[deliverable/linux.git] / drivers / video / backlight / pwm_bl.c

/*
 * linux/drivers/video/backlight/pwm_bl.c
 *
 * simple PWM based backlight control, board code has to setup
 * 1) pin configuration so PWM waveforms can output
 * 2) platform_data being correctly configured
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/pwm.h>
#include <linux/pwm_backlight.h>
#include <linux/slab.h>

struct pwm_bl_data {
	struct pwm_device	*pwm;
	struct device		*dev;
	unsigned int		period;
	unsigned int		lth_brightness;
	unsigned int		*levels;
	int			(*notify)(struct device *,
					  int brightness);
	void			(*notify_after)(struct device *,
					int brightness);
	int			(*check_fb)(struct device *, struct fb_info *);
	void			(*exit)(struct device *);
};

static int pwm_backlight_update_status(struct backlight_device *bl)
{
	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
	int brightness = bl->props.brightness;
	int max = bl->props.max_brightness;

	if (bl->props.power != FB_BLANK_UNBLANK)
		brightness = 0;

	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
		brightness = 0;

	if (pb->notify)
		brightness = pb->notify(pb->dev, brightness);

	if (brightness == 0) {
		pwm_config(pb->pwm, 0, pb->period);
		pwm_disable(pb->pwm);
	} else {
		if (pb->levels) {
			brightness = pb->levels[brightness];
			max = pb->levels[max];
		}

		brightness = pb->lth_brightness +
			(brightness * (pb->period - pb->lth_brightness) / max);
		pwm_config(pb->pwm, brightness, pb->period);
		pwm_enable(pb->pwm);
	}

	if (pb->notify_after)
		pb->notify_after(pb->dev, brightness);

	return 0;
}

static int pwm_backlight_get_brightness(struct backlight_device *bl)
{
	return bl->props.brightness;
}

static int pwm_backlight_check_fb(struct backlight_device *bl,
				  struct fb_info *info)
{
	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);

	return !pb->check_fb || pb->check_fb(pb->dev, info);
}

static const struct backlight_ops pwm_backlight_ops = {
	.update_status	= pwm_backlight_update_status,
	.get_brightness	= pwm_backlight_get_brightness,
	.check_fb	= pwm_backlight_check_fb,
};

#ifdef CONFIG_OF
static int pwm_backlight_parse_dt(struct device *dev,
				  struct platform_pwm_backlight_data *data)
{
	struct device_node *node = dev->of_node;
	struct property *prop;
	int length;
	u32 value;
	int ret;

	if (!node)
		return -ENODEV;

	memset(data, 0, sizeof(*data));

	/* determine the number of brightness levels */
	prop = of_find_property(node, "brightness-levels", &length);
	if (!prop)
		return -EINVAL;

	data->max_brightness = length / sizeof(u32);

	/* read brightness levels from DT property */
	if (data->max_brightness > 0) {
		size_t size = sizeof(*data->levels) * data->max_brightness;

		data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
		if (!data->levels)
			return -ENOMEM;

		ret = of_property_read_u32_array(node, "brightness-levels",
						 data->levels,
						 data->max_brightness);
		if (ret < 0)
			return ret;

		ret = of_property_read_u32(node, "default-brightness-level",
					   &value);
		if (ret < 0)
			return ret;

		if (value >= data->max_brightness) {
			dev_warn(dev, "invalid default brightness level: %u, using %u\n",
				 value, data->max_brightness - 1);
			value = data->max_brightness - 1;
		}

		data->dft_brightness = value;
		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.
	 */

	return 0;
}

static struct of_device_id pwm_backlight_of_match[] = {
	{ .compatible = "pwm-backlight" },
	{ }
};

MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
#else
static int pwm_backlight_parse_dt(struct device *dev,
				  struct platform_pwm_backlight_data *data)
{
	return -ENODEV;
}
#endif

static int pwm_backlight_probe(struct platform_device *pdev)
{
	struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
	struct platform_pwm_backlight_data defdata;
	struct backlight_properties props;
	struct backlight_device *bl;
	struct pwm_bl_data *pb;
	unsigned int max;
	int ret;

	if (!data) {
		ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
		if (ret < 0) {
			dev_err(&pdev->dev, "failed to find platform data\n");
			return ret;
		}

		data = &defdata;
	}

	if (data->init) {
		ret = data->init(&pdev->dev);
		if (ret < 0)
			return ret;
	}

	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
	if (!pb) {
		dev_err(&pdev->dev, "no memory for state\n");
		ret = -ENOMEM;
		goto err_alloc;
	}

	if (data->levels) {
		max = data->levels[data->max_brightness];
		pb->levels = data->levels;
	} else
		max = data->max_brightness;

	pb->notify = data->notify;
	pb->notify_after = data->notify_after;
	pb->check_fb = data->check_fb;
	pb->exit = data->exit;
	pb->dev = &pdev->dev;

	pb->pwm = pwm_get(&pdev->dev, NULL);
	if (IS_ERR(pb->pwm)) {
		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");

		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
		if (IS_ERR(pb->pwm)) {
			dev_err(&pdev->dev, "unable to request legacy PWM\n");
			ret = PTR_ERR(pb->pwm);
			goto err_alloc;
		}
	}

	dev_dbg(&pdev->dev, "got pwm for backlight\n");

	/*
	 * The DT case will set the pwm_period_ns field to 0 and store the
	 * period, parsed from the DT, in the PWM device. For the non-DT case,
	 * set the period from platform data.
	 */
	if (data->pwm_period_ns > 0)
		pwm_set_period(pb->pwm, data->pwm_period_ns);

	pb->period = pwm_get_period(pb->pwm);
	pb->lth_brightness = data->lth_brightness * (pb->period / max);

	memset(&props, 0, sizeof(struct backlight_properties));
	props.type = BACKLIGHT_RAW;
	props.max_brightness = data->max_brightness;
	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
				       &pwm_backlight_ops, &props);
	if (IS_ERR(bl)) {
		dev_err(&pdev->dev, "failed to register backlight\n");
		ret = PTR_ERR(bl);
		goto err_bl;
	}

	bl->props.brightness = data->dft_brightness;
	backlight_update_status(bl);

	platform_set_drvdata(pdev, bl);
	return 0;

err_bl:
	pwm_put(pb->pwm);
err_alloc:
	if (data->exit)
		data->exit(&pdev->dev);
	return ret;
}

static int pwm_backlight_remove(struct platform_device *pdev)
{
	struct backlight_device *bl = platform_get_drvdata(pdev);
	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);

	backlight_device_unregister(bl);
	pwm_config(pb->pwm, 0, pb->period);
	pwm_disable(pb->pwm);
	pwm_put(pb->pwm);
	if (pb->exit)
		pb->exit(&pdev->dev);
	return 0;
}

#ifdef CONFIG_PM
static int pwm_backlight_suspend(struct device *dev)
{
	struct backlight_device *bl = dev_get_drvdata(dev);
	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);

	if (pb->notify)
		pb->notify(pb->dev, 0);
	pwm_config(pb->pwm, 0, pb->period);
	pwm_disable(pb->pwm);
	if (pb->notify_after)
		pb->notify_after(pb->dev, 0);
	return 0;
}

static int pwm_backlight_resume(struct device *dev)
{
	struct backlight_device *bl = dev_get_drvdata(dev);

	backlight_update_status(bl);
	return 0;
}

static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
			 pwm_backlight_resume);

#endif

static struct platform_driver pwm_backlight_driver = {
	.driver		= {
		.name		= "pwm-backlight",
		.owner		= THIS_MODULE,
#ifdef CONFIG_PM
		.pm		= &pwm_backlight_pm_ops,
#endif
		.of_match_table	= of_match_ptr(pwm_backlight_of_match),
	},
	.probe		= pwm_backlight_probe,
	.remove		= pwm_backlight_remove,
};

module_platform_driver(pwm_backlight_driver);

