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path: root/drivers/video/backlight
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Diffstat (limited to 'drivers/video/backlight')
-rw-r--r--drivers/video/backlight/pwm_bl.c57
1 files changed, 50 insertions, 7 deletions
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 4053efbe5edb..cdef4a346555 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -10,6 +10,8 @@
* published by the Free Software Foundation.
*/
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
@@ -28,6 +30,8 @@ struct pwm_bl_data {
unsigned int lth_brightness;
unsigned int *levels;
bool enabled;
+ int enable_gpio;
+ unsigned long enable_gpio_flags;
int (*notify)(struct device *,
int brightness);
void (*notify_after)(struct device *,
@@ -55,6 +59,14 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness,
pb->lth_brightness;
pwm_config(pb->pwm, duty_cycle, pb->period);
+
+ if (gpio_is_valid(pb->enable_gpio)) {
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ gpio_set_value(pb->enable_gpio, 0);
+ else
+ gpio_set_value(pb->enable_gpio, 1);
+ }
+
pwm_enable(pb->pwm);
pb->enabled = true;
}
@@ -67,6 +79,13 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
pwm_config(pb->pwm, 0, pb->period);
pwm_disable(pb->pwm);
+ if (gpio_is_valid(pb->enable_gpio)) {
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ gpio_set_value(pb->enable_gpio, 1);
+ else
+ gpio_set_value(pb->enable_gpio, 0);
+ }
+
pb->enabled = false;
}
@@ -119,6 +138,7 @@ static int pwm_backlight_parse_dt(struct device *dev,
struct platform_pwm_backlight_data *data)
{
struct device_node *node = dev->of_node;
+ enum of_gpio_flags flags;
struct property *prop;
int length;
u32 value;
@@ -159,11 +179,13 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->max_brightness--;
}
- /*
- * TODO: Most users of this driver use a number of GPIOs to control
- * backlight power. Support for specifying these needs to be
- * added.
- */
+ data->enable_gpio = of_get_named_gpio_flags(node, "enable-gpios", 0,
+ &flags);
+ if (data->enable_gpio == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ if (gpio_is_valid(data->enable_gpio) && (flags & OF_GPIO_ACTIVE_LOW))
+ data->enable_gpio_flags |= PWM_BACKLIGHT_GPIO_ACTIVE_LOW;
return 0;
}
@@ -221,6 +243,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
} else
max = data->max_brightness;
+ pb->enable_gpio = data->enable_gpio;
+ pb->enable_gpio_flags = data->enable_gpio_flags;
pb->notify = data->notify;
pb->notify_after = data->notify_after;
pb->check_fb = data->check_fb;
@@ -228,6 +252,22 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->dev = &pdev->dev;
pb->enabled = false;
+ if (gpio_is_valid(pb->enable_gpio)) {
+ unsigned long flags;
+
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ flags = GPIOF_OUT_INIT_HIGH;
+ else
+ flags = GPIOF_OUT_INIT_LOW;
+
+ ret = gpio_request_one(pb->enable_gpio, flags, "enable");
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n",
+ pb->enable_gpio, ret);
+ goto err_alloc;
+ }
+ }
+
pb->pwm = devm_pwm_get(&pdev->dev, NULL);
if (IS_ERR(pb->pwm)) {
dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
@@ -236,7 +276,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
if (IS_ERR(pb->pwm)) {
dev_err(&pdev->dev, "unable to request legacy PWM\n");
ret = PTR_ERR(pb->pwm);
- goto err_alloc;
+ goto err_gpio;
}
}
@@ -261,7 +301,7 @@ 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);
- goto err_alloc;
+ goto err_gpio;
}
if (data->dft_brightness > data->max_brightness) {
@@ -277,6 +317,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, bl);
return 0;
+err_gpio:
+ if (gpio_is_valid(pb->enable_gpio))
+ gpio_free(pb->enable_gpio);
err_alloc:
if (data->exit)
data->exit(&pdev->dev);