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

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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>
 */

#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 ssize_t capture_show(struct device *child,
			    struct device_attribute *attr,
			    char *buf)
{
	struct pwm_device *pwm = child_to_pwm_device(child);
	struct pwm_capture result;
	int ret;

	ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
	if (ret)
		return ret;

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

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

static struct attribute *pwm_attrs[] = {
	&dev_attr_period.attr,
	&dev_attr_duty_cycle.attr,
	&dev_attr_enable.attr,
	&dev_attr_polarity.attr,
	&dev_attr_capture.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;
	char *pwm_prop[2];
	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);
		put_device(&export->child);
		export = NULL;
		return ret;
	}
	pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
	pwm_prop[1] = NULL;
	kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
	kfree(pwm_prop[0]);

	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;
	char *pwm_prop[2];

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

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

	pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
	pwm_prop[1] = NULL;
	kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
	kfree(pwm_prop[0]);

	/* 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 it's 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;
	unsigned int i;

	parent = class_find_device(&pwm_class, NULL, chip,
				   pwmchip_sysfs_match);
	if (!parent)
		return;

	for (i = 0; i < chip->npwm; i++) {
		struct pwm_device *pwm = &chip->pwms[i];

		if (test_bit(PWMF_EXPORTED, &pwm->flags))
			pwm_unexport_child(parent, pwm);
	}

	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
3e0a4e85	1	// SPDX-License-Identifier: GPL-2.0-or-later
76abbdde HS	2	/*
	3	* A simple sysfs interface for the generic PWM framework
	4	*
	5	* Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
	6	*
	7	* Based on previous work by Lars Poeschel <poeschel@lemonage.de>
76abbdde HS	8	*/
	9
	10	#include <linux/device.h>
	11	#include <linux/mutex.h>
	12	#include <linux/err.h>
	13	#include <linux/slab.h>
	14	#include <linux/kdev_t.h>
	15	#include <linux/pwm.h>
	16
	17	struct pwm_export {
	18	struct device child;
	19	struct pwm_device *pwm;
459a25af	20	struct mutex lock;
76abbdde HS	21	};
	22
	23	static struct pwm_export child_to_pwm_export(struct device child)
	24	{
	25	return container_of(child, struct pwm_export, child);
	26	}
	27
	28	static struct pwm_device child_to_pwm_device(struct device child)
	29	{
	30	struct pwm_export *export = child_to_pwm_export(child);
	31
	32	return export->pwm;
	33	}
	34
65cdc691 OS	35	static ssize_t period_show(struct device *child,
	36	struct device_attribute *attr,
	37	char *buf)
76abbdde HS	38	{
76abbdde HS	39	const struct pwm_device *pwm = child_to_pwm_device(child);
39100cee	40	struct pwm_state state;
76abbdde	41
39100cee BB	42	pwm_get_state(pwm, &state);
	43
	44	return sprintf(buf, "%u\n", state.period);
76abbdde HS	45	}
76abbdde HS	46
65cdc691 OS	47	static ssize_t period_store(struct device *child,
	48	struct device_attribute *attr,
	49	const char *buf, size_t size)
76abbdde	50	{
459a25af BB	51	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	52	struct pwm_device *pwm = export->pwm;
39100cee	53	struct pwm_state state;
76abbdde HS	54	unsigned int val;
