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path: root/drivers/video/backlight/pwm_bl.c
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Diffstat (limited to 'drivers/video/backlight/pwm_bl.c')
-rw-r--r--drivers/video/backlight/pwm_bl.c28
1 files changed, 25 insertions, 3 deletions
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index ae3c6b6fd..64f9e1b86 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -198,7 +198,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
struct platform_pwm_backlight_data defdata;
struct backlight_properties props;
struct backlight_device *bl;
+ struct device_node *node = pdev->dev.of_node;
struct pwm_bl_data *pb;
+ int initial_blank = FB_BLANK_UNBLANK;
int ret;
if (!data) {
@@ -242,7 +244,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->enabled = false;
pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
- GPIOD_OUT_HIGH);
+ GPIOD_ASIS);
if (IS_ERR(pb->enable_gpio)) {
ret = PTR_ERR(pb->enable_gpio);
goto err_alloc;
@@ -264,15 +266,32 @@ 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);
+ }
+
pb->power_supply = devm_regulator_get(&pdev->dev, "power");
if (IS_ERR(pb->power_supply)) {
ret = PTR_ERR(pb->power_supply);
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
- && !pdev->dev.of_node) {
+ if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) {
dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
pb->legacy = true;
pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
@@ -309,6 +328,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
ret = PTR_ERR(bl);
+ if (pb->legacy)
+ pwm_free(pb->pwm);
goto err_alloc;
}
@@ -320,6 +341,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
}
bl->props.brightness = data->dft_brightness;
+ bl->props.power = initial_blank;
backlight_update_status(bl);
platform_set_drvdata(pdev, bl);