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1// SPDX-License-Identifier: GPL-2.0-or-later
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>
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
17struct pwm_export {
18 struct device child;
19 struct pwm_device *pwm;
20 struct mutex lock;
21 struct pwm_state suspend;
22};
23
24static struct pwm_export *child_to_pwm_export(struct device *child)
25{
26 return container_of(child, struct pwm_export, child);
27}
28
29static struct pwm_device *child_to_pwm_device(struct device *child)
30{
31 struct pwm_export *export = child_to_pwm_export(child);
32
33 return export->pwm;
34}
35
36static ssize_t period_show(struct device *child,
37 struct device_attribute *attr,
38 char *buf)
39{
40 const struct pwm_device *pwm = child_to_pwm_device(child);
41 struct pwm_state state;
42
43 pwm_get_state(pwm, &state);
44
45 return sysfs_emit(buf, "%llu\n", state.period);
46}
47
48static ssize_t period_store(struct device *child,
49 struct device_attribute *attr,
50 const char *buf, size_t size)
51{
52 struct pwm_export *export = child_to_pwm_export(child);
53 struct pwm_device *pwm = export->pwm;
54 struct pwm_state state;
55 u64 val;
56 int ret;
57
58 ret = kstrtou64(buf, 0, &val);
59 if (ret)
60 return ret;
61
62 mutex_lock(&export->lock);
63 pwm_get_state(pwm, &state);
64 state.period = val;
65 ret = pwm_apply_might_sleep(pwm, &state);
66 mutex_unlock(&export->lock);
67
68 return ret ? : size;
69}
70
71static ssize_t duty_cycle_show(struct device *child,
72 struct device_attribute *attr,
73 char *buf)
74{
75 const struct pwm_device *pwm = child_to_pwm_device(child);
76 struct pwm_state state;
77
78 pwm_get_state(pwm, &state);
79
80 return sysfs_emit(buf, "%llu\n", state.duty_cycle);
81}
82
83static ssize_t duty_cycle_store(struct device *child,
84 struct device_attribute *attr,
85 const char *buf, size_t size)
86{
87 struct pwm_export *export = child_to_pwm_export(child);
88 struct pwm_device *pwm = export->pwm;
89 struct pwm_state state;
90 u64 val;
91 int ret;
92
93 ret = kstrtou64(buf, 0, &val);
94 if (ret)
95 return ret;
96
97 mutex_lock(&export->lock);
98 pwm_get_state(pwm, &state);
99 state.duty_cycle = val;
100 ret = pwm_apply_might_sleep(pwm, &state);
101 mutex_unlock(&export->lock);
102
103 return ret ? : size;
104}
105
106static ssize_t enable_show(struct device *child,
107 struct device_attribute *attr,
108 char *buf)
109{
110 const struct pwm_device *pwm = child_to_pwm_device(child);
111 struct pwm_state state;
112
113 pwm_get_state(pwm, &state);
114
115 return sysfs_emit(buf, "%d\n", state.enabled);
116}
117
118static ssize_t enable_store(struct device *child,
119 struct device_attribute *attr,
120 const char *buf, size_t size)
121{
122 struct pwm_export *export = child_to_pwm_export(child);
123 struct pwm_device *pwm = export->pwm;
124 struct pwm_state state;
125 int val, ret;
126
127 ret = kstrtoint(buf, 0, &val);
128 if (ret)
129 return ret;
130
131 mutex_lock(&export->lock);
132
133 pwm_get_state(pwm, &state);
134
135 switch (val) {
136 case 0:
137 state.enabled = false;
138 break;
139 case 1:
140 state.enabled = true;
141 break;
142 default:
143 ret = -EINVAL;
144 goto unlock;
145 }
146
147 ret = pwm_apply_might_sleep(pwm, &state);
148
149unlock:
150 mutex_unlock(&export->lock);
151 return ret ? : size;
152}
153
154static ssize_t polarity_show(struct device *child,
155 struct device_attribute *attr,
156 char *buf)
157{
158 const struct pwm_device *pwm = child_to_pwm_device(child);
159 const char *polarity = "unknown";
160 struct pwm_state state;
161
162 pwm_get_state(pwm, &state);
163
164 switch (state.polarity) {
165 case PWM_POLARITY_NORMAL:
166 polarity = "normal";
167 break;
168
169 case PWM_POLARITY_INVERSED:
170 polarity = "inversed";
