gpiolib.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Internal GPIO functions.
  4 *
  5 * Copyright (C) 2013, Intel Corporation
  6 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
  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 * @owner: helps prevent removal of modules exporting active GPIOs
 31 * @chip: pointer to the corresponding gpiochip, holding static
 32 * data for this device
 33 * @descs: array of ngpio descriptors.
 34 * @valid_mask: If not %NULL, holds bitmask of GPIOs which are valid to be
 35 * used from the chip.
 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 */
 62struct gpio_device {
 63	struct device		dev;
 64	struct cdev		chrdev;
 65	int			id;
 66	struct module		*owner;
 67	struct gpio_chip __rcu	*chip;
 68	struct gpio_desc	*descs;
 69	unsigned long		*valid_mask;
 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
 94static 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 */
100extern 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 */
129struct 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
147int 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);
152int 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
158int gpiod_set_transitory(struct gpio_desc *desc, bool transitory);
159
160void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action);
161int gpiod_direction_output_nonotify(struct gpio_desc *desc, int value);
162int gpiod_direction_input_nonotify(struct gpio_desc *desc);
163
164struct 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 */
185struct gpio_desc {
186	struct gpio_device	*gdev;
187	unsigned long		flags;
188/* flag symbols are bit numbers */
189#define GPIOD_FLAG_REQUESTED		0  /* GPIO is in use */
190#define GPIOD_FLAG_IS_OUT		1  /* GPIO is in output mode */
191#define GPIOD_FLAG_EXPORT		2  /* GPIO is exported to user-space */
192#define GPIOD_FLAG_SYSFS		3  /* GPIO is exported via /sys/class/gpio */
193#define GPIOD_FLAG_ACTIVE_LOW		6  /* GPIO is active-low */
194#define GPIOD_FLAG_OPEN_DRAIN		7  /* GPIO is open drain type */
195#define GPIOD_FLAG_OPEN_SOURCE		8  /* GPIO is open source type */
196#define GPIOD_FLAG_USED_AS_IRQ		9  /* GPIO is connected to an IRQ */
197#define GPIOD_FLAG_IRQ_IS_ENABLED	10 /* GPIO is connected to an enabled IRQ */
198#define GPIOD_FLAG_IS_HOGGED		11 /* GPIO is hogged */
199#define GPIOD_FLAG_TRANSITORY		12 /* GPIO may lose value in sleep or reset */
200#define GPIOD_FLAG_PULL_UP		13 /* GPIO has pull up enabled */
201#define GPIOD_FLAG_PULL_DOWN		14 /* GPIO has pull down enabled */
202#define GPIOD_FLAG_BIAS_DISABLE		15 /* GPIO has pull disabled */
203#define GPIOD_FLAG_EDGE_RISING		16 /* GPIO CDEV detects rising edge events */
204#define GPIOD_FLAG_EDGE_FALLING		17 /* GPIO CDEV detects falling edge events */
205#define GPIOD_FLAG_EVENT_CLOCK_REALTIME	18 /* GPIO CDEV reports REALTIME timestamps in events */
206#define GPIOD_FLAG_EVENT_CLOCK_HTE	19 /* GPIO CDEV reports hardware timestamps in events */
207#define GPIOD_FLAG_SHARED		20 /* GPIO is shared by multiple consumers */
208#define GPIOD_FLAG_SHARED_PROXY		21 /* GPIO is a virtual proxy to a physically shared pin. */
209
210	/* Connection label */
211	struct gpio_desc_label __rcu *label;
212	/* Name of the GPIO */
213	const char		*name;
214#ifdef CONFIG_OF_DYNAMIC
215	struct device_node	*hog;
216#endif
217#ifdef CONFIG_GPIO_CDEV
218	/* debounce period in microseconds */
219	unsigned int		debounce_period_us;
220#endif
221};
222
223#define gpiod_not_found(desc)		(IS_ERR(desc) && PTR_ERR(desc) == -ENOENT)
224
225struct gpio_chip_guard {
226	struct gpio_device *gdev;
227	struct gpio_chip *gc;
228	int idx;
229};
230
231DEFINE_CLASS(gpio_chip_guard,
232	     struct gpio_chip_guard,
233	     srcu_read_unlock(&_T.gdev->srcu, _T.idx),
234	     ({
235		struct gpio_chip_guard _guard;
236
237		_guard.gdev = desc->gdev;
238		_guard.idx = srcu_read_lock(&_guard.gdev->srcu);
239		_guard.gc = srcu_dereference(_guard.gdev->chip,
240					     &_guard.gdev->srcu);
241
242		_guard;
243	     }),
244	     struct gpio_desc *desc)
245
246int gpiod_request(struct gpio_desc *desc, const char *label);
247int gpiod_request_commit(struct gpio_desc *desc, const char *label);
248void gpiod_free(struct gpio_desc *desc);
249void gpiod_free_commit(struct gpio_desc *desc);
250
251static inline int gpiod_request_user(struct gpio_desc *desc, const char *label)
252{
253	int ret;
254
255	ret = gpiod_request(desc, label);
256	if (ret == -EPROBE_DEFER)
257		ret = -ENODEV;
258
259	return ret;
260}
261
262struct gpio_desc *gpiod_find_and_request(struct device *consumer,
263					 struct fwnode_handle *fwnode,
264					 const char *con_id,
265					 unsigned int idx,
266					 enum gpiod_flags flags,
267					 const char *label,
268					 bool platform_lookup_allowed);
269
270int gpio_do_set_config(struct gpio_desc *desc, unsigned long config);
271int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
272		unsigned long lflags, enum gpiod_flags dflags);
273int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce);
274int gpiod_hog(struct gpio_desc *desc, const char *name,
275		unsigned long lflags, enum gpiod_flags dflags);
276int gpiochip_get_ngpios(struct gpio_chip *gc, struct device *dev);
277struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum);
278const char *gpiod_get_label(struct gpio_desc *desc);
279
280/* With descriptor prefix */
281
282#define __gpiod_pr(level, desc, fmt, ...) \
283do { \
284	scoped_guard(srcu, &desc->gdev->desc_srcu) { \
285		pr_##level("gpio-%d (%s): " fmt, desc_to_gpio(desc), \
286			   gpiod_get_label(desc) ?: "?", ##__VA_ARGS__); \
287	} \
288} while (0)
289
290#define gpiod_err(desc, fmt, ...) __gpiod_pr(err, desc, fmt, ##__VA_ARGS__)
291#define gpiod_warn(desc, fmt, ...) __gpiod_pr(warn, desc, fmt, ##__VA_ARGS__)
292#define gpiod_dbg(desc, fmt, ...) __gpiod_pr(debug, desc, fmt, ##__VA_ARGS__)
293
294/* With chip prefix */
295
296#define __gpiochip_pr(level, gc, fmt, ...) \
297do { \
298	dev_##level(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__); \
299} while (0)
300
301#define gpiochip_err(gc, fmt, ...) __gpiochip_pr(err, gc, fmt, ##__VA_ARGS__)
302#define gpiochip_warn(gc, fmt, ...) __gpiochip_pr(warn, gc, fmt, ##__VA_ARGS__)
303#define gpiochip_info(gc, fmt, ...) __gpiochip_pr(info, gc, fmt, ##__VA_ARGS__)
304#define gpiochip_dbg(gc, fmt, ...) __gpiochip_pr(dbg, gc, fmt, ##__VA_ARGS__)
305
306#endif /* GPIOLIB_H */