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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
26struct pwm_export {
27 struct device child;
28 struct pwm_device *pwm;
29};
30
31static struct pwm_export *child_to_pwm_export(struct device *child)
32{
33 return container_of(child, struct pwm_export, child);
34}
35
36static struct pwm_device *child_to_pwm_device(struct device *child)
37{
38 struct pwm_export *export = child_to_pwm_export(child);
39
40 return export->pwm;
41}
42
43static ssize_t period_show(struct device *child,
44 struct device_attribute *attr,
45 char *buf)
46{
47 const struct pwm_device *pwm = child_to_pwm_device(child);
48
49 return sprintf(buf, "%u\n", pwm_get_period(pwm));
50}
51
52static ssize_t period_store(struct device *child,
53 struct device_attribute *attr,
54 const char *buf, size_t size)
55{
56 struct pwm_device *pwm = child_to_pwm_device(child);
57 unsigned int val;
58 int ret;
59
60 ret = kstrtouint(buf, 0, &val);
61 if (ret)
62 return ret;
63
64 ret = pwm_config(pwm, pwm_get_duty_cycle(pwm), val);
65
66 return ret ? : size;
67}
68
69static ssize_t duty_cycle_show(struct device *child,
70 struct device_attribute *attr,
71 char *buf)
72{
73 const struct pwm_device *pwm = child_to_pwm_device(child);
74
75 return sprintf(buf, "%u\n", pwm_get_duty_cycle(pwm));
76}
77
78static ssize_t duty_cycle_store(struct device *child,
79 struct device_attribute *attr,
80 const char *buf, size_t size)
81{
82 struct pwm_device *pwm = child_to_pwm_device(child);
83 unsigned int val;
84 int ret;
85
86 ret = kstrtouint(buf, 0, &val);
87 if (ret)
88 return ret;
89
90 ret = pwm_config(pwm, val, pwm_get_period(pwm));
91
92 return ret ? : size;
93}
94
95static ssize_t enable_show(struct device *child,
96 struct device_attribute *attr,
97 char *buf)
98{
99 const struct pwm_device *pwm = child_to_pwm_device(child);
100
101 return sprintf(buf, "%d\n", pwm_is_enabled(pwm));
102}
103
104static ssize_t enable_store(struct device *child,
105 struct device_attribute *attr,
106 const char *buf, size_t size)
107{
108 struct pwm_device *pwm = child_to_pwm_device(child);
109 int val, ret;
110
111 ret = kstrtoint(buf, 0, &val);
112 if (ret)
113 return ret;
114
115 switch (val) {
116 case 0:
117 pwm_disable(pwm);
118 break;
119 case 1:
120 ret = pwm_enable(pwm);
121 break;
122 default:
123 ret = -EINVAL;
124 break;
125 }
126
127 return ret ? : size;
128}
129
130static ssize_t polarity_show(struct device *child,
131 struct device_attribute *attr,
132 char *buf)
133{
134 const struct pwm_device *pwm = child_to_pwm_device(child);
135 const char *polarity = "unknown";
136
137 switch (pwm_get_polarity(pwm)) {
138 case PWM_POLARITY_NORMAL:
139 polarity = "normal";
140 break;
141
142 case PWM_POLARITY_INVERSED:
143 polarity = "inversed";
144 break;
145 }
146
147 return sprintf(buf, "%s\n", polarity);
148}
149
150static ssize_t polarity_store(struct device *child,
151 struct device_attribute *attr,
152 const char *buf, size_t size)
153{
154 struct pwm_device *pwm = child_to_pwm_device(child);
155 enum pwm_polarity polarity;
156 int ret;
157
158 if (sysfs_streq(buf, "normal"))
159 polarity = PWM_POLARITY_NORMAL;
160 else if (sysfs_streq(buf, "inversed"))
161 polarity = PWM_POLARITY_INVERSED;
162 else
163 return -EINVAL;
164
165 ret = pwm_set_polarity(pwm, polarity);
166
167 return ret ? : size;
168}
169
170static DEVICE_ATTR_RW(period);
171static DEVICE_ATTR_RW(duty_cycle);
172static DEVICE_ATTR_RW(enable);
173static DEVICE_ATTR_RW(polarity);
174
175static struct attribute *pwm_attrs[] = {
176 &dev_attr_period.attr,