171 break;
172 }
173
174 return sysfs_emit(buf, "%s\n", polarity);
175}
176
177static ssize_t polarity_store(struct device *child,
178 struct device_attribute *attr,
179 const char *buf, size_t size)
180{
181 struct pwm_export *export = child_to_pwm_export(child);
182 struct pwm_device *pwm = export->pwm;
183 enum pwm_polarity polarity;
184 struct pwm_state state;
185 int ret;
186
187 if (sysfs_streq(buf, "normal"))
188 polarity = PWM_POLARITY_NORMAL;
189 else if (sysfs_streq(buf, "inversed"))
190 polarity = PWM_POLARITY_INVERSED;
191 else
192 return -EINVAL;
193
194 mutex_lock(&export->lock);
195 pwm_get_state(pwm, &state);
196 state.polarity = polarity;
197 ret = pwm_apply_might_sleep(pwm, &state);
198 mutex_unlock(&export->lock);
199
200 return ret ? : size;
201}
202
203static ssize_t capture_show(struct device *child,
204 struct device_attribute *attr,
205 char *buf)
206{
207 struct pwm_device *pwm = child_to_pwm_device(child);
208 struct pwm_capture result;
209 int ret;
210
211 ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
212 if (ret)
213 return ret;
214
215 return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle);
216}
217
218static DEVICE_ATTR_RW(period);
219static DEVICE_ATTR_RW(duty_cycle);
220static DEVICE_ATTR_RW(enable);
221static DEVICE_ATTR_RW(polarity);
222static DEVICE_ATTR_RO(capture);
223
224static struct attribute *pwm_attrs[] = {
225 &dev_attr_period.attr,
226 &dev_attr_duty_cycle.attr,
227 &dev_attr_enable.attr,
228 &dev_attr_polarity.attr,
229 &dev_attr_capture.attr,
230 NULL
231};
232ATTRIBUTE_GROUPS(pwm);
233
234static void pwm_export_release(struct device *child)
235{
236 struct pwm_export *export = child_to_pwm_export(child);
237
238 kfree(export);
239}
240
241static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
242{
243 struct pwm_export *export;
244 char *pwm_prop[2];
245 int ret;
246
247 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
248 return -EBUSY;
249
250 export = kzalloc(sizeof(*export), GFP_KERNEL);
251 if (!export) {
252 clear_bit(PWMF_EXPORTED, &pwm->flags);
253 return -ENOMEM;
254 }
255
256 export->pwm = pwm;
257 mutex_init(&export->lock);
258
259 export->child.release = pwm_export_release;
260 export->child.parent = parent;
261 export->child.devt = MKDEV(0, 0);
262 export->child.groups = pwm_groups;
263 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
264
265 ret = device_register(&export->child);
266 if (ret) {
267 clear_bit(PWMF_EXPORTED, &pwm->flags);
268 put_device(&export->child);
269 export = NULL;
270 return ret;
271 }
272 pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
273 pwm_prop[1] = NULL;
274 kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
275 kfree(pwm_prop[0]);
276
277 return 0;
278}
279
280static int pwm_unexport_match(struct device *child, void *data)
281{
282 return child_to_pwm_device(child) == data;
283}
284
285static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
286{
287 struct device *child;
288 char *pwm_prop[2];
289
290 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
291 return -ENODEV;
292
293 child = device_find_child(parent, pwm, pwm_unexport_match);
294 if (!child)
295 return -ENODEV;
296
297 pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
298 pwm_prop[1] = NULL;
299 kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
300 kfree(pwm_prop[0]);
301
302 /* for device_find_child() */
303 put_device(child);
304 device_unregister(child);
305 pwm_put(pwm);
306
307 return 0;
308}
309
310static ssize_t export_store(struct device *parent,
311 struct device_attribute *attr,
312 const char *buf, size_t len)
313{
314 struct pwm_chip *chip = dev_get_drvdata(parent);
315 struct pwm_device *pwm;
316 unsigned int hwpwm;
317 int ret;
318
319 ret = kstrtouint(buf, 0, &hwpwm);