	55	int ret;
	56
	57	ret = kstrtouint(buf, 0, &val);
	58	if (ret)
	59	return ret;
	60
459a25af	61	mutex_lock(&export->lock);
39100cee BB	62	pwm_get_state(pwm, &state);
	63	state.period = val;
	64	ret = pwm_apply_state(pwm, &state);
459a25af	65	mutex_unlock(&export->lock);
76abbdde HS	66
	67	return ret ? : size;
	68	}
	69
65cdc691 OS	70	static ssize_t duty_cycle_show(struct device *child,
	71	struct device_attribute *attr,
	72	char *buf)
76abbdde HS	73	{
76abbdde HS	74	const struct pwm_device *pwm = child_to_pwm_device(child);
39100cee BB	75	struct pwm_state state;
	76
	77	pwm_get_state(pwm, &state);
76abbdde	78
39100cee	79	return sprintf(buf, "%u\n", state.duty_cycle);
76abbdde HS	80	}
76abbdde HS	81
65cdc691 OS	82	static ssize_t duty_cycle_store(struct device *child,
	83	struct device_attribute *attr,
	84	const char *buf, size_t size)
76abbdde	85	{
459a25af BB	86	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	87	struct pwm_device *pwm = export->pwm;
39100cee	88	struct pwm_state state;
76abbdde HS	89	unsigned int val;
	90	int ret;
	91
	92	ret = kstrtouint(buf, 0, &val);
	93	if (ret)
	94	return ret;
	95
459a25af	96	mutex_lock(&export->lock);
39100cee BB	97	pwm_get_state(pwm, &state);
	98	state.duty_cycle = val;
	99	ret = pwm_apply_state(pwm, &state);
459a25af	100	mutex_unlock(&export->lock);
76abbdde HS	101
	102	return ret ? : size;
	103	}
	104
65cdc691 OS	105	static ssize_t enable_show(struct device *child,
	106	struct device_attribute *attr,
	107	char *buf)
76abbdde HS	108	{
76abbdde HS	109	const struct pwm_device *pwm = child_to_pwm_device(child);
39100cee	110	struct pwm_state state;
76abbdde	111
39100cee BB	112	pwm_get_state(pwm, &state);
	113
	114	return sprintf(buf, "%d\n", state.enabled);
76abbdde HS	115	}
76abbdde HS	116
65cdc691 OS	117	static ssize_t enable_store(struct device *child,
	118	struct device_attribute *attr,
	119	const char *buf, size_t size)
76abbdde	120	{
459a25af BB	121	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	122	struct pwm_device *pwm = export->pwm;
39100cee	123	struct pwm_state state;
76abbdde HS	124	int val, ret;
	125
	126	ret = kstrtoint(buf, 0, &val);
	127	if (ret)
	128	return ret;
	129
459a25af BB	130	mutex_lock(&export->lock);
459a25af BB	131
39100cee BB	132	pwm_get_state(pwm, &state);
39100cee BB	133
76abbdde HS	134	switch (val) {
76abbdde HS	135	case 0:
39100cee	136	state.enabled = false;
76abbdde HS	137	break;
76abbdde HS	138	case 1:
39100cee	139	state.enabled = true;
76abbdde HS	140	break;
	141	default:
	142	ret = -EINVAL;
39100cee	143	goto unlock;
76abbdde HS	144	}
76abbdde HS	145
fe5aa34d	146	ret = pwm_apply_state(pwm, &state);
459a25af	147
39100cee BB	148	unlock:
39100cee BB	149	mutex_unlock(&export->lock);
76abbdde HS	150	return ret ? : size;
	151	}
	152
65cdc691 OS	153	static ssize_t polarity_show(struct device *child,
	154	struct device_attribute *attr,
	155	char *buf)
76abbdde HS	156	{
76abbdde HS	157	const struct pwm_device *pwm = child_to_pwm_device(child);
5a063d87	158	const char *polarity = "unknown";
39100cee BB	159	struct pwm_state state;
	160
	161	pwm_get_state(pwm, &state);
76abbdde	162
39100cee	163	switch (state.polarity) {
5a063d87 TR	164	case PWM_POLARITY_NORMAL:
	165	polarity = "normal";
	166	break;
	167
	168	case PWM_POLARITY_INVERSED:
	169	polarity = "inversed";
	170	break;
	171	}
	172
	173	return sprintf(buf, "%s\n", polarity);
76abbdde HS	174	}
76abbdde HS	175
65cdc691 OS	176	static ssize_t polarity_store(struct device *child,
	177	struct device_attribute *attr,
	178	const char *buf, size_t size)
