kernel / drivers / gpio / gpiolib.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Internal GPIO functions.
 *
 * Copyright (C) 2013, Intel Corporation
 * Author: Mika Westerberg <[e-mail]>
 */

#ifndef GPIOLIB_H
#define GPIOLIB_H

#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h> /* for enum gpiod_flags */
#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
#include <linux/srcu.h>
#include <linux/workqueue.h>

#define GPIOCHIP_NAME	"gpiochip"

/**
 * struct gpio_device - internal state container for GPIO devices
 * @dev: the GPIO device struct
 * @chrdev: character device for the GPIO device
 * @id: numerical ID number for the GPIO chip
 * @owner: helps prevent removal of modules exporting active GPIOs
 * @chip: pointer to the corresponding gpiochip, holding static
 * data for this device
 * @descs: array of ngpio descriptors.
 * @valid_mask: If not %NULL, holds bitmask of GPIOs which are valid to be
 * used from the chip.
 * @desc_srcu: ensures consistent state of GPIO descriptors exposed to users
 * @ngpio: the number of GPIO lines on this GPIO device, equal to the size
 * of the @descs array.
 * @can_sleep: indicate whether the GPIO chip driver's callbacks can sleep
 * implying that they cannot be used from atomic context
 * @base: GPIO base in the DEPRECATED global Linux GPIO numberspace, assigned
 * at device creation time.
 * @label: a descriptive name for the GPIO device, such as the part number
 * or name of the IP component in a System on Chip.
 * @data: per-instance data assigned by the driver
 * @list: links gpio_device:s together for traversal
 * @line_state_notifier: used to notify subscribers about lines being
 *                       requested, released or reconfigured
 * @line_state_lock: RW-spinlock protecting the line state notifier
 * @line_state_wq: used to emit line state events from a separate thread in
 *                 process context
 * @device_notifier: used to notify character device wait queues about the GPIO
 *                   device being unregistered
 * @srcu: protects the pointer to the underlying GPIO chip
 * @pin_ranges: range of pins served by the GPIO driver
 *
 * This state container holds most of the runtime variable data
 * for a GPIO device and can hold references and live on after the
 * GPIO chip has been removed, if it is still being used from
 * userspace.
 */
struct gpio_device {
	struct device		dev;
	struct cdev		chrdev;
	int			id;
	struct module		*owner;
	struct gpio_chip __rcu	*chip;
	struct gpio_desc	*descs;
	unsigned long		*valid_mask;
	struct srcu_struct	desc_srcu;
	unsigned int		base;
	u16			ngpio;
	bool			can_sleep;
	const char		*label;
	void			*data;
	struct list_head        list;
	struct raw_notifier_head line_state_notifier;
	rwlock_t		line_state_lock;
	struct workqueue_struct	*line_state_wq;
	struct blocking_notifier_head device_notifier;
	struct srcu_struct	srcu;

#ifdef CONFIG_PINCTRL
	/*
	 * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
	 * describe the actual pin range which they serve in an SoC. This
	 * information would be used by pinctrl subsystem to configure
	 * corresponding pins for gpio usage.
	 */
	struct list_head pin_ranges;
#endif
};

static inline struct gpio_device *to_gpio_device(struct device *dev)
{
	return container_of(dev, struct gpio_device, dev);
}

/* GPIO suffixes used for ACPI and device tree lookup */
extern const char *const gpio_suffixes[];

#define for_each_gpio_property_name(propname, con_id)					\
	for (const char * const *__suffixes = gpio_suffixes;				\
	     *__suffixes && ({								\
		const char *__gs = *__suffixes;						\
											\
		if (con_id)								\
			snprintf(propname, sizeof(propname), "%s-%s", con_id, __gs);	\
		else									\
			snprintf(propname, sizeof(propname), "%s", __gs);		\
		1;									\
	     });									\
	     __suffixes++)

