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H Hartley Sweeten76abbdde2013-06-11 10:38:59 -07001/*
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;
Boris BREZILLON459a25a2016-03-30 22:03:27 +020029 struct mutex lock;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070030};
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
Olliver Schinagl65cdc692015-10-26 22:32:37 +010044static ssize_t period_show(struct device *child,
45 struct device_attribute *attr,
46 char *buf)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070047{
48 const struct pwm_device *pwm = child_to_pwm_device(child);
Boris Brezillon39100ce2016-04-14 21:17:43 +020049 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070050
Boris Brezillon39100ce2016-04-14 21:17:43 +020051 pwm_get_state(pwm, &state);
52
53 return sprintf(buf, "%u\n", state.period);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070054}
55
Olliver Schinagl65cdc692015-10-26 22:32:37 +010056static ssize_t period_store(struct device *child,
57 struct device_attribute *attr,
58 const char *buf, size_t size)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070059{
Boris BREZILLON459a25a2016-03-30 22:03:27 +020060 struct pwm_export *export = child_to_pwm_export(child);
61 struct pwm_device *pwm = export->pwm;
Boris Brezillon39100ce2016-04-14 21:17:43 +020062 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070063 unsigned int val;
64 int ret;
65
66 ret = kstrtouint(buf, 0, &val);
67 if (ret)
68 return ret;
69
Boris BREZILLON459a25a2016-03-30 22:03:27 +020070 mutex_lock(&export->lock);
Boris Brezillon39100ce2016-04-14 21:17:43 +020071 pwm_get_state(pwm, &state);
72 state.period = val;
73 ret = pwm_apply_state(pwm, &state);
Boris BREZILLON459a25a2016-03-30 22:03:27 +020074 mutex_unlock(&export->lock);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070075
76 return ret ? : size;
77}
78
Olliver Schinagl65cdc692015-10-26 22:32:37 +010079static ssize_t duty_cycle_show(struct device *child,
80 struct device_attribute *attr,
81 char *buf)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070082{
83 const struct pwm_device *pwm = child_to_pwm_device(child);
Boris Brezillon39100ce2016-04-14 21:17:43 +020084 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070085
Boris Brezillon39100ce2016-04-14 21:17:43 +020086 pwm_get_state(pwm, &state);
87
88 return sprintf(buf, "%u\n", state.duty_cycle);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070089}
90
Olliver Schinagl65cdc692015-10-26 22:32:37 +010091static ssize_t duty_cycle_store(struct device *child,
92 struct device_attribute *attr,
93 const char *buf, size_t size)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070094{
Boris BREZILLON459a25a2016-03-30 22:03:27 +020095 struct pwm_export *export = child_to_pwm_export(child);
96 struct pwm_device *pwm = export->pwm;
Boris Brezillon39100ce2016-04-14 21:17:43 +020097 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -070098 unsigned int val;
99 int ret;
100
101 ret = kstrtouint(buf, 0, &val);
102 if (ret)
103 return ret;
104
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200105 mutex_lock(&export->lock);
Boris Brezillon39100ce2016-04-14 21:17:43 +0200106 pwm_get_state(pwm, &state);
107 state.duty_cycle = val;
108 ret = pwm_apply_state(pwm, &state);
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200109 mutex_unlock(&export->lock);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700110
111 return ret ? : size;
112}
113
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100114static ssize_t enable_show(struct device *child,
115 struct device_attribute *attr,
116 char *buf)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700117{
118 const struct pwm_device *pwm = child_to_pwm_device(child);
Boris Brezillon39100ce2016-04-14 21:17:43 +0200119 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700120
Boris Brezillon39100ce2016-04-14 21:17:43 +0200121 pwm_get_state(pwm, &state);
122
123 return sprintf(buf, "%d\n", state.enabled);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700124}
125
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100126static ssize_t enable_store(struct device *child,
127 struct device_attribute *attr,
128 const char *buf, size_t size)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700129{
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200130 struct pwm_export *export = child_to_pwm_export(child);
131 struct pwm_device *pwm = export->pwm;
