blob: 405dfcaadc4cf688d9cb8c4277f561031fe67f0f [file] [log] [blame]
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +09001#include <linux/idr.h>
2#include <linux/mutex.h>
3#include <linux/device.h>
4#include <linux/sysfs.h>
5#include <linux/gpio/consumer.h>
6#include <linux/gpio/driver.h>
7#include <linux/interrupt.h>
8#include <linux/kdev_t.h>
Johan Hovoldc43960f2015-05-04 17:10:37 +02009#include <linux/slab.h>
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090010
11#include "gpiolib.h"
12
Johan Hovoldcef17172015-05-04 17:10:48 +020013#define GPIO_IRQF_TRIGGER_FALLING BIT(0)
14#define GPIO_IRQF_TRIGGER_RISING BIT(1)
15#define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \
16 GPIO_IRQF_TRIGGER_RISING)
17
Johan Hovoldc43960f2015-05-04 17:10:37 +020018struct gpiod_data {
19 struct gpio_desc *desc;
Johan Hovold6ffcb792015-05-04 17:10:44 +020020
21 struct mutex mutex;
Johan Hovolda08f5c22015-05-04 17:10:39 +020022 struct kernfs_node *value_kn;
Johan Hovold2ec74a92015-05-04 17:10:41 +020023 int irq;
Johan Hovoldcef17172015-05-04 17:10:48 +020024 unsigned char irq_flags;
Johan Hovold427fdee2015-05-04 17:10:47 +020025
26 bool direction_can_change;
Johan Hovoldc43960f2015-05-04 17:10:37 +020027};
28
Johan Hovold6ffcb792015-05-04 17:10:44 +020029/*
30 * Lock to serialise gpiod export and unexport, and prevent re-export of
31 * gpiod whose chip is being unregistered.
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090032 */
33static DEFINE_MUTEX(sysfs_lock);
34
35/*
36 * /sys/class/gpio/gpioN... only for GPIOs that are exported
37 * /direction
38 * * MAY BE OMITTED if kernel won't allow direction changes
39 * * is read/write as "in" or "out"
40 * * may also be written as "high" or "low", initializing
41 * output value as specified ("out" implies "low")
42 * /value
43 * * always readable, subject to hardware behavior
44 * * may be writable, as zero/nonzero
45 * /edge
46 * * configures behavior of poll(2) on /value
47 * * available only if pin can generate IRQs on input
48 * * is read/write as "none", "falling", "rising", or "both"
49 * /active_low
50 * * configures polarity of /value
51 * * is read/write as zero/nonzero
52 * * also affects existing and subsequent "falling" and "rising"
53 * /edge configuration
54 */
55
Johan Hovold6beac9d2015-05-04 17:10:34 +020056static ssize_t direction_show(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090057 struct device_attribute *attr, char *buf)
58{
Johan Hovoldc43960f2015-05-04 17:10:37 +020059 struct gpiod_data *data = dev_get_drvdata(dev);
60 struct gpio_desc *desc = data->desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090061 ssize_t status;
62
Johan Hovold6ffcb792015-05-04 17:10:44 +020063 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090064
Johan Hovoldf0b78662015-05-04 17:10:36 +020065 gpiod_get_direction(desc);
66 status = sprintf(buf, "%s\n",
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090067 test_bit(FLAG_IS_OUT, &desc->flags)
68 ? "out" : "in");
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090069
Johan Hovold6ffcb792015-05-04 17:10:44 +020070 mutex_unlock(&data->mutex);
71
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090072 return status;
73}
74
Johan Hovold6beac9d2015-05-04 17:10:34 +020075static ssize_t direction_store(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090076 struct device_attribute *attr, const char *buf, size_t size)
77{
Johan Hovoldc43960f2015-05-04 17:10:37 +020078 struct gpiod_data *data = dev_get_drvdata(dev);
79 struct gpio_desc *desc = data->desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090080 ssize_t status;
81
Johan Hovold6ffcb792015-05-04 17:10:44 +020082 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090083
Johan Hovoldf0b78662015-05-04 17:10:36 +020084 if (sysfs_streq(buf, "high"))
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090085 status = gpiod_direction_output_raw(desc, 1);
86 else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
87 status = gpiod_direction_output_raw(desc, 0);
88 else if (sysfs_streq(buf, "in"))
89 status = gpiod_direction_input(desc);
90 else
91 status = -EINVAL;
92
Johan Hovold6ffcb792015-05-04 17:10:44 +020093 mutex_unlock(&data->mutex);
94
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090095 return status ? : size;
96}
