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76abbdde HS |
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 | ||
26 | struct pwm_export { | |
27 | struct device child; | |
28 | struct pwm_device *pwm; | |
29 | }; | |
30 | ||
31 | static struct pwm_export *child_to_pwm_export(struct device *child) | |
32 | { | |
33 | return container_of(child, struct pwm_export, child); | |
34 | } | |
35 | ||
36 | static 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 | ||
43 | static 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 | ||
52 | static 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 | ||
69 | static 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 | ||
78 | static 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 | ||
95 | static 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 | ||
105 | static 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 | ||
131 | static 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 | ||
140 | static 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 | ||
160 | static DEVICE_ATTR(period, 0644, pwm_period_show, pwm_period_store); | |
161 | static DEVICE_ATTR(duty_cycle, 0644, pwm_duty_cycle_show, pwm_duty_cycle_store); | |
162 | static DEVICE_ATTR(enable, 0644, pwm_enable_show, pwm_enable_store); | |
163 | static DEVICE_ATTR(polarity, 0644, pwm_polarity_show, pwm_polarity_store); | |
164 | ||
165 | static 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 | }; | |
172 | ||
173 | static const struct attribute_group pwm_attr_group = { | |
174 | .attrs = pwm_attrs, | |
175 | }; | |
176 | ||
177 | static const struct attribute_group *pwm_attr_groups[] = { | |
178 | &pwm_attr_group, | |
179 | NULL, | |
180 | }; | |
181 | ||
182 | static void pwm_export_release(struct device *child) | |
183 | { | |
184 | struct pwm_export *export = child_to_pwm_export(child); | |
185 | ||
186 | kfree(export); | |
187 | } | |
188 | ||
189 | static int pwm_export_child(struct device *parent, struct pwm_device *pwm) | |
190 | { | |
191 | struct pwm_export *export; | |
192 | int ret; | |
193 | ||
194 | if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags)) | |
195 | return -EBUSY; | |
196 | ||
197 | export = kzalloc(sizeof(*export), GFP_KERNEL); | |
198 | if (!export) { | |
199 | clear_bit(PWMF_EXPORTED, &pwm->flags); | |
200 | return -ENOMEM; | |
201 | } | |
202 | ||
203 | export->pwm = pwm; | |
204 | ||
205 | export->child.release = pwm_export_release; | |
206 | export->child.parent = parent; | |
207 | export->child.devt = MKDEV(0, 0); | |
208 | export->child.groups = pwm_attr_groups; | |
209 | dev_set_name(&export->child, "pwm%u", pwm->hwpwm); | |
210 | ||
211 | ret = device_register(&export->child); | |
212 | if (ret) { | |
213 | clear_bit(PWMF_EXPORTED, &pwm->flags); | |
214 | kfree(export); | |
215 | return ret; | |
216 | } | |
217 | ||
218 | return 0; | |
219 | } | |
220 | ||
221 | static int pwm_unexport_match(struct device *child, void *data) | |
222 | { | |
223 | return child_to_pwm_device(child) == data; | |
224 | } | |
225 | ||
226 | static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm) | |
227 | { | |
228 | struct device *child; | |
229 | ||
230 | if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) | |
231 | return -ENODEV; | |
232 | ||
233 | child = device_find_child(parent, pwm, pwm_unexport_match); | |
234 | if (!child) | |
235 | return -ENODEV; | |
236 | ||
237 | /* for device_find_child() */ | |
238 | put_device(child); | |
239 | device_unregister(child); | |
240 | pwm_put(pwm); | |
241 | ||
242 | return 0; | |
