diff options
| -rw-r--r-- | drivers/video/backlight/pwm_bl.c | 56 |
1 files changed, 37 insertions, 19 deletions
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 12614006211e..5712ddd053dd 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -192,6 +192,32 @@ static int pwm_backlight_parse_dt(struct device *dev, } #endif +static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb) +{ + struct device_node *node = pb->dev->of_node; + + /* Not booted with device tree or no phandle link to the node */ + if (!node || !node->phandle) + return FB_BLANK_UNBLANK; + + /* + * If the driver is probed from the device tree and there is a + * phandle link pointing to the backlight node, it is safe to + * assume that another driver will enable the backlight at the + * appropriate time. Therefore, if it is disabled, keep it so. + */ + + /* if the enable GPIO is disabled, do not enable the backlight */ + if (pb->enable_gpio && gpiod_get_value(pb->enable_gpio) == 0) + return FB_BLANK_POWERDOWN; + + /* The regulator is disabled, do not enable the backlight */ + if (!regulator_is_enabled(pb->power_supply)) + return FB_BLANK_POWERDOWN; + + return FB_BLANK_UNBLANK; +} + static int pwm_backlight_probe(struct platform_device *pdev) { struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev); @@ -200,7 +226,6 @@ static int pwm_backlight_probe(struct platform_device *pdev) struct backlight_device *bl; struct device_node *node = pdev->dev.of_node; struct pwm_bl_data *pb; - int initial_blank = FB_BLANK_UNBLANK; struct pwm_args pargs; int ret; @@ -267,20 +292,16 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->enable_gpio = gpio_to_desc(data->enable_gpio); } - if (pb->enable_gpio) { - /* - * If the driver is probed from the device tree and there is a - * phandle link pointing to the backlight node, it is safe to - * assume that another driver will enable the backlight at the - * appropriate time. Therefore, if it is disabled, keep it so. - */ - if (node && node->phandle && - gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT && - gpiod_get_value(pb->enable_gpio) == 0) - initial_blank = FB_BLANK_POWERDOWN; - else - gpiod_direction_output(pb->enable_gpio, 1); - } + /* + * If the GPIO is configured as input, change the direction to output + * and set the GPIO as active. + * Do not force the GPIO to active when it was already output as it + * could cause backlight flickering or we would enable the backlight too + * early. Leave the decision of the initial backlight state for later. + */ + if (pb->enable_gpio && + gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_IN) + gpiod_direction_output(pb->enable_gpio, 1); pb->power_supply = devm_regulator_get(&pdev->dev, "power"); if (IS_ERR(pb->power_supply)) { @@ -288,9 +309,6 @@ static int pwm_backlight_probe(struct platform_device *pdev) goto err_alloc; } - if (node && node->phandle && !regulator_is_enabled(pb->power_supply)) - initial_blank = FB_BLANK_POWERDOWN; - pb->pwm = devm_pwm_get(&pdev->dev, NULL); if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) { dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); @@ -347,7 +365,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) } bl->props.brightness = data->dft_brightness; - bl->props.power = initial_blank; + bl->props.power = pwm_backlight_initial_power_state(pb); backlight_update_status(bl); platform_set_drvdata(pdev, bl); |