1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Internal GPIO functions.
4 *
5 * Copyright (C) 2013, Intel Corporation
6 * Author: Mika Westerberg <[email protected]>
7 */
8
9 #ifndef GPIOLIB_H
10 #define GPIOLIB_H
11
12 #include <linux/cdev.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/gpio/consumer.h> /* for enum gpiod_flags */
16 #include <linux/gpio/driver.h>
17 #include <linux/module.h>
18 #include <linux/notifier.h>
19 #include <linux/spinlock.h>
20 #include <linux/srcu.h>
21 #include <linux/workqueue.h>
22
23 #define GPIOCHIP_NAME "gpiochip"
24
25 /**
26 * struct gpio_device - internal state container for GPIO devices
27 * @dev: the GPIO device struct
28 * @chrdev: character device for the GPIO device
29 * @id: numerical ID number for the GPIO chip
30 * @mockdev: class device used by the deprecated sysfs interface (may be
31 * NULL)
32 * @owner: helps prevent removal of modules exporting active GPIOs
33 * @chip: pointer to the corresponding gpiochip, holding static
34 * data for this device
35 * @descs: array of ngpio descriptors.
36 * @desc_srcu: ensures consistent state of GPIO descriptors exposed to users
37 * @ngpio: the number of GPIO lines on this GPIO device, equal to the size
38 * of the @descs array.
39 * @can_sleep: indicate whether the GPIO chip driver's callbacks can sleep
40 * implying that they cannot be used from atomic context
41 * @base: GPIO base in the DEPRECATED global Linux GPIO numberspace, assigned
42 * at device creation time.
43 * @label: a descriptive name for the GPIO device, such as the part number
44 * or name of the IP component in a System on Chip.
45 * @data: per-instance data assigned by the driver
46 * @list: links gpio_device:s together for traversal
47 * @line_state_notifier: used to notify subscribers about lines being
48 * requested, released or reconfigured
49 * @line_state_lock: RW-spinlock protecting the line state notifier
50 * @line_state_wq: used to emit line state events from a separate thread in
51 * process context
52 * @device_notifier: used to notify character device wait queues about the GPIO
53 * device being unregistered
54 * @srcu: protects the pointer to the underlying GPIO chip
55 * @pin_ranges: range of pins served by the GPIO driver
56 *
57 * This state container holds most of the runtime variable data
58 * for a GPIO device and can hold references and live on after the
59 * GPIO chip has been removed, if it is still being used from
60 * userspace.
61 */
62 struct gpio_device {
63 struct device dev;
64 struct cdev chrdev;
65 int id;
66 struct device *mockdev;
67 struct module *owner;
68 struct gpio_chip __rcu *chip;
69 struct gpio_desc *descs;
70 struct srcu_struct desc_srcu;
71 unsigned int base;
72 u16 ngpio;
73 bool can_sleep;
74 const char *label;
75 void *data;
76 struct list_head list;
77 struct raw_notifier_head line_state_notifier;
78 rwlock_t line_state_lock;
79 struct workqueue_struct *line_state_wq;
80 struct blocking_notifier_head device_notifier;
81 struct srcu_struct srcu;
82
83 #ifdef CONFIG_PINCTRL
84 /*
85 * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
86 * describe the actual pin range which they serve in an SoC. This
87 * information would be used by pinctrl subsystem to configure
88 * corresponding pins for gpio usage.
89 */
90 struct list_head pin_ranges;
91 #endif
92 };
93
to_gpio_device(struct device * dev)94 static inline struct gpio_device *to_gpio_device(struct device *dev)
95 {
96 return container_of(dev, struct gpio_device, dev);
97 }
98
99 /* GPIO suffixes used for ACPI and device tree lookup */
100 extern const char *const gpio_suffixes[];
101
102 #define for_each_gpio_property_name(propname, con_id) \
103 for (const char * const *__suffixes = gpio_suffixes; \
104 *__suffixes && ({ \
105 const char *__gs = *__suffixes; \
106 \
107 if (con_id) \
108 snprintf(propname, sizeof(propname), "%s-%s", con_id, __gs); \
109 else \
110 snprintf(propname, sizeof(propname), "%s", __gs); \
111 1; \
112 }); \
113 __suffixes++)
114
115 /**
116 * struct gpio_array - Opaque descriptor for a structure of GPIO array attributes
117 *
118 * @desc: Array of pointers to the GPIO descriptors
119 * @size: Number of elements in desc
120 * @gdev: Parent GPIO device
121 * @get_mask: Get mask used in fastpath
122 * @set_mask: Set mask used in fastpath
123 * @invert_mask: Invert mask used in fastpath
124 *
125 * This structure is attached to struct gpiod_descs obtained from
126 * gpiod_get_array() and can be passed back to get/set array functions in order
127 * to activate fast processing path if applicable.