/**
 * struct gpio_array - Opaque descriptor for a structure of GPIO array attributes
 *
 * @desc:		Array of pointers to the GPIO descriptors
 * @size:		Number of elements in desc
 * @gdev:		Parent GPIO device
 * @get_mask:		Get mask used in fastpath
 * @set_mask:		Set mask used in fastpath
 * @invert_mask:	Invert mask used in fastpath
 *
 * This structure is attached to struct gpiod_descs obtained from
 * gpiod_get_array() and can be passed back to get/set array functions in order
 * to activate fast processing path if applicable.
 */
struct gpio_array {
	struct gpio_desc	**desc;
	unsigned int		size;
	struct gpio_device	*gdev;
	unsigned long		*get_mask;
	unsigned long		*set_mask;
	unsigned long		invert_mask[];
};

#define for_each_gpio_desc(gc, desc)					\
	for (unsigned int __i = 0;					\
	     __i < gc->ngpio && (desc = gpiochip_get_desc(gc, __i));	\
	     __i++)							\

#define for_each_gpio_desc_with_flag(gc, desc, flag)			\
	for_each_gpio_desc(gc, desc)					\
		if (!test_bit(flag, &desc->flags)) {} else

int gpiod_get_array_value_complex(bool raw, bool can_sleep,
				  unsigned int array_size,
				  struct gpio_desc **desc_array,
				  struct gpio_array *array_info,
				  unsigned long *value_bitmap);
int gpiod_set_array_value_complex(bool raw, bool can_sleep,
				  unsigned int array_size,
				  struct gpio_desc **desc_array,
				  struct gpio_array *array_info,
				  unsigned long *value_bitmap);

int gpiod_set_transitory(struct gpio_desc *desc, bool transitory);

void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action);
int gpiod_direction_output_nonotify(struct gpio_desc *desc, int value);
int gpiod_direction_input_nonotify(struct gpio_desc *desc);

struct gpio_desc_label {
	struct rcu_head rh;
	char str[];
};

/**
 * struct gpio_desc - Opaque descriptor for a GPIO
 *
 * @gdev:		Pointer to the parent GPIO device
 * @flags:		Binary descriptor flags
 * @label:		Name of the consumer
 * @name:		Line name
 * @hog:		Pointer to the device node that hogs this line (if any)
 * @debounce_period_us:	Debounce period in microseconds
 *
 * These are obtained using gpiod_get() and are preferable to the old
 * integer-based handles.
 *
 * Contrary to integers, a pointer to a &struct gpio_desc is guaranteed to be
 * valid until the GPIO is released.
 */
struct gpio_desc {
	struct gpio_device	*gdev;
	unsigned long		flags;
/* flag symbols are bit numbers */
#define GPIOD_FLAG_REQUESTED		0  /* GPIO is in use */
#define GPIOD_FLAG_IS_OUT		1  /* GPIO is in output mode */
#define GPIOD_FLAG_EXPORT		2  /* GPIO is exported to user-space */
#define GPIOD_FLAG_SYSFS		3  /* GPIO is exported via /sys/class/gpio */
#define GPIOD_FLAG_ACTIVE_LOW		6  /* GPIO is active-low */
#define GPIOD_FLAG_OPEN_DRAIN		7  /* GPIO is open drain type */
#define GPIOD_FLAG_OPEN_SOURCE		8  /* GPIO is open source type */
#define GPIOD_FLAG_USED_AS_IRQ		9  /* GPIO is connected to an IRQ */
#define GPIOD_FLAG_IRQ_IS_ENABLED	10 /* GPIO is connected to an enabled IRQ */
#define GPIOD_FLAG_IS_HOGGED		11 /* GPIO is hogged */
#define GPIOD_FLAG_TRANSITORY		12 /* GPIO may lose value in sleep or reset */
#define GPIOD_FLAG_PULL_UP		13 /* GPIO has pull up enabled */
#define GPIOD_FLAG_PULL_DOWN		14 /* GPIO has pull down enabled */
#define GPIOD_FLAG_BIAS_DISABLE		15 /* GPIO has pull disabled */
#define GPIOD_FLAG_EDGE_RISING		16 /* GPIO CDEV detects rising edge events */
#define GPIOD_FLAG_EDGE_FALLING		17 /* GPIO CDEV detects falling edge events */
#define GPIOD_FLAG_EVENT_CLOCK_REALTIME	18 /* GPIO CDEV reports REALTIME timestamps in events */
#define GPIOD_FLAG_EVENT_CLOCK_HTE	19 /* GPIO CDEV reports hardware timestamps in events */
#define GPIOD_FLAG_SHARED		20 /* GPIO is shared by multiple consumers */
#define GPIOD_FLAG_SHARED_PROXY		21 /* GPIO is a virtual proxy to a physically shared pin. */