Johan Hovold6beac9d2015-05-04 17:10:34 +020097static DEVICE_ATTR_RW(direction);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +090098
Johan Hovold6beac9d2015-05-04 17:10:34 +020099static ssize_t value_show(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900100 struct device_attribute *attr, char *buf)
101{
Johan Hovoldc43960f2015-05-04 17:10:37 +0200102 struct gpiod_data *data = dev_get_drvdata(dev);
103 struct gpio_desc *desc = data->desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900104 ssize_t status;
105
Johan Hovold6ffcb792015-05-04 17:10:44 +0200106 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900107
Johan Hovoldf0b78662015-05-04 17:10:36 +0200108 status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900109
Johan Hovold6ffcb792015-05-04 17:10:44 +0200110 mutex_unlock(&data->mutex);
111
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900112 return status;
113}
114
Johan Hovold6beac9d2015-05-04 17:10:34 +0200115static ssize_t value_store(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900116 struct device_attribute *attr, const char *buf, size_t size)
117{
Johan Hovoldc43960f2015-05-04 17:10:37 +0200118 struct gpiod_data *data = dev_get_drvdata(dev);
119 struct gpio_desc *desc = data->desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900120 ssize_t status;
121
Johan Hovold6ffcb792015-05-04 17:10:44 +0200122 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900123
Johan Hovoldf0b78662015-05-04 17:10:36 +0200124 if (!test_bit(FLAG_IS_OUT, &desc->flags)) {
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900125 status = -EPERM;
Johan Hovoldf0b78662015-05-04 17:10:36 +0200126 } else {
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900127 long value;
128
129 status = kstrtol(buf, 0, &value);
130 if (status == 0) {
131 gpiod_set_value_cansleep(desc, value);
132 status = size;
133 }
134 }
135
Johan Hovold6ffcb792015-05-04 17:10:44 +0200136 mutex_unlock(&data->mutex);
137
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900138 return status;
139}
Johan Hovold6beac9d2015-05-04 17:10:34 +0200140static DEVICE_ATTR_RW(value);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900141
142static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
143{
Johan Hovolda08f5c22015-05-04 17:10:39 +0200144 struct gpiod_data *data = priv;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900145
Johan Hovolda08f5c22015-05-04 17:10:39 +0200146 sysfs_notify_dirent(data->value_kn);
147
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900148 return IRQ_HANDLED;
149}
150
Johan Hovold6ffcb792015-05-04 17:10:44 +0200151/* Caller holds gpiod-data mutex. */
Johan Hovoldcef17172015-05-04 17:10:48 +0200152static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900153{
Johan Hovold0f628502015-05-04 17:10:38 +0200154 struct gpiod_data *data = dev_get_drvdata(dev);
155 struct gpio_desc *desc = data->desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900156 unsigned long irq_flags;
Johan Hovold2ec74a92015-05-04 17:10:41 +0200157 int ret;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900158
Johan Hovold2ec74a92015-05-04 17:10:41 +0200159 data->irq = gpiod_to_irq(desc);
160 if (data->irq < 0)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900161 return -EIO;
162
Johan Hovold2ec74a92015-05-04 17:10:41 +0200163 data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value");
164 if (!data->value_kn)
165 return -ENODEV;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900166
167 irq_flags = IRQF_SHARED;
Johan Hovoldcef17172015-05-04 17:10:48 +0200168 if (flags & GPIO_IRQF_TRIGGER_FALLING)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900169 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
170 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
Johan Hovoldcef17172015-05-04 17:10:48 +0200171 if (flags & GPIO_IRQF_TRIGGER_RISING)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900172 irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
173 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
174
Johan Hovold52176d02015-05-04 17:10:28 +0200175 /*
176 * FIXME: This should be done in the irq_request_resources callback
177 * when the irq is requested, but a few drivers currently fail
178 * to do so.
179 *
180 * Remove this redundant call (along with the corresponding
181 * unlock) when those drivers have been fixed.
