[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 void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness,
				   int max)
{
	int duty_cycle, err;

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

	duty_cycle = (duty_cycle * (pb->period - pb->lth_brightness) / max) +
		     pb->lth_brightness;

	pwm_config(pb->pwm, duty_cycle, pb->period);
	pwm_enable(pb->pwm);
}

static void pwm_backlight_power_off(struct pwm_bl_data *pb)
{
	pwm_config(pb->pwm, 0, pb->period);
	pwm_disable(pb->pwm);
}

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

	if (bl->props.power != FB_BLANK_UNBLANK ||
	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
	    bl->props.state & BL_CORE_FBBLANK)
		brightness = 0;

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

	if (brightness > 0)
		pwm_backlight_power_on(pb, brightness, max);
	else
		pwm_backlight_power_off(pb);

	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 = bl_get_data(bl);

	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;

		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;
	}

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

	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 = bl_get_data(bl);

	backlight_device_unregister(bl);
	pwm_backlight_power_off(pb);

	if (pb->exit)
		pb->exit(&pdev->dev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int pwm_backlight_suspend(struct device *dev)
{
	struct backlight_device *bl = dev_get_drvdata(dev);
	struct pwm_bl_data *pb = bl_get_data(bl);

	if (pb->notify)
		pb->notify(pb->dev, 0);

	pwm_backlight_power_off(pb);

	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;
}
#endif

static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
			 pwm_backlight_resume);