320 if (ret < 0)
321 return ret;
322
323 if (hwpwm >= chip->npwm)
324 return -ENODEV;
325
326 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
327 if (IS_ERR(pwm))
328 return PTR_ERR(pwm);
329
330 ret = pwm_export_child(parent, pwm);
331 if (ret < 0)
332 pwm_put(pwm);
333
334 return ret ? : len;
335}
336static DEVICE_ATTR_WO(export);
337
338static ssize_t unexport_store(struct device *parent,
339 struct device_attribute *attr,
340 const char *buf, size_t len)
341{
342 struct pwm_chip *chip = dev_get_drvdata(parent);
343 unsigned int hwpwm;
344 int ret;
345
346 ret = kstrtouint(buf, 0, &hwpwm);
347 if (ret < 0)
348 return ret;
349
350 if (hwpwm >= chip->npwm)
351 return -ENODEV;
352
353 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
354
355 return ret ? : len;
356}
357static DEVICE_ATTR_WO(unexport);
358
359static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
360 char *buf)
361{
362 const struct pwm_chip *chip = dev_get_drvdata(parent);
363
364 return sysfs_emit(buf, "%u\n", chip->npwm);
365}
366static DEVICE_ATTR_RO(npwm);
367
368static struct attribute *pwm_chip_attrs[] = {
369 &dev_attr_export.attr,
370 &dev_attr_unexport.attr,
371 &dev_attr_npwm.attr,
372 NULL,
373};
374ATTRIBUTE_GROUPS(pwm_chip);
375
376/* takes export->lock on success */
377static struct pwm_export *pwm_class_get_state(struct device *parent,
378 struct pwm_device *pwm,
379 struct pwm_state *state)
380{
381 struct device *child;
382 struct pwm_export *export;
383
384 if (!test_bit(PWMF_EXPORTED, &pwm->flags))
385 return NULL;
386
387 child = device_find_child(parent, pwm, pwm_unexport_match);
388 if (!child)
389 return NULL;
390
391 export = child_to_pwm_export(child);
392 put_device(child); /* for device_find_child() */
393
394 mutex_lock(&export->lock);
395 pwm_get_state(pwm, state);
396
397 return export;
398}
399
400static int pwm_class_apply_state(struct pwm_export *export,
401 struct pwm_device *pwm,
402 struct pwm_state *state)
403{
404 int ret = pwm_apply_might_sleep(pwm, state);
405
406 /* release lock taken in pwm_class_get_state */
407 mutex_unlock(&export->lock);
408
409 return ret;
410}
411
412static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm)
413{
414 struct pwm_chip *chip = dev_get_drvdata(parent);
415 unsigned int i;
416 int ret = 0;
417
418 for (i = 0; i < npwm; i++) {
419 struct pwm_device *pwm = &chip->pwms[i];
420 struct pwm_state state;
421 struct pwm_export *export;
422
423 export = pwm_class_get_state(parent, pwm, &state);
424 if (!export)
425 continue;
426
427 /* If pwmchip was not enabled before suspend, do nothing. */
428 if (!export->suspend.enabled) {
429 /* release lock taken in pwm_class_get_state */
430 mutex_unlock(&export->lock);
431 continue;
432 }
433
434 state.enabled = export->suspend.enabled;
435 ret = pwm_class_apply_state(export, pwm, &state);
436 if (ret < 0)
437 break;
438 }
439
440 return ret;
441}
442
443static int pwm_class_suspend(struct device *parent)
444{
445 struct pwm_chip *chip = dev_get_drvdata(parent);
446 unsigned int i;
447 int ret = 0;
448
449 for (i = 0; i < chip->npwm; i++) {
450 struct pwm_device *pwm = &chip->pwms[i];
451 struct pwm_state state;
452 struct pwm_export *export;
453
454 export = pwm_class_get_state(parent, pwm, &state);
455 if (!export)
456 continue;
457
458 /*
459 * If pwmchip was not enabled before suspend, save
460 * state for resume time and do nothing else.
461 */
462 export->suspend = state;
463 if (!state.enabled) {
464 /* release lock taken in pwm_class_get_state */
465 mutex_unlock(&export->lock);
466 continue;
467 }
468
469 state.enabled = false;
470 ret = pwm_class_apply_state(export, pwm, &state);
471 if (ret < 0) {
472 /*
473 * roll back the PWM devices that were disabled by
474 * this suspend function.