182 */
183 ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900184 if (ret < 0)
Johan Hovold2ec74a92015-05-04 17:10:41 +0200185 goto err_put_kn;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900186
Johan Hovold2ec74a92015-05-04 17:10:41 +0200187 ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags,
Johan Hovolda08f5c22015-05-04 17:10:39 +0200188 "gpiolib", data);
Johan Hovold52176d02015-05-04 17:10:28 +0200189 if (ret < 0)
190 goto err_unlock;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900191
Johan Hovoldcef17172015-05-04 17:10:48 +0200192 data->irq_flags = flags;
Johan Hovold2ec74a92015-05-04 17:10:41 +0200193
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900194 return 0;
195
Johan Hovold52176d02015-05-04 17:10:28 +0200196err_unlock:
197 gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
Johan Hovold2ec74a92015-05-04 17:10:41 +0200198err_put_kn:
199 sysfs_put(data->value_kn);
200
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900201 return ret;
202}
203
Johan Hovold6ffcb792015-05-04 17:10:44 +0200204/*
205 * Caller holds gpiod-data mutex (unless called after class-device
206 * deregistration).
207 */
Johan Hovold2ec74a92015-05-04 17:10:41 +0200208static void gpio_sysfs_free_irq(struct device *dev)
209{
210 struct gpiod_data *data = dev_get_drvdata(dev);
211 struct gpio_desc *desc = data->desc;
212
Johan Hovoldcef17172015-05-04 17:10:48 +0200213 data->irq_flags = 0;
Johan Hovold2ec74a92015-05-04 17:10:41 +0200214 free_irq(data->irq, data);
215 gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
216 sysfs_put(data->value_kn);
217}
218
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900219static const struct {
220 const char *name;
Johan Hovoldcef17172015-05-04 17:10:48 +0200221 unsigned char flags;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900222} trigger_types[] = {
223 { "none", 0 },
Johan Hovoldcef17172015-05-04 17:10:48 +0200224 { "falling", GPIO_IRQF_TRIGGER_FALLING },
225 { "rising", GPIO_IRQF_TRIGGER_RISING },
226 { "both", GPIO_IRQF_TRIGGER_BOTH },
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900227};
228
Johan Hovold6beac9d2015-05-04 17:10:34 +0200229static ssize_t edge_show(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900230 struct device_attribute *attr, char *buf)
231{
Johan Hovoldc43960f2015-05-04 17:10:37 +0200232 struct gpiod_data *data = dev_get_drvdata(dev);
Johan Hovoldf0b78662015-05-04 17:10:36 +0200233 ssize_t status = 0;
234 int i;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900235
Johan Hovold6ffcb792015-05-04 17:10:44 +0200236 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900237
Johan Hovoldf0b78662015-05-04 17:10:36 +0200238 for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {
Johan Hovoldcef17172015-05-04 17:10:48 +0200239 if (data->irq_flags == trigger_types[i].flags) {
Johan Hovoldf0b78662015-05-04 17:10:36 +0200240 status = sprintf(buf, "%s\n", trigger_types[i].name);
241 break;
242 }
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900243 }
244
Johan Hovold6ffcb792015-05-04 17:10:44 +0200245 mutex_unlock(&data->mutex);
246
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900247 return status;
248}
249
Johan Hovold6beac9d2015-05-04 17:10:34 +0200250static ssize_t edge_store(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900251 struct device_attribute *attr, const char *buf, size_t size)
252{
Johan Hovoldb91e1802015-05-04 17:10:40 +0200253 struct gpiod_data *data = dev_get_drvdata(dev);
Johan Hovoldcef17172015-05-04 17:10:48 +0200254 unsigned char flags;
Johan Hovold2ec74a92015-05-04 17:10:41 +0200255 ssize_t status = size;
Johan Hovolde4339ce2015-05-04 17:10:42 +0200256 int i;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900257
Johan Hovolde4339ce2015-05-04 17:10:42 +0200258 for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900259 if (sysfs_streq(trigger_types[i].name, buf))
Johan Hovolde4339ce2015-05-04 17:10:42 +0200260 break;
261 }
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900262
Johan Hovolde4339ce2015-05-04 17:10:42 +0200263 if (i == ARRAY_SIZE(trigger_types))
264 return -EINVAL;
265
Johan Hovoldb91e1802015-05-04 17:10:40 +0200266 flags = trigger_types[i].flags;
267
Johan Hovold6ffcb792015-05-04 17:10:44 +0200268 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900269
Johan Hovoldcef17172015-05-04 17:10:48 +0200270 if (flags == data->irq_flags) {
Johan Hovoldb91e1802015-05-04 17:10:40 +0200271 status = size;
272 goto out_unlock;
273 }
274
Johan Hovoldcef17172015-05-04 17:10:48 +0200275 if (data->irq_flags)
