mirror of https://gitee.com/openkylin/linux.git
127 lines
3.1 KiB
C
127 lines
3.1 KiB
C
/*
|
|
* gpio_backlight.c - Simple GPIO-controlled backlight
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/backlight.h>
|
|
#include <linux/err.h>
|
|
#include <linux/fb.h>
|
|
#include <linux/gpio.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/platform_data/gpio_backlight.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/slab.h>
|
|
|
|
struct gpio_backlight {
|
|
struct device *dev;
|
|
struct device *fbdev;
|
|
|
|
int gpio;
|
|
int active;
|
|
};
|
|
|
|
static int gpio_backlight_update_status(struct backlight_device *bl)
|
|
{
|
|
struct gpio_backlight *gbl = bl_get_data(bl);
|
|
int brightness = bl->props.brightness;
|
|
|
|
if (bl->props.power != FB_BLANK_UNBLANK ||
|
|
bl->props.fb_blank != FB_BLANK_UNBLANK ||
|
|
bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
|
|
brightness = 0;
|
|
|
|
gpio_set_value(gbl->gpio, brightness ? gbl->active : !gbl->active);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gpio_backlight_get_brightness(struct backlight_device *bl)
|
|
{
|
|
return bl->props.brightness;
|
|
}
|
|
|
|
static int gpio_backlight_check_fb(struct backlight_device *bl,
|
|
struct fb_info *info)
|
|
{
|
|
struct gpio_backlight *gbl = bl_get_data(bl);
|
|
|
|
return gbl->fbdev == NULL || gbl->fbdev == info->dev;
|
|
}
|
|
|
|
static const struct backlight_ops gpio_backlight_ops = {
|
|
.options = BL_CORE_SUSPENDRESUME,
|
|
.update_status = gpio_backlight_update_status,
|
|
.get_brightness = gpio_backlight_get_brightness,
|
|
.check_fb = gpio_backlight_check_fb,
|
|
};
|
|
|
|
static int gpio_backlight_probe(struct platform_device *pdev)
|
|
{
|
|
struct gpio_backlight_platform_data *pdata =
|
|
dev_get_platdata(&pdev->dev);
|
|
struct backlight_properties props;
|
|
struct backlight_device *bl;
|
|
struct gpio_backlight *gbl;
|
|
int ret;
|
|
|
|
if (!pdata) {
|
|
dev_err(&pdev->dev, "failed to find platform data\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
|
|
if (gbl == NULL)
|
|
return -ENOMEM;
|
|
|
|
gbl->dev = &pdev->dev;
|
|
gbl->fbdev = pdata->fbdev;
|
|
gbl->gpio = pdata->gpio;
|
|
gbl->active = pdata->active_low ? 0 : 1;
|
|
|
|
ret = devm_gpio_request_one(gbl->dev, gbl->gpio, GPIOF_DIR_OUT |
|
|
(gbl->active ? GPIOF_INIT_LOW
|
|
: GPIOF_INIT_HIGH),
|
|
pdata->name);
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "unable to request GPIO\n");
|
|
return ret;
|
|
}
|
|
|
|
memset(&props, 0, sizeof(props));
|
|
props.type = BACKLIGHT_RAW;
|
|
props.max_brightness = 1;
|
|
bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
|
|
&pdev->dev, gbl, &gpio_backlight_ops,
|
|
&props);
|
|
if (IS_ERR(bl)) {
|
|
dev_err(&pdev->dev, "failed to register backlight\n");
|
|
return PTR_ERR(bl);
|
|
}
|
|
|
|
bl->props.brightness = pdata->def_value;
|
|
backlight_update_status(bl);
|
|
|
|
platform_set_drvdata(pdev, bl);
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver gpio_backlight_driver = {
|
|
.driver = {
|
|
.name = "gpio-backlight",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.probe = gpio_backlight_probe,
|
|
};
|
|
|
|
module_platform_driver(gpio_backlight_driver);
|
|
|
|
MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
|
|
MODULE_DESCRIPTION("GPIO-based Backlight Driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:gpio-backlight");
|