475 */
476 pwm_class_resume_npwm(parent, i);
477 break;
478 }
479 }
480
481 return ret;
482}
483
484static int pwm_class_resume(struct device *parent)
485{
486 struct pwm_chip *chip = dev_get_drvdata(parent);
487
488 return pwm_class_resume_npwm(parent, chip->npwm);
489}
490
491static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
492
493static struct class pwm_class = {
494 .name = "pwm",
495 .dev_groups = pwm_chip_groups,
496 .pm = pm_sleep_ptr(&pwm_class_pm_ops),
497};
498
499static int pwmchip_sysfs_match(struct device *parent, const void *data)
500{
501 return dev_get_drvdata(parent) == data;
502}
503
504void pwmchip_sysfs_export(struct pwm_chip *chip)
505{
506 struct device *parent;
507
508 /*
509 * If device_create() fails the pwm_chip is still usable by
510 * the kernel it's just not exported.
511 */
512 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
513 "pwmchip%d", chip->id);
514 if (IS_ERR(parent)) {
515 dev_warn(chip->dev,
516 "device_create failed for pwm_chip sysfs export\n");
517 }
518}
519
520void pwmchip_sysfs_unexport(struct pwm_chip *chip)
521{
522 struct device *parent;
523 unsigned int i;
524
525 parent = class_find_device(&pwm_class, NULL, chip,
526 pwmchip_sysfs_match);
527 if (!parent)
528 return;
529
530 for (i = 0; i < chip->npwm; i++) {
531 struct pwm_device *pwm = &chip->pwms[i];
532
533 if (test_bit(PWMF_EXPORTED, &pwm->flags))
534 pwm_unexport_child(parent, pwm);
535 }
536
537 put_device(parent);
538 device_unregister(parent);
539}
540
541static int __init pwm_sysfs_init(void)
542{
543 return class_register(&pwm_class);
544}
545subsys_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};
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 pwm_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->period);
50}
51
52static ssize_t pwm_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->duty_cycle, val);
65
66 return ret ? : size;
67}
68
69static ssize_t pwm_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->duty_cycle);
76}
77
78static ssize_t pwm_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->period);
91
92 return ret ? : size;
93}
94
95static ssize_t pwm_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 int enabled = test_bit(PWMF_ENABLED, &pwm->flags);
101
102 return sprintf(buf, "%d\n", enabled);
103}
104
105static ssize_t pwm_enable_store(struct device *child,
106 struct device_attribute *attr,
107 const char *buf, size_t size)
108{
109 struct pwm_device *pwm = child_to_pwm_device(child);
110 int val, ret;
111
112 ret = kstrtoint(buf, 0, &val);
113 if (ret)
114 return ret;
115
116 switch (val) {
117 case 0:
118 pwm_disable(pwm);
119 break;
120 case 1:
121 ret = pwm_enable(pwm);
122 break;
123 default:
124 ret = -EINVAL;
125 break;
126 }
127
128 return ret ? : size;
129}
130
131static ssize_t pwm_polarity_show(struct device *child,
132 struct device_attribute *attr,
133 char *buf)
134{
135 const struct pwm_device *pwm = child_to_pwm_device(child);
136
137 return sprintf(buf, "%s\n", pwm->polarity ? "inversed" : "normal");
138}
139
140static ssize_t pwm_polarity_store(struct device *child,
141 struct device_attribute *attr,
142 const char *buf, size_t size)
143{
144 struct pwm_device *pwm = child_to_pwm_device(child);
145 enum pwm_polarity polarity;
146 int ret;
147
148 if (sysfs_streq(buf, "normal"))
149 polarity = PWM_POLARITY_NORMAL;
150 else if (sysfs_streq(buf, "inversed"))
151 polarity = PWM_POLARITY_INVERSED;
152 else
153 return -EINVAL;
154
155 ret = pwm_set_polarity(pwm, polarity);
156
157 return ret ? : size;
158}
159
160static DEVICE_ATTR(period, 0644, pwm_period_show, pwm_period_store);
161static DEVICE_ATTR(duty_cycle, 0644, pwm_duty_cycle_show, pwm_duty_cycle_store);
162static DEVICE_ATTR(enable, 0644, pwm_enable_show, pwm_enable_store);
163static DEVICE_ATTR(polarity, 0644, pwm_polarity_show, pwm_polarity_store);
164
165static 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,
170 NULL
171};
172ATTRIBUTE_GROUPS(pwm);
173
174static void pwm_export_release(struct device *child)
175{
