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pwm-backlight: Use new enable_gpio field

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Make use of the new enable_gpio field and allow it to be set from DT as
well. Now that all legacy users of platform data have been converted to
initialize this field to an invalid value, it is safe to use the field
from the driver.

Signed-off-by: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Thierry Reding 2013-08-30 12:32:18 +02:00 committed by Thierry Reding
parent 611c86c6de
commit 8265b2e4e6
2 changed files with 55 additions and 7 deletions
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5
Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
View file

@ -14,8 +14,11 @@ Required properties:
Optional properties:
- pwm-names: a list of names for the PWM devices specified in the
"pwms" property (see PWM binding[0])
- enable-gpios: contains a single GPIO specifier for the GPIO which enables
and disables the backlight (see GPIO binding[1])
[0]: Documentation/devicetree/bindings/pwm/pwm.txt
[1]: Documentation/devicetree/bindings/gpio/gpio.txt
Example:
@ -25,4 +28,6 @@ Example:
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
enable-gpios = <&gpio 58 0>;
};

57
drivers/video/backlight/pwm_bl.c
View file

@ -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);