Johan Hovold2ec74a92015-05-04 17:10:41 +0200276 gpio_sysfs_free_irq(dev);
277
278 if (flags) {
279 status = gpio_sysfs_request_irq(dev, flags);
280 if (!status)
281 status = size;
282 }
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900283
Johan Hovoldb91e1802015-05-04 17:10:40 +0200284out_unlock:
Johan Hovold6ffcb792015-05-04 17:10:44 +0200285 mutex_unlock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900286
287 return status;
288}
Johan Hovold6beac9d2015-05-04 17:10:34 +0200289static DEVICE_ATTR_RW(edge);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900290
Johan Hovold6ffcb792015-05-04 17:10:44 +0200291/* Caller holds gpiod-data mutex. */
Johan Hovold2f323b82015-05-04 17:10:46 +0200292static int gpio_sysfs_set_active_low(struct device *dev, int value)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900293{
Johan Hovold0f628502015-05-04 17:10:38 +0200294 struct gpiod_data *data = dev_get_drvdata(dev);
295 struct gpio_desc *desc = data->desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900296 int status = 0;
Johan Hovoldcef17172015-05-04 17:10:48 +0200297 unsigned int flags = data->irq_flags;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900298
299 if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
300 return 0;
301
302 if (value)
303 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
304 else
305 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
306
307 /* reconfigure poll(2) support if enabled on one edge only */
Johan Hovoldcef17172015-05-04 17:10:48 +0200308 if (flags == GPIO_IRQF_TRIGGER_FALLING ||
309 flags == GPIO_IRQF_TRIGGER_RISING) {
Johan Hovold2ec74a92015-05-04 17:10:41 +0200310 gpio_sysfs_free_irq(dev);
Johan Hovoldcef17172015-05-04 17:10:48 +0200311 status = gpio_sysfs_request_irq(dev, flags);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900312 }
313
314 return status;
315}
316
Johan Hovold6beac9d2015-05-04 17:10:34 +0200317static ssize_t active_low_show(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900318 struct device_attribute *attr, char *buf)
319{
Johan Hovoldc43960f2015-05-04 17:10:37 +0200320 struct gpiod_data *data = dev_get_drvdata(dev);
321 struct gpio_desc *desc = data->desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900322 ssize_t status;
323
Johan Hovold6ffcb792015-05-04 17:10:44 +0200324 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900325
Johan Hovoldf0b78662015-05-04 17:10:36 +0200326 status = sprintf(buf, "%d\n",
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900327 !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
328
Johan Hovold6ffcb792015-05-04 17:10:44 +0200329 mutex_unlock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900330
331 return status;
332}
333
Johan Hovold6beac9d2015-05-04 17:10:34 +0200334static ssize_t active_low_store(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900335 struct device_attribute *attr, const char *buf, size_t size)
336{
Johan Hovold6ffcb792015-05-04 17:10:44 +0200337 struct gpiod_data *data = dev_get_drvdata(dev);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900338 ssize_t status;
Johan Hovoldf0b78662015-05-04 17:10:36 +0200339 long value;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900340
Johan Hovold6ffcb792015-05-04 17:10:44 +0200341 mutex_lock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900342
Johan Hovoldf0b78662015-05-04 17:10:36 +0200343 status = kstrtol(buf, 0, &value);
344 if (status == 0)
Johan Hovold2f323b82015-05-04 17:10:46 +0200345 status = gpio_sysfs_set_active_low(dev, value);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900346
Johan Hovold6ffcb792015-05-04 17:10:44 +0200347 mutex_unlock(&data->mutex);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900348
349 return status ? : size;
350}
Johan Hovold6beac9d2015-05-04 17:10:34 +0200351static DEVICE_ATTR_RW(active_low);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900352
Johan Hovoldebbeba12015-01-13 13:00:06 +0100353static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
354 int n)
355{
356 struct device *dev = container_of(kobj, struct device, kobj);
Johan Hovoldc43960f2015-05-04 17:10:37 +0200357 struct gpiod_data *data = dev_get_drvdata(dev);
358 struct gpio_desc *desc = data->desc;
Johan Hovoldebbeba12015-01-13 13:00:06 +0100359 umode_t mode = attr->mode;
Johan Hovold427fdee2015-05-04 17:10:47 +0200360 bool show_direction = data->direction_can_change;
Johan Hovoldebbeba12015-01-13 13:00:06 +0100361
362 if (attr == &dev_attr_direction.attr) {
363 if (!show_direction)
364 mode = 0;
