2 * A simple sysfs interface for the generic PWM framework
4 * Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
6 * Based on previous work by Lars Poeschel <poeschel@lemonage.de>
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)
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.
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>
28 struct pwm_device *pwm;
31 static struct pwm_export *child_to_pwm_export(struct device *child)
33 return container_of(child, struct pwm_export, child);
36 static struct pwm_device *child_to_pwm_device(struct device *child)
38 struct pwm_export *export = child_to_pwm_export(child);
43 static ssize_t pwm_period_show(struct device *child,
44 struct device_attribute *attr,
47 const struct pwm_device *pwm = child_to_pwm_device(child);
49 return sprintf(buf, "%u\n", pwm->period);
52 static ssize_t pwm_period_store(struct device *child,
53 struct device_attribute *attr,
54 const char *buf, size_t size)
56 struct pwm_device *pwm = child_to_pwm_device(child);
60 ret = kstrtouint(buf, 0, &val);
64 ret = pwm_config(pwm, pwm->duty_cycle, val);
69 static ssize_t pwm_duty_cycle_show(struct device *child,
70 struct device_attribute *attr,
73 const struct pwm_device *pwm = child_to_pwm_device(child);
75 return sprintf(buf, "%u\n", pwm->duty_cycle);
78 static ssize_t pwm_duty_cycle_store(struct device *child,
79 struct device_attribute *attr,
80 const char *buf, size_t size)
82 struct pwm_device *pwm = child_to_pwm_device(child);
86 ret = kstrtouint(buf, 0, &val);
90 ret = pwm_config(pwm, val, pwm->period);
95 static ssize_t pwm_enable_show(struct device *child,
96 struct device_attribute *attr,
99 const struct pwm_device *pwm = child_to_pwm_device(child);
100 int enabled = test_bit(PWMF_ENABLED, &pwm->flags);
102 return sprintf(buf, "%d\n", enabled);
105 static ssize_t pwm_enable_store(struct device *child,
106 struct device_attribute *attr,
107 const char *buf, size_t size)
109 struct pwm_device *pwm = child_to_pwm_device(child);
112 ret = kstrtoint(buf, 0, &val);
121 ret = pwm_enable(pwm);
131 static ssize_t pwm_polarity_show(struct device *child,
132 struct device_attribute *attr,
135 const struct pwm_device *pwm = child_to_pwm_device(child);
137 return sprintf(buf, "%s\n", pwm->polarity ? "inversed" : "normal");
140 static ssize_t pwm_polarity_store(struct device *child,
141 struct device_attribute *attr,
142 const char *buf, size_t size)
144 struct pwm_device *pwm = child_to_pwm_device(child);
145 enum pwm_polarity polarity;
148 if (sysfs_streq(buf, "normal"))
149 polarity = PWM_POLARITY_NORMAL;
150 else if (sysfs_streq(buf, "inversed"))
151 polarity = PWM_POLARITY_INVERSED;
155 ret = pwm_set_polarity(pwm, polarity);
160 static DEVICE_ATTR(period, 0644, pwm_period_show, pwm_period_store);
161 static DEVICE_ATTR(duty_cycle, 0644, pwm_duty_cycle_show, pwm_duty_cycle_store);
162 static DEVICE_ATTR(enable, 0644, pwm_enable_show, pwm_enable_store);
163 static DEVICE_ATTR(polarity, 0644, pwm_polarity_show, pwm_polarity_store);
165 static struct attribute *pwm_attrs[] = {
166 &dev_attr_period.attr,
167 &dev_attr_duty_cycle.attr,
168 &dev_attr_enable.attr,
169 &dev_attr_polarity.attr,
173 static const struct attribute_group pwm_attr_group = {
177 static const struct attribute_group *pwm_attr_groups[] = {
182 static void pwm_export_release(struct device *child)
184 struct pwm_export *export = child_to_pwm_export(child);
189 static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
191 struct pwm_export *export;
194 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
197 export = kzalloc(sizeof(*export), GFP_KERNEL);
199 clear_bit(PWMF_EXPORTED, &pwm->flags);
205 export->child.release = pwm_export_release;
206 export->child.parent = parent;
207 export->child.devt = MKDEV(0, 0);
208 export->child.groups = pwm_attr_groups;
209 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
211 ret = device_register(&export->child);
213 clear_bit(PWMF_EXPORTED, &pwm->flags);
221 static int pwm_unexport_match(struct device *child, void *data)
223 return child_to_pwm_device(child) == data;
226 static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
228 struct device *child;
230 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
233 child = device_find_child(parent, pwm, pwm_unexport_match);
237 /* for device_find_child() */
239 device_unregister(child);
245 static ssize_t pwm_export_store(struct device *parent,
246 struct device_attribute *attr,
247 const char *buf, size_t len)
249 struct pwm_chip *chip = dev_get_drvdata(parent);
250 struct pwm_device *pwm;
254 ret = kstrtouint(buf, 0, &hwpwm);
258 if (hwpwm >= chip->npwm)
261 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
265 ret = pwm_export_child(parent, pwm);
271 static DEVICE_ATTR(export, 0200, NULL, pwm_export_store);
273 static ssize_t pwm_unexport_store(struct device *parent,
274 struct device_attribute *attr,
275 const char *buf, size_t len)
277 struct pwm_chip *chip = dev_get_drvdata(parent);
281 ret = kstrtouint(buf, 0, &hwpwm);
285 if (hwpwm >= chip->npwm)
288 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
292 static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store);
294 static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
297 const struct pwm_chip *chip = dev_get_drvdata(parent);
299 return sprintf(buf, "%u\n", chip->npwm);
301 static DEVICE_ATTR_RO(npwm);
303 static struct attribute *pwm_chip_attrs[] = {
304 &dev_attr_export.attr,
305 &dev_attr_unexport.attr,
309 ATTRIBUTE_GROUPS(pwm_chip);
311 static struct class pwm_class = {
313 .owner = THIS_MODULE,
314 .dev_groups = pwm_chip_groups,
317 static int pwmchip_sysfs_match(struct device *parent, const void *data)
319 return dev_get_drvdata(parent) == data;
322 void pwmchip_sysfs_export(struct pwm_chip *chip)
324 struct device *parent;
327 * If device_create() fails the pwm_chip is still usable by
328 * the kernel its just not exported.
330 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
331 "pwmchip%d", chip->base);
332 if (IS_ERR(parent)) {
334 "device_create failed for pwm_chip sysfs export\n");
338 void pwmchip_sysfs_unexport(struct pwm_chip *chip)
340 struct device *parent;
342 parent = class_find_device(&pwm_class, NULL, chip,
343 pwmchip_sysfs_match);
345 /* for class_find_device() */
347 device_unregister(parent);
351 static int __init pwm_sysfs_init(void)
353 return class_register(&pwm_class);
355 subsys_initcall(pwm_sysfs_init);