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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};
22
23static struct pwm_export *child_to_pwm_export(struct device *child)
24{
25 return container_of(child, struct pwm_export, child);
26}
27
28static struct pwm_device *child_to_pwm_device(struct device *child)
29{
30 struct pwm_export *export = child_to_pwm_export(child);
31
32 return export->pwm;
33}
34
35static ssize_t period_show(struct device *child,
36 struct device_attribute *attr,
37 char *buf)
38{
39 const struct pwm_device *pwm = child_to_pwm_device(child);
40 struct pwm_state state;
41
42 pwm_get_state(pwm, &state);
43
44 return sprintf(buf, "%u\n", state.period);
45}
46
47static ssize_t period_store(struct device *child,
48 struct device_attribute *attr,
49 const char *buf, size_t size)
50{
51 struct pwm_export *export = child_to_pwm_export(child);
52 struct pwm_device *pwm = export->pwm;
53 struct pwm_state state;
54 unsigned int val;
55 int ret;
56
57 ret = kstrtouint(buf, 0, &val);
58 if (ret)
59 return ret;
60
61 mutex_lock(&export->lock);
62 pwm_get_state(pwm, &state);
63 state.period = val;
64 ret = pwm_apply_state(pwm, &state);
65 mutex_unlock(&export->lock);
66
67 return ret ? : size;
68}
69
70static ssize_t duty_cycle_show(struct device *child,
71 struct device_attribute *attr,
72 char *buf)
73{
74 const struct pwm_device *pwm = child_to_pwm_device(child);
75 struct pwm_state state;
76
77 pwm_get_state(pwm, &state);
78
79 return sprintf(buf, "%u\n", state.duty_cycle);
80}
81
82static ssize_t duty_cycle_store(struct device *child,
83 struct device_attribute *attr,
84 const char *buf, size_t size)
85{
86 struct pwm_export *export = child_to_pwm_export(child);
87 struct pwm_device *pwm = export->pwm;
88 struct pwm_state state;
89 unsigned int val;
90 int ret;
91
92 ret = kstrtouint(buf, 0, &val);
93 if (ret)
94 return ret;
95
96 mutex_lock(&export->lock);
97 pwm_get_state(pwm, &state);
98 state.duty_cycle = val;
99 ret = pwm_apply_state(pwm, &state);
100 mutex_unlock(&export->lock);
101
102 return ret ? : size;
103}
104
105static ssize_t enable_show(struct device *child,
106 struct device_attribute *attr,
107 char *buf)
108{
109 const struct pwm_device *pwm = child_to_pwm_device(child);
110 struct pwm_state state;
111
112 pwm_get_state(pwm, &state);
113
114 return sprintf(buf, "%d\n", state.enabled);
115}
116
117static ssize_t enable_store(struct device *child,
118 struct device_attribute *attr,
119 const char *buf, size_t size)
120{
121 struct pwm_export *export = child_to_pwm_export(child);
122 struct pwm_device *pwm = export->pwm;
123 struct pwm_state state;
124 int val, ret;
125
126 ret = kstrtoint(buf, 0, &val);
127 if (ret)
128 return ret;
129
130 mutex_lock(&export->lock);
131
132 pwm_get_state(pwm, &state);
133
134 switch (val) {
135 case 0:
136 state.enabled = false;
137 break;
138 case 1:
139 state.enabled = true;
140 break;
141 default:
142 ret = -EINVAL;
143 goto unlock;
144 }
145
146 ret = pwm_apply_state(pwm, &state);
147
148unlock:
149 mutex_unlock(&export->lock);
150 return ret ? : size;
151}
152
153static ssize_t polarity_show(struct device *child,
154 struct device_attribute *attr,
155 char *buf)
156{
157 const struct pwm_device *pwm = child_to_pwm_device(child);
158 const char *polarity = "unknown";
159 struct pwm_state state;
160
161 pwm_get_state(pwm, &state);
162
163 switch (state.polarity) {
164 case PWM_POLARITY_NORMAL:
165 polarity = "normal";
166 break;
167
168 case PWM_POLARITY_INVERSED:
169 polarity = "inversed";
170 break;
171 }
172
173 return sprintf(buf, "%s\n", polarity);
174}
175
176static ssize_t polarity_store(struct device *child,
177 struct device_attribute *attr,
178 const char *buf, size_t size)
179{
180 struct pwm_export *export = child_to_pwm_export(child);
181 struct pwm_device *pwm = export->pwm;
182 enum pwm_polarity polarity;
183 struct pwm_state state;
184 int ret;
185
186 if (sysfs_streq(buf, "normal"))
187 polarity = PWM_POLARITY_NORMAL;
188 else if (sysfs_streq(buf, "inversed"))
189 polarity = PWM_POLARITY_INVERSED;
190 else
191 return -EINVAL;
192
193 mutex_lock(&export->lock);
194 pwm_get_state(pwm, &state);
195 state.polarity = polarity;
196 ret = pwm_apply_state(pwm, &state);
197 mutex_unlock(&export->lock);
198
199 return ret ? : size;
200}
201
202static ssize_t capture_show(struct device *child,
203 struct device_attribute *attr,
204 char *buf)
205{
206 struct pwm_device *pwm = child_to_pwm_device(child);
207 struct pwm_capture result;
208 int ret;
209
210 ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
211 if (ret)
212 return ret;
213
214 return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
215}
216
217static DEVICE_ATTR_RW(period);
218static DEVICE_ATTR_RW(duty_cycle);
219static DEVICE_ATTR_RW(enable);
220static DEVICE_ATTR_RW(polarity);