	/* Connection label */
	struct gpio_desc_label __rcu *label;
	/* Name of the GPIO */
	const char		*name;
#ifdef CONFIG_OF_DYNAMIC
	struct device_node	*hog;
#endif
#ifdef CONFIG_GPIO_CDEV
	/* debounce period in microseconds */
	unsigned int		debounce_period_us;
#endif
};

#define gpiod_not_found(desc)		(IS_ERR(desc) && PTR_ERR(desc) == -ENOENT)

struct gpio_chip_guard {
	struct gpio_device *gdev;
	struct gpio_chip *gc;
	int idx;
};

DEFINE_CLASS(gpio_chip_guard,
	     struct gpio_chip_guard,
	     srcu_read_unlock(&_T.gdev->srcu, _T.idx),
	     ({
		struct gpio_chip_guard _guard;

		_guard.gdev = desc->gdev;
		_guard.idx = srcu_read_lock(&_guard.gdev->srcu);
		_guard.gc = srcu_dereference(_guard.gdev->chip,
					     &_guard.gdev->srcu);

		_guard;
	     }),
	     struct gpio_desc *desc)

int gpiod_request(struct gpio_desc *desc, const char *label);
void gpiod_free(struct gpio_desc *desc);

static inline int gpiod_request_user(struct gpio_desc *desc, const char *label)
{
	int ret;

	ret = gpiod_request(desc, label);
	if (ret == -EPROBE_DEFER)
		ret = -ENODEV;

	return ret;
}

struct gpio_desc *gpiod_find_and_request(struct device *consumer,
					 struct fwnode_handle *fwnode,
					 const char *con_id,
					 unsigned int idx,
					 enum gpiod_flags flags,
					 const char *label,
					 bool platform_lookup_allowed);

int gpio_do_set_config(struct gpio_desc *desc, unsigned long config);
int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
		unsigned long lflags, enum gpiod_flags dflags);
int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce);
int gpiod_hog(struct gpio_desc *desc, const char *name,
		unsigned long lflags, enum gpiod_flags dflags);
int gpiochip_get_ngpios(struct gpio_chip *gc, struct device *dev);
struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum);
const char *gpiod_get_label(struct gpio_desc *desc);

/* With descriptor prefix */

#define __gpiod_pr(level, desc, fmt, ...) \
do { \
	scoped_guard(srcu, &desc->gdev->desc_srcu) { \
		pr_##level("gpio-%d (%s): " fmt, desc_to_gpio(desc), \
			   gpiod_get_label(desc) ?: "?", ##__VA_ARGS__); \
	} \
} while (0)

#define gpiod_err(desc, fmt, ...) __gpiod_pr(err, desc, fmt, ##__VA_ARGS__)
#define gpiod_warn(desc, fmt, ...) __gpiod_pr(warn, desc, fmt, ##__VA_ARGS__)
#define gpiod_dbg(desc, fmt, ...) __gpiod_pr(debug, desc, fmt, ##__VA_ARGS__)

/* With chip prefix */

#define __gpiochip_pr(level, gc, fmt, ...) \
do { \
	dev_##level(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__); \
} while (0)

#define gpiochip_err(gc, fmt, ...) __gpiochip_pr(err, gc, fmt, ##__VA_ARGS__)
#define gpiochip_warn(gc, fmt, ...) __gpiochip_pr(warn, gc, fmt, ##__VA_ARGS__)
#define gpiochip_info(gc, fmt, ...) __gpiochip_pr(info, gc, fmt, ##__VA_ARGS__)
#define gpiochip_dbg(gc, fmt, ...) __gpiochip_pr(dbg, gc, fmt, ##__VA_ARGS__)

#endif /* GPIOLIB_H */