[linux-2.6-block.git] / drivers / pwm / sysfs.c

/*
 * A simple sysfs interface for the generic PWM framework
 *
 * Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
 *
 * Based on previous work by Lars Poeschel <poeschel@lemonage.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/kdev_t.h>
#include <linux/pwm.h>

struct pwm_export {
	struct device child;
	struct pwm_device *pwm;
	struct mutex lock;
};

static struct pwm_export *child_to_pwm_export(struct device *child)
{
	return container_of(child, struct pwm_export, child);
}

static struct pwm_device *child_to_pwm_device(struct device *child)
{
	struct pwm_export *export = child_to_pwm_export(child);

	return export->pwm;
}

static ssize_t period_show(struct device *child,
			   struct device_attribute *attr,
			   char *buf)
{
	const struct pwm_device *pwm = child_to_pwm_device(child);
	struct pwm_state state;

	pwm_get_state(pwm, &state);

	return sprintf(buf, "%u\n", state.period);
}

static ssize_t period_store(struct device *child,
			    struct device_attribute *attr,
			    const char *buf, size_t size)
{
	struct pwm_export *export = child_to_pwm_export(child);
	struct pwm_device *pwm = export->pwm;
	struct pwm_state state;
	unsigned int val;
	int ret;

	ret = kstrtouint(buf, 0, &val);
	if (ret)
		return ret;

	mutex_lock(&export->lock);
	pwm_get_state(pwm, &state);
	state.period = val;
	ret = pwm_apply_state(pwm, &state);
	mutex_unlock(&export->lock);

	return ret ? : size;
}

static ssize_t duty_cycle_show(struct device *child,
			       struct device_attribute *attr,
			       char *buf)
{
	const struct pwm_device *pwm = child_to_pwm_device(child);
	struct pwm_state state;

	pwm_get_state(pwm, &state);

	return sprintf(buf, "%u\n", state.duty_cycle);
}

static ssize_t duty_cycle_store(struct device *child,
				struct device_attribute *attr,
				const char *buf, size_t size)
{
	struct pwm_export *export = child_to_pwm_export(child);
	struct pwm_device *pwm = export->pwm;
	struct pwm_state state;
	unsigned int val;
	int ret;

	ret = kstrtouint(buf, 0, &val);
	if (ret)
		return ret;

	mutex_lock(&export->lock);
	pwm_get_state(pwm, &state);
	state.duty_cycle = val;
	ret = pwm_apply_state(pwm, &state);
	mutex_unlock(&export->lock);

	return ret ? : size;
}

static ssize_t enable_show(struct device *child,
			   struct device_attribute *attr,
			   char *buf)
{
	const struct pwm_device *pwm = child_to_pwm_device(child);
	struct pwm_state state;

	pwm_get_state(pwm, &state);

	return sprintf(buf, "%d\n", state.enabled);
}

static ssize_t enable_store(struct device *child,
			    struct device_attribute *attr,
			    const char *buf, size_t size)
{
	struct pwm_export *export = child_to_pwm_export(child);
	struct pwm_device *pwm = export->pwm;
	struct pwm_state state;
	int val, ret;

	ret = kstrtoint(buf, 0, &val);
	if (ret)
		return ret;

	mutex_lock(&export->lock);

	pwm_get_state(pwm, &state);

	switch (val) {
	case 0:
		state.enabled = false;
		break;
	case 1:
		state.enabled = true;
		break;
	default:
		ret = -EINVAL;
		goto unlock;
	}

	ret = pwm_apply_state(pwm, &state);

unlock:
	mutex_unlock(&export->lock);
	return ret ? : size;
}

static ssize_t polarity_show(struct device *child,
			     struct device_attribute *attr,
			     char *buf)
{
	const struct pwm_device *pwm = child_to_pwm_device(child);
	const char *polarity = "unknown";
	struct pwm_state state;

	pwm_get_state(pwm, &state);