243 | } | |
244 | ||
245 | static ssize_t pwm_export_store(struct device *parent, | |
246 | struct device_attribute *attr, | |
247 | const char *buf, size_t len) | |
248 | { | |
249 | struct pwm_chip *chip = dev_get_drvdata(parent); | |
250 | struct pwm_device *pwm; | |
251 | unsigned int hwpwm; | |
252 | int ret; | |
253 | ||
254 | ret = kstrtouint(buf, 0, &hwpwm); | |
255 | if (ret < 0) | |
256 | return ret; | |
257 | ||
258 | if (hwpwm >= chip->npwm) | |
259 | return -ENODEV; | |
260 | ||
261 | pwm = pwm_request_from_chip(chip, hwpwm, "sysfs"); | |
262 | if (IS_ERR(pwm)) | |
263 | return PTR_ERR(pwm); | |
264 | ||
265 | ret = pwm_export_child(parent, pwm); | |
266 | if (ret < 0) | |
267 | pwm_put(pwm); | |
268 | ||
269 | return ret ? : len; | |
270 | } | |
9da01759 | 271 | static DEVICE_ATTR(export, 0200, NULL, pwm_export_store); |
76abbdde HS |
272 | |
273 | static ssize_t pwm_unexport_store(struct device *parent, | |
274 | struct device_attribute *attr, | |
275 | const char *buf, size_t len) | |
276 | { | |
277 | struct pwm_chip *chip = dev_get_drvdata(parent); | |
278 | unsigned int hwpwm; | |
279 | int ret; | |
280 | ||
281 | ret = kstrtouint(buf, 0, &hwpwm); | |
282 | if (ret < 0) | |
283 | return ret; | |
284 | ||
285 | if (hwpwm >= chip->npwm) | |
286 | return -ENODEV; | |
287 | ||
288 | ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]); | |
289 | ||
290 | return ret ? : len; | |
291 | } | |
9da01759 | 292 | static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store); |
76abbdde | 293 | |
9da01759 GKH |
294 | static ssize_t npwm_show(struct device *parent, struct device_attribute *attr, |
295 | char *buf) | |
76abbdde HS |
296 | { |
297 | const struct pwm_chip *chip = dev_get_drvdata(parent); | |
298 | ||
299 | return sprintf(buf, "%u\n", chip->npwm); | |
300 | } | |
9da01759 | 301 | static DEVICE_ATTR_RO(npwm); |
76abbdde | 302 | |
9da01759 GKH |
303 | static struct attribute *pwm_chip_attrs[] = { |
304 | &dev_attr_export.attr, | |
305 | &dev_attr_unexport.attr, | |
306 | &dev_attr_npwm.attr, | |
307 | NULL, | |
76abbdde | 308 | }; |
9da01759 | 309 | ATTRIBUTE_GROUPS(pwm_chip); |
76abbdde HS |
310 | |
311 | static struct class pwm_class = { | |
312 | .name = "pwm", | |
313 | .owner = THIS_MODULE, | |
9da01759 | 314 | .dev_groups = pwm_chip_groups, |
76abbdde HS |
315 | }; |
316 | ||
317 | static int pwmchip_sysfs_match(struct device *parent, const void *data) | |
318 | { | |
319 | return dev_get_drvdata(parent) == data; | |
320 | } | |
321 | ||
322 | void pwmchip_sysfs_export(struct pwm_chip *chip) | |
323 | { | |
324 | struct device *parent; | |
325 | ||
326 | /* | |
327 | * If device_create() fails the pwm_chip is still usable by | |
328 | * the kernel its just not exported. | |
329 | */ | |
330 | parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip, | |
331 | "pwmchip%d", chip->base); | |
332 | if (IS_ERR(parent)) { | |
333 | dev_warn(chip->dev, | |
334 | "device_create failed for pwm_chip sysfs export\n"); | |
335 | } | |
336 | } | |
337 | ||
338 | void pwmchip_sysfs_unexport(struct pwm_chip *chip) | |
339 | { | |
340 | struct device *parent; | |
341 | ||
342 | parent = class_find_device(&pwm_class, NULL, chip, | |
343 | pwmchip_sysfs_match); | |
344 | if (parent) { | |
345 | /* for class_find_device() */ | |
346 | put_device(parent); | |
347 | device_unregister(parent); | |
348 | } | |
349 | } | |
350 | ||
351 | static int __init pwm_sysfs_init(void) | |
352 | { | |
353 | return class_register(&pwm_class); | |
354 | } | |
355 | subsys_initcall(pwm_sysfs_init); |