MODULE_DESCRIPTION("PWM based Backlight Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pwm-backlight");
Commit	Line	Data
42796d37	1	/*
	2	* linux/drivers/video/backlight/pwm_bl.c
	3	*
	4	* simple PWM based backlight control, board code has to setup
	5	* 1) pin configuration so PWM waveforms can output
b8cdd877	6	* 2) platform_data being correctly configured
42796d37	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/kernel.h>
	15	#include <linux/init.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/fb.h>
	18	#include <linux/backlight.h>
	19	#include <linux/err.h>
	20	#include <linux/pwm.h>
	21	#include <linux/pwm_backlight.h>
5a0e3ad6	22	#include <linux/slab.h>
42796d37	23
	24	struct pwm_bl_data {
	25	struct pwm_device *pwm;
cfc3899f	26	struct device *dev;
42796d37	27	unsigned int period;
fef7764f	28	unsigned int lth_brightness;
3e3ed6cd	29	unsigned int *levels;
cfc3899f BD	30	int (notify)(struct device ,
cfc3899f BD	31	int brightness);
cc7993f6 DL	32	void (notify_after)(struct device ,
cc7993f6 DL	33	int brightness);
ef0a5e80	34	int (check_fb)(struct device , struct fb_info *);
3e3ed6cd	35	void (exit)(struct device );
42796d37	36	};
	37
	38	static int pwm_backlight_update_status(struct backlight_device *bl)
	39	{
	40	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
	41	int brightness = bl->props.brightness;
	42	int max = bl->props.max_brightness;
	43
	44	if (bl->props.power != FB_BLANK_UNBLANK)
	45	brightness = 0;
	46
	47	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
	48	brightness = 0;
	49
3b73125a	50	if (pb->notify)
cfc3899f	51	brightness = pb->notify(pb->dev, brightness);
3b73125a	52
42796d37	53	if (brightness == 0) {
	54	pwm_config(pb->pwm, 0, pb->period);
	55	pwm_disable(pb->pwm);
	56	} else {
3e3ed6cd TR	57	if (pb->levels) {
	58	brightness = pb->levels[brightness];
	59	max = pb->levels[max];
	60	}
	61
fef7764f AM	62	brightness = pb->lth_brightness +
	63	(brightness * (pb->period - pb->lth_brightness) / max);
	64	pwm_config(pb->pwm, brightness, pb->period);
42796d37	65	pwm_enable(pb->pwm);
42796d37	66	}
cc7993f6 DL	67
	68	if (pb->notify_after)
	69	pb->notify_after(pb->dev, brightness);
	70
42796d37	71	return 0;
	72	}
	73
	74	static int pwm_backlight_get_brightness(struct backlight_device *bl)
	75	{
	76	return bl->props.brightness;
	77	}
	78
ef0a5e80 RM	79	static int pwm_backlight_check_fb(struct backlight_device *bl,
	80	struct fb_info *info)
	81	{
	82	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
	83
	84	return !pb->check_fb \|\| pb->check_fb(pb->dev, info);
	85	}
	86
9905a43b	87	static const struct backlight_ops pwm_backlight_ops = {
42796d37	88	.update_status = pwm_backlight_update_status,
42796d37	89	.get_brightness = pwm_backlight_get_brightness,
ef0a5e80	90	.check_fb = pwm_backlight_check_fb,
42796d37	91	};
42796d37	92
3e3ed6cd TR	93	#ifdef CONFIG_OF
	94	static int pwm_backlight_parse_dt(struct device *dev,
	95	struct platform_pwm_backlight_data *data)
	96	{
	97	struct device_node *node = dev->of_node;
	98	struct property *prop;
	99	int length;
	100	u32 value;
	101	int ret;
	102
	103	if (!node)
	104	return -ENODEV;
	105
	106	memset(data, 0, sizeof(*data));
	107
	108	/* determine the number of brightness levels */
