blob: 4bd0c639e16da9d49598f637c5473ae37e419def [file] [log] [blame]
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;
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};
Axel Lin6ca142a2013-12-04 18:29:53 +0800172ATTRIBUTE_GROUPS(pwm);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700173
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);
Axel Lin6ca142a2013-12-04 18:29:53 +0800200 export->child.groups = pwm_groups;
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700201 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}
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700263static DEVICE_ATTR(export, 0200, NULL, pwm_export_store);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700264
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}
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700284static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700285
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700286static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
287 char *buf)
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700288{
289 const struct pwm_chip *chip = dev_get_drvdata(parent);
290
291 return sprintf(buf, "%u\n", chip->npwm);
292}
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700293static DEVICE_ATTR_RO(npwm);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700294
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700295static struct attribute *pwm_chip_attrs[] = {
296 &dev_attr_export.attr,
297 &dev_attr_unexport.attr,
298 &dev_attr_npwm.attr,
299 NULL,
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700300};
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700301ATTRIBUTE_GROUPS(pwm_chip);
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700302
303static struct class pwm_class = {
304 .name = "pwm",
305 .owner = THIS_MODULE,
Greg Kroah-Hartman9da01752013-07-24 15:05:39 -0700306 .dev_groups = pwm_chip_groups,
H Hartley Sweeten76abbdde2013-06-11 10:38:59 -0700307};
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);