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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 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.class = parent->class;
267 export->child.release = pwm_export_release;
268 export->child.parent = parent;
269 export->child.devt = MKDEV(0, 0);
270 export->child.groups = pwm_groups;
271 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
272
273 ret = device_register(&export->child);
274 if (ret) {
275 clear_bit(PWMF_EXPORTED, &pwm->flags);
276 put_device(&export->child);
277 export = NULL;
278 return ret;
279 }
280
281 return 0;
282}
283
284static int pwm_unexport_match(struct device *child, void *data)
285{
286 return child_to_pwm_device(child) == data;
287}
288
289static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
290{
291 struct device *child;
292
293 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
294 return -ENODEV;
295
296 child = device_find_child(parent, pwm, pwm_unexport_match);
297 if (!child)
298 return -ENODEV;
299
300 /* for device_find_child() */
301 put_device(child);
302 device_unregister(child);
303 pwm_put(pwm);
304
305 return 0;
306}
307
308static ssize_t export_store(struct device *parent,
309 struct device_attribute *attr,
310 const char *buf, size_t len)
311{
312 struct pwm_chip *chip = dev_get_drvdata(parent);
313 struct pwm_device *pwm;
314 unsigned int hwpwm;
315 int ret;
316
317 ret = kstrtouint(buf, 0, &hwpwm);
318 if (ret < 0)
319 return ret;
320
321 if (hwpwm >= chip->npwm)
322 return -ENODEV;
323
324 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
325 if (IS_ERR(pwm))
326 return PTR_ERR(pwm);
327
328 ret = pwm_export_child(parent, pwm);
329 if (ret < 0)
330 pwm_put(pwm);
331
332 return ret ? : len;
333}
334static DEVICE_ATTR_WO(export);
335
336static ssize_t unexport_store(struct device *parent,
337 struct device_attribute *attr,
338 const char *buf, size_t len)
339{
340 struct pwm_chip *chip = dev_get_drvdata(parent);
341 unsigned int hwpwm;
342 int ret;
343
344 ret = kstrtouint(buf, 0, &hwpwm);
345 if (ret < 0)
346 return ret;
347
348 if (hwpwm >= chip->npwm)
349 return -ENODEV;
350
351 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
352
353 return ret ? : len;
354}
355static DEVICE_ATTR_WO(unexport);
356
357static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
358 char *buf)
359{
360 const struct pwm_chip *chip = dev_get_drvdata(parent);
361
362 return sprintf(buf, "%u\n", chip->npwm);
363}
364static DEVICE_ATTR_RO(npwm);
365
366static struct attribute *pwm_chip_attrs[] = {
367 &dev_attr_export.attr,
368 &dev_attr_unexport.attr,
369 &dev_attr_npwm.attr,
370 NULL,
371};
372ATTRIBUTE_GROUPS(pwm_chip);
373
374static struct class pwm_class = {
375 .name = "pwm",
376 .owner = THIS_MODULE,
377 .dev_groups = pwm_chip_groups,
378};
379
380static int pwmchip_sysfs_match(struct device *parent, const void *data)
381{
382 return dev_get_drvdata(parent) == data;
383}
384
385void pwmchip_sysfs_export(struct pwm_chip *chip)
386{
387 struct device *parent;
388
389 /*
390 * If device_create() fails the pwm_chip is still usable by
391 * the kernel its just not exported.
392 */
393 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
394 "pwmchip%d", chip->base);
395 if (IS_ERR(parent)) {
396 dev_warn(chip->dev,
397 "device_create failed for pwm_chip sysfs export\n");
398 }
399}
400
401void pwmchip_sysfs_unexport(struct pwm_chip *chip)
402{
403 struct device *parent;
404
405 parent = class_find_device(&pwm_class, NULL, chip,
406 pwmchip_sysfs_match);
407 if (parent) {
408 /* for class_find_device() */
409 put_device(parent);
410 device_unregister(parent);
411 }
412}
413
414void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
415{
416 struct device *parent;
417 unsigned int i;
418
419 parent = class_find_device(&pwm_class, NULL, chip,
420 pwmchip_sysfs_match);
421 if (!parent)
422 return;
423
424 for (i = 0; i < chip->npwm; i++) {
425 struct pwm_device *pwm = &chip->pwms[i];
426
427 if (test_bit(PWMF_EXPORTED, &pwm->flags))
428 pwm_unexport_child(parent, pwm);
429 }
430
431 put_device(parent);
432}
433
434static int __init pwm_sysfs_init(void)
435{
436 return class_register(&pwm_class);
437}
438subsys_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);