365 } else if (attr == &dev_attr_edge.attr) {
366 if (gpiod_to_irq(desc) < 0)
367 mode = 0;
368 if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags))
369 mode = 0;
370 }
371
372 return mode;
373}
374
Johan Hovold0915e6f2015-01-13 13:00:05 +0100375static struct attribute *gpio_attrs[] = {
Johan Hovoldebbeba12015-01-13 13:00:06 +0100376 &dev_attr_direction.attr,
377 &dev_attr_edge.attr,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900378 &dev_attr_value.attr,
379 &dev_attr_active_low.attr,
380 NULL,
381};
Johan Hovoldebbeba12015-01-13 13:00:06 +0100382
383static const struct attribute_group gpio_group = {
384 .attrs = gpio_attrs,
385 .is_visible = gpio_is_visible,
386};
387
388static const struct attribute_group *gpio_groups[] = {
389 &gpio_group,
390 NULL
391};
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900392
393/*
394 * /sys/class/gpio/gpiochipN/
395 * /base ... matching gpio_chip.base (N)
396 * /label ... matching gpio_chip.label
397 * /ngpio ... matching gpio_chip.ngpio
398 */
399
Johan Hovold6beac9d2015-05-04 17:10:34 +0200400static ssize_t base_show(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900401 struct device_attribute *attr, char *buf)
402{
403 const struct gpio_chip *chip = dev_get_drvdata(dev);
404
405 return sprintf(buf, "%d\n", chip->base);
406}
Johan Hovold6beac9d2015-05-04 17:10:34 +0200407static DEVICE_ATTR_RO(base);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900408
Johan Hovold6beac9d2015-05-04 17:10:34 +0200409static ssize_t label_show(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900410 struct device_attribute *attr, char *buf)
411{
412 const struct gpio_chip *chip = dev_get_drvdata(dev);
413
414 return sprintf(buf, "%s\n", chip->label ? : "");
415}
Johan Hovold6beac9d2015-05-04 17:10:34 +0200416static DEVICE_ATTR_RO(label);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900417
Johan Hovold6beac9d2015-05-04 17:10:34 +0200418static ssize_t ngpio_show(struct device *dev,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900419 struct device_attribute *attr, char *buf)
420{
421 const struct gpio_chip *chip = dev_get_drvdata(dev);
422
423 return sprintf(buf, "%u\n", chip->ngpio);
424}
Johan Hovold6beac9d2015-05-04 17:10:34 +0200425static DEVICE_ATTR_RO(ngpio);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900426
Johan Hovold121b6a72015-01-13 13:00:04 +0100427static struct attribute *gpiochip_attrs[] = {
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900428 &dev_attr_base.attr,
429 &dev_attr_label.attr,
430 &dev_attr_ngpio.attr,
431 NULL,
432};
Johan Hovold121b6a72015-01-13 13:00:04 +0100433ATTRIBUTE_GROUPS(gpiochip);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900434
435/*
436 * /sys/class/gpio/export ... write-only
437 * integer N ... number of GPIO to export (full access)
438 * /sys/class/gpio/unexport ... write-only
439 * integer N ... number of GPIO to unexport
440 */
441static ssize_t export_store(struct class *class,
442 struct class_attribute *attr,
443 const char *buf, size_t len)
444{
445 long gpio;
446 struct gpio_desc *desc;
447 int status;
448
449 status = kstrtol(buf, 0, &gpio);
450 if (status < 0)
451 goto done;
452
453 desc = gpio_to_desc(gpio);
454 /* reject invalid GPIOs */
455 if (!desc) {
456 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
457 return -EINVAL;
458 }
459
460 /* No extra locking here; FLAG_SYSFS just signifies that the
461 * request and export were done by on behalf of userspace, so
462 * they may be undone on its behalf too.
463 */
464
465 status = gpiod_request(desc, "sysfs");
466 if (status < 0) {
467 if (status == -EPROBE_DEFER)
468 status = -ENODEV;
469 goto done;
470 }
471 status = gpiod_export(desc, true);
472 if (status < 0)
473 gpiod_free(desc);
474 else
475 set_bit(FLAG_SYSFS, &desc->flags);
476
477done:
478 if (status)
479 pr_debug("%s: status %d\n", __func__, status);
480 return status ? : len;
481}
482
483static ssize_t unexport_store(struct class *class,
484 struct class_attribute *attr,
485 const char *buf, size_t len)
486{
487 long gpio;
488 struct gpio_desc *desc;
489 int status;
490
491 status = kstrtol(buf, 0, &gpio);
492 if (status < 0)
493 goto done;
494
495 desc = gpio_to_desc(gpio);
496 /* reject bogus commands (gpio_unexport ignores them) */
497 if (!desc) {
498 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
499 return -EINVAL;
500 }
501
502 status = -EINVAL;
503
504 /* No extra locking here; FLAG_SYSFS just signifies that the
505 * request and export were done by on behalf of userspace, so
506 * they may be undone on its behalf too.
