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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 | ||
15da7b50 | 49 | return sprintf(buf, "%u\n", pwm_get_period(pwm)); |
76abbdde HS |
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 | ||
15da7b50 | 64 | ret = pwm_config(pwm, pwm_get_duty_cycle(pwm), val); |
76abbdde HS |
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 | ||
15da7b50 | 75 | return sprintf(buf, "%u\n", pwm_get_duty_cycle(pwm)); |
76abbdde HS |
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 | ||
15da7b50 | 90 | ret = pwm_config(pwm, val, pwm_get_period(pwm)); |
76abbdde HS |
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); | |
5c31252c | 100 | int enabled = pwm_is_enabled(pwm); |
76abbdde HS |
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); | |
5a063d87 | 136 | const char *polarity = "unknown"; |
76abbdde | 137 | |
5a063d87 TR |
138 | switch (pwm_get_polarity(pwm)) { |
139 | case PWM_POLARITY_NORMAL: | |
140 | polarity = "normal"; | |
141 | break; | |
142 | ||
143 | case PWM_POLARITY_INVERSED: | |
144 | polarity = "inversed"; | |
145 | break; | |
146 | } | |
147 | ||
148 | return sprintf(buf, "%s\n", polarity); | |
76abbdde HS |
149 | } |
150 | ||
151 | static ssize_t pwm_polarity_store(struct device *child, | |
152 | struct device_attribute *attr, | |
153 | const char *buf, size_t size) | |
154 | { | |
155 | struct pwm_device *pwm = child_to_pwm_device(child); | |
156 | enum pwm_polarity polarity; | |
157 | int ret; | |
158 | ||
159 | if (sysfs_streq(buf, "normal")) | |
160 | polarity = PWM_POLARITY_NORMAL; | |
161 | else if (sysfs_streq(buf, "inversed")) | |
162 | polarity = PWM_POLARITY_INVERSED; | |
163 | else | |
164 | return -EINVAL; | |
165 | ||
166 | ret = pwm_set_polarity(pwm, polarity); | |
167 | ||
168 | return ret ? : size; | |
169 | } | |
170 | ||
171 | static DEVICE_ATTR(period, 0644, pwm_period_show, pwm_period_store); | |
172 | static DEVICE_ATTR(duty_cycle, 0644, pwm_duty_cycle_show, pwm_duty_cycle_store); | |
173 | static DEVICE_ATTR(enable, 0644, pwm_enable_show, pwm_enable_store); | |
174 | static DEVICE_ATTR(polarity, 0644, pwm_polarity_show, pwm_polarity_store); | |
175 | ||
176 | static struct attribute *pwm_attrs[] = { | |
177 | &dev_attr_period.attr, | |
178 | &dev_attr_duty_cycle.attr, | |
179 | &dev_attr_enable.attr, | |
180 | &dev_attr_polarity.attr, | |
181 | NULL | |
182 | }; | |
6ca142ad | 183 | ATTRIBUTE_GROUPS(pwm); |
76abbdde HS |
184 | |
185 | static void pwm_export_release(struct device *child) | |
186 | { | |
187 | struct pwm_export *export = child_to_pwm_export(child); | |
188 | ||
189 | kfree(export); | |
190 | } | |
191 | ||
192 | static int pwm_export_child(struct device *parent, struct pwm_device *pwm) | |
193 | { | |
194 | struct pwm_export *export; | |
195 | int ret; | |
196 | ||
197 | if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags)) | |
198 | return -EBUSY; | |
199 | ||
200 | export = kzalloc(sizeof(*export), GFP_KERNEL); | |
201 | if (!export) { | |
202 | clear_bit(PWMF_EXPORTED, &pwm->flags); | |
203 | return -ENOMEM; | |
204 | } | |
205 | ||
206 | export->pwm = pwm; | |
207 | ||
208 | export->child.release = pwm_export_release; | |
209 | export->child.parent = parent; | |
210 | export->child.devt = MKDEV(0, 0); | |
6ca142ad | 211 | export->child.groups = pwm_groups; |
76abbdde HS |
212 | dev_set_name(&export->child, "pwm%u", pwm->hwpwm); |
213 | ||
214 | ret = device_register(&export->child); | |
215 | if (ret) { | |
216 | clear_bit(PWMF_EXPORTED, &pwm->flags); | |
217 | kfree(export); | |
218 | return ret; | |
219 | } | |
220 | ||
221 | return 0; | |
222 | } | |
223 | ||
224 | static int pwm_unexport_match(struct device *child, void *data) | |
225 | { | |
226 | return child_to_pwm_device(child) == data; | |
227 | } | |
228 | ||
229 | static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm) | |
230 | { | |
231 | struct device *child; | |
232 | ||