	switch (state.polarity) {
	case PWM_POLARITY_NORMAL:
		polarity = "normal";
		break;

	case PWM_POLARITY_INVERSED:
		polarity = "inversed";
		break;
	}

	return sprintf(buf, "%s\n", polarity);
}

static ssize_t polarity_store(struct device *child,
			      struct device_attribute *attr,
			      const char *buf, size_t size)
{
	struct pwm_export *export = child_to_pwm_export(child);
	struct pwm_device *pwm = export->pwm;
	enum pwm_polarity polarity;
	struct pwm_state state;
	int ret;

	if (sysfs_streq(buf, "normal"))
		polarity = PWM_POLARITY_NORMAL;
	else if (sysfs_streq(buf, "inversed"))
		polarity = PWM_POLARITY_INVERSED;
	else
		return -EINVAL;

	mutex_lock(&export->lock);
	pwm_get_state(pwm, &state);
	state.polarity = polarity;
	ret = pwm_apply_state(pwm, &state);
	mutex_unlock(&export->lock);

	return ret ? : size;
}

static DEVICE_ATTR_RW(period);
static DEVICE_ATTR_RW(duty_cycle);
static DEVICE_ATTR_RW(enable);
static DEVICE_ATTR_RW(polarity);

static struct attribute *pwm_attrs[] = {
	&dev_attr_period.attr,
	&dev_attr_duty_cycle.attr,
	&dev_attr_enable.attr,
	&dev_attr_polarity.attr,
	NULL
};
ATTRIBUTE_GROUPS(pwm);

static void pwm_export_release(struct device *child)
{
	struct pwm_export *export = child_to_pwm_export(child);

	kfree(export);
}

static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
{
	struct pwm_export *export;
	int ret;

	if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
		return -EBUSY;

	export = kzalloc(sizeof(*export), GFP_KERNEL);
	if (!export) {
		clear_bit(PWMF_EXPORTED, &pwm->flags);
		return -ENOMEM;
	}

	export->pwm = pwm;
	mutex_init(&export->lock);

	export->child.release = pwm_export_release;
	export->child.parent = parent;
	export->child.devt = MKDEV(0, 0);
	export->child.groups = pwm_groups;
	dev_set_name(&export->child, "pwm%u", pwm->hwpwm);

	ret = device_register(&export->child);
	if (ret) {
		clear_bit(PWMF_EXPORTED, &pwm->flags);
		kfree(export);
		return ret;
	}

	return 0;
}

static int pwm_unexport_match(struct device *child, void *data)
{
	return child_to_pwm_device(child) == data;
}

static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
{
	struct device *child;

	if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
		return -ENODEV;

	child = device_find_child(parent, pwm, pwm_unexport_match);
	if (!child)
		return -ENODEV;

	/* for device_find_child() */
	put_device(child);
	device_unregister(child);
	pwm_put(pwm);

	return 0;
}

static ssize_t export_store(struct device *parent,
			    struct device_attribute *attr,
			    const char *buf, size_t len)
{
	struct pwm_chip *chip = dev_get_drvdata(parent);
	struct pwm_device *pwm;
	unsigned int hwpwm;
	int ret;

	ret = kstrtouint(buf, 0, &hwpwm);
	if (ret < 0)
		return ret;

	if (hwpwm >= chip->npwm)
		return -ENODEV;

	pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
	if (IS_ERR(pwm))
		return PTR_ERR(pwm);

	ret = pwm_export_child(parent, pwm);
	if (ret < 0)
		pwm_put(pwm);

	return ret ? : len;
}
static DEVICE_ATTR_WO(export);

static ssize_t unexport_store(struct device *parent,
			      struct device_attribute *attr,
			      const char *buf, size_t len)
{
	struct pwm_chip *chip = dev_get_drvdata(parent);
	unsigned int hwpwm;
	int ret;

	ret = kstrtouint(buf, 0, &hwpwm);
	if (ret < 0)
		return ret;

	if (hwpwm >= chip->npwm)
		return -ENODEV;

	ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);

	return ret ? : len;
}
static DEVICE_ATTR_WO(unexport);

static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
			 char *buf)
{
	const struct pwm_chip *chip = dev_get_drvdata(parent);

	return sprintf(buf, "%u\n", chip->npwm);
}
static DEVICE_ATTR_RO(npwm);

static struct attribute *pwm_chip_attrs[] = {
	&dev_attr_export.attr,
	&dev_attr_unexport.attr,
	&dev_attr_npwm.attr,
	NULL,
};
ATTRIBUTE_GROUPS(pwm_chip);

static struct class pwm_class = {
	.name = "pwm",
	.owner = THIS_MODULE,
	.dev_groups = pwm_chip_groups,
};

static int pwmchip_sysfs_match(struct device *parent, const void *data)
{
	return dev_get_drvdata(parent) == data;
}

void pwmchip_sysfs_export(struct pwm_chip *chip)
{
	struct device *parent;

	/*
	 * If device_create() fails the pwm_chip is still usable by
	 * the kernel its just not exported.
	 */
	parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
			       "pwmchip%d", chip->base);
	if (IS_ERR(parent)) {
		dev_warn(chip->dev,
			 "device_create failed for pwm_chip sysfs export\n");
	}
}

void pwmchip_sysfs_unexport(struct pwm_chip *chip)
{
	struct device *parent;

	parent = class_find_device(&pwm_class, NULL, chip,
				   pwmchip_sysfs_match);
	if (parent) {
		/* for class_find_device() */
		put_device(parent);
		device_unregister(parent);
	}
}