128 */
129 struct gpio_array {
130 struct gpio_desc **desc;
131 unsigned int size;
132 struct gpio_device *gdev;
133 unsigned long *get_mask;
134 unsigned long *set_mask;
135 unsigned long invert_mask[];
136 };
137
138 #define for_each_gpio_desc(gc, desc) \
139 for (unsigned int __i = 0; \
140 __i < gc->ngpio && (desc = gpiochip_get_desc(gc, __i)); \
141 __i++) \
142
143 #define for_each_gpio_desc_with_flag(gc, desc, flag) \
144 for_each_gpio_desc(gc, desc) \
145 if (!test_bit(flag, &desc->flags)) {} else
146
147 int gpiod_get_array_value_complex(bool raw, bool can_sleep,
148 unsigned int array_size,
149 struct gpio_desc **desc_array,
150 struct gpio_array *array_info,
151 unsigned long *value_bitmap);
152 int gpiod_set_array_value_complex(bool raw, bool can_sleep,
153 unsigned int array_size,
154 struct gpio_desc **desc_array,
155 struct gpio_array *array_info,
156 unsigned long *value_bitmap);
157
158 int gpiod_set_transitory(struct gpio_desc *desc, bool transitory);
159
160 void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action);
161 int gpiod_direction_output_nonotify(struct gpio_desc *desc, int value);
162 int gpiod_direction_input_nonotify(struct gpio_desc *desc);
163
164 struct gpio_desc_label {
165 struct rcu_head rh;
166 char str[];
167 };
168
169 /**
170 * struct gpio_desc - Opaque descriptor for a GPIO
171 *
172 * @gdev: Pointer to the parent GPIO device
173 * @flags: Binary descriptor flags
174 * @label: Name of the consumer
175 * @name: Line name
176 * @hog: Pointer to the device node that hogs this line (if any)
177 * @debounce_period_us: Debounce period in microseconds
178 *
179 * These are obtained using gpiod_get() and are preferable to the old
180 * integer-based handles.
181 *
182 * Contrary to integers, a pointer to a &struct gpio_desc is guaranteed to be
183 * valid until the GPIO is released.
184 */
185 struct gpio_desc {
186 struct gpio_device *gdev;
187 unsigned long flags;
188 /* flag symbols are bit numbers */
189 #define FLAG_REQUESTED 0
190 #define FLAG_IS_OUT 1
191 #define FLAG_EXPORT 2 /* protected by sysfs_lock */
192 #define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */
193 #define FLAG_ACTIVE_LOW 6 /* value has active low */
194 #define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */
195 #define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */
196 #define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
197 #define FLAG_IRQ_IS_ENABLED 10 /* GPIO is connected to an enabled IRQ */
198 #define FLAG_IS_HOGGED 11 /* GPIO is hogged */
199 #define FLAG_TRANSITORY 12 /* GPIO may lose value in sleep or reset */
200 #define FLAG_PULL_UP 13 /* GPIO has pull up enabled */
201 #define FLAG_PULL_DOWN 14 /* GPIO has pull down enabled */
202 #define FLAG_BIAS_DISABLE 15 /* GPIO has pull disabled */
203 #define FLAG_EDGE_RISING 16 /* GPIO CDEV detects rising edge events */
204 #define FLAG_EDGE_FALLING 17 /* GPIO CDEV detects falling edge events */
205 #define FLAG_EVENT_CLOCK_REALTIME 18 /* GPIO CDEV reports REALTIME timestamps in events */
206 #define FLAG_EVENT_CLOCK_HTE 19 /* GPIO CDEV reports hardware timestamps in events */
207
208 /* Connection label */
209 struct gpio_desc_label __rcu *label;
210 /* Name of the GPIO */
211 const char *name;
212 #ifdef CONFIG_OF_DYNAMIC
213 struct device_node *hog;
214 #endif
215 #ifdef CONFIG_GPIO_CDEV
216 /* debounce period in microseconds */
