) { ret = pwm_backlight_brightness_default(&pdev->dev, data, state.period); if (ret < 0) { @@ -559,24 +579,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->levels = data->levels; } - /* - * FIXME: pwm_apply_args() should be removed when switching to - * the atomic PWM API. - */ - pwm_apply_args(pb->pwm); - - /* - * The DT case will set the pwm_period_ns field to 0 and store the - * period, parsed from the DT, in the PWM device. For the non-DT case, - * set the period from platform data if it has not already been set - * via the PWM lookup table. - */ - pwm_get_args(pb->pwm, &pargs); - pb->period = pargs.period; - if (!pb->period && (data->pwm_period_ns > 0)) - pb->period = data->pwm_period_ns; - - pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale); + pb->lth_brightness = data->lth_brightness * (state.period / pb->scale); memset(&props, 0, sizeof(struct backlight_properties)); props.type = BACKLIGHT_RAW; -- 2.30.2