[mirror_ubuntu-artful-kernel.git] / drivers / video / backlight / gpio_backlight.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/of.h>
#include <linux/of_gpio.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;
	int def_value;
};

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_cansleep(gbl->gpio,
				brightness ? gbl->active : !gbl->active);

	return 0;
}

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,
	.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 =
		dev_get_platdata(&pdev->dev);
	struct backlight_properties props;
	struct backlight_device *bl;
	struct gpio_backlight *gbl;
	struct device_node *np = pdev->dev.of_node;
	unsigned long flags = GPIOF_DIR_OUT;
	int ret;

	if (!pdata && !np) {
		dev_err(&pdev->dev,
			"failed to find platform data or device tree node.\n");
		return -ENODEV;
	}

	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
	if (gbl == NULL)
		return -ENOMEM;

	gbl->dev = &pdev->dev;

	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;
	}

	if (gbl->active)
		flags |= gbl->def_value ? GPIOF_INIT_HIGH : GPIOF_INIT_LOW;
	else
		flags |= gbl->def_value ? GPIOF_INIT_LOW : GPIOF_INIT_HIGH;

	ret = devm_gpio_request_one(gbl->dev, gbl->gpio, flags,
				    pdata ? pdata->name : "backlight");
	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 = 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 */ }
};

MODULE_DEVICE_TABLE(of, gpio_backlight_of_match);
#endif

static struct platform_driver gpio_backlight_driver = {
	.driver		= {
		.name		= "gpio-backlight",
		.of_match_table = of_match_ptr(gpio_backlight_of_match),
	},
	.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");
Commit	Line	Data
8b770e3c LP	1	/*
	2	* gpio_backlight.c - Simple GPIO-controlled backlight
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
	9	#include <linux/backlight.h>
	10	#include <linux/err.h>
	11	#include <linux/fb.h>
	12	#include <linux/gpio.h>
	13	#include <linux/init.h>
	14	#include <linux/kernel.h>
	15	#include <linux/module.h>
9a6adb33 DC	16	#include <linux/of.h>
9a6adb33 DC	17	#include <linux/of_gpio.h>
8b770e3c LP	18	#include <linux/platform_data/gpio_backlight.h>
	19	#include <linux/platform_device.h>
	20	#include <linux/slab.h>
	21
	22	struct gpio_backlight {
	23	struct device *dev;
	24	struct device *fbdev;
	25
	26	int gpio;
	27	int active;
9a6adb33	28	int def_value;
8b770e3c LP	29	};
	30
	31	static int gpio_backlight_update_status(struct backlight_device *bl)
	32	{
	33	struct gpio_backlight *gbl = bl_get_data(bl);
	34	int brightness = bl->props.brightness;
	35
	36	if (bl->props.power != FB_BLANK_UNBLANK \|\|
	37	bl->props.fb_blank != FB_BLANK_UNBLANK \|\|
	38	bl->props.state & (BL_CORE_SUSPENDED \| BL_CORE_FBBLANK))
	39	brightness = 0;
	40
ab1e59b4 TL	41	gpio_set_value_cansleep(gbl->gpio,
ab1e59b4 TL	42	brightness ? gbl->active : !gbl->active);
8b770e3c LP	43
	44	return 0;
	45	}
	46
8b770e3c LP	47	static int gpio_backlight_check_fb(struct backlight_device *bl,
	48	struct fb_info *info)
	49	{
	50	struct gpio_backlight *gbl = bl_get_data(bl);
	51
	52	return gbl->fbdev == NULL \|\| gbl->fbdev == info->dev;
	53	}
	54
	55	static const struct backlight_ops gpio_backlight_ops = {
	56	.options = BL_CORE_SUSPENDRESUME,
	57	.update_status = gpio_backlight_update_status,
8b770e3c LP	58	.check_fb = gpio_backlight_check_fb,
	59	};
	60
9a6adb33 DC	61	static int gpio_backlight_probe_dt(struct platform_device *pdev,