	109	prop = of_find_property(node, "brightness-levels", &length);
	110	if (!prop)
	111	return -EINVAL;
	112
	113	data->max_brightness = length / sizeof(u32);
	114
	115	/* read brightness levels from DT property */
	116	if (data->max_brightness > 0) {
	117	size_t size = sizeof(data->levels) data->max_brightness;
	118
	119	data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
	120	if (!data->levels)
	121	return -ENOMEM;
	122
	123	ret = of_property_read_u32_array(node, "brightness-levels",
	124	data->levels,
	125	data->max_brightness);
	126	if (ret < 0)
	127	return ret;
	128
	129	ret = of_property_read_u32(node, "default-brightness-level",
	130	&value);
	131	if (ret < 0)
	132	return ret;
	133
	134	if (value >= data->max_brightness) {
	135	dev_warn(dev, "invalid default brightness level: %u, using %u\n",
	136	value, data->max_brightness - 1);
	137	value = data->max_brightness - 1;
	138	}
	139
	140	data->dft_brightness = value;
	141	data->max_brightness--;
	142	}
	143
	144	/*
	145	* TODO: Most users of this driver use a number of GPIOs to control
	146	* backlight power. Support for specifying these needs to be
	147	* added.
	148	*/
	149
	150	return 0;
	151	}
	152
	153	static struct of_device_id pwm_backlight_of_match[] = {
	154	{ .compatible = "pwm-backlight" },
	155	{ }
	156	};
157
158	MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
159	#else
160	static int pwm_backlight_parse_dt(struct device *dev,
161	struct platform_pwm_backlight_data *data)
162	{
163	return -ENODEV;
164	}
165	#endif
166
42796d37	167	static int pwm_backlight_probe(struct platform_device *pdev)
	168	{
	169	struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
3e3ed6cd TR	170	struct platform_pwm_backlight_data defdata;
3e3ed6cd TR	171	struct backlight_properties props;
42796d37	172	struct backlight_device *bl;
42796d37	173	struct pwm_bl_data *pb;
3e3ed6cd	174	unsigned int max;
3b73125a	175	int ret;
42796d37	176
14563a4e	177	if (!data) {
3e3ed6cd TR	178	ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
	179	if (ret < 0) {
	180	dev_err(&pdev->dev, "failed to find platform data\n");
	181	return ret;
	182	}
	183
	184	data = &defdata;
14563a4e	185	}
42796d37	186
3b73125a PZ	187	if (data->init) {
	188	ret = data->init(&pdev->dev);
	189	if (ret < 0)
	190	return ret;
	191	}
	192
ce969228	193	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
3b73125a	194	if (!pb) {
14563a4e	195	dev_err(&pdev->dev, "no memory for state\n");
3b73125a PZ	196	ret = -ENOMEM;
	197	goto err_alloc;
	198	}
42796d37	199
3e3ed6cd TR	200	if (data->levels) {
	201	max = data->levels[data->max_brightness];
	202	pb->levels = data->levels;
	203	} else
	204	max = data->max_brightness;
	205
3b73125a	206	pb->notify = data->notify;
cc7993f6	207	pb->notify_after = data->notify_after;
ef0a5e80	208	pb->check_fb = data->check_fb;
3e3ed6cd	209	pb->exit = data->exit;
cfc3899f	210	pb->dev = &pdev->dev;
42796d37	211
3e3ed6cd	212	pb->pwm = pwm_get(&pdev->dev, NULL);
43bda1a6	213	if (IS_ERR(pb->pwm)) {
3e3ed6cd TR	214	dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
	215
	216	pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
	217	if (IS_ERR(pb->pwm)) {
	218	dev_err(&pdev->dev, "unable to request legacy PWM\n");
	219	ret = PTR_ERR(pb->pwm);
	220	goto err_alloc;