static int __init pwm_sysfs_init(void)
{
	return class_register(&pwm_class);
}
subsys_initcall(pwm_sysfs_init);
Commit	Line	Data
76abbdde HS	1	/*
	2	* A simple sysfs interface for the generic PWM framework
	3	*
	4	* Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
	5	*
	6	* Based on previous work by Lars Poeschel <poeschel@lemonage.de>
	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 as published by
	10	* the Free Software Foundation; either version 2, or (at your option)
	11	* any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*/
	18
	19	#include <linux/device.h>
	20	#include <linux/mutex.h>
	21	#include <linux/err.h>
	22	#include <linux/slab.h>
	23	#include <linux/kdev_t.h>
	24	#include <linux/pwm.h>
	25
	26	struct pwm_export {
	27	struct device child;
	28	struct pwm_device *pwm;
459a25af	29	struct mutex lock;
76abbdde HS	30	};
	31
	32	static struct pwm_export child_to_pwm_export(struct device child)
	33	{
	34	return container_of(child, struct pwm_export, child);
	35	}
	36
	37	static struct pwm_device child_to_pwm_device(struct device child)
	38	{
	39	struct pwm_export *export = child_to_pwm_export(child);
	40
	41	return export->pwm;
	42	}
	43
65cdc691 OS	44	static ssize_t period_show(struct device *child,
	45	struct device_attribute *attr,
	46	char *buf)
76abbdde HS	47	{
76abbdde HS	48	const struct pwm_device *pwm = child_to_pwm_device(child);
39100cee	49	struct pwm_state state;
76abbdde	50
39100cee BB	51	pwm_get_state(pwm, &state);
	52
	53	return sprintf(buf, "%u\n", state.period);
76abbdde HS	54	}
76abbdde HS	55
65cdc691 OS	56	static ssize_t period_store(struct device *child,
	57	struct device_attribute *attr,
	58	const char *buf, size_t size)
76abbdde	59	{
459a25af BB	60	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	61	struct pwm_device *pwm = export->pwm;
39100cee	62	struct pwm_state state;
76abbdde HS	63	unsigned int val;
	64	int ret;
	65
	66	ret = kstrtouint(buf, 0, &val);
	67	if (ret)
	68	return ret;
	69
459a25af	70	mutex_lock(&export->lock);
39100cee BB	71	pwm_get_state(pwm, &state);
	72	state.period = val;
	73	ret = pwm_apply_state(pwm, &state);
459a25af	74	mutex_unlock(&export->lock);
76abbdde HS	75
	76	return ret ? : size;
	77	}
	78
65cdc691 OS	79	static ssize_t duty_cycle_show(struct device *child,
	80	struct device_attribute *attr,
	81	char *buf)
76abbdde HS	82	{
76abbdde HS	83	const struct pwm_device *pwm = child_to_pwm_device(child);
39100cee BB	84	struct pwm_state state;
	85
	86	pwm_get_state(pwm, &state);
76abbdde	87
39100cee	88	return sprintf(buf, "%u\n", state.duty_cycle);
76abbdde HS	89	}
76abbdde HS	90
65cdc691 OS	91	static ssize_t duty_cycle_store(struct device *child,
	92	struct device_attribute *attr,
	93	const char *buf, size_t size)
76abbdde	94	{
459a25af BB	95	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	96	struct pwm_device *pwm = export->pwm;
39100cee	97	struct pwm_state state;
76abbdde HS	98	unsigned int val;
	99	int ret;
	100
	101	ret = kstrtouint(buf, 0, &val);
	102	if (ret)
	103	return ret;
	104
459a25af	105	mutex_lock(&export->lock);
39100cee BB	106	pwm_get_state(pwm, &state);
	107	state.duty_cycle = val;
	108	ret = pwm_apply_state(pwm, &state);
459a25af	109	mutex_unlock(&export->lock);
76abbdde HS	110
	111	return ret ? : size;
	112	}
	113
65cdc691 OS	114	static ssize_t enable_show(struct device *child,
	115	struct device_attribute *attr,
	116	char *buf)
76abbdde HS	117	{
76abbdde HS	118	const struct pwm_device *pwm = child_to_pwm_device(child);
39100cee	119	struct pwm_state state;
76abbdde	120
39100cee BB	121	pwm_get_state(pwm, &state);
	122
	123	return sprintf(buf, "%d\n", state.enabled);
76abbdde HS	124	}
76abbdde HS	125
65cdc691 OS	126	static ssize_t enable_store(struct device *child,
