[linux-2.6-block.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> /* Only for legacy support */
#include <linux/gpio/consumer.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;

	struct gpio_desc *gpiod;
	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;

	gpiod_set_value_cansleep(gbl->gpiod, brightness);

	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 *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	enum gpiod_flags flags;
	int ret;

	gbl->def_value = of_property_read_bool(np, "default-on");
	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;

	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);
	if (IS_ERR(gbl->gpiod)) {
		ret = PTR_ERR(gbl->gpiod);

		if (ret != -EPROBE_DEFER) {
			dev_err(dev,
				"Error: The gpios parameter is missing or invalid.\n");
		}
		return ret;
	}

	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;
	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 {
		/*
		 * Legacy platform data GPIO retrieveal. Do not expand
		 * the use of this code path, currently only used by one
		 * SH board.
		 */
		unsigned long flags = GPIOF_DIR_OUT;

		gbl->fbdev = pdata->fbdev;
		gbl->def_value = pdata->def_value;
		flags |= gbl->def_value ? GPIOF_INIT_HIGH : GPIOF_INIT_LOW;

		ret = devm_gpio_request_one(gbl->dev, pdata->gpio, flags,
					    pdata ? pdata->name : "backlight");
		if (ret < 0) {
			dev_err(&pdev->dev, "unable to request GPIO\n");
			return ret;
		}
		gbl->gpiod = gpio_to_desc(pdata->gpio);
		if (!gbl->gpiod)
			return -EINVAL;
	}

	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>
de738900 LW	12	#include <linux/gpio.h> /* Only for legacy support */
de738900 LW	13	#include <linux/gpio/consumer.h>
8b770e3c LP	14	#include <linux/init.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
9a6adb33 DC	17	#include <linux/of.h>
9a6adb33 DC	18	#include <linux/of_gpio.h>
8b770e3c LP	19	#include <linux/platform_data/gpio_backlight.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/slab.h>
	22
	23	struct gpio_backlight {
	24	struct device *dev;
	25	struct device *fbdev;
	26
de738900	27	struct gpio_desc *gpiod;
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
2606706e	41	gpiod_set_value_cansleep(gbl->gpiod, brightness);
8b770e3c LP	42
	43	return 0;
	44	}
	45
8b770e3c LP	46	static int gpio_backlight_check_fb(struct backlight_device *bl,
	47	struct fb_info *info)
	48	{
	49	struct gpio_backlight *gbl = bl_get_data(bl);
	50
	51	return gbl->fbdev == NULL \|\| gbl->fbdev == info->dev;
	52	}
	53
	54	static const struct backlight_ops gpio_backlight_ops = {
	55	.options = BL_CORE_SUSPENDRESUME,
	56	.update_status = gpio_backlight_update_status,
8b770e3c LP	57	.check_fb = gpio_backlight_check_fb,
	58	};
	59
9a6adb33 DC	60	static int gpio_backlight_probe_dt(struct platform_device *pdev,
	61	struct gpio_backlight *gbl)
	62	{
de738900 LW	63	struct device *dev = &pdev->dev;
	64	struct device_node *np = dev->of_node;
	65	enum gpiod_flags flags;
	66	int ret;
	67
	68	gbl->def_value = of_property_read_bool(np, "default-on");
	69	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
9a6adb33	70
de738900 LW	71	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);
	72	if (IS_ERR(gbl->gpiod)) {
	73	ret = PTR_ERR(gbl->gpiod);
9a6adb33	74
de738900 LW	75	if (ret != -EPROBE_DEFER) {
de738900 LW	76	dev_err(dev,
9a6adb33 DC	77	"Error: The gpios parameter is missing or invalid.\n");
9a6adb33 DC	78	}
de738900	79	return ret;
9a6adb33 DC	80	}
9a6adb33 DC	81
9a6adb33 DC	82	return 0;
	83	}
	84
8b770e3c LP	85	static int gpio_backlight_probe(struct platform_device *pdev)
8b770e3c LP	86	{
c512794c JH	87	struct gpio_backlight_platform_data *pdata =
c512794c JH	88	dev_get_platdata(&pdev->dev);
8b770e3c LP	89	struct backlight_properties props;
	90	struct backlight_device *bl;
	91	struct gpio_backlight *gbl;
9a6adb33	92	struct device_node *np = pdev->dev.of_node;
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 {
de738900 LW	112	/*
	113	* Legacy platform data GPIO retrieveal. Do not expand
	114	* the use of this code path, currently only used by one
	115	* SH board.
	116	*/
	117	unsigned long flags = GPIOF_DIR_OUT;
	118
9a6adb33	119	gbl->fbdev = pdata->fbdev;
9a6adb33	120	gbl->def_value = pdata->def_value;
2606706e	121	flags \|= gbl->def_value ? GPIOF_INIT_HIGH : GPIOF_INIT_LOW;
de738900 LW	122
	123	ret = devm_gpio_request_one(gbl->dev, pdata->gpio, flags,
	124	pdata ? pdata->name : "backlight");
	125	if (ret < 0) {
	126	dev_err(&pdev->dev, "unable to request GPIO\n");
	127	return ret;
	128	}
	129	gbl->gpiod = gpio_to_desc(pdata->gpio);
	130	if (!gbl->gpiod)
	131	return -EINVAL;
8b770e3c LP	132	}
	133
	134	memset(&props, 0, sizeof(props));
	135	props.type = BACKLIGHT_RAW;
	136	props.max_brightness = 1;
ff472015 JH	137	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
	138	&pdev->dev, gbl, &gpio_backlight_ops,
	139	&props);
8b770e3c LP	140	if (IS_ERR(bl)) {
	141	dev_err(&pdev->dev, "failed to register backlight\n");
	142	return PTR_ERR(bl);
	143	}
	144
9a6adb33	145	bl->props.brightness = gbl->def_value;
8b770e3c LP	146	backlight_update_status(bl);
	147
	148	platform_set_drvdata(pdev, bl);
	149	return 0;
	150	}
	151
9a6adb33 DC	152	#ifdef CONFIG_OF
	153	static struct of_device_id gpio_backlight_of_match[] = {
	154	{ .compatible = "gpio-backlight" },
	155	{ /* sentinel */ }
	156	};
4d866723 AB	157
4d866723 AB	158	MODULE_DEVICE_TABLE(of, gpio_backlight_of_match);
9a6adb33 DC	159	#endif
9a6adb33 DC	160
8b770e3c LP	161	static struct platform_driver gpio_backlight_driver = {
	162	.driver = {
	163	.name = "gpio-backlight",
9a6adb33	164	.of_match_table = of_match_ptr(gpio_backlight_of_match),
8b770e3c LP	165	},
8b770e3c LP	166	.probe = gpio_backlight_probe,
8b770e3c LP	167	};
	168
	169	module_platform_driver(gpio_backlight_driver);
	170
	171	MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
	172	MODULE_DESCRIPTION("GPIO-based Backlight Driver");
	173	MODULE_LICENSE("GPL");
	174	MODULE_ALIAS("platform:gpio-backlight");