	221	}
	222	}
	223
	224	dev_dbg(&pdev->dev, "got pwm for backlight\n");
	225
	226	/*
	227	* The DT case will set the pwm_period_ns field to 0 and store the
	228	* period, parsed from the DT, in the PWM device. For the non-DT case,
	229	* set the period from platform data.
	230	*/
	231	if (data->pwm_period_ns > 0)
	232	pwm_set_period(pb->pwm, data->pwm_period_ns);
	233
	234	pb->period = pwm_get_period(pb->pwm);
	235	pb->lth_brightness = data->lth_brightness * (pb->period / max);
42796d37	236
a19a6ee6	237	memset(&props, 0, sizeof(struct backlight_properties));
bb7ca747	238	props.type = BACKLIGHT_RAW;
a19a6ee6 MG	239	props.max_brightness = data->max_brightness;
	240	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
	241	&pwm_backlight_ops, &props);
42796d37	242	if (IS_ERR(bl)) {
42796d37	243	dev_err(&pdev->dev, "failed to register backlight\n");
3b73125a PZ	244	ret = PTR_ERR(bl);
3b73125a PZ	245	goto err_bl;
42796d37	246	}
42796d37	247
42796d37	248	bl->props.brightness = data->dft_brightness;
	249	backlight_update_status(bl);
	250
	251	platform_set_drvdata(pdev, bl);
	252	return 0;
3b73125a PZ	253
3b73125a PZ	254	err_bl:
3e3ed6cd	255	pwm_put(pb->pwm);
3b73125a PZ	256	err_alloc:
	257	if (data->exit)
	258	data->exit(&pdev->dev);
	259	return ret;
42796d37	260	}
	261
	262	static int pwm_backlight_remove(struct platform_device *pdev)
	263	{
	264	struct backlight_device *bl = platform_get_drvdata(pdev);
	265	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
	266
	267	backlight_device_unregister(bl);
	268	pwm_config(pb->pwm, 0, pb->period);
	269	pwm_disable(pb->pwm);
3e3ed6cd TR	270	pwm_put(pb->pwm);
	271	if (pb->exit)
	272	pb->exit(&pdev->dev);
42796d37	273	return 0;
	274	}
	275
	276	#ifdef CONFIG_PM
e2c17bc6	277	static int pwm_backlight_suspend(struct device *dev)
42796d37	278	{
e2c17bc6	279	struct backlight_device *bl = dev_get_drvdata(dev);
42796d37	280	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
42796d37	281
82e8b542	282	if (pb->notify)
cfc3899f	283	pb->notify(pb->dev, 0);
42796d37	284	pwm_config(pb->pwm, 0, pb->period);
42796d37	285	pwm_disable(pb->pwm);
cc7993f6 DL	286	if (pb->notify_after)
cc7993f6 DL	287	pb->notify_after(pb->dev, 0);
42796d37	288	return 0;
	289	}
	290
e2c17bc6	291	static int pwm_backlight_resume(struct device *dev)
42796d37	292	{
e2c17bc6	293	struct backlight_device *bl = dev_get_drvdata(dev);
42796d37	294
	295	backlight_update_status(bl);
	296	return 0;
	297	}
e2c17bc6 MB	298
	299	static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
	300	pwm_backlight_resume);
	301
42796d37	302	#endif
	303
	304	static struct platform_driver pwm_backlight_driver = {
	305	.driver = {
3e3ed6cd TR	306	.name = "pwm-backlight",
3e3ed6cd TR	307	.owner = THIS_MODULE,
e2c17bc6	308	#ifdef CONFIG_PM
3e3ed6cd	309	.pm = &pwm_backlight_pm_ops,
e2c17bc6	310	#endif
3e3ed6cd	311	.of_match_table = of_match_ptr(pwm_backlight_of_match),
42796d37	312	},
	313	.probe = pwm_backlight_probe,
	314	.remove = pwm_backlight_remove,
42796d37	315	};
42796d37	316
81178e02	317	module_platform_driver(pwm_backlight_driver);
42796d37	318
	319	MODULE_DESCRIPTION("PWM based Backlight Driver");
	320	MODULE_LICENSE("GPL");
8cd68198 BD	321	MODULE_ALIAS("platform:pwm-backlight");
8cd68198 BD	322