177 &dev_attr_duty_cycle.attr,
178 &dev_attr_enable.attr,
179 &dev_attr_polarity.attr,
180 NULL
181};
182ATTRIBUTE_GROUPS(pwm);
183
184static void pwm_export_release(struct device *child)
185{
186 struct pwm_export *export = child_to_pwm_export(child);
187
188 kfree(export);
189}
190
191static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
192{
193 struct pwm_export *export;
194 int ret;
195
196 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
197 return -EBUSY;
198
199 export = kzalloc(sizeof(*export), GFP_KERNEL);
200 if (!export) {
201 clear_bit(PWMF_EXPORTED, &pwm->flags);
202 return -ENOMEM;
203 }
204
205 export->pwm = pwm;
206
207 export->child.release = pwm_export_release;
208 export->child.parent = parent;
209 export->child.devt = MKDEV(0, 0);
210 export->child.groups = pwm_groups;
211 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
212
213 ret = device_register(&export->child);
214 if (ret) {
215 clear_bit(PWMF_EXPORTED, &pwm->flags);
216 kfree(export);
217 return ret;
218 }
219
220 return 0;
221}
222
223static int pwm_unexport_match(struct device *child, void *data)
224{
225 return child_to_pwm_device(child) == data;
226}
227
228static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
229{
230 struct device *child;
231
232 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
233 return -ENODEV;
234
235 child = device_find_child(parent, pwm, pwm_unexport_match);
236 if (!child)
237 return -ENODEV;
238
239 /* for device_find_child() */
240 put_device(child);
241 device_unregister(child);
242 pwm_put(pwm);
243
244 return 0;
245}
246
247static ssize_t export_store(struct device *parent,
248 struct device_attribute *attr,
249 const char *buf, size_t len)
250{
251 struct pwm_chip *chip = dev_get_drvdata(parent);
252 struct pwm_device *pwm;
253 unsigned int hwpwm;
254 int ret;
255
256 ret = kstrtouint(buf, 0, &hwpwm);
257 if (ret < 0)
258 return ret;
259
260 if (hwpwm >= chip->npwm)
261 return -ENODEV;
262
263 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
264 if (IS_ERR(pwm))
265 return PTR_ERR(pwm);
266
267 ret = pwm_export_child(parent, pwm);
268 if (ret < 0)
269 pwm_put(pwm);
270
271 return ret ? : len;
272}
273static DEVICE_ATTR_WO(export);
274
275static ssize_t unexport_store(struct device *parent,
276 struct device_attribute *attr,
277 const char *buf, size_t len)
278{
279 struct pwm_chip *chip = dev_get_drvdata(parent);
280 unsigned int hwpwm;
281 int ret;
282
283 ret = kstrtouint(buf, 0, &hwpwm);
284 if (ret < 0)
285 return ret;
286
287 if (hwpwm >= chip->npwm)
288 return -ENODEV;
289
290 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
291
292 return ret ? : len;
293}
294static DEVICE_ATTR_WO(unexport);
295
296static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
297 char *buf)
298{
299 const struct pwm_chip *chip = dev_get_drvdata(parent);
300
301 return sprintf(buf, "%u\n", chip->npwm);
302}
303static DEVICE_ATTR_RO(npwm);
304
305static struct attribute *pwm_chip_attrs[] = {
306 &dev_attr_export.attr,
307 &dev_attr_unexport.attr,
308 &dev_attr_npwm.attr,
309 NULL,
310};
311ATTRIBUTE_GROUPS(pwm_chip);
312
313static struct class pwm_class = {
314 .name = "pwm",
315 .owner = THIS_MODULE,
316 .dev_groups = pwm_chip_groups,
317};
318
319static int pwmchip_sysfs_match(struct device *parent, const void *data)
320{
321 return dev_get_drvdata(parent) == data;
322}
323
324void pwmchip_sysfs_export(struct pwm_chip *chip)
325{
326 struct device *parent;
327
328 /*
329 * If device_create() fails the pwm_chip is still usable by
330 * the kernel its just not exported.