static struct platform_driver pwm_backlight_driver = {
	.driver		= {
		.name		= "pwm-backlight",
		.owner		= THIS_MODULE,
		.pm		= &pwm_backlight_pm_ops,
		.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	};
42796d37	37
62b744a8 TR	38	static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness,
	39	int max)
	40	{
	41	int duty_cycle, err;
	42
	43	if (pb->levels) {
	44	duty_cycle = pb->levels[brightness];
	45	max = pb->levels[max];
	46	} else {
	47	duty_cycle = brightness;
	48	}
	49
	50	duty_cycle = (duty_cycle * (pb->period - pb->lth_brightness) / max) +
	51	pb->lth_brightness;
	52
	53	pwm_config(pb->pwm, duty_cycle, pb->period);
	54	pwm_enable(pb->pwm);
	55	}
	56
	57	static void pwm_backlight_power_off(struct pwm_bl_data *pb)
	58	{
	59	pwm_config(pb->pwm, 0, pb->period);
	60	pwm_disable(pb->pwm);
	61	}
	62
42796d37	63	static int pwm_backlight_update_status(struct backlight_device *bl)
42796d37	64	{
e6e3dbf9	65	struct pwm_bl_data *pb = bl_get_data(bl);
42796d37	66	int brightness = bl->props.brightness;
	67	int max = bl->props.max_brightness;
	68
0132267d AC	69	if (bl->props.power != FB_BLANK_UNBLANK \|\|
	70	bl->props.fb_blank != FB_BLANK_UNBLANK \|\|
	71	bl->props.state & BL_CORE_FBBLANK)
42796d37	72	brightness = 0;
42796d37	73
3b73125a	74	if (pb->notify)
cfc3899f	75	brightness = pb->notify(pb->dev, brightness);
3b73125a	76
62b744a8 TR	77	if (brightness > 0)
	78	pwm_backlight_power_on(pb, brightness, max);
	79	else
	80	pwm_backlight_power_off(pb);
cc7993f6 DL	81
	82	if (pb->notify_after)
	83	pb->notify_after(pb->dev, brightness);
	84
42796d37	85	return 0;
	86	}
	87
	88	static int pwm_backlight_get_brightness(struct backlight_device *bl)
	89	{
	90	return bl->props.brightness;
	91	}
	92
ef0a5e80 RM	93	static int pwm_backlight_check_fb(struct backlight_device *bl,
	94	struct fb_info *info)
	95	{
e6e3dbf9	96	struct pwm_bl_data *pb = bl_get_data(bl);
ef0a5e80 RM	97
	98	return !pb->check_fb \|\| pb->check_fb(pb->dev, info);
	99	}
	100
9905a43b	101	static const struct backlight_ops pwm_backlight_ops = {
42796d37	102	.update_status = pwm_backlight_update_status,
42796d37	103	.get_brightness = pwm_backlight_get_brightness,
ef0a5e80	104	.check_fb = pwm_backlight_check_fb,
42796d37	105	};
42796d37	106
3e3ed6cd TR	107	#ifdef CONFIG_OF
	108	static int pwm_backlight_parse_dt(struct device *dev,
	109	struct platform_pwm_backlight_data *data)
	110	{
	111	struct device_node *node = dev->of_node;
	112	struct property *prop;
	113	int length;
	114	u32 value;
	115	int ret;
	116
	117	if (!node)
	118	return -ENODEV;
	119
	120	memset(data, 0, sizeof(*data));
	121
	122	/* determine the number of brightness levels */
	123	prop = of_find_property(node, "brightness-levels", &length);
	124	if (!prop)
	125	return -EINVAL;
	126
	127	data->max_brightness = length / sizeof(u32);
	128
	129	/* read brightness levels from DT property */
	130	if (data->max_brightness > 0) {
	131	size_t size = sizeof(data->levels) data->max_brightness;
	132
	133	data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
	134	if (!data->levels)
	135	return -ENOMEM;
	136
	137	ret = of_property_read_u32_array(node, "brightness-levels",
	138	data->levels,
	139	data->max_brightness);
	140	if (ret < 0)
	141	return ret;
	142
	143	ret = of_property_read_u32(node, "default-brightness-level",
	144	&value);
	145	if (ret < 0)
	146	return ret;
	147
3e3ed6cd TR	148	data->dft_brightness = value;
	149	data->max_brightness--;
	150	}
	151
	152	/*
	153	* TODO: Most users of this driver use a number of GPIOs to control
	154	* backlight power. Support for specifying these needs to be
	155	* added.
	156	*/
	157
	158	return 0;
	159	}
	160
	161	static struct of_device_id pwm_backlight_of_match[] = {
	162	{ .compatible = "pwm-backlight" },
	163	{ }
	164	};
	165
	166	MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
	167	#else
	168	static int pwm_backlight_parse_dt(struct device *dev,
	169	struct platform_pwm_backlight_data *data)
	170	{
	171	return -ENODEV;
	172	}
	173	#endif
	174
42796d37	175	static int pwm_backlight_probe(struct platform_device *pdev)
	176	{
	177	struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
3e3ed6cd TR	178	struct platform_pwm_backlight_data defdata;
3e3ed6cd TR	179	struct backlight_properties props;
42796d37	180	struct backlight_device *bl;
42796d37	181	struct pwm_bl_data *pb;
3e3ed6cd	182	unsigned int max;
3b73125a	183	int ret;
42796d37	184
14563a4e	185	if (!data) {
3e3ed6cd TR	186	ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
	187	if (ret < 0) {
	188	dev_err(&pdev->dev, "failed to find platform data\n");
	189	return ret;