507 */
508 if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
509 status = 0;
510 gpiod_free(desc);
511 }
512done:
513 if (status)
514 pr_debug("%s: status %d\n", __func__, status);
515 return status ? : len;
516}
517
518static struct class_attribute gpio_class_attrs[] = {
519 __ATTR(export, 0200, NULL, export_store),
520 __ATTR(unexport, 0200, NULL, unexport_store),
521 __ATTR_NULL,
522};
523
524static struct class gpio_class = {
525 .name = "gpio",
526 .owner = THIS_MODULE,
527
528 .class_attrs = gpio_class_attrs,
529};
530
531
532/**
533 * gpiod_export - export a GPIO through sysfs
534 * @gpio: gpio to make available, already requested
535 * @direction_may_change: true if userspace may change gpio direction
536 * Context: arch_initcall or later
537 *
538 * When drivers want to make a GPIO accessible to userspace after they
539 * have requested it -- perhaps while debugging, or as part of their
540 * public interface -- they may use this routine. If the GPIO can
541 * change direction (some can't) and the caller allows it, userspace
542 * will see "direction" sysfs attribute which may be used to change
543 * the gpio's direction. A "value" attribute will always be provided.
544 *
545 * Returns zero on success, else an error.
546 */
547int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
548{
Johan Hovold483d8212015-04-21 17:42:09 +0200549 struct gpio_chip *chip;
Johan Hovoldc43960f2015-05-04 17:10:37 +0200550 struct gpiod_data *data;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900551 unsigned long flags;
552 int status;
553 const char *ioname = NULL;
554 struct device *dev;
555 int offset;
556
557 /* can't export until sysfs is available ... */
558 if (!gpio_class.p) {
559 pr_debug("%s: called too early!\n", __func__);
560 return -ENOENT;
561 }
562
563 if (!desc) {
564 pr_debug("%s: invalid gpio descriptor\n", __func__);
565 return -EINVAL;
566 }
567
Johan Hovold483d8212015-04-21 17:42:09 +0200568 chip = desc->chip;
569
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900570 mutex_lock(&sysfs_lock);
571
Johan Hovold483d8212015-04-21 17:42:09 +0200572 /* check if chip is being removed */
Johan Hovold6a4b6b02015-05-04 17:10:31 +0200573 if (!chip || !chip->cdev) {
Johan Hovold483d8212015-04-21 17:42:09 +0200574 status = -ENODEV;
Johan Hovoldc43960f2015-05-04 17:10:37 +0200575 goto err_unlock;
Johan Hovold483d8212015-04-21 17:42:09 +0200576 }
577
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900578 spin_lock_irqsave(&gpio_lock, flags);
579 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
580 test_bit(FLAG_EXPORT, &desc->flags)) {
581 spin_unlock_irqrestore(&gpio_lock, flags);
582 gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n",
583 __func__,
584 test_bit(FLAG_REQUESTED, &desc->flags),
585 test_bit(FLAG_EXPORT, &desc->flags));
586 status = -EPERM;
Johan Hovoldc43960f2015-05-04 17:10:37 +0200587 goto err_unlock;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900588 }
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900589 spin_unlock_irqrestore(&gpio_lock, flags);
590
Johan Hovoldc43960f2015-05-04 17:10:37 +0200591 data = kzalloc(sizeof(*data), GFP_KERNEL);
592 if (!data) {
593 status = -ENOMEM;
594 goto err_unlock;
595 }
596
597 data->desc = desc;
Johan Hovold6ffcb792015-05-04 17:10:44 +0200598 mutex_init(&data->mutex);
Johan Hovold427fdee2015-05-04 17:10:47 +0200599 if (chip->direction_input && chip->direction_output)
600 data->direction_can_change = direction_may_change;
601 else
602 data->direction_can_change = false;
Johan Hovoldc43960f2015-05-04 17:10:37 +0200603
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900604 offset = gpio_chip_hwgpio(desc);
Johan Hovoldcecf58a2015-05-04 17:10:29 +0200605 if (chip->names && chip->names[offset])
606 ioname = chip->names[offset];
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900607
Linus Walleij58383c72015-11-04 09:56:26 +0100608 dev = device_create_with_groups(&gpio_class, chip->parent,
Johan Hovoldc43960f2015-05-04 17:10:37 +0200609 MKDEV(0, 0), data, gpio_groups,
Johan Hovold0915e6f2015-01-13 13:00:05 +0100610 ioname ? ioname : "gpio%u",
611 desc_to_gpio(desc));
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900612 if (IS_ERR(dev)) {
613 status = PTR_ERR(dev);
Johan Hovoldc43960f2015-05-04 17:10:37 +0200614 goto err_free_data;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900615 }
616
