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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 | ||
65cdc691 OS |
43 | static ssize_t period_show(struct device *child, |
44 | struct device_attribute *attr, | |
45 | char *buf) | |
76abbdde HS |
46 | { |
47 | const struct pwm_device *pwm = child_to_pwm_device(child); | |
48 | ||
15da7b50 | 49 | return sprintf(buf, "%u\n", pwm_get_period(pwm)); |
76abbdde HS |
50 | } |
51 | ||
65cdc691 OS |
52 | static ssize_t period_store(struct device *child, |
53 | struct device_attribute *attr, | |
54 | const char *buf, size_t size) | |
76abbdde HS |
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 | ||
15da7b50 | 64 | ret = pwm_config(pwm, pwm_get_duty_cycle(pwm), val); |
76abbdde HS |
65 | |
66 | return ret ? : size; | |
67 | } | |
68 | ||
65cdc691 OS |
69 | static ssize_t duty_cycle_show(struct device *child, |
70 | struct device_attribute *attr, | |
71 | char *buf) | |
76abbdde HS |
72 | { |
73 | const struct pwm_device *pwm = child_to_pwm_device(child); | |
74 | ||
15da7b50 | 75 | return sprintf(buf, "%u\n", pwm_get_duty_cycle(pwm)); |
76abbdde HS |
76 | } |
77 | ||
65cdc691 OS |
78 | static ssize_t duty_cycle_store(struct device *child, |
79 | struct device_attribute *attr, | |
80 | const char *buf, size_t size) | |
76abbdde HS |
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 | ||
15da7b50 | 90 | ret = pwm_config(pwm, val, pwm_get_period(pwm)); |
76abbdde HS |
91 | |
92 | return ret ? : size; | |
93 | } | |
94 | ||
65cdc691 OS |
95 | static ssize_t enable_show(struct device *child, |
96 | struct device_attribute *attr, | |
97 | char *buf) | |
76abbdde HS |
98 | { |
99 | const struct pwm_device *pwm = child_to_pwm_device(child); | |
76abbdde | 100 | |
0344d0d6 | 101 | return sprintf(buf, "%d\n", pwm_is_enabled(pwm)); |
76abbdde HS |
102 | } |
103 | ||
65cdc691 OS |
104 | static ssize_t enable_store(struct device *child, |
105 | struct device_attribute *attr, | |
106 | const char *buf, size_t size) | |
76abbdde HS |
107 | { |
108 | struct pwm_device *pwm = child_to_pwm_device(child); | |
109 | int val, ret; | |
110 | ||
111 | ret = kstrtoint(buf, 0, &val); | |
112 | if (ret) | |
113 | return ret; | |
114 | ||
115 | switch (val) { | |
116 | case 0: | |
117 | pwm_disable(pwm); | |
118 | break; | |
119 | case 1: | |
120 | ret = pwm_enable(pwm); | |
121 | break; | |
122 | default: | |
123 | ret = -EINVAL; | |
124 | break; | |
125 | } | |
126 | ||
127 | return ret ? : size; | |
128 | } | |
129 | ||
65cdc691 OS |
130 | static ssize_t polarity_show(struct device *child, |
131 | struct device_attribute *attr, | |
132 | char *buf) | |
76abbdde HS |
133 | { |
134 | const struct pwm_device *pwm = child_to_pwm_device(child); | |
5a063d87 | 135 | const char *polarity = "unknown"; |
76abbdde | 136 | |
5a063d87 TR |
137 | switch (pwm_get_polarity(pwm)) { |
138 | case PWM_POLARITY_NORMAL: | |
139 | polarity = "normal"; | |
140 | break; | |
141 | ||
142 | case PWM_POLARITY_INVERSED: | |
143 | polarity = "inversed"; | |
144 | break; | |
145 | } | |
146 | ||
147 | return sprintf(buf, "%s\n", polarity); | |
76abbdde HS |
148 | } |
149 | ||
65cdc691 OS |
150 | static ssize_t polarity_store(struct device *child, |