221static DEVICE_ATTR_RO(capture);
222
223static struct attribute *pwm_attrs[] = {
224 &dev_attr_period.attr,
225 &dev_attr_duty_cycle.attr,
226 &dev_attr_enable.attr,
227 &dev_attr_polarity.attr,
228 &dev_attr_capture.attr,
229 NULL
230};
231ATTRIBUTE_GROUPS(pwm);
232
233static void pwm_export_release(struct device *child)
234{
235 struct pwm_export *export = child_to_pwm_export(child);
236
237 kfree(export);
238}
239
240static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
241{
242 struct pwm_export *export;
243 char *pwm_prop[2];
244 int ret;
245
246 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
247 return -EBUSY;
248
249 export = kzalloc(sizeof(*export), GFP_KERNEL);
250 if (!export) {
251 clear_bit(PWMF_EXPORTED, &pwm->flags);
252 return -ENOMEM;
253 }
254
255 export->pwm = pwm;
256 mutex_init(&export->lock);
257
258 export->child.release = pwm_export_release;
259 export->child.parent = parent;
260 export->child.devt = MKDEV(0, 0);
261 export->child.groups = pwm_groups;
262 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
263
264 ret = device_register(&export->child);
265 if (ret) {
266 clear_bit(PWMF_EXPORTED, &pwm->flags);
267 put_device(&export->child);
268 export = NULL;
269 return ret;
270 }
271 pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
272 pwm_prop[1] = NULL;
273 kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
274 kfree(pwm_prop[0]);
275
276 return 0;
277}
278
279static int pwm_unexport_match(struct device *child, void *data)
280{
281 return child_to_pwm_device(child) == data;
282}
283
284static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
285{
286 struct device *child;
287 char *pwm_prop[2];
288
289 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
290 return -ENODEV;
291
292 child = device_find_child(parent, pwm, pwm_unexport_match);
293 if (!child)
294 return -ENODEV;
295
296 pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
297 pwm_prop[1] = NULL;
298 kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
299 kfree(pwm_prop[0]);
300
301
302 put_device(child);
303 device_unregister(child);
304 pwm_put(pwm);
305
306 return 0;
307}
308
309static ssize_t export_store(struct device *parent,
310 struct device_attribute *attr,
311 const char *buf, size_t len)
312{
313 struct pwm_chip *chip = dev_get_drvdata(parent);
314 struct pwm_device *pwm;
315 unsigned int hwpwm;
316 int ret;
317
318 ret = kstrtouint(buf, 0, &hwpwm);
319 if (ret < 0)
320 return ret;
321
322 if (hwpwm >= chip->npwm)
323 return -ENODEV;
324
325 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
326 if (IS_ERR(pwm))
327 return PTR_ERR(pwm);
328
329 ret = pwm_export_child(parent, pwm);
330 if (ret < 0)
331 pwm_put(pwm);
332
333 return ret ? : len;
334}
335static DEVICE_ATTR_WO(export);
336
337static ssize_t unexport_store(struct device *parent,
338 struct device_attribute *attr,
339 const char *buf, size_t len)
340{
341 struct pwm_chip *chip = dev_get_drvdata(parent);
342 unsigned int hwpwm;
343 int ret;
344
345 ret = kstrtouint(buf, 0, &hwpwm);
346 if (ret < 0)
347 return ret;
348
349 if (hwpwm >= chip->npwm)
350 return -ENODEV;
351
352 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
353
354 return ret ? : len;
355}
356static DEVICE_ATTR_WO(unexport);
357
358static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
359 char *buf)
360{
361 const struct pwm_chip *chip = dev_get_drvdata(parent);
362
363 return sprintf(buf, "%u\n", chip->npwm);
364}
365static DEVICE_ATTR_RO(npwm);
366
367static struct attribute *pwm_chip_attrs[] = {
368 &dev_attr_export.attr,
369 &dev_attr_unexport.attr,
370 &dev_attr_npwm.attr,
371 NULL,
372};
373ATTRIBUTE_GROUPS(pwm_chip);
374
375static struct class pwm_class = {
376 .name = "pwm",
377 .owner = THIS_MODULE,
378 .dev_groups = pwm_chip_groups,
379};
380
381static int pwmchip_sysfs_match(struct device *parent, const void *data)
382{
383 return dev_get_drvdata(parent) == data;
384}
385
386void pwmchip_sysfs_export(struct pwm_chip *chip)
387{
388 struct device *parent;
389
390
391
392
393
394 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
395 "pwmchip%d", chip->base);
396 if (IS_ERR(parent)) {
397 dev_warn(chip->dev,
398 "device_create failed for pwm_chip sysfs export\n");
399 }
400}
401
402void pwmchip_sysfs_unexport(struct pwm_chip *chip)
403{
404 struct device *parent;
405 unsigned int i;
406
407 parent = class_find_device(&pwm_class, NULL, chip,
408 pwmchip_sysfs_match);
409 if (!parent)
410 return;
411
412 for (i = 0; i < chip->npwm; i++) {
413 struct pwm_device *pwm = &chip->pwms[i];
414
415 if (test_bit(PWMF_EXPORTED, &pwm->flags))
416 pwm_unexport_child(parent, pwm);
417 }
418
419 put_device(parent);
420 device_unregister(parent);
421}
422
423static int __init pwm_sysfs_init(void)
424{
425 return class_register(&pwm_class);
426}
427subsys_initcall(pwm_sysfs_init);
428