176 struct pwm_export *export = child_to_pwm_export(child);
177
178 kfree(export);
179}
180
181static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
182{
183 struct pwm_export *export;
184 int ret;
185
186 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
187 return -EBUSY;
188
189 export = kzalloc(sizeof(*export), GFP_KERNEL);
190 if (!export) {
191 clear_bit(PWMF_EXPORTED, &pwm->flags);
192 return -ENOMEM;
193 }
194
195 export->pwm = pwm;
196
197 export->child.release = pwm_export_release;
198 export->child.parent = parent;
199 export->child.devt = MKDEV(0, 0);
200 export->child.groups = pwm_groups;
201 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
202
203 ret = device_register(&export->child);
204 if (ret) {
205 clear_bit(PWMF_EXPORTED, &pwm->flags);
206 kfree(export);
207 return ret;
208 }
209
210 return 0;
211}
212
213static int pwm_unexport_match(struct device *child, void *data)
214{
215 return child_to_pwm_device(child) == data;
216}
217
218static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
219{
220 struct device *child;
221
222 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
223 return -ENODEV;
224
225 child = device_find_child(parent, pwm, pwm_unexport_match);
226 if (!child)
227 return -ENODEV;
228
229 /* for device_find_child() */
230 put_device(child);
231 device_unregister(child);
232 pwm_put(pwm);
233
234 return 0;
235}
236
237static ssize_t pwm_export_store(struct device *parent,
238 struct device_attribute *attr,
239 const char *buf, size_t len)
240{
241 struct pwm_chip *chip = dev_get_drvdata(parent);
242 struct pwm_device *pwm;
243 unsigned int hwpwm;
244 int ret;
245
246 ret = kstrtouint(buf, 0, &hwpwm);
247 if (ret < 0)
248 return ret;
249
250 if (hwpwm >= chip->npwm)
251 return -ENODEV;
252
253 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
254 if (IS_ERR(pwm))
255 return PTR_ERR(pwm);
256
257 ret = pwm_export_child(parent, pwm);
258 if (ret < 0)
259 pwm_put(pwm);
260
261 return ret ? : len;
262}
263static DEVICE_ATTR(export, 0200, NULL, pwm_export_store);
264
265static ssize_t pwm_unexport_store(struct device *parent,
266 struct device_attribute *attr,
267 const char *buf, size_t len)
268{
269 struct pwm_chip *chip = dev_get_drvdata(parent);
270 unsigned int hwpwm;
271 int ret;
272
273 ret = kstrtouint(buf, 0, &hwpwm);
274 if (ret < 0)
275 return ret;
276
277 if (hwpwm >= chip->npwm)
278 return -ENODEV;
279
280 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
281
282 return ret ? : len;
283}
284static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store);
285
286static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
287 char *buf)
288{
289 const struct pwm_chip *chip = dev_get_drvdata(parent);
290
291 return sprintf(buf, "%u\n", chip->npwm);
292}
293static DEVICE_ATTR_RO(npwm);
294
295static struct attribute *pwm_chip_attrs[] = {
296 &dev_attr_export.attr,
297 &dev_attr_unexport.attr,
298 &dev_attr_npwm.attr,
299 NULL,
300};
301ATTRIBUTE_GROUPS(pwm_chip);
302
303static struct class pwm_class = {
304 .name = "pwm",
305 .owner = THIS_MODULE,
306 .dev_groups = pwm_chip_groups,
307};
308
309static int pwmchip_sysfs_match(struct device *parent, const void *data)
310{
311 return dev_get_drvdata(parent) == data;
312}
313
314void pwmchip_sysfs_export(struct pwm_chip *chip)
315{
316 struct device *parent;
317
318 /*
319 * If device_create() fails the pwm_chip is still usable by
320 * the kernel its just not exported.
321 */
322 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
323 "pwmchip%d", chip->base);
324 if (IS_ERR(parent)) {
325 dev_warn(chip->dev,
326 "device_create failed for pwm_chip sysfs export\n");
327 }
328}
329
330void pwmchip_sysfs_unexport(struct pwm_chip *chip)
331{
332 struct device *parent;
333
334 parent = class_find_device(&pwm_class, NULL, chip,
335 pwmchip_sysfs_match);
336 if (parent) {
337 /* for class_find_device() */
338 put_device(parent);
339 device_unregister(parent);
340 }
341}
342
343static int __init pwm_sysfs_init(void)
344{
345 return class_register(&pwm_class);
346}
347subsys_initcall(pwm_sysfs_init);