217 unsigned int debounce_period_us;
218 #endif
219 };
220
221 #define gpiod_not_found(desc) (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT)
222
223 struct gpio_chip_guard {
224 struct gpio_device *gdev;
225 struct gpio_chip *gc;
226 int idx;
227 };
228
229 DEFINE_CLASS(gpio_chip_guard,
230 struct gpio_chip_guard,
231 srcu_read_unlock(&_T.gdev->srcu, _T.idx),
232 ({
233 struct gpio_chip_guard _guard;
234
235 _guard.gdev = desc->gdev;
236 _guard.idx = srcu_read_lock(&_guard.gdev->srcu);
237 _guard.gc = srcu_dereference(_guard.gdev->chip,
238 &_guard.gdev->srcu);
239
240 _guard;
241 }),
242 struct gpio_desc *desc)
243
244 int gpiod_request(struct gpio_desc *desc, const char *label);
245 void gpiod_free(struct gpio_desc *desc);
246
gpiod_request_user(struct gpio_desc * desc,const char * label)247 static inline int gpiod_request_user(struct gpio_desc *desc, const char *label)
248 {
249 int ret;
250
251 ret = gpiod_request(desc, label);
252 if (ret == -EPROBE_DEFER)
253 ret = -ENODEV;
254
255 return ret;
256 }
257
258 struct gpio_desc *gpiod_find_and_request(struct device *consumer,
259 struct fwnode_handle *fwnode,
260 const char *con_id,
261 unsigned int idx,
262 enum gpiod_flags flags,
263 const char *label,
264 bool platform_lookup_allowed);
265
266 int gpio_do_set_config(struct gpio_desc *desc, unsigned long config);
267 int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
268 unsigned long lflags, enum gpiod_flags dflags);
269 int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce);
270 int gpiod_hog(struct gpio_desc *desc, const char *name,
271 unsigned long lflags, enum gpiod_flags dflags);
272 int gpiochip_get_ngpios(struct gpio_chip *gc, struct device *dev);
273 struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum);
274 const char *gpiod_get_label(struct gpio_desc *desc);
275
276 /*
277 * Return the GPIO number of the passed descriptor relative to its chip
278 */
gpio_chip_hwgpio(const struct gpio_desc * desc)279 static inline int gpio_chip_hwgpio(const struct gpio_desc *desc)
280 {
281 return desc - &desc->gdev->descs[0];
282 }
283
284 /* With descriptor prefix */
285
286 #define gpiod_err(desc, fmt, ...) \
287 do { \
288 scoped_guard(srcu, &desc->gdev->desc_srcu) { \
289 pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), \
290 gpiod_get_label(desc) ? : "?", ##__VA_ARGS__); \
291 } \
292 } while (0)
293
294 #define gpiod_warn(desc, fmt, ...) \
295 do { \
296 scoped_guard(srcu, &desc->gdev->desc_srcu) { \
297 pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), \
298 gpiod_get_label(desc) ? : "?", ##__VA_ARGS__); \
299 } \
300 } while (0)
301
302 #define gpiod_dbg(desc, fmt, ...) \
303 do { \
304 scoped_guard(srcu, &desc->gdev->desc_srcu) { \
305 pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), \
306 gpiod_get_label(desc) ? : "?", ##__VA_ARGS__); \
307 } \
308 } while (0)
309
310 /* With chip prefix */
311
312 #define chip_err(gc, fmt, ...) \
313 dev_err(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__)
314 #define chip_warn(gc, fmt, ...) \
315 dev_warn(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__)
316 #define chip_info(gc, fmt, ...) \
317 dev_info(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__)
318 #define chip_dbg(gc, fmt, ...) \
319 dev_dbg(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__)
320
321 #endif /* GPIOLIB_H */
322