151 | struct device_attribute *attr, | |
152 | const char *buf, size_t size) | |
76abbdde HS |
153 | { |
154 | struct pwm_device *pwm = child_to_pwm_device(child); | |
155 | enum pwm_polarity polarity; | |
156 | int ret; | |
157 | ||
158 | if (sysfs_streq(buf, "normal")) | |
159 | polarity = PWM_POLARITY_NORMAL; | |
160 | else if (sysfs_streq(buf, "inversed")) | |
161 | polarity = PWM_POLARITY_INVERSED; | |
162 | else | |
163 | return -EINVAL; | |
164 | ||
165 | ret = pwm_set_polarity(pwm, polarity); | |
166 | ||
167 | return ret ? : size; | |
168 | } | |
169 | ||
65cdc691 OS |
170 | static DEVICE_ATTR_RW(period); |
171 | static DEVICE_ATTR_RW(duty_cycle); | |
172 | static DEVICE_ATTR_RW(enable); | |
173 | static DEVICE_ATTR_RW(polarity); | |
76abbdde HS |
174 | |
175 | static struct attribute *pwm_attrs[] = { | |
176 | &dev_attr_period.attr, | |
177 | &dev_attr_duty_cycle.attr, | |
178 | &dev_attr_enable.attr, | |
179 | &dev_attr_polarity.attr, | |
180 | NULL | |
181 | }; | |
6ca142ad | 182 | ATTRIBUTE_GROUPS(pwm); |
76abbdde HS |
183 | |
184 | static void pwm_export_release(struct device *child) | |
185 | { | |
186 | struct pwm_export *export = child_to_pwm_export(child); | |
187 | ||
188 | kfree(export); | |
189 | } | |
190 | ||
191 | static int pwm_export_child(struct device *parent, struct pwm_device *pwm) | |
192 | { | |
193 | struct pwm_export *export; | |
194 | int ret; | |
195 | ||
196 | if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags)) | |
197 | return -EBUSY; | |
198 | ||
199 | export = kzalloc(sizeof(*export), GFP_KERNEL); | |
200 | if (!export) { | |
201 | clear_bit(PWMF_EXPORTED, &pwm->flags); | |
202 | return -ENOMEM; | |
203 | } | |
204 | ||
205 | export->pwm = pwm; | |
206 | ||
207 | export->child.release = pwm_export_release; | |
208 | export->child.parent = parent; | |
209 | export->child.devt = MKDEV(0, 0); | |
6ca142ad | 210 | export->child.groups = pwm_groups; |
76abbdde HS |
211 | dev_set_name(&export->child, "pwm%u", pwm->hwpwm); |
212 | ||
213 | ret = device_register(&export->child); | |
214 | if (ret) { | |
215 | clear_bit(PWMF_EXPORTED, &pwm->flags); | |
216 | kfree(export); | |
217 | return ret; | |
218 | } | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
223 | static int pwm_unexport_match(struct device *child, void *data) | |
224 | { | |
225 | return child_to_pwm_device(child) == data; | |
226 | } | |
227 | ||
228 | static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm) | |
229 | { | |
230 | struct device *child; | |
231 | ||
232 | if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) | |
233 | return -ENODEV; | |
234 | ||
235 | child = device_find_child(parent, pwm, pwm_unexport_match); | |
236 | if (!child) | |
237 | return -ENODEV; | |
238 | ||
239 | /* for device_find_child() */ | |
240 | put_device(child); | |
241 | device_unregister(child); | |
242 | pwm_put(pwm); | |
243 | ||
244 | return 0; | |
245 | } | |
246 | ||
65cdc691 OS |
247 | static ssize_t export_store(struct device *parent, |
248 | struct device_attribute *attr, | |
249 | const char *buf, size_t len) | |
76abbdde HS |
250 | { |
251 | struct pwm_chip *chip = dev_get_drvdata(parent); | |
252 | struct pwm_device *pwm; | |
253 | unsigned int hwpwm; | |