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900617 set_bit(FLAG_EXPORT, &desc->flags);
618 mutex_unlock(&sysfs_lock);
619 return 0;
620
Johan Hovoldc43960f2015-05-04 17:10:37 +0200621err_free_data:
622 kfree(data);
623err_unlock:
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900624 mutex_unlock(&sysfs_lock);
625 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
626 return status;
627}
628EXPORT_SYMBOL_GPL(gpiod_export);
629
Johan Hovoldc43960f2015-05-04 17:10:37 +0200630static int match_export(struct device *dev, const void *desc)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900631{
Johan Hovoldc43960f2015-05-04 17:10:37 +0200632 struct gpiod_data *data = dev_get_drvdata(dev);
633
634 return data->desc == desc;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900635}
636
637/**
638 * gpiod_export_link - create a sysfs link to an exported GPIO node
639 * @dev: device under which to create symlink
640 * @name: name of the symlink
641 * @gpio: gpio to create symlink to, already exported
642 *
643 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
644 * node. Caller is responsible for unlinking.
645 *
646 * Returns zero on success, else an error.
647 */
648int gpiod_export_link(struct device *dev, const char *name,
649 struct gpio_desc *desc)
650{
Johan Hovold56d30ec2015-05-04 17:10:43 +0200651 struct device *cdev;
652 int ret;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900653
654 if (!desc) {
655 pr_warn("%s: invalid GPIO\n", __func__);
656 return -EINVAL;
657 }
658
Johan Hovold56d30ec2015-05-04 17:10:43 +0200659 cdev = class_find_device(&gpio_class, NULL, desc, match_export);
660 if (!cdev)
661 return -ENODEV;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900662
Johan Hovold56d30ec2015-05-04 17:10:43 +0200663 ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name);
664 put_device(cdev);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900665
Johan Hovold56d30ec2015-05-04 17:10:43 +0200666 return ret;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900667}
668EXPORT_SYMBOL_GPL(gpiod_export_link);
669
670/**
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900671 * gpiod_unexport - reverse effect of gpio_export()
672 * @gpio: gpio to make unavailable
673 *
674 * This is implicit on gpio_free().
675 */
676void gpiod_unexport(struct gpio_desc *desc)
677{
Johan Hovold72eba6f2015-05-04 17:10:45 +0200678 struct gpiod_data *data;
679 struct device *dev;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900680
681 if (!desc) {
682 pr_warn("%s: invalid GPIO\n", __func__);
683 return;
684 }
685
686 mutex_lock(&sysfs_lock);
687
Johan Hovold72eba6f2015-05-04 17:10:45 +0200688 if (!test_bit(FLAG_EXPORT, &desc->flags))
689 goto err_unlock;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900690
Johan Hovold72eba6f2015-05-04 17:10:45 +0200691 dev = class_find_device(&gpio_class, NULL, desc, match_export);
692 if (!dev)
693 goto err_unlock;
694
695 data = dev_get_drvdata(dev);
696
Johan Hovold72eba6f2015-05-04 17:10:45 +0200697 clear_bit(FLAG_EXPORT, &desc->flags);
698
699 device_unregister(dev);
700
701 /*
702 * Release irq after deregistration to prevent race with edge_store.
703 */
Johan Hovoldcef17172015-05-04 17:10:48 +0200704 if (data->irq_flags)
Johan Hovold72eba6f2015-05-04 17:10:45 +0200705 gpio_sysfs_free_irq(dev);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900706
707 mutex_unlock(&sysfs_lock);
708
Johan Hovold72eba6f2015-05-04 17:10:45 +0200709 put_device(dev);
710 kfree(data);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900711
Johan Hovold72eba6f2015-05-04 17:10:45 +0200712 return;
713
714err_unlock:
715 mutex_unlock(&sysfs_lock);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900716}
717EXPORT_SYMBOL_GPL(gpiod_unexport);
718
Johan Hovold426577b2015-05-04 17:10:32 +0200719int gpiochip_sysfs_register(struct gpio_chip *chip)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900720{
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900721 struct device *dev;
722
Johan Hovold426577b2015-05-04 17:10:32 +0200723 /*
724 * Many systems add gpio chips for SOC support very early,
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900725 * before driver model support is available. In those cases we
Johan Hovold426577b2015-05-04 17:10:32 +0200726 * register later, in gpiolib_sysfs_init() ... here we just
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900727 * verify that _some_ field of gpio_class got initialized.
