This source file includes following definitions.
- child_to_pwm_export
- child_to_pwm_device
- period_show
- period_store
- duty_cycle_show
- duty_cycle_store
- enable_show
- enable_store
- polarity_show
- polarity_store
- capture_show
- pwm_export_release
- pwm_export_child
- pwm_unexport_match
- pwm_unexport_child
- export_store
- unexport_store
- npwm_show
- pwm_class_get_state
- pwm_class_apply_state
- pwm_class_resume_npwm
- pwm_class_suspend
- pwm_class_resume
- pwmchip_sysfs_match
- pwmchip_sysfs_export
- pwmchip_sysfs_unexport
- pwm_sysfs_init
1
2
3
4
5
6
7
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
17 struct pwm_export {
18 struct device child;
19 struct pwm_device *pwm;
20 struct mutex lock;
21 struct pwm_state suspend;
22 };
23
24 static struct pwm_export *child_to_pwm_export(struct device *child)
25 {
26 return container_of(child, struct pwm_export, child);
27 }
28
29 static 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
36 static 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, "%u\n", state.period);
46 }
47
48 static 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 unsigned int val;
56 int ret;
57
58 ret = kstrtouint(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
71 static 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, "%u\n", state.duty_cycle);
81 }
82
83 static 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
106 static 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
118 static 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
149 unlock:
150 mutex_unlock(&export->lock);
151 return ret ? : size;
152 }
153
154 static 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
177 static 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
203 static 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
218 static DEVICE_ATTR_RW(period);
219 static DEVICE_ATTR_RW(duty_cycle);
220 static DEVICE_ATTR_RW(enable);
221 static DEVICE_ATTR_RW(polarity);
222 static DEVICE_ATTR_RO(capture);
223
224 static 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 };
232 ATTRIBUTE_GROUPS(pwm);
233
234 static void pwm_export_release(struct device *child)
235 {
236 struct pwm_export *export = child_to_pwm_export(child);
237
238 kfree(export);
239 }
240
241 static 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
280 static int pwm_unexport_match(struct device *child, void *data)
281 {
282 return child_to_pwm_device(child) == data;
283 }
284
285 static 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
303 put_device(child);
304 device_unregister(child);
305 pwm_put(pwm);
306
307 return 0;
308 }
309
310 static 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 }
336 static DEVICE_ATTR_WO(export);
337
338 static 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 }
357 static DEVICE_ATTR_WO(unexport);
358
359 static 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 }
366 static DEVICE_ATTR_RO(npwm);
367
368 static struct attribute *pwm_chip_attrs[] = {
369 &dev_attr_export.attr,
370 &dev_attr_unexport.attr,
371 &dev_attr_npwm.attr,
372 NULL,
373 };
374 ATTRIBUTE_GROUPS(pwm_chip);
375
376
377 static 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);
393
394 mutex_lock(&export->lock);
395 pwm_get_state(pwm, state);
396
397 return export;
398 }
399
400 static 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
407 mutex_unlock(&export->lock);
408
409 return ret;
410 }
411
412 static 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
436 static 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
457
458
459 pwm_class_resume_npwm(parent, i);
460 break;
461 }
462 }
463
464 return ret;
465 }
466
467 static 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
474 static SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
475
476 static 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
483 static int pwmchip_sysfs_match(struct device *parent, const void *data)
484 {
485 return dev_get_drvdata(parent) == data;
486 }
487
488 void pwmchip_sysfs_export(struct pwm_chip *chip)
489 {
490 struct device *parent;
491
492
493
494
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
504 void 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
525 static int __init pwm_sysfs_init(void)
526 {
527 return class_register(&pwm_class);
528 }
529 subsys_initcall(pwm_sysfs_init);