76abbdde	179	{
459a25af BB	180	struct pwm_export *export = child_to_pwm_export(child);
459a25af BB	181	struct pwm_device *pwm = export->pwm;
76abbdde	182	enum pwm_polarity polarity;
39100cee	183	struct pwm_state state;
76abbdde HS	184	int ret;
	185
	186	if (sysfs_streq(buf, "normal"))
	187	polarity = PWM_POLARITY_NORMAL;
	188	else if (sysfs_streq(buf, "inversed"))
	189	polarity = PWM_POLARITY_INVERSED;
	190	else
	191	return -EINVAL;
	192
459a25af	193	mutex_lock(&export->lock);
39100cee BB	194	pwm_get_state(pwm, &state);
	195	state.polarity = polarity;
	196	ret = pwm_apply_state(pwm, &state);
459a25af	197	mutex_unlock(&export->lock);
76abbdde HS	198
	199	return ret ? : size;
	200	}
	201
1a366fe9 LJ	202	static ssize_t capture_show(struct device *child,
	203	struct device_attribute *attr,
	204	char *buf)
	205	{
	206	struct pwm_device *pwm = child_to_pwm_device(child);
	207	struct pwm_capture result;
	208	int ret;
	209
	210	ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
	211	if (ret)
	212	return ret;
	213
	214	return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
	215	}
	216
65cdc691 OS	217	static DEVICE_ATTR_RW(period);
	218	static DEVICE_ATTR_RW(duty_cycle);
	219	static DEVICE_ATTR_RW(enable);
	220	static DEVICE_ATTR_RW(polarity);
1a366fe9	221	static DEVICE_ATTR_RO(capture);
76abbdde HS	222
	223	static struct attribute *pwm_attrs[] = {
	224	&dev_attr_period.attr,
	225	&dev_attr_duty_cycle.attr,
	226	&dev_attr_enable.attr,
	227	&dev_attr_polarity.attr,
1a366fe9	228	&dev_attr_capture.attr,
76abbdde HS	229	NULL
76abbdde HS	230	};
6ca142ad	231	ATTRIBUTE_GROUPS(pwm);
76abbdde HS	232
	233	static void pwm_export_release(struct device *child)
	234	{
	235	struct pwm_export *export = child_to_pwm_export(child);
	236
	237	kfree(export);
	238	}
	239
	240	static int pwm_export_child(struct device parent, struct pwm_device pwm)
	241	{
	242	struct pwm_export *export;
552c02e3	243	char *pwm_prop[2];
76abbdde HS	244	int ret;
	245
	246	if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
	247	return -EBUSY;
	248
	249	export = kzalloc(sizeof(*export), GFP_KERNEL);
	250	if (!export) {
	251	clear_bit(PWMF_EXPORTED, &pwm->flags);
	252	return -ENOMEM;
	253	}
	254
	255	export->pwm = pwm;
459a25af	256	mutex_init(&export->lock);
76abbdde HS	257
	258	export->child.release = pwm_export_release;
	259	export->child.parent = parent;
	260	export->child.devt = MKDEV(0, 0);
6ca142ad	261	export->child.groups = pwm_groups;
76abbdde HS	262	dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
	263
	264	ret = device_register(&export->child);
	265	if (ret) {
	266	clear_bit(PWMF_EXPORTED, &pwm->flags);
8bbf5b42 AY	267	put_device(&export->child);
8bbf5b42 AY	268	export = NULL;
76abbdde HS	269	return ret;
76abbdde HS	270	}
552c02e3 FG	271	pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
	272	pwm_prop[1] = NULL;
	273	kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
	274	kfree(pwm_prop[0]);
76abbdde HS	275
	276	return 0;
	277	}
	278
	279	static int pwm_unexport_match(struct device child, void data)
	280	{
	281	return child_to_pwm_device(child) == data;
	282	}
	283
	284	static int pwm_unexport_child(struct device parent, struct pwm_device pwm)
	285	{
	286	struct device *child;
552c02e3	287	char *pwm_prop[2];
76abbdde HS	288
	289	if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
	290	return -ENODEV;
	291
	292	child = device_find_child(parent, pwm, pwm_unexport_match);
	293	if (!child)
	294	return -ENODEV;
	295
552c02e3 FG	296	pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
