/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Internal GPIO functions.
 *
 * Copyright (C) 2013, Intel Corporation
 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
 */

#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);
int gpiod_request_commit(struct gpio_desc *desc, const char *label);
void gpiod_free(struct gpio_desc *desc);
void gpiod_free_commit(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 */