[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 {
		int duty_cycle;

		if (pb->levels) {
			duty_cycle = pb->levels[brightness];
			max = pb->levels[max];
		} else {
			duty_cycle = brightness;
		}

		duty_cycle = pb->lth_brightness +
		     (duty_cycle * (pb->period - pb->lth_brightness) / max);
		pwm_config(pb->pwm, duty_cycle, 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 = devm_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_alloc;
	}

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

	platform_set_drvdata(pdev, bl);
	return 0;

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);
	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 {
9fb978b1 AC	57	int duty_cycle;
9fb978b1 AC	58
3e3ed6cd	59	if (pb->levels) {
9fb978b1	60	duty_cycle = pb->levels[brightness];
3e3ed6cd	61	max = pb->levels[max];
9fb978b1 AC	62	} else {
9fb978b1 AC	63	duty_cycle = brightness;
3e3ed6cd TR	64	}
3e3ed6cd TR	65
9fb978b1 AC	66	duty_cycle = pb->lth_brightness +
	67	(duty_cycle * (pb->period - pb->lth_brightness) / max);
	68	pwm_config(pb->pwm, duty_cycle, pb->period);
42796d37	69	pwm_enable(pb->pwm);
42796d37	70	}
cc7993f6 DL	71
	72	if (pb->notify_after)
	73	pb->notify_after(pb->dev, brightness);
	74
42796d37	75	return 0;
	76	}
	77
	78	static int pwm_backlight_get_brightness(struct backlight_device *bl)
	79	{
	80	return bl->props.brightness;
	81	}
	82
ef0a5e80 RM	83	static int pwm_backlight_check_fb(struct backlight_device *bl,
	84	struct fb_info *info)
	85	{
	86	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
	87
	88	return !pb->check_fb \|\| pb->check_fb(pb->dev, info);
	89	}
	90
9905a43b	91	static const struct backlight_ops pwm_backlight_ops = {
42796d37	92	.update_status = pwm_backlight_update_status,
42796d37	93	.get_brightness = pwm_backlight_get_brightness,
ef0a5e80	94	.check_fb = pwm_backlight_check_fb,
42796d37	95	};
42796d37	96
3e3ed6cd TR	97	#ifdef CONFIG_OF
	98	static int pwm_backlight_parse_dt(struct device *dev,
	99	struct platform_pwm_backlight_data *data)
	100	{
	101	struct device_node *node = dev->of_node;
	102	struct property *prop;
	103	int length;
	104	u32 value;
	105	int ret;
	106
	107	if (!node)
	108	return -ENODEV;
	109
	110	memset(data, 0, sizeof(*data));
	111
	112	/* determine the number of brightness levels */
	113	prop = of_find_property(node, "brightness-levels", &length);
	114	if (!prop)
	115	return -EINVAL;
	116
	117	data->max_brightness = length / sizeof(u32);
	118
	119	/* read brightness levels from DT property */
	120	if (data->max_brightness > 0) {
	121	size_t size = sizeof(data->levels) data->max_brightness;
	122
	123	data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
	124	if (!data->levels)
	125	return -ENOMEM;
	126
	127	ret = of_property_read_u32_array(node, "brightness-levels",
	128	data->levels,
	129	data->max_brightness);
	130	if (ret < 0)
	131	return ret;
	132
	133	ret = of_property_read_u32(node, "default-brightness-level",
	134	&value);
	135	if (ret < 0)
	136	return ret;
	137
	138	if (value >= data->max_brightness) {
	139	dev_warn(dev, "invalid default brightness level: %u, using %u\n",
	140	value, data->max_brightness - 1);
	141	value = data->max_brightness - 1;
	142	}
	143
	144	data->dft_brightness = value;
	145	data->max_brightness--;
	146	}
	147
	148	/*
	149	* TODO: Most users of this driver use a number of GPIOs to control
	150	* backlight power. Support for specifying these needs to be
	151	* added.
	152	*/
	153
	154	return 0;
	155	}
	156
	157	static struct of_device_id pwm_backlight_of_match[] = {
	158	{ .compatible = "pwm-backlight" },
	159	{ }
	160	};
161
162	MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
163	#else
164	static int pwm_backlight_parse_dt(struct device *dev,
165	struct platform_pwm_backlight_data *data)
166	{
167	return -ENODEV;
168	}
169	#endif
170
42796d37	171	static int pwm_backlight_probe(struct platform_device *pdev)
	172	{
	173	struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
3e3ed6cd TR	174	struct platform_pwm_backlight_data defdata;
3e3ed6cd TR	175	struct backlight_properties props;
42796d37	176	struct backlight_device *bl;
42796d37	177	struct pwm_bl_data *pb;
3e3ed6cd	178	unsigned int max;
3b73125a	179	int ret;
42796d37	180
14563a4e	181	if (!data) {
3e3ed6cd TR	182	ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
	183	if (ret < 0) {
	184	dev_err(&pdev->dev, "failed to find platform data\n");
