#ifndef _ASM_GENERIC_GPIO_H
  #define _ASM_GENERIC_GPIO_H

  #include <linux/kernel.h>

  #include <linux/types.h>

  #include <linux/errno.h>

  #include <linux/of.h>

  #ifdef CONFIG_GPIOLIB

  #include <linux/compiler.h>

  /* Platforms may implement their GPIO interface with library code,
   * at a small performance cost for non-inlined operations and some
   * extra memory (for code and for per-GPIO table entries).
   *
   * While the GPIO programming interface defines valid GPIO numbers
   * to be in the range 0..MAX_INT, this library restricts them to the

   * smaller range 0..ARCH_NR_GPIOS-1.

   *
   * ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of
   * builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is
   * actually an estimate of a board-specific value.

   */
  
  #ifndef ARCH_NR_GPIOS
  #define ARCH_NR_GPIOS		256
  #endif

  /*
   * "valid" GPIO numbers are nonnegative and may be passed to
   * setup routines like gpio_request().  only some valid numbers
   * can successfully be requested and used.
   *
   * Invalid GPIO numbers are useful for indicating no-such-GPIO in
   * platform data and other tables.
   */

  static inline bool gpio_is_valid(int number)

  {

  	return number >= 0 && number < ARCH_NR_GPIOS;

  }

  struct device;

  struct gpio;

  struct seq_file;

  struct module;

  struct device_node;

  
  /**
   * struct gpio_chip - abstract a GPIO controller
   * @label: for diagnostics

   * @dev: optional device providing the GPIOs
   * @owner: helps prevent removal of modules exporting active GPIOs

   * @request: optional hook for chip-specific activation, such as
   *	enabling module power and clock; may sleep
   * @free: optional hook for chip-specific deactivation, such as
   *	disabling module power and clock; may sleep

   * @direction_input: configures signal "offset" as input, or returns error
   * @get: returns value for signal "offset"; for output signals this
   *	returns either the value actually sensed, or zero
   * @direction_output: configures signal "offset" as output, or returns error
   * @set: assigns output value for signal "offset"

   * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
   *	implementation may not sleep

   * @dbg_show: optional routine to show contents in debugfs; default code
   *	will be used when this is omitted, but custom code can show extra
   *	state (such as pullup/pulldown configuration).
   * @base: identifies the first GPIO number handled by this chip; or, if
   *	negative during registration, requests dynamic ID allocation.
   * @ngpio: the number of GPIOs handled by this controller; the last GPIO
   *	handled is (base + ngpio - 1).
   * @can_sleep: flag must be set iff get()/set() methods sleep, as they
   *	must while accessing GPIO expander chips over I2C or SPI

   * @names: if set, must be an array of strings to use as alternative
   *      names for the GPIOs in this chip. Any entry in the array
   *      may be NULL if there is no alias for the GPIO, however the

   *      array must be @ngpio entries long.  A name can include a single printk
   *      format specifier for an unsigned int.  It is substituted by the actual
   *      number of the gpio.

   *
   * A gpio_chip can help platforms abstract various sources of GPIOs so
   * they can all be accessed through a common programing interface.
   * Example sources would be SOC controllers, FPGAs, multifunction
   * chips, dedicated GPIO expanders, and so on.
   *
   * Each chip controls a number of signals, identified in method calls
   * by "offset" values in the range 0..(@ngpio - 1).  When those signals
   * are referenced through calls like gpio_get_value(gpio), the offset
   * is calculated by subtracting @base from the gpio number.
   */
  struct gpio_chip {

  	const char		*label;

  	struct device		*dev;

  	struct module		*owner;

  	int			(*request)(struct gpio_chip *chip,
  						unsigned offset);
  	void			(*free)(struct gpio_chip *chip,
  						unsigned offset);

  	int			(*direction_input)(struct gpio_chip *chip,
  						unsigned offset);
  	int			(*get)(struct gpio_chip *chip,
  						unsigned offset);
  	int			(*direction_output)(struct gpio_chip *chip,
  						unsigned offset, int value);

  	int			(*set_debounce)(struct gpio_chip *chip,
  						unsigned offset, unsigned debounce);

  	void			(*set)(struct gpio_chip *chip,
  						unsigned offset, int value);

  
  	int			(*to_irq)(struct gpio_chip *chip,
  						unsigned offset);

  	void			(*dbg_show)(struct seq_file *s,
  						struct gpio_chip *chip);
  	int			base;
  	u16			ngpio;

  	const char		*const *names;

  	unsigned		can_sleep:1;

  	unsigned		exported:1;