331 */
332 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
333 "pwmchip%d", chip->base);
334 if (IS_ERR(parent)) {
335 dev_warn(chip->dev,
336 "device_create failed for pwm_chip sysfs export\n");
337 }
338}
339
340void pwmchip_sysfs_unexport(struct pwm_chip *chip)
341{
342 struct device *parent;
343
344 parent = class_find_device(&pwm_class, NULL, chip,
345 pwmchip_sysfs_match);
346 if (parent) {
347 /* for class_find_device() */
348 put_device(parent);
349 device_unregister(parent);
350 }
351}
352
353static int __init pwm_sysfs_init(void)
354{
355 return class_register(&pwm_class);
356}
357subsys_initcall(pwm_sysfs_init);
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
26struct pwm_export {
27 struct device child;
28 struct pwm_device *pwm;
29 struct mutex lock;
30};
31
32static struct pwm_export *child_to_pwm_export(struct device *child)
33{
34 return container_of(child, struct pwm_export, child);
35}
36
37static 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
44static ssize_t period_show(struct device *child,
45 struct device_attribute *attr,
46 char *buf)
47{
48 const struct pwm_device *pwm = child_to_pwm_device(child);
49 struct pwm_state state;
50
51 pwm_get_state(pwm, &state);
52
53 return sprintf(buf, "%u\n", state.period);
54}
55
56static ssize_t period_store(struct device *child,
57 struct device_attribute *attr,
58 const char *buf, size_t size)
59{
60 struct pwm_export *export = child_to_pwm_export(child);
61 struct pwm_device *pwm = export->pwm;
62 struct pwm_state state;
63 unsigned int val;
64 int ret;
65
66 ret = kstrtouint(buf, 0, &val);
67 if (ret)
68 return ret;
69
70 mutex_lock(&export->lock);
71 pwm_get_state(pwm, &state);
72 state.period = val;
73 ret = pwm_apply_state(pwm, &state);
74 mutex_unlock(&export->lock);
75
76 return ret ? : size;
77}
78
79static ssize_t duty_cycle_show(struct device *child,
80 struct device_attribute *attr,
81 char *buf)
82{
83 const struct pwm_device *pwm = child_to_pwm_device(child);
84 struct pwm_state state;
85
86 pwm_get_state(pwm, &state);
87
88 return sprintf(buf, "%u\n", state.duty_cycle);
89}
90
91static ssize_t duty_cycle_store(struct device *child,
92 struct device_attribute *attr,
93 const char *buf, size_t size)
94{
95 struct pwm_export *export = child_to_pwm_export(child);
96 struct pwm_device *pwm = export->pwm;
97 struct pwm_state state;
98 unsigned int val;
99 int ret;
100
101 ret = kstrtouint(buf, 0, &val);
102 if (ret)
103 return ret;
104
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);
110
111 return ret ? : size;
112}
113
114static ssize_t enable_show(struct device *child,
115 struct device_attribute *attr,
116 char *buf)
117{
118 const struct pwm_device *pwm = child_to_pwm_device(child);
119 struct pwm_state state;
120
121 pwm_get_state(pwm, &state);
122
123 return sprintf(buf, "%d\n", state.enabled);
124}
125
126static ssize_t enable_store(struct device *child,
127 struct device_attribute *attr,
128 const char *buf, size_t size)
129{
130 struct pwm_export *export = child_to_pwm_export(child);
131 struct pwm_device *pwm = export->pwm;
132 struct pwm_state state;
133 int val, ret;
134
135 ret = kstrtoint(buf, 0, &val);
136 if (ret)
137 return ret;
138
139 mutex_lock(&export->lock);
140
141 pwm_get_state(pwm, &state);
142
143 switch (val) {
144 case 0:
145 state.enabled = false;
146 break;
147 case 1:
148 state.enabled = true;
149 break;
150 default:
151 ret = -EINVAL;
152 goto unlock;
153 }
154
155 ret = pwm_apply_state(pwm, &state);
156
157unlock:
158 mutex_unlock(&export->lock);
159 return ret ? : size;
160}
161
162static ssize_t polarity_show(struct device *child,
163 struct device_attribute *attr,
164 char *buf)
165{
166 const struct pwm_device *pwm = child_to_pwm_device(child);
167 const char *polarity = "unknown";
168 struct pwm_state state;
169
170 pwm_get_state(pwm, &state);
171
172 switch (state.polarity) {
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);
183}
184
185static ssize_t polarity_store(struct device *child,
186 struct device_attribute *attr,
187 const char *buf, size_t size)
188{
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;
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
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);
207
208 return ret ? : size;
209}
210
211static ssize_t capture_show(struct device *child,
212 struct device_attribute *attr,
213 char *buf)
214{
215 struct pwm_device *pwm = child_to_pwm_device(child);
216 struct pwm_capture result;
217 int ret;
218
219 ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
220 if (ret)
221 return ret;
222
223 return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
224}
225
226static DEVICE_ATTR_RW(period);
227static DEVICE_ATTR_RW(duty_cycle);
228static DEVICE_ATTR_RW(enable);
229static DEVICE_ATTR_RW(polarity);