	127	struct device_attribute *attr,
	128	const char *buf, size_t size)
76abbdde	129	{
459a25af BB	130	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	131	struct pwm_device *pwm = export->pwm;
39100cee	132	struct pwm_state state;
76abbdde HS	133	int val, ret;
	134
	135	ret = kstrtoint(buf, 0, &val);
	136	if (ret)
	137	return ret;
	138
459a25af BB	139	mutex_lock(&export->lock);
459a25af BB	140
39100cee BB	141	pwm_get_state(pwm, &state);
39100cee BB	142
76abbdde HS	143	switch (val) {
76abbdde HS	144	case 0:
39100cee	145	state.enabled = false;
76abbdde HS	146	break;
76abbdde HS	147	case 1:
39100cee	148	state.enabled = true;
76abbdde HS	149	break;
	150	default:
	151	ret = -EINVAL;
39100cee	152	goto unlock;
76abbdde HS	153	}
76abbdde HS	154
fe5aa34d	155	ret = pwm_apply_state(pwm, &state);
459a25af	156
39100cee BB	157	unlock:
39100cee BB	158	mutex_unlock(&export->lock);
76abbdde HS	159	return ret ? : size;
	160	}
	161
65cdc691 OS	162	static ssize_t polarity_show(struct device *child,
	163	struct device_attribute *attr,
	164	char *buf)
76abbdde HS	165	{
76abbdde HS	166	const struct pwm_device *pwm = child_to_pwm_device(child);
5a063d87	167	const char *polarity = "unknown";
39100cee BB	168	struct pwm_state state;
	169
	170	pwm_get_state(pwm, &state);
76abbdde	171
39100cee	172	switch (state.polarity) {
5a063d87 TR	173	case PWM_POLARITY_NORMAL:
	174	polarity = "normal";
	175	break;
	176
	177	case PWM_POLARITY_INVERSED:
	178	polarity = "inversed";
	179	break;
	180	}
	181
	182	return sprintf(buf, "%s\n", polarity);
76abbdde HS	183	}
76abbdde HS	184
65cdc691 OS	185	static ssize_t polarity_store(struct device *child,
	186	struct device_attribute *attr,
	187	const char *buf, size_t size)
76abbdde	188	{
459a25af BB	189	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	190	struct pwm_device *pwm = export->pwm;
76abbdde	191	enum pwm_polarity polarity;
39100cee	192	struct pwm_state state;
76abbdde HS	193	int ret;
	194
	195	if (sysfs_streq(buf, "normal"))
	196	polarity = PWM_POLARITY_NORMAL;
	197	else if (sysfs_streq(buf, "inversed"))
	198	polarity = PWM_POLARITY_INVERSED;
	199	else
	200	return -EINVAL;
	201
459a25af	202	mutex_lock(&export->lock);
39100cee BB	203	pwm_get_state(pwm, &state);
	204	state.polarity = polarity;
	205	ret = pwm_apply_state(pwm, &state);
459a25af	206	mutex_unlock(&export->lock);
76abbdde HS	207
	208	return ret ? : size;
	209	}
	210
65cdc691 OS	211	static DEVICE_ATTR_RW(period);
	212	static DEVICE_ATTR_RW(duty_cycle);
	213	static DEVICE_ATTR_RW(enable);
	214	static DEVICE_ATTR_RW(polarity);
76abbdde HS	215
	216	static struct attribute *pwm_attrs[] = {
	217	&dev_attr_period.attr,
	218	&dev_attr_duty_cycle.attr,
	219	&dev_attr_enable.attr,
	220	&dev_attr_polarity.attr,
	221	NULL
	222	};
6ca142ad	223	ATTRIBUTE_GROUPS(pwm);
76abbdde HS	224
	225	static void pwm_export_release(struct device *child)
	226	{
	227	struct pwm_export *export = child_to_pwm_export(child);
	228
	229	kfree(export);
	230	}
	231
	232	static int pwm_export_child(struct device parent, struct pwm_device pwm)
	233	{
	234	struct pwm_export *export;
	235	int ret;
	236
	237	if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
	238	return -EBUSY;
	239
	240	export = kzalloc(sizeof(*export), GFP_KERNEL);
	241	if (!export) {
	242	clear_bit(PWMF_EXPORTED, &pwm->flags);
	243	return -ENOMEM;
	244	}
	245
	246	export->pwm = pwm;
459a25af	247	mutex_init(&export->lock);
76abbdde HS	248
	249	export->child.release = pwm_export_release;
	250	export->child.parent = parent;
	251	export->child.devt = MKDEV(0, 0);
6ca142ad	252	export->child.groups = pwm_groups;
76abbdde HS	253	dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
	254
	255	ret = device_register(&export->child);