233 | if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) | |
234 | return -ENODEV; | |
235 | ||
236 | child = device_find_child(parent, pwm, pwm_unexport_match); | |
237 | if (!child) | |
238 | return -ENODEV; | |
239 | ||
240 | /* for device_find_child() */ | |
241 | put_device(child); | |
242 | device_unregister(child); | |
243 | pwm_put(pwm); | |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
248 | static ssize_t pwm_export_store(struct device *parent, | |
249 | struct device_attribute *attr, | |
250 | const char *buf, size_t len) | |
251 | { | |
252 | struct pwm_chip *chip = dev_get_drvdata(parent); | |
253 | struct pwm_device *pwm; | |
254 | unsigned int hwpwm; | |
255 | int ret; | |
256 | ||
257 | ret = kstrtouint(buf, 0, &hwpwm); | |
258 | if (ret < 0) | |
259 | return ret; | |
260 | ||
261 | if (hwpwm >= chip->npwm) | |
262 | return -ENODEV; | |
263 | ||
264 | pwm = pwm_request_from_chip(chip, hwpwm, "sysfs"); | |
265 | if (IS_ERR(pwm)) | |
266 | return PTR_ERR(pwm); | |
267 | ||
268 | ret = pwm_export_child(parent, pwm); | |
269 | if (ret < 0) | |
270 | pwm_put(pwm); | |
271 | ||
272 | return ret ? : len; | |
273 | } | |
9da01759 | 274 | static DEVICE_ATTR(export, 0200, NULL, pwm_export_store); |
76abbdde HS |
275 | |
276 | static ssize_t pwm_unexport_store(struct device *parent, | |
277 | struct device_attribute *attr, | |
278 | const char *buf, size_t len) | |
279 | { | |
280 | struct pwm_chip *chip = dev_get_drvdata(parent); | |
281 | unsigned int hwpwm; | |
282 | int ret; | |
283 | ||
284 | ret = kstrtouint(buf, 0, &hwpwm); | |
285 | if (ret < 0) | |
286 | return ret; | |
287 | ||
288 | if (hwpwm >= chip->npwm) | |
289 | return -ENODEV; | |
290 | ||
291 | ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]); | |
292 | ||
293 | return ret ? : len; | |
294 | } | |
9da01759 | 295 | static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store); |
76abbdde | 296 | |
9da01759 GKH |
297 | static ssize_t npwm_show(struct device *parent, struct device_attribute *attr, |
298 | char *buf) | |
76abbdde HS |
299 | { |
300 | const struct pwm_chip *chip = dev_get_drvdata(parent); | |
301 | ||
302 | return sprintf(buf, "%u\n", chip->npwm); | |
303 | } | |
9da01759 | 304 | static DEVICE_ATTR_RO(npwm); |
76abbdde | 305 | |
9da01759 GKH |
306 | static struct attribute *pwm_chip_attrs[] = { |
307 | &dev_attr_export.attr, | |
308 | &dev_attr_unexport.attr, | |
309 | &dev_attr_npwm.attr, | |
310 | NULL, | |
76abbdde | 311 | }; |
9da01759 | 312 | ATTRIBUTE_GROUPS(pwm_chip); |
76abbdde HS |
313 | |
314 | static struct class pwm_class = { | |
412820dd TR |
315 | .name = "pwm", |
316 | .owner = THIS_MODULE, | |
317 | .dev_groups = pwm_chip_groups, | |
76abbdde HS |
318 | }; |
319 | ||
320 | static int pwmchip_sysfs_match(struct device *parent, const void *data) | |
321 | { | |
322 | return dev_get_drvdata(parent) == data; | |
323 | } | |
324 | ||
325 | void pwmchip_sysfs_export(struct pwm_chip *chip) | |
326 | { | |
327 | struct device *parent; | |
328 | ||
329 | /* | |
330 | * If device_create() fails the pwm_chip is still usable by | |
331 | * the kernel its just not exported. | |
332 | */ | |
333 | parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip, | |
334 | "pwmchip%d", chip->base); | |
335 | if (IS_ERR(parent)) { | |
336 | dev_warn(chip->dev, | |
337 | "device_create failed for pwm_chip sysfs export\n"); | |
338 | } | |
339 | } | |
340 | ||
341 | void pwmchip_sysfs_unexport(struct pwm_chip *chip) | |
342 | { | |
343 | struct device *parent; | |
344 | ||
345 | parent = class_find_device(&pwm_class, NULL, chip, | |
346 | pwmchip_sysfs_match); | |
347 | if (parent) { | |
348 | /* for class_find_device() */ | |
349 | put_device(parent); | |
350 | device_unregister(parent); | |
351 | } | |
352 | } | |
353 | ||
354 | static int __init pwm_sysfs_init(void) | |
355 | { | |
356 | return class_register(&pwm_class); | |
357 | } | |
358 | subsys_initcall(pwm_sysfs_init); |