source: src/linux/universal/linux-3.18/drivers/pwm/sysfs.c @ 31869

Last change on this file since 31869 was 31869, checked in by brainslayer, 3 months ago

update

File size: 8.1 KB
Line 
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
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};
172ATTRIBUTE_GROUPS(pwm);
173
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);
200        export->child.groups = pwm_groups;
201        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}
263static DEVICE_ATTR(export, 0200, NULL, pwm_export_store);
264
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}
284static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store);
285
286static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
287                         char *buf)
288{
289        const struct pwm_chip *chip = dev_get_drvdata(parent);
290
291        return sprintf(buf, "%u\n", chip->npwm);
292}
293static DEVICE_ATTR_RO(npwm);
294
295static struct attribute *pwm_chip_attrs[] = {
296        &dev_attr_export.attr,
297        &dev_attr_unexport.attr,
298        &dev_attr_npwm.attr,
299        NULL,
300};
301ATTRIBUTE_GROUPS(pwm_chip);
302
303static struct class pwm_class = {
304        .name           = "pwm",
305        .owner          = THIS_MODULE,
306        .dev_groups     = pwm_chip_groups,
307};
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
343void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
344{
345        struct device *parent;
346        unsigned int i;
347
348        parent = class_find_device(&pwm_class, NULL, chip,
349                                   pwmchip_sysfs_match);
350        if (!parent)
351                return;
352
353        for (i = 0; i < chip->npwm; i++) {
354                struct pwm_device *pwm = &chip->pwms[i];
355
356                if (test_bit(PWMF_EXPORTED, &pwm->flags))
357                        pwm_unexport_child(parent, pwm);
358        }
359}
360
361static int __init pwm_sysfs_init(void)
362{
363        return class_register(&pwm_class);
364}
365subsys_initcall(pwm_sysfs_init);
Note: See TracBrowser for help on using the repository browser.