	62	struct gpio_backlight *gbl)
	63	{
	64	struct device_node *np = pdev->dev.of_node;
	65	enum of_gpio_flags gpio_flags;
	66
	67	gbl->gpio = of_get_gpio_flags(np, 0, &gpio_flags);
	68
	69	if (!gpio_is_valid(gbl->gpio)) {
	70	if (gbl->gpio != -EPROBE_DEFER) {
	71	dev_err(&pdev->dev,
	72	"Error: The gpios parameter is missing or invalid.\n");
	73	}
	74	return gbl->gpio;
	75	}
	76
	77	gbl->active = (gpio_flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1;
	78
	79	gbl->def_value = of_property_read_bool(np, "default-on");
	80
	81	return 0;
	82	}
	83
8b770e3c LP	84	static int gpio_backlight_probe(struct platform_device *pdev)
8b770e3c LP	85	{
c512794c JH	86	struct gpio_backlight_platform_data *pdata =
c512794c JH	87	dev_get_platdata(&pdev->dev);
8b770e3c LP	88	struct backlight_properties props;
	89	struct backlight_device *bl;
	90	struct gpio_backlight *gbl;
9a6adb33	91	struct device_node *np = pdev->dev.of_node;
2f4647a1	92	unsigned long flags = GPIOF_DIR_OUT;
8b770e3c LP	93	int ret;
8b770e3c LP	94
9a6adb33 DC	95	if (!pdata && !np) {
	96	dev_err(&pdev->dev,
	97	"failed to find platform data or device tree node.\n");
8b770e3c LP	98	return -ENODEV;
	99	}
	100
	101	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
	102	if (gbl == NULL)
	103	return -ENOMEM;
	104
	105	gbl->dev = &pdev->dev;
9a6adb33 DC	106
	107	if (np) {
	108	ret = gpio_backlight_probe_dt(pdev, gbl);
	109	if (ret)
	110	return ret;
	111	} else {
	112	gbl->fbdev = pdata->fbdev;
	113	gbl->gpio = pdata->gpio;
	114	gbl->active = pdata->active_low ? 0 : 1;
	115	gbl->def_value = pdata->def_value;
	116	}
8b770e3c	117
2f4647a1 SA	118	if (gbl->active)
	119	flags \|= gbl->def_value ? GPIOF_INIT_HIGH : GPIOF_INIT_LOW;
	120	else
	121	flags \|= gbl->def_value ? GPIOF_INIT_LOW : GPIOF_INIT_HIGH;
	122
	123	ret = devm_gpio_request_one(gbl->dev, gbl->gpio, flags,
9a6adb33	124	pdata ? pdata->name : "backlight");
8b770e3c LP	125	if (ret < 0) {
	126	dev_err(&pdev->dev, "unable to request GPIO\n");
	127	return ret;
	128	}
	129
	130	memset(&props, 0, sizeof(props));
	131	props.type = BACKLIGHT_RAW;
	132	props.max_brightness = 1;
ff472015 JH	133	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
	134	&pdev->dev, gbl, &gpio_backlight_ops,
	135	&props);
8b770e3c LP	136	if (IS_ERR(bl)) {
	137	dev_err(&pdev->dev, "failed to register backlight\n");
	138	return PTR_ERR(bl);
	139	}
	140
9a6adb33	141	bl->props.brightness = gbl->def_value;
8b770e3c LP	142	backlight_update_status(bl);
	143
	144	platform_set_drvdata(pdev, bl);
	145	return 0;
	146	}
	147
9a6adb33 DC	148	#ifdef CONFIG_OF
	149	static struct of_device_id gpio_backlight_of_match[] = {
	150	{ .compatible = "gpio-backlight" },
	151	{ /* sentinel */ }
	152	};
4d866723 AB	153
4d866723 AB	154	MODULE_DEVICE_TABLE(of, gpio_backlight_of_match);
9a6adb33 DC	155	#endif
9a6adb33 DC	156
8b770e3c LP	157	static struct platform_driver gpio_backlight_driver = {
	158	.driver = {
	159	.name = "gpio-backlight",
9a6adb33	160	.of_match_table = of_match_ptr(gpio_backlight_of_match),
8b770e3c LP	161	},
8b770e3c LP	162	.probe = gpio_backlight_probe,
8b770e3c LP	163	};
	164
	165	module_platform_driver(gpio_backlight_driver);
	166
	167	MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
	168	MODULE_DESCRIPTION("GPIO-based Backlight Driver");
	169	MODULE_LICENSE("GPL");
	170	MODULE_ALIAS("platform:gpio-backlight");