	256	if (ret) {
	257	clear_bit(PWMF_EXPORTED, &pwm->flags);
	258	kfree(export);
	259	return ret;
	260	}
	261
	262	return 0;
	263	}
	264
	265	static int pwm_unexport_match(struct device child, void data)
	266	{
	267	return child_to_pwm_device(child) == data;
	268	}
	269
	270	static int pwm_unexport_child(struct device parent, struct pwm_device pwm)
	271	{
	272	struct device *child;
	273
	274	if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
	275	return -ENODEV;
	276
	277	child = device_find_child(parent, pwm, pwm_unexport_match);
	278	if (!child)
	279	return -ENODEV;
	280
	281	/* for device_find_child() */
	282	put_device(child);
	283	device_unregister(child);
	284	pwm_put(pwm);
	285
	286	return 0;
	287	}
	288
65cdc691 OS	289	static ssize_t export_store(struct device *parent,
	290	struct device_attribute *attr,
	291	const char *buf, size_t len)
76abbdde HS	292	{
	293	struct pwm_chip *chip = dev_get_drvdata(parent);
	294	struct pwm_device *pwm;
	295	unsigned int hwpwm;
	296	int ret;
	297
	298	ret = kstrtouint(buf, 0, &hwpwm);
	299	if (ret < 0)
	300	return ret;
	301
	302	if (hwpwm >= chip->npwm)
	303	return -ENODEV;
	304
	305	pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
	306	if (IS_ERR(pwm))
	307	return PTR_ERR(pwm);
	308
	309	ret = pwm_export_child(parent, pwm);
	310	if (ret < 0)
	311	pwm_put(pwm);
	312
	313	return ret ? : len;
	314	}
65cdc691	315	static DEVICE_ATTR_WO(export);
76abbdde	316
65cdc691 OS	317	static ssize_t unexport_store(struct device *parent,
	318	struct device_attribute *attr,
	319	const char *buf, size_t len)
76abbdde HS	320	{
	321	struct pwm_chip *chip = dev_get_drvdata(parent);
	322	unsigned int hwpwm;
	323	int ret;
	324
	325	ret = kstrtouint(buf, 0, &hwpwm);
	326	if (ret < 0)
	327	return ret;
	328
	329	if (hwpwm >= chip->npwm)
	330	return -ENODEV;
	331
	332	ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
	333
	334	return ret ? : len;
	335	}
65cdc691	336	static DEVICE_ATTR_WO(unexport);
76abbdde	337
9da01759 GKH	338	static ssize_t npwm_show(struct device parent, struct device_attribute attr,
9da01759 GKH	339	char *buf)
76abbdde HS	340	{
	341	const struct pwm_chip *chip = dev_get_drvdata(parent);
	342
	343	return sprintf(buf, "%u\n", chip->npwm);
	344	}
9da01759	345	static DEVICE_ATTR_RO(npwm);
76abbdde	346
9da01759 GKH	347	static struct attribute *pwm_chip_attrs[] = {
	348	&dev_attr_export.attr,
	349	&dev_attr_unexport.attr,
	350	&dev_attr_npwm.attr,
	351	NULL,
76abbdde	352	};
9da01759	353	ATTRIBUTE_GROUPS(pwm_chip);
76abbdde HS	354
76abbdde HS	355	static struct class pwm_class = {
412820dd TR	356	.name = "pwm",
	357	.owner = THIS_MODULE,
	358	.dev_groups = pwm_chip_groups,
76abbdde HS	359	};
	360
	361	static int pwmchip_sysfs_match(struct device parent, const void data)
	362	{
	363	return dev_get_drvdata(parent) == data;
	364	}
	365
	366	void pwmchip_sysfs_export(struct pwm_chip *chip)
	367	{
	368	struct device *parent;
	369
	370	/*
	371	* If device_create() fails the pwm_chip is still usable by
	372	* the kernel its just not exported.
	373	*/
	374	parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
	375	"pwmchip%d", chip->base);
	376	if (IS_ERR(parent)) {
	377	dev_warn(chip->dev,
	378	"device_create failed for pwm_chip sysfs export\n");
	379	}
	380	}
	381
	382	void pwmchip_sysfs_unexport(struct pwm_chip *chip)
	383	{
	384	struct device *parent;
	385
	386	parent = class_find_device(&pwm_class, NULL, chip,
	387	pwmchip_sysfs_match);
	388	if (parent) {
	389	/* for class_find_device() */
	390	put_device(parent);
	391	device_unregister(parent);
	392	}
	393	}
	394
	395	static int __init pwm_sysfs_init(void)
	396	{
	397	return class_register(&pwm_class);
	398	}
	399	subsys_initcall(pwm_sysfs_init);