  
  #if defined(CONFIG_OF_GPIO)
  	/*
  	 * If CONFIG_OF is enabled, then all GPIO controllers described in the
  	 * device tree automatically may have an OF translation
  	 */
  	struct device_node *of_node;
  	int of_gpio_n_cells;

  	int (*of_xlate)(struct gpio_chip *gc,
  		        const struct of_phandle_args *gpiospec, u32 *flags);

  #endif

  };
  
  extern const char *gpiochip_is_requested(struct gpio_chip *chip,
  			unsigned offset);

  extern struct gpio_chip *gpio_to_chip(unsigned gpio);

  extern int __must_check gpiochip_reserve(int start, int ngpio);

  
  /* add/remove chips */
  extern int gpiochip_add(struct gpio_chip *chip);
  extern int __must_check gpiochip_remove(struct gpio_chip *chip);

  extern struct gpio_chip *gpiochip_find(void *data,
  					int (*match)(struct gpio_chip *chip,
  						     void *data));

  
  
  /* Always use the library code for GPIO management calls,
   * or when sleeping may be involved.
   */

  extern int gpio_request(unsigned gpio, const char *label);

  extern void gpio_free(unsigned gpio);

  extern int gpio_direction_input(unsigned gpio);
  extern int gpio_direction_output(unsigned gpio, int value);

  extern int gpio_set_debounce(unsigned gpio, unsigned debounce);

  extern int gpio_get_value_cansleep(unsigned gpio);
  extern void gpio_set_value_cansleep(unsigned gpio, int value);
  
  
  /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
   * the GPIO is constant and refers to some always-present controller,
   * giving direct access to chip registers and tight bitbanging loops.
   */
  extern int __gpio_get_value(unsigned gpio);
  extern void __gpio_set_value(unsigned gpio, int value);
  
  extern int __gpio_cansleep(unsigned gpio);

  extern int __gpio_to_irq(unsigned gpio);

  extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);

  extern int gpio_request_array(const struct gpio *array, size_t num);
  extern void gpio_free_array(const struct gpio *array, size_t num);

  /* bindings for managed devices that want to request gpios */
  int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
  void devm_gpio_free(struct device *dev, unsigned int gpio);

  #ifdef CONFIG_GPIO_SYSFS
  
  /*
   * A sysfs interface can be exported by individual drivers if they want,
   * but more typically is configured entirely from userspace.
   */
  extern int gpio_export(unsigned gpio, bool direction_may_change);

  extern int gpio_export_link(struct device *dev, const char *name,
  			unsigned gpio);

  extern int gpio_sysfs_set_active_low(unsigned gpio, int value);

  extern void gpio_unexport(unsigned gpio);
  
  #endif	/* CONFIG_GPIO_SYSFS */

  #else	/* !CONFIG_GPIOLIB */

  static inline bool gpio_is_valid(int number)

  {
  	/* only non-negative numbers are valid */
  	return number >= 0;
  }

  /* platforms that don't directly support access to GPIOs through I2C, SPI,
   * or other blocking infrastructure can use these wrappers.
   */
  
  static inline int gpio_cansleep(unsigned gpio)
  {
  	return 0;
  }
  
  static inline int gpio_get_value_cansleep(unsigned gpio)
  {
  	might_sleep();

  	return __gpio_get_value(gpio);

  }
  
  static inline void gpio_set_value_cansleep(unsigned gpio, int value)
  {
  	might_sleep();

  	__gpio_set_value(gpio, value);

  }

  #endif /* !CONFIG_GPIOLIB */

  
  #ifndef CONFIG_GPIO_SYSFS

  struct device;

  /* sysfs support is only available with gpiolib, where it's optional */
  
  static inline int gpio_export(unsigned gpio, bool direction_may_change)
  {
  	return -ENOSYS;
  }

  static inline int gpio_export_link(struct device *dev, const char *name,
  				unsigned gpio)
  {
  	return -ENOSYS;
  }

  static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
  {
  	return -ENOSYS;
  }

  static inline void gpio_unexport(unsigned gpio)
  {
  }
  #endif	/* CONFIG_GPIO_SYSFS */

  #endif /* _ASM_GENERIC_GPIO_H */