	190	}
	191
	192	data = &defdata;
14563a4e	193	}
42796d37	194
3b73125a PZ	195	if (data->init) {
	196	ret = data->init(&pdev->dev);
	197	if (ret < 0)
	198	return ret;
	199	}
	200
ce969228	201	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
3b73125a	202	if (!pb) {
14563a4e	203	dev_err(&pdev->dev, "no memory for state\n");
3b73125a PZ	204	ret = -ENOMEM;
	205	goto err_alloc;
	206	}
42796d37	207
3e3ed6cd TR	208	if (data->levels) {
	209	max = data->levels[data->max_brightness];
	210	pb->levels = data->levels;
	211	} else
	212	max = data->max_brightness;
	213
3b73125a	214	pb->notify = data->notify;
cc7993f6	215	pb->notify_after = data->notify_after;
ef0a5e80	216	pb->check_fb = data->check_fb;
3e3ed6cd	217	pb->exit = data->exit;
cfc3899f	218	pb->dev = &pdev->dev;
42796d37	219
60ce7028	220	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
43bda1a6	221	if (IS_ERR(pb->pwm)) {
3e3ed6cd TR	222	dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
	223
	224	pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
	225	if (IS_ERR(pb->pwm)) {
	226	dev_err(&pdev->dev, "unable to request legacy PWM\n");
	227	ret = PTR_ERR(pb->pwm);
	228	goto err_alloc;
	229	}
	230	}
	231
	232	dev_dbg(&pdev->dev, "got pwm for backlight\n");
	233
	234	/*
	235	* The DT case will set the pwm_period_ns field to 0 and store the
	236	* period, parsed from the DT, in the PWM device. For the non-DT case,
	237	* set the period from platform data.
	238	*/
	239	if (data->pwm_period_ns > 0)
	240	pwm_set_period(pb->pwm, data->pwm_period_ns);
	241
	242	pb->period = pwm_get_period(pb->pwm);
	243	pb->lth_brightness = data->lth_brightness * (pb->period / max);
42796d37	244
a19a6ee6	245	memset(&props, 0, sizeof(struct backlight_properties));
bb7ca747	246	props.type = BACKLIGHT_RAW;
a19a6ee6 MG	247	props.max_brightness = data->max_brightness;
	248	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
	249	&pwm_backlight_ops, &props);
42796d37	250	if (IS_ERR(bl)) {
42796d37	251	dev_err(&pdev->dev, "failed to register backlight\n");
3b73125a	252	ret = PTR_ERR(bl);
60ce7028	253	goto err_alloc;
42796d37	254	}
42796d37	255
83cfd726 PU	256	if (data->dft_brightness > data->max_brightness) {
	257	dev_warn(&pdev->dev,
	258	"invalid default brightness level: %u, using %u\n",
	259	data->dft_brightness, data->max_brightness);
	260	data->dft_brightness = data->max_brightness;
	261	}
	262
42796d37	263	bl->props.brightness = data->dft_brightness;
	264	backlight_update_status(bl);
	265
	266	platform_set_drvdata(pdev, bl);
	267	return 0;
3b73125a	268
3b73125a PZ	269	err_alloc:
	270	if (data->exit)
	271	data->exit(&pdev->dev);
	272	return ret;
42796d37	273	}
	274
	275	static int pwm_backlight_remove(struct platform_device *pdev)
	276	{
	277	struct backlight_device *bl = platform_get_drvdata(pdev);
e6e3dbf9	278	struct pwm_bl_data *pb = bl_get_data(bl);
42796d37	279
42796d37	280	backlight_device_unregister(bl);
62b744a8	281	pwm_backlight_power_off(pb);
668e63c6	282
3e3ed6cd TR	283	if (pb->exit)
3e3ed6cd TR	284	pb->exit(&pdev->dev);
668e63c6	285
42796d37	286	return 0;
	287	}
	288
c791126b	289	#ifdef CONFIG_PM_SLEEP
e2c17bc6	290	static int pwm_backlight_suspend(struct device *dev)
42796d37	291	{
e2c17bc6	292	struct backlight_device *bl = dev_get_drvdata(dev);
e6e3dbf9	293	struct pwm_bl_data *pb = bl_get_data(bl);
42796d37	294
82e8b542	295	if (pb->notify)
cfc3899f	296	pb->notify(pb->dev, 0);
668e63c6	297
62b744a8	298	pwm_backlight_power_off(pb);
668e63c6	299
cc7993f6 DL	300	if (pb->notify_after)
cc7993f6 DL	301	pb->notify_after(pb->dev, 0);
668e63c6	302
42796d37	303	return 0;
	304	}
	305
e2c17bc6	306	static int pwm_backlight_resume(struct device *dev)
42796d37	307	{
e2c17bc6	308	struct backlight_device *bl = dev_get_drvdata(dev);
42796d37	309
42796d37	310	backlight_update_status(bl);
668e63c6	311
42796d37	312	return 0;
42796d37	313	}
c791126b	314	#endif
e2c17bc6 MB	315
	316	static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
	317	pwm_backlight_resume);
	318
42796d37	319	static struct platform_driver pwm_backlight_driver = {
42796d37	320	.driver = {
3e3ed6cd TR	321	.name = "pwm-backlight",
3e3ed6cd TR	322	.owner = THIS_MODULE,
3e3ed6cd	323	.pm = &pwm_backlight_pm_ops,
3e3ed6cd	324	.of_match_table = of_match_ptr(pwm_backlight_of_match),
42796d37	325	},
	326	.probe = pwm_backlight_probe,
	327	.remove = pwm_backlight_remove,
42796d37	328	};
42796d37	329
81178e02	330	module_platform_driver(pwm_backlight_driver);
42796d37	331
	332	MODULE_DESCRIPTION("PWM based Backlight Driver");
	333	MODULE_LICENSE("GPL");
8cd68198	334	MODULE_ALIAS("platform:pwm-backlight");