728 */
729 if (!gpio_class.p)
730 return 0;
731
732 /* use chip->base for the ID; it's already known to be unique */
Linus Walleij58383c72015-11-04 09:56:26 +0100733 dev = device_create_with_groups(&gpio_class, chip->parent,
734 MKDEV(0, 0),
Johan Hovold121b6a72015-01-13 13:00:04 +0100735 chip, gpiochip_groups,
736 "gpiochip%d", chip->base);
737 if (IS_ERR(dev))
Johan Hovold6a4b6b02015-05-04 17:10:31 +0200738 return PTR_ERR(dev);
Johan Hovold3ff74be2015-05-04 17:10:30 +0200739
740 mutex_lock(&sysfs_lock);
Johan Hovold6a4b6b02015-05-04 17:10:31 +0200741 chip->cdev = dev;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900742 mutex_unlock(&sysfs_lock);
743
Johan Hovold6a4b6b02015-05-04 17:10:31 +0200744 return 0;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900745}
746
Johan Hovold426577b2015-05-04 17:10:32 +0200747void gpiochip_sysfs_unregister(struct gpio_chip *chip)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900748{
Johan Hovold483d8212015-04-21 17:42:09 +0200749 struct gpio_desc *desc;
750 unsigned int i;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900751
Johan Hovold6a4b6b02015-05-04 17:10:31 +0200752 if (!chip->cdev)
753 return;
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900754
Johan Hovold6a4b6b02015-05-04 17:10:31 +0200755 device_unregister(chip->cdev);
756
757 /* prevent further gpiod exports */
758 mutex_lock(&sysfs_lock);
759 chip->cdev = NULL;
760 mutex_unlock(&sysfs_lock);
Johan Hovold483d8212015-04-21 17:42:09 +0200761
762 /* unregister gpiod class devices owned by sysfs */
763 for (i = 0; i < chip->ngpio; i++) {
764 desc = &chip->desc[i];
765 if (test_and_clear_bit(FLAG_SYSFS, &desc->flags))
766 gpiod_free(desc);
767 }
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900768}
769
770static int __init gpiolib_sysfs_init(void)
771{
772 int status;
773 unsigned long flags;
774 struct gpio_chip *chip;
775
776 status = class_register(&gpio_class);
777 if (status < 0)
778 return status;
779
780 /* Scan and register the gpio_chips which registered very
781 * early (e.g. before the class_register above was called).
782 *
783 * We run before arch_initcall() so chip->dev nodes can have
784 * registered, and so arch_initcall() can always gpio_export().
785 */
786 spin_lock_irqsave(&gpio_lock, flags);
787 list_for_each_entry(chip, &gpio_chips, list) {
Johan Hovold6a4b6b02015-05-04 17:10:31 +0200788 if (chip->cdev)
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900789 continue;
790
Alexandre Courbot14141a92014-07-22 16:17:40 +0900791 /*
Johan Hovold426577b2015-05-04 17:10:32 +0200792 * TODO we yield gpio_lock here because
793 * gpiochip_sysfs_register() acquires a mutex. This is unsafe
794 * and needs to be fixed.
Alexandre Courbot14141a92014-07-22 16:17:40 +0900795 *
796 * Also it would be nice to use gpiochip_find() here so we
797 * can keep gpio_chips local to gpiolib.c, but the yield of
798 * gpio_lock prevents us from doing this.
799 */
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900800 spin_unlock_irqrestore(&gpio_lock, flags);
Johan Hovold426577b2015-05-04 17:10:32 +0200801 status = gpiochip_sysfs_register(chip);
Alexandre Courbot0eb4c6c2014-07-01 14:45:15 +0900802 spin_lock_irqsave(&gpio_lock, flags);
803 }
804 spin_unlock_irqrestore(&gpio_lock, flags);
805
806
807 return status;
808}
809postcore_initcall(gpiolib_sysfs_init);