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backlight: gpio-backlight: Add DT support

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Signed-off-by: Denis Carikli <denis@eukrea.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Denis Carikli 2014-02-27 15:28:33 +01:00 committed by Lee Jones
parent 35762a47c0
commit 9a6adb339e
2 changed files with 67 additions and 7 deletions
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16
Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt Normal file
View file

@ -0,0 +1,16 @@
gpio-backlight bindings
Required properties:
- compatible: "gpio-backlight"
- gpios: describes the gpio that is used for enabling/disabling the backlight.
refer to bindings/gpio/gpio.txt for more details.
Optional properties:
- default-on: enable the backlight at boot.
Example:
backlight {
compatible = "gpio-backlight";
gpios = <&gpio3 4 GPIO_ACTIVE_HIGH>;
default-on;
};

58
drivers/video/backlight/gpio_backlight.c
View file

@ -13,6 +13,8 @@
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/platform_data/gpio_backlight.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
@ -23,6 +25,7 @@ struct gpio_backlight {
int gpio;
int active;
int def_value;
};
static int gpio_backlight_update_status(struct backlight_device *bl)
@ -60,6 +63,29 @@ static const struct backlight_ops gpio_backlight_ops = {
.check_fb = gpio_backlight_check_fb,
};
static int gpio_backlight_probe_dt(struct platform_device *pdev,
struct gpio_backlight *gbl)
{
struct device_node *np = pdev->dev.of_node;
enum of_gpio_flags gpio_flags;
gbl->gpio = of_get_gpio_flags(np, 0, &gpio_flags);
if (!gpio_is_valid(gbl->gpio)) {
if (gbl->gpio != -EPROBE_DEFER) {
dev_err(&pdev->dev,
"Error: The gpios parameter is missing or invalid.\n");
}
return gbl->gpio;
}
gbl->active = (gpio_flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1;
gbl->def_value = of_property_read_bool(np, "default-on");
return 0;
}
static int gpio_backlight_probe(struct platform_device *pdev)
{
struct gpio_backlight_platform_data *pdata =
@ -67,10 +93,12 @@ static int gpio_backlight_probe(struct platform_device *pdev)
struct backlight_properties props;
struct backlight_device *bl;
struct gpio_backlight *gbl;
struct device_node *np = pdev->dev.of_node;
int ret;
if (!pdata) {
dev_err(&pdev->dev, "failed to find platform data\n");
if (!pdata && !np) {
dev_err(&pdev->dev,
"failed to find platform data or device tree node.\n");
return -ENODEV;
}
@ -79,14 +107,22 @@ static int gpio_backlight_probe(struct platform_device *pdev)
return -ENOMEM;
gbl->dev = &pdev->dev;
gbl->fbdev = pdata->fbdev;
gbl->gpio = pdata->gpio;
gbl->active = pdata->active_low ? 0 : 1;
if (np) {
ret = gpio_backlight_probe_dt(pdev, gbl);
if (ret)
return ret;
} else {
gbl->fbdev = pdata->fbdev;
gbl->gpio = pdata->gpio;
gbl->active = pdata->active_low ? 0 : 1;
gbl->def_value = pdata->def_value;
}
ret = devm_gpio_request_one(gbl->dev, gbl->gpio, GPIOF_DIR_OUT |
(gbl->active ? GPIOF_INIT_LOW
: GPIOF_INIT_HIGH),
pdata->name);
pdata ? pdata->name : "backlight");
if (ret < 0) {
dev_err(&pdev->dev, "unable to request GPIO\n");
return ret;
@ -103,17 +139,25 @@ static int gpio_backlight_probe(struct platform_device *pdev)
return PTR_ERR(bl);
}
bl->props.brightness = pdata->def_value;
bl->props.brightness = gbl->def_value;
backlight_update_status(bl);
platform_set_drvdata(pdev, bl);
return 0;
}
#ifdef CONFIG_OF
static struct of_device_id gpio_backlight_of_match[] = {
{ .compatible = "gpio-backlight" },
{ /* sentinel */ }
};
#endif
static struct platform_driver gpio_backlight_driver = {
.driver = {
.name = "gpio-backlight",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(gpio_backlight_of_match),
},
.probe = gpio_backlight_probe,
};