Boris Brezillon39100ce2016-04-14 21:17:43 +0200132 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700133 int val, ret;
134
135 ret = kstrtoint(buf, 0, &val);
136 if (ret)
137 return ret;
138
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200139 mutex_lock(&export->lock);
140
Boris Brezillon39100ce2016-04-14 21:17:43 +0200141 pwm_get_state(pwm, &state);
142
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700143 switch (val) {
144 case 0:
Boris Brezillon39100ce2016-04-14 21:17:43 +0200145 state.enabled = false;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700146 break;
147 case 1:
Boris Brezillon39100ce2016-04-14 21:17:43 +0200148 state.enabled = true;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700149 break;
150 default:
151 ret = -EINVAL;
Boris Brezillon39100ce2016-04-14 21:17:43 +0200152 goto unlock;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700153 }
154
Boris Brezillon39100ce2016-04-14 21:17:43 +0200155 pwm_apply_state(pwm, &state);
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200156
Boris Brezillon39100ce2016-04-14 21:17:43 +0200157unlock:
158 mutex_unlock(&export->lock);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700159 return ret ? : size;
160}
161
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100162static ssize_t polarity_show(struct device *child,
163 struct device_attribute *attr,
164 char *buf)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700165{
166 const struct pwm_device *pwm = child_to_pwm_device(child);
Thierry Reding5a063d82015-07-20 09:56:05 +0200167 const char *polarity = "unknown";
Boris Brezillon39100ce2016-04-14 21:17:43 +0200168 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700169
Boris Brezillon39100ce2016-04-14 21:17:43 +0200170 pwm_get_state(pwm, &state);
171
172 switch (state.polarity) {
Thierry Reding5a063d82015-07-20 09:56:05 +0200173 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);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700183}
184
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100185static ssize_t polarity_store(struct device *child,
186 struct device_attribute *attr,
187 const char *buf, size_t size)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700188{
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200189 struct pwm_export *export = child_to_pwm_export(child);
190 struct pwm_device *pwm = export->pwm;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700191 enum pwm_polarity polarity;
Boris Brezillon39100ce2016-04-14 21:17:43 +0200192 struct pwm_state state;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700193 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
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200202 mutex_lock(&export->lock);
Boris Brezillon39100ce2016-04-14 21:17:43 +0200203 pwm_get_state(pwm, &state);
204 state.polarity = polarity;
205 ret = pwm_apply_state(pwm, &state);
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200206 mutex_unlock(&export->lock);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700207
208 return ret ? : size;
209}
210
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100211static DEVICE_ATTR_RW(period);
212static DEVICE_ATTR_RW(duty_cycle);
213static DEVICE_ATTR_RW(enable);
214static DEVICE_ATTR_RW(polarity);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700215
216static struct attribute *pwm_attrs[] = {
217 &dev_attr_period.attr,
218 &dev_attr_duty_cycle.attr,
219 &dev_attr_enable.attr,
220 &dev_attr_polarity.attr,
221 NULL
222};
Axel Lin6ca142a2013-12-04 18:29:53 +0800223ATTRIBUTE_GROUPS(pwm);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700224
225static void pwm_export_release(struct device *child)
226{
227 struct pwm_export *export = child_to_pwm_export(child);
228
229 kfree(export);
230}
231
232static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
233{
234 struct pwm_export *export;
235 int ret;
236
237 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
238 return -EBUSY;
239
240 export = kzalloc(sizeof(*export), GFP_KERNEL);
241 if (!export) {
242 clear_bit(PWMF_EXPORTED, &pwm->flags);
243 return -ENOMEM;
244 }
245
246 export->pwm = pwm;
Boris BREZILLON459a25a2016-03-30 22:03:27 +0200247 mutex_init(&export->lock);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700248
249 export->child.release = pwm_export_release;
250 export->child.parent = parent;
251 export->child.devt = MKDEV(0, 0);
