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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 sprintf(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_state(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 sprintf(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 unsigned int val;
91 int ret;
92
93 ret = kstrtouint(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_state(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 sprintf(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_state(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 sprintf(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_state(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 sprintf(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 sprintf(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_state(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 state.enabled = export->suspend.enabled;
428 ret = pwm_class_apply_state(export, pwm, &state);
429 if (ret < 0)
430 break;
431 }
432
433 return ret;
434}
435
436static int __maybe_unused pwm_class_suspend(struct device *parent)
437{
438 struct pwm_chip *chip = dev_get_drvdata(parent);
439 unsigned int i;
440 int ret = 0;
441
442 for (i = 0; i < chip->npwm; i++) {
443 struct pwm_device *pwm = &chip->pwms[i];
444 struct pwm_state state;
445 struct pwm_export *export;
446
447 export = pwm_class_get_state(parent, pwm, &state);
448 if (!export)
449 continue;
450
451 export->suspend = state;
452 state.enabled = false;
453 ret = pwm_class_apply_state(export, pwm, &state);
454 if (ret < 0) {
455 /*
456 * roll back the PWM devices that were disabled by
457 * this suspend function.
458 */
459 pwm_class_resume_npwm(parent, i);
460 break;
461 }
462 }
463
464 return ret;
465}
466
467static int __maybe_unused pwm_class_resume(struct device *parent)
468{
469 struct pwm_chip *chip = dev_get_drvdata(parent);
470
471 return pwm_class_resume_npwm(parent, chip->npwm);
472}
473
474static SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
475
476static struct class pwm_class = {
477 .name = "pwm",
478 .owner = THIS_MODULE,
479 .dev_groups = pwm_chip_groups,
480 .pm = &pwm_class_pm_ops,
481};
482
483static int pwmchip_sysfs_match(struct device *parent, const void *data)
484{
485 return dev_get_drvdata(parent) == data;
486}
487
488void pwmchip_sysfs_export(struct pwm_chip *chip)
489{
490 struct device *parent;
491
492 /*
493 * If device_create() fails the pwm_chip is still usable by
494 * the kernel it's just not exported.
495 */
496 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
497 "pwmchip%d", chip->base);
498 if (IS_ERR(parent)) {
499 dev_warn(chip->dev,
500 "device_create failed for pwm_chip sysfs export\n");
501 }
502}
503
504void pwmchip_sysfs_unexport(struct pwm_chip *chip)
505{
506 struct device *parent;
507 unsigned int i;
508
509 parent = class_find_device(&pwm_class, NULL, chip,
510 pwmchip_sysfs_match);
511 if (!parent)
512 return;
513
514 for (i = 0; i < chip->npwm; i++) {
515 struct pwm_device *pwm = &chip->pwms[i];
516
517 if (test_bit(PWMF_EXPORTED, &pwm->flags))
518 pwm_unexport_child(parent, pwm);
519 }
520
521 put_device(parent);
522 device_unregister(parent);
523}
524
525static int __init pwm_sysfs_init(void)
526{
527 return class_register(&pwm_class);
528}
529subsys_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);