	185	return ret;
	186	}
	187
	188	data = &defdata;
14563a4e	189	}
42796d37	190
3b73125a PZ	191	if (data->init) {
	192	ret = data->init(&pdev->dev);
	193	if (ret < 0)
	194	return ret;
	195	}
	196
ce969228	197	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
3b73125a	198	if (!pb) {
14563a4e	199	dev_err(&pdev->dev, "no memory for state\n");
3b73125a PZ	200	ret = -ENOMEM;
	201	goto err_alloc;
	202	}
42796d37	203
3e3ed6cd TR	204	if (data->levels) {
	205	max = data->levels[data->max_brightness];
	206	pb->levels = data->levels;
	207	} else
	208	max = data->max_brightness;
	209
3b73125a	210	pb->notify = data->notify;
cc7993f6	211	pb->notify_after = data->notify_after;
ef0a5e80	212	pb->check_fb = data->check_fb;
3e3ed6cd	213	pb->exit = data->exit;
cfc3899f	214	pb->dev = &pdev->dev;
42796d37	215
60ce7028	216	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
43bda1a6	217	if (IS_ERR(pb->pwm)) {
3e3ed6cd TR	218	dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
	219
	220	pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
	221	if (IS_ERR(pb->pwm)) {
	222	dev_err(&pdev->dev, "unable to request legacy PWM\n");
	223	ret = PTR_ERR(pb->pwm);
	224	goto err_alloc;
	225	}
	226	}
	227
	228	dev_dbg(&pdev->dev, "got pwm for backlight\n");
	229
	230	/*
	231	* The DT case will set the pwm_period_ns field to 0 and store the
	232	* period, parsed from the DT, in the PWM device. For the non-DT case,
	233	* set the period from platform data.
	234	*/
	235	if (data->pwm_period_ns > 0)
	236	pwm_set_period(pb->pwm, data->pwm_period_ns);
	237
	238	pb->period = pwm_get_period(pb->pwm);
	239	pb->lth_brightness = data->lth_brightness * (pb->period / max);
42796d37	240
a19a6ee6	241	memset(&props, 0, sizeof(struct backlight_properties));
bb7ca747	242	props.type = BACKLIGHT_RAW;
a19a6ee6 MG	243	props.max_brightness = data->max_brightness;
	244	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
	245	&pwm_backlight_ops, &props);
42796d37	246	if (IS_ERR(bl)) {
42796d37	247	dev_err(&pdev->dev, "failed to register backlight\n");
3b73125a	248	ret = PTR_ERR(bl);
60ce7028	249	goto err_alloc;
42796d37	250	}
42796d37	251
42796d37	252	bl->props.brightness = data->dft_brightness;
	253	backlight_update_status(bl);
	254
	255	platform_set_drvdata(pdev, bl);
	256	return 0;
3b73125a	257
3b73125a PZ	258	err_alloc:
	259	if (data->exit)
	260	data->exit(&pdev->dev);
	261	return ret;
42796d37	262	}
	263
	264	static int pwm_backlight_remove(struct platform_device *pdev)
	265	{
	266	struct backlight_device *bl = platform_get_drvdata(pdev);
	267	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
	268
	269	backlight_device_unregister(bl);
	270	pwm_config(pb->pwm, 0, pb->period);
	271	pwm_disable(pb->pwm);
3e3ed6cd TR	272	if (pb->exit)
3e3ed6cd TR	273	pb->exit(&pdev->dev);
42796d37	274	return 0;
	275	}
	276
	277	#ifdef CONFIG_PM
e2c17bc6	278	static int pwm_backlight_suspend(struct device *dev)
42796d37	279	{
e2c17bc6	280	struct backlight_device *bl = dev_get_drvdata(dev);
42796d37	281	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
42796d37	282
82e8b542	283	if (pb->notify)
cfc3899f	284	pb->notify(pb->dev, 0);
42796d37	285	pwm_config(pb->pwm, 0, pb->period);
42796d37	286	pwm_disable(pb->pwm);
cc7993f6 DL	287	if (pb->notify_after)
cc7993f6 DL	288	pb->notify_after(pb->dev, 0);
42796d37	289	return 0;
	290	}
	291
e2c17bc6	292	static int pwm_backlight_resume(struct device *dev)
42796d37	293	{
e2c17bc6	294	struct backlight_device *bl = dev_get_drvdata(dev);
42796d37	295
	296	backlight_update_status(bl);
	297	return 0;
	298	}
e2c17bc6 MB	299
	300	static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
	301	pwm_backlight_resume);
	302
42796d37	303	#endif
	304
	305	static struct platform_driver pwm_backlight_driver = {
	306	.driver = {
3e3ed6cd TR	307	.name = "pwm-backlight",
3e3ed6cd TR	308	.owner = THIS_MODULE,
e2c17bc6	309	#ifdef CONFIG_PM
3e3ed6cd	310	.pm = &pwm_backlight_pm_ops,
e2c17bc6	311	#endif
3e3ed6cd	312	.of_match_table = of_match_ptr(pwm_backlight_of_match),
42796d37	313	},
	314	.probe = pwm_backlight_probe,
	315	.remove = pwm_backlight_remove,
42796d37	316	};
42796d37	317
81178e02	318	module_platform_driver(pwm_backlight_driver);
42796d37	319
	320	MODULE_DESCRIPTION("PWM based Backlight Driver");
	321	MODULE_LICENSE("GPL");
8cd68198 BD	322	MODULE_ALIAS("platform:pwm-backlight");
8cd68198 BD	323