Axel Lin6ca142a2013-12-04 18:29:53 +0800252 export->child.groups = pwm_groups;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700253 dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
254
255 ret = device_register(&export->child);
256 if (ret) {
257 clear_bit(PWMF_EXPORTED, &pwm->flags);
258 kfree(export);
259 return ret;
260 }
261
262 return 0;
263}
264
265static int pwm_unexport_match(struct device *child, void *data)
266{
267 return child_to_pwm_device(child) == data;
268}
269
270static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
271{
272 struct device *child;
273
274 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
275 return -ENODEV;
276
277 child = device_find_child(parent, pwm, pwm_unexport_match);
278 if (!child)
279 return -ENODEV;
280
281 /* for device_find_child() */
282 put_device(child);
283 device_unregister(child);
284 pwm_put(pwm);
285
286 return 0;
287}
288
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100289static ssize_t export_store(struct device *parent,
290 struct device_attribute *attr,
291 const char *buf, size_t len)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700292{
293 struct pwm_chip *chip = dev_get_drvdata(parent);
294 struct pwm_device *pwm;
295 unsigned int hwpwm;
296 int ret;
297
298 ret = kstrtouint(buf, 0, &hwpwm);
299 if (ret < 0)
300 return ret;
301
302 if (hwpwm >= chip->npwm)
303 return -ENODEV;
304
305 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
306 if (IS_ERR(pwm))
307 return PTR_ERR(pwm);
308
309 ret = pwm_export_child(parent, pwm);
310 if (ret < 0)
311 pwm_put(pwm);
312
313 return ret ? : len;
314}
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100315static DEVICE_ATTR_WO(export);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700316
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100317static ssize_t unexport_store(struct device *parent,
318 struct device_attribute *attr,
319 const char *buf, size_t len)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700320{
321 struct pwm_chip *chip = dev_get_drvdata(parent);
322 unsigned int hwpwm;
323 int ret;
324
325 ret = kstrtouint(buf, 0, &hwpwm);
326 if (ret < 0)
327 return ret;
328
329 if (hwpwm >= chip->npwm)
330 return -ENODEV;
331
332 ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
333
334 return ret ? : len;
335}
Olliver Schinagl65cdc692015-10-26 22:32:37 +0100336static DEVICE_ATTR_WO(unexport);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700337
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700338static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
339 char *buf)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700340{
341 const struct pwm_chip *chip = dev_get_drvdata(parent);
342
343 return sprintf(buf, "%u\n", chip->npwm);
344}
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700345static DEVICE_ATTR_RO(npwm);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700346
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700347static struct attribute *pwm_chip_attrs[] = {
348 &dev_attr_export.attr,
349 &dev_attr_unexport.attr,
350 &dev_attr_npwm.attr,
351 NULL,
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700352};
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700353ATTRIBUTE_GROUPS(pwm_chip);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700354
355static struct class pwm_class = {
Thierry Reding412820d2015-07-20 09:58:09 +0200356 .name = "pwm",
357 .owner = THIS_MODULE,
358 .dev_groups = pwm_chip_groups,
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700359};
360
361static int pwmchip_sysfs_match(struct device *parent, const void *data)
362{
363 return dev_get_drvdata(parent) == data;
364}
365
366void pwmchip_sysfs_export(struct pwm_chip *chip)
367{
368 struct device *parent;
369
370 /*
371 * If device_create() fails the pwm_chip is still usable by
372 * the kernel its just not exported.
373 */
374 parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip,
375 "pwmchip%d", chip->base);
376 if (IS_ERR(parent)) {
377 dev_warn(chip->dev,
378 "device_create failed for pwm_chip sysfs export\n");
379 }
380}
381
382void pwmchip_sysfs_unexport(struct pwm_chip *chip)
383{
384 struct device *parent;
385
386 parent = class_find_device(&pwm_class, NULL, chip,
387 pwmchip_sysfs_match);
388 if (parent) {
389 /* for class_find_device() */
390 put_device(parent);
391 device_unregister(parent);
392 }
393}
394
395static int __init pwm_sysfs_init(void)
396{
397 return class_register(&pwm_class);
398}
399subsys_initcall(pwm_sysfs_init);