	297	pwm_prop[1] = NULL;
	298	kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
	299	kfree(pwm_prop[0]);
	300
76abbdde HS	301	/* for device_find_child() */
	302	put_device(child);
	303	device_unregister(child);
	304	pwm_put(pwm);
	305
	306	return 0;
	307	}
	308
65cdc691 OS	309	static ssize_t export_store(struct device *parent,
	310	struct device_attribute *attr,
	311	const char *buf, size_t len)
76abbdde HS	312	{
	313	struct pwm_chip *chip = dev_get_drvdata(parent);
	314	struct pwm_device *pwm;
	315	unsigned int hwpwm;
	316	int ret;
	317
	318	ret = kstrtouint(buf, 0, &hwpwm);
	319	if (ret < 0)
	320	return ret;
	321
	322	if (hwpwm >= chip->npwm)
	323	return -ENODEV;
	324
	325	pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
	326	if (IS_ERR(pwm))
	327	return PTR_ERR(pwm);
	328
	329	ret = pwm_export_child(parent, pwm);
	330	if (ret < 0)
	331	pwm_put(pwm);
	332
	333	return ret ? : len;
	334	}
65cdc691	335	static DEVICE_ATTR_WO(export);
76abbdde	336
65cdc691 OS	337	static ssize_t unexport_store(struct device *parent,
	338	struct device_attribute *attr,
	339	const char *buf, size_t len)
76abbdde HS	340	{
	341	struct pwm_chip *chip = dev_get_drvdata(parent);
	342	unsigned int hwpwm;
	343	int ret;
	344
	345	ret = kstrtouint(buf, 0, &hwpwm);
	346	if (ret < 0)
	347	return ret;
	348
	349	if (hwpwm >= chip->npwm)
	350	return -ENODEV;
	351
	352	ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
	353
	354	return ret ? : len;
	355	}
65cdc691	356	static DEVICE_ATTR_WO(unexport);
76abbdde	357
9da01759 GKH	358	static ssize_t npwm_show(struct device parent, struct device_attribute attr,
9da01759 GKH	359	char *buf)
76abbdde HS	360	{
	361	const struct pwm_chip *chip = dev_get_drvdata(parent);
	362
	363	return sprintf(buf, "%u\n", chip->npwm);
	364	}
9da01759	365	static DEVICE_ATTR_RO(npwm);
76abbdde	366
9da01759 GKH	367	static struct attribute *pwm_chip_attrs[] = {
	368	&dev_attr_export.attr,
	369	&dev_attr_unexport.attr,
	370	&dev_attr_npwm.attr,
	371	NULL,
76abbdde	372	};
9da01759	373	ATTRIBUTE_GROUPS(pwm_chip);
76abbdde HS	374
76abbdde HS	375	static struct class pwm_class = {
412820dd TR	376	.name = "pwm",
	377	.owner = THIS_MODULE,
	378	.dev_groups = pwm_chip_groups,
76abbdde HS	379	};
	380
	381	static int pwmchip_sysfs_match(struct device parent, const void data)
	382	{
	383	return dev_get_drvdata(parent) == data;
	384	}
	385
	386	void pwmchip_sysfs_export(struct pwm_chip *chip)
	387	{
	388	struct device *parent;
	389
	390	/*
	391	* If device_create() fails the pwm_chip is still usable by
9ff06679	392	* the kernel it's just not exported.
76abbdde HS	393	*/
	394	parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
	395	"pwmchip%d", chip->base);
	396	if (IS_ERR(parent)) {
	397	dev_warn(chip->dev,
	398	"device_create failed for pwm_chip sysfs export\n");
	399	}
	400	}
	401
	402	void pwmchip_sysfs_unexport(struct pwm_chip *chip)
0733424c DH	403	{
	404	struct device *parent;
	405	unsigned int i;
	406
	407	parent = class_find_device(&pwm_class, NULL, chip,
	408	pwmchip_sysfs_match);
	409	if (!parent)
	410	return;
	411
	412	for (i = 0; i < chip->npwm; i++) {
	413	struct pwm_device *pwm = &chip->pwms[i];
	414
	415	if (test_bit(PWMF_EXPORTED, &pwm->flags))
	416	pwm_unexport_child(parent, pwm);
	417	}
0e1614ac JH	418
0e1614ac JH	419	put_device(parent);
347ab948	420	device_unregister(parent);
0733424c DH	421	}
0733424c DH	422
76abbdde HS	423	static int __init pwm_sysfs_init(void)
	424	{
	425	return class_register(&pwm_class);
	426	}
	427	subsys_initcall(pwm_sysfs_init);