254 | int ret; | |
255 | ||
256 | ret = kstrtouint(buf, 0, &hwpwm); | |
257 | if (ret < 0) | |
258 | return ret; | |
259 | ||
260 | if (hwpwm >= chip->npwm) | |
261 | return -ENODEV; | |
262 | ||
263 | pwm = pwm_request_from_chip(chip, hwpwm, "sysfs"); | |
264 | if (IS_ERR(pwm)) | |
265 | return PTR_ERR(pwm); | |
266 | ||
267 | ret = pwm_export_child(parent, pwm); | |
268 | if (ret < 0) | |
269 | pwm_put(pwm); | |
270 | ||
271 | return ret ? : len; | |
272 | } | |
65cdc691 | 273 | static DEVICE_ATTR_WO(export); |
76abbdde | 274 | |
65cdc691 OS |
275 | static ssize_t unexport_store(struct device *parent, |
276 | struct device_attribute *attr, | |
277 | const char *buf, size_t len) | |
76abbdde HS |
278 | { |
279 | struct pwm_chip *chip = dev_get_drvdata(parent); | |
280 | unsigned int hwpwm; | |
281 | int ret; | |
282 | ||
283 | ret = kstrtouint(buf, 0, &hwpwm); | |
284 | if (ret < 0) | |
285 | return ret; | |
286 | ||
287 | if (hwpwm >= chip->npwm) | |
288 | return -ENODEV; | |
289 | ||
290 | ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]); | |
291 | ||
292 | return ret ? : len; | |
293 | } | |
65cdc691 | 294 | static DEVICE_ATTR_WO(unexport); |
76abbdde | 295 | |
9da01759 GKH |
296 | static ssize_t npwm_show(struct device *parent, struct device_attribute *attr, |
297 | char *buf) | |
76abbdde HS |
298 | { |
299 | const struct pwm_chip *chip = dev_get_drvdata(parent); | |
300 | ||
301 | return sprintf(buf, "%u\n", chip->npwm); | |
302 | } | |
9da01759 | 303 | static DEVICE_ATTR_RO(npwm); |
76abbdde | 304 | |
9da01759 GKH |
305 | static struct attribute *pwm_chip_attrs[] = { |
306 | &dev_attr_export.attr, | |
307 | &dev_attr_unexport.attr, | |
308 | &dev_attr_npwm.attr, | |
309 | NULL, | |
76abbdde | 310 | }; |
9da01759 | 311 | ATTRIBUTE_GROUPS(pwm_chip); |
76abbdde HS |
312 | |
313 | static struct class pwm_class = { | |
412820dd TR |
314 | .name = "pwm", |
315 | .owner = THIS_MODULE, | |
316 | .dev_groups = pwm_chip_groups, | |
76abbdde HS |
317 | }; |
318 | ||
319 | static int pwmchip_sysfs_match(struct device *parent, const void *data) | |
320 | { | |
321 | return dev_get_drvdata(parent) == data; | |
322 | } | |
323 | ||
324 | void pwmchip_sysfs_export(struct pwm_chip *chip) | |
325 | { | |
326 | struct device *parent; | |
327 | ||
328 | /* | |
329 | * If device_create() fails the pwm_chip is still usable by | |
330 | * the kernel its just not exported. | |
331 | */ | |
332 | parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip, | |
333 | "pwmchip%d", chip->base); | |
334 | if (IS_ERR(parent)) { | |
335 | dev_warn(chip->dev, | |
336 | "device_create failed for pwm_chip sysfs export\n"); | |
337 | } | |
338 | } | |
339 | ||
340 | void pwmchip_sysfs_unexport(struct pwm_chip *chip) | |
341 | { | |
342 | struct device *parent; | |
343 | ||
344 | parent = class_find_device(&pwm_class, NULL, chip, | |
345 | pwmchip_sysfs_match); | |
346 | if (parent) { | |
347 | /* for class_find_device() */ | |
348 | put_device(parent); | |
349 | device_unregister(parent); | |
350 | } | |
351 | } | |
352 | ||
353 | static int __init pwm_sysfs_init(void) | |
354 | { | |
355 | return class_register(&pwm_class); | |
356 | } | |
357 | subsys_initcall(pwm_sysfs_init); |