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;
32 static struct pwm_export *child_to_pwm_export(struct device *child)
34 return container_of(child, struct pwm_export, child);
37 static struct pwm_device *child_to_pwm_device(struct device *child)
39 struct pwm_export *export = child_to_pwm_export(child);
44 static ssize_t period_show(struct device *child,
45 struct device_attribute *attr,
48 const struct pwm_device *pwm = child_to_pwm_device(child);
49 struct pwm_state state;
51 pwm_get_state(pwm, &state);
53 return sprintf(buf, "%u\n", state.period);
56 static ssize_t period_store(struct device *child,
57 struct device_attribute *attr,
58 const char *buf, size_t size)
60 struct pwm_export *export = child_to_pwm_export(child);
61 struct pwm_device *pwm = export->pwm;
62 struct pwm_state state;
66 ret = kstrtouint(buf, 0, &val);
70 mutex_lock(&export->lock);
71 pwm_get_state(pwm, &state);
73 ret = pwm_apply_state(pwm, &state);
74 mutex_unlock(&export->lock);
79 static ssize_t duty_cycle_show(struct device *child,
80 struct device_attribute *attr,
83 const struct pwm_device *pwm = child_to_pwm_device(child);
84 struct pwm_state state;
86 pwm_get_state(pwm, &state);
88 return sprintf(buf, "%u\n", state.duty_cycle);
91 static ssize_t duty_cycle_store(struct device *child,
92 struct device_attribute *attr,
93 const char *buf, size_t size)
95 struct pwm_export *export = child_to_pwm_export(child);
96 struct pwm_device *pwm = export->pwm;
97 struct pwm_state state;
101 ret = kstrtouint(buf, 0, &val);
105 mutex_lock(&export->lock);
106 pwm_get_state(pwm, &state);
107 state.duty_cycle = val;
108 ret = pwm_apply_state(pwm, &state);
109 mutex_unlock(&export->lock);
114 static ssize_t enable_show(struct device *child,
115 struct device_attribute *attr,
118 const struct pwm_device *pwm = child_to_pwm_device(child);
119 struct pwm_state state;
121 pwm_get_state(pwm, &state);
123 return sprintf(buf, "%d\n", state.enabled);
126 static ssize_t enable_store(struct device *child,
127 struct device_attribute *attr,
128 const char *buf, size_t size)
130 struct pwm_export *export = child_to_pwm_export(child);
131 struct pwm_device *pwm = export->pwm;
132 struct pwm_state state;
135 ret = kstrtoint(buf, 0, &val);
139 mutex_lock(&export->lock);
141 pwm_get_state(pwm, &state);
145 state.enabled = false;
148 state.enabled = true;
155 ret = pwm_apply_state(pwm, &state);
158 mutex_unlock(&export->lock);
162 static ssize_t polarity_show(struct device *child,
163 struct device_attribute *attr,
166 const struct pwm_device *pwm = child_to_pwm_device(child);
167 const char *polarity = "unknown";
168 struct pwm_state state;
170 pwm_get_state(pwm, &state);
172 switch (state.polarity) {
173 case PWM_POLARITY_NORMAL:
177 case PWM_POLARITY_INVERSED:
178 polarity = "inversed";
182 return sprintf(buf, "%s\n", polarity);
185 static ssize_t polarity_store(struct device *child,
186 struct device_attribute *attr,
187 const char *buf, size_t size)
189 struct pwm_export *export = child_to_pwm_export(child);
190 struct pwm_device *pwm = export->pwm;
191 enum pwm_polarity polarity;
192 struct pwm_state state;
195 if (sysfs_streq(buf, "normal"))
196 polarity = PWM_POLARITY_NORMAL;
197 else if (sysfs_streq(buf, "inversed"))
198 polarity = PWM_POLARITY_INVERSED;
202 mutex_lock(&export->lock);
203 pwm_get_state(pwm, &state);
204 state.polarity = polarity;
205 ret = pwm_apply_state(pwm, &state);
206 mutex_unlock(&export->lock);
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);
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,
223 ATTRIBUTE_GROUPS(pwm);
225 static void pwm_export_release(struct device *child)
227 struct pwm_export *export = child_to_pwm_export(child);
232 static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
234 struct pwm_export *export;
237 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
240 export = kzalloc(sizeof(*export), GFP_KERNEL);
242 clear_bit(PWMF_EXPORTED, &pwm->flags);
247 mutex_init(&export->lock);
249 export->child.release = pwm_export_release;
250 export->child.parent = parent;
251 export->child.devt = MKDEV(0, 0);
252 export->child.groups = pwm_groups;
253 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
255 ret = device_register(&export->child);
257 clear_bit(PWMF_EXPORTED, &pwm->flags);
265 static int pwm_unexport_match(struct device *child, void *data)
267 return child_to_pwm_device(child) == data;
270 static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
272 struct device *child;
274 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
277 child = device_find_child(parent, pwm, pwm_unexport_match);
281 /* for device_find_child() */
283 device_unregister(child);
289 static ssize_t export_store(struct device *parent,
290 struct device_attribute *attr,
291 const char *buf, size_t len)
293 struct pwm_chip *chip = dev_get_drvdata(parent);
294 struct pwm_device *pwm;
298 ret = kstrtouint(buf, 0, &hwpwm);
302 if (hwpwm >= chip->npwm)
305 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
309 ret = pwm_export_child(parent, pwm);
315 static DEVICE_ATTR_WO(export);
317 static ssize_t unexport_store(struct device *parent,
318 struct device_attribute *attr,
319 const char *buf, size_t len)
321 struct pwm_chip *chip = dev_get_drvdata(parent);
325 ret = kstrtouint(buf, 0, &hwpwm);
329 if (hwpwm >= chip->npwm)
332 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
336 static DEVICE_ATTR_WO(unexport);
338 static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
341 const struct pwm_chip *chip = dev_get_drvdata(parent);
343 return sprintf(buf, "%u\n", chip->npwm);
345 static DEVICE_ATTR_RO(npwm);
347 static struct attribute *pwm_chip_attrs[] = {
348 &dev_attr_export.attr,
349 &dev_attr_unexport.attr,
353 ATTRIBUTE_GROUPS(pwm_chip);
355 static struct class pwm_class = {
357 .owner = THIS_MODULE,
358 .dev_groups = pwm_chip_groups,
361 static int pwmchip_sysfs_match(struct device *parent, const void *data)
363 return dev_get_drvdata(parent) == data;
366 void pwmchip_sysfs_export(struct pwm_chip *chip)
368 struct device *parent;
371 * If device_create() fails the pwm_chip is still usable by
372 * the kernel its just not exported.
374 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
375 "pwmchip%d", chip->base);
376 if (IS_ERR(parent)) {
378 "device_create failed for pwm_chip sysfs export\n");
382 void pwmchip_sysfs_unexport(struct pwm_chip *chip)
384 struct device *parent;
386 parent = class_find_device(&pwm_class, NULL, chip,
387 pwmchip_sysfs_match);
389 /* for class_find_device() */
391 device_unregister(parent);
395 static int __init pwm_sysfs_init(void)
397 return class_register(&pwm_class);
399 subsys_initcall(pwm_sysfs_init);