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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/pwm/sysfs.c
2 * A simple sysfs interface for the generic PWM framework
4 * Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
6 * Based on previous work by Lars Poeschel <poeschel@lemonage.de>
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)
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.
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>
28 struct pwm_device
*pwm
;
31 static struct pwm_export
*child_to_pwm_export(struct device
*child
)
33 return container_of(child
, struct pwm_export
, child
);
36 static struct pwm_device
*child_to_pwm_device(struct device
*child
)
38 struct pwm_export
*export
= child_to_pwm_export(child
);
43 static ssize_t
pwm_period_show(struct device
*child
,
44 struct device_attribute
*attr
,
47 const struct pwm_device
*pwm
= child_to_pwm_device(child
);
49 return sprintf(buf
, "%u\n", pwm
->period
);
52 static ssize_t
pwm_period_store(struct device
*child
,
53 struct device_attribute
*attr
,
54 const char *buf
, size_t size
)
56 struct pwm_device
*pwm
= child_to_pwm_device(child
);
60 ret
= kstrtouint(buf
, 0, &val
);
64 ret
= pwm_config(pwm
, pwm
->duty_cycle
, val
);
69 static ssize_t
pwm_duty_cycle_show(struct device
*child
,
70 struct device_attribute
*attr
,
73 const struct pwm_device
*pwm
= child_to_pwm_device(child
);
75 return sprintf(buf
, "%u\n", pwm
->duty_cycle
);
78 static ssize_t
pwm_duty_cycle_store(struct device
*child
,
79 struct device_attribute
*attr
,
80 const char *buf
, size_t size
)
82 struct pwm_device
*pwm
= child_to_pwm_device(child
);
86 ret
= kstrtouint(buf
, 0, &val
);
90 ret
= pwm_config(pwm
, val
, pwm
->period
);
95 static ssize_t
pwm_enable_show(struct device
*child
,
96 struct device_attribute
*attr
,
99 const struct pwm_device
*pwm
= child_to_pwm_device(child
);
100 int enabled
= test_bit(PWMF_ENABLED
, &pwm
->flags
);
102 return sprintf(buf
, "%d\n", enabled
);
105 static ssize_t
pwm_enable_store(struct device
*child
,
106 struct device_attribute
*attr
,
107 const char *buf
, size_t size
)
109 struct pwm_device
*pwm
= child_to_pwm_device(child
);
112 ret
= kstrtoint(buf
, 0, &val
);
121 ret
= pwm_enable(pwm
);
131 static ssize_t
pwm_polarity_show(struct device
*child
,
132 struct device_attribute
*attr
,
135 const struct pwm_device
*pwm
= child_to_pwm_device(child
);
137 return sprintf(buf
, "%s\n", pwm
->polarity
? "inversed" : "normal");
140 static ssize_t
pwm_polarity_store(struct device
*child
,
141 struct device_attribute
*attr
,
142 const char *buf
, size_t size
)
144 struct pwm_device
*pwm
= child_to_pwm_device(child
);
145 enum pwm_polarity polarity
;
148 if (sysfs_streq(buf
, "normal"))
149 polarity
= PWM_POLARITY_NORMAL
;
150 else if (sysfs_streq(buf
, "inversed"))
151 polarity
= PWM_POLARITY_INVERSED
;
155 ret
= pwm_set_polarity(pwm
, polarity
);
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
);
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
,
172 ATTRIBUTE_GROUPS(pwm
);
174 static void pwm_export_release(struct device
*child
)
176 struct pwm_export
*export
= child_to_pwm_export(child
);
181 static int pwm_export_child(struct device
*parent
, struct pwm_device
*pwm
)
183 struct pwm_export
*export
;
186 if (test_and_set_bit(PWMF_EXPORTED
, &pwm
->flags
))
189 export
= kzalloc(sizeof(*export
), GFP_KERNEL
);
191 clear_bit(PWMF_EXPORTED
, &pwm
->flags
);
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
);
203 ret
= device_register(&export
->child
);
205 clear_bit(PWMF_EXPORTED
, &pwm
->flags
);
213 static int pwm_unexport_match(struct device
*child
, void *data
)
215 return child_to_pwm_device(child
) == data
;
218 static int pwm_unexport_child(struct device
*parent
, struct pwm_device
*pwm
)
220 struct device
*child
;
222 if (!test_and_clear_bit(PWMF_EXPORTED
, &pwm
->flags
))
225 child
= device_find_child(parent
, pwm
, pwm_unexport_match
);
229 /* for device_find_child() */
231 device_unregister(child
);
237 static ssize_t
pwm_export_store(struct device
*parent
,
238 struct device_attribute
*attr
,
239 const char *buf
, size_t len
)
241 struct pwm_chip
*chip
= dev_get_drvdata(parent
);
242 struct pwm_device
*pwm
;
246 ret
= kstrtouint(buf
, 0, &hwpwm
);
250 if (hwpwm
>= chip
->npwm
)
253 pwm
= pwm_request_from_chip(chip
, hwpwm
, "sysfs");
257 ret
= pwm_export_child(parent
, pwm
);
263 static DEVICE_ATTR(export
, 0200, NULL
, pwm_export_store
);
265 static ssize_t
pwm_unexport_store(struct device
*parent
,
266 struct device_attribute
*attr
,
267 const char *buf
, size_t len
)
269 struct pwm_chip
*chip
= dev_get_drvdata(parent
);
273 ret
= kstrtouint(buf
, 0, &hwpwm
);
277 if (hwpwm
>= chip
->npwm
)
280 ret
= pwm_unexport_child(parent
, &chip
->pwms
[hwpwm
]);
284 static DEVICE_ATTR(unexport
, 0200, NULL
, pwm_unexport_store
);
286 static ssize_t
npwm_show(struct device
*parent
, struct device_attribute
*attr
,
289 const struct pwm_chip
*chip
= dev_get_drvdata(parent
);
291 return sprintf(buf
, "%u\n", chip
->npwm
);
293 static DEVICE_ATTR_RO(npwm
);
295 static struct attribute
*pwm_chip_attrs
[] = {
296 &dev_attr_export
.attr
,
297 &dev_attr_unexport
.attr
,
301 ATTRIBUTE_GROUPS(pwm_chip
);
303 static struct class pwm_class
= {
305 .owner
= THIS_MODULE
,
306 .dev_groups
= pwm_chip_groups
,
309 static int pwmchip_sysfs_match(struct device
*parent
, const void *data
)
311 return dev_get_drvdata(parent
) == data
;
314 void pwmchip_sysfs_export(struct pwm_chip
*chip
)
316 struct device
*parent
;
319 * If device_create() fails the pwm_chip is still usable by
320 * the kernel its just not exported.
322 parent
= device_create(&pwm_class
, chip
->dev
, MKDEV(0, 0), chip
,
323 "pwmchip%d", chip
->base
);
324 if (IS_ERR(parent
)) {
326 "device_create failed for pwm_chip sysfs export\n");
330 void pwmchip_sysfs_unexport(struct pwm_chip
*chip
)
332 struct device
*parent
;
334 parent
= class_find_device(&pwm_class
, NULL
, chip
,
335 pwmchip_sysfs_match
);
337 /* for class_find_device() */
339 device_unregister(parent
);
343 static int __init
pwm_sysfs_init(void)
345 return class_register(&pwm_class
);
347 subsys_initcall(pwm_sysfs_init
);