230static DEVICE_ATTR_RO(capture);
231
232static struct attribute *pwm_attrs[] = {
233 &dev_attr_period.attr,
234 &dev_attr_duty_cycle.attr,
235 &dev_attr_enable.attr,
236 &dev_attr_polarity.attr,
237 &dev_attr_capture.attr,
238 NULL
239};
240ATTRIBUTE_GROUPS(pwm);
241
242static void pwm_export_release(struct device *child)
243{
244 struct pwm_export *export = child_to_pwm_export(child);
245
246 kfree(export);
247}
248
249static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
250{
251 struct pwm_export *export;
252 int ret;
253
254 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
255 return -EBUSY;
256
257 export = kzalloc(sizeof(*export), GFP_KERNEL);
258 if (!export) {
259 clear_bit(PWMF_EXPORTED, &pwm->flags);
260 return -ENOMEM;
261 }
262
263 export->pwm = pwm;
264 mutex_init(&export->lock);
265
266 export->child.release = pwm_export_release;
267 export->child.parent = parent;
268 export->child.devt = MKDEV(0, 0);
269 export->child.groups = pwm_groups;
270 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
271
272 ret = device_register(&export->child);
273 if (ret) {
274 clear_bit(PWMF_EXPORTED, &pwm->flags);
275 kfree(export);
276 return ret;
277 }
278
279 return 0;
280}
281
282static int pwm_unexport_match(struct device *child, void *data)
283{
284 return child_to_pwm_device(child) == data;
285}
286
287static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
288{
289 struct device *child;
290
291 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
292 return -ENODEV;
293
294 child = device_find_child(parent, pwm, pwm_unexport_match);
295 if (!child)
296 return -ENODEV;
297
298 /* for device_find_child() */
299 put_device(child);
300 device_unregister(child);
301 pwm_put(pwm);
302
303 return 0;
304}
305
306static ssize_t export_store(struct device *parent,
307 struct device_attribute *attr,
308 const char *buf, size_t len)
309{
310 struct pwm_chip *chip = dev_get_drvdata(parent);
311 struct pwm_device *pwm;
312 unsigned int hwpwm;
313 int ret;
314
315 ret = kstrtouint(buf, 0, &hwpwm);
316 if (ret < 0)
317 return ret;
318
319 if (hwpwm >= chip->npwm)
320 return -ENODEV;
321
322 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
323 if (IS_ERR(pwm))
324 return PTR_ERR(pwm);
325
326 ret = pwm_export_child(parent, pwm);
327 if (ret < 0)
328 pwm_put(pwm);
329
330 return ret ? : len;
331}
332static DEVICE_ATTR_WO(export);
333
334static ssize_t unexport_store(struct device *parent,
335 struct device_attribute *attr,
336 const char *buf, size_t len)
337{
338 struct pwm_chip *chip = dev_get_drvdata(parent);
339 unsigned int hwpwm;
340 int ret;
341
342 ret = kstrtouint(buf, 0, &hwpwm);
343 if (ret < 0)
344 return ret;
345
346 if (hwpwm >= chip->npwm)
347 return -ENODEV;
348
349 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
350
351 return ret ? : len;
352}
353static DEVICE_ATTR_WO(unexport);
354
355static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
356 char *buf)
357{
358 const struct pwm_chip *chip = dev_get_drvdata(parent);
359
360 return sprintf(buf, "%u\n", chip->npwm);
361}
362static DEVICE_ATTR_RO(npwm);
363
364static struct attribute *pwm_chip_attrs[] = {
365 &dev_attr_export.attr,
366 &dev_attr_unexport.attr,
367 &dev_attr_npwm.attr,
368 NULL,
369};
370ATTRIBUTE_GROUPS(pwm_chip);
371
372static struct class pwm_class = {
373 .name = "pwm",
374 .owner = THIS_MODULE,
375 .dev_groups = pwm_chip_groups,
376};
377
378static int pwmchip_sysfs_match(struct device *parent, const void *data)
379{
380 return dev_get_drvdata(parent) == data;
381}
382
383void pwmchip_sysfs_export(struct pwm_chip *chip)
384{
385 struct device *parent;
386
387 /*
388 * If device_create() fails the pwm_chip is still usable by
389 * the kernel its just not exported.
390 */
391 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
392 "pwmchip%d", chip->base);
393 if (IS_ERR(parent)) {
394 dev_warn(chip->dev,
395 "device_create failed for pwm_chip sysfs export\n");
396 }
397}
398
399void pwmchip_sysfs_unexport(struct pwm_chip *chip)
400{
401 struct device *parent;
402
403 parent = class_find_device(&pwm_class, NULL, chip,
404 pwmchip_sysfs_match);
405 if (parent) {
406 /* for class_find_device() */
407 put_device(parent);
408 device_unregister(parent);
409 }
410}
411
412void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
413{
414 struct device *parent;
415 unsigned int i;
416
417 parent = class_find_device(&pwm_class, NULL, chip,
418 pwmchip_sysfs_match);
419 if (!parent)
420 return;
421
422 for (i = 0; i < chip->npwm; i++) {
423 struct pwm_device *pwm = &chip->pwms[i];
424
425 if (test_bit(PWMF_EXPORTED, &pwm->flags))
426 pwm_unexport_child(parent, pwm);
427 }
428
429 put_device(parent);
430}
431
432static int __init pwm_sysfs_init(void)
433{
434 return class_register(&pwm_class);
435}
436subsys_initcall(pwm_sysfs_init);