[deliverable/linux.git] / include / asm-generic / gpio.h

#ifndef _ASM_GENERIC_GPIO_H
#define _ASM_GENERIC_GPIO_H

#include <linux/types.h>

#ifdef CONFIG_HAVE_GPIO_LIB

#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.
 */

#ifndef ARCH_NR_GPIOS
#define ARCH_NR_GPIOS		256
#endif

static inline int gpio_is_valid(int number)
{
	/* only some non-negative numbers are valid */
	return ((unsigned)number) < ARCH_NR_GPIOS;
}

struct seq_file;
struct module;

/**
 * struct gpio_chip - abstract a GPIO controller
 * @label: for diagnostics
 * @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"
 * @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
 *
 * 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 {
	char			*label;
	struct module		*owner;

	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);
	void			(*set)(struct gpio_chip *chip,
						unsigned offset, int value);
	void			(*dbg_show)(struct seq_file *s,
						struct gpio_chip *chip);
	int			base;
	u16			ngpio;
	unsigned		can_sleep:1;
};

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


/* 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_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);


#else

static inline int 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

#endif /* _ASM_GENERIC_GPIO_H */
Commit	Line	Data
4c20386c DB	1	#ifndef _ASM_GENERIC_GPIO_H
	2	#define _ASM_GENERIC_GPIO_H
	3
6ea0205b DB	4	#include <linux/types.h>
6ea0205b DB	5
d2876d08 DB	6	#ifdef CONFIG_HAVE_GPIO_LIB
d2876d08 DB	7
6ea0205b DB	8	#include <linux/compiler.h>
6ea0205b DB	9
d2876d08 DB	10	/* Platforms may implement their GPIO interface with library code,
	11	* at a small performance cost for non-inlined operations and some
	12	* extra memory (for code and for per-GPIO table entries).
	13	*
	14	* While the GPIO programming interface defines valid GPIO numbers
	15	* to be in the range 0..MAX_INT, this library restricts them to the
	16	* smaller range 0..ARCH_NR_GPIOS.
	17	*/
	18
	19	#ifndef ARCH_NR_GPIOS
	20	#define ARCH_NR_GPIOS 256
	21	#endif
	22
e6de1808 GL	23	static inline int gpio_is_valid(int number)
	24	{
	25	/* only some non-negative numbers are valid */
	26	return ((unsigned)number) < ARCH_NR_GPIOS;
	27	}
	28
d2876d08	29	struct seq_file;
438d8908	30	struct module;
d2876d08 DB	31
	32	/**
	33	* struct gpio_chip - abstract a GPIO controller
	34	* @label: for diagnostics
	35	* @direction_input: configures signal "offset" as input, or returns error
	36	* @get: returns value for signal "offset"; for output signals this
	37	* returns either the value actually sensed, or zero
	38	* @direction_output: configures signal "offset" as output, or returns error
	39	* @set: assigns output value for signal "offset"
	40	* @dbg_show: optional routine to show contents in debugfs; default code
	41	* will be used when this is omitted, but custom code can show extra
	42	* state (such as pullup/pulldown configuration).
	43	* @base: identifies the first GPIO number handled by this chip; or, if
	44	* negative during registration, requests dynamic ID allocation.
	45	* @ngpio: the number of GPIOs handled by this controller; the last GPIO
	46	* handled is (base + ngpio - 1).
	47	* @can_sleep: flag must be set iff get()/set() methods sleep, as they
	48	* must while accessing GPIO expander chips over I2C or SPI
	49	*
	50	* A gpio_chip can help platforms abstract various sources of GPIOs so
	51	* they can all be accessed through a common programing interface.
	52	* Example sources would be SOC controllers, FPGAs, multifunction
	53	* chips, dedicated GPIO expanders, and so on.
	54	*
	55	* Each chip controls a number of signals, identified in method calls
	56	* by "offset" values in the range 0..(@ngpio - 1). When those signals
	57	* are referenced through calls like gpio_get_value(gpio), the offset
	58	* is calculated by subtracting @base from the gpio number.
	59	*/
	60	struct gpio_chip {
	61	char *label;
438d8908	62	struct module *owner;
d2876d08 DB	63
	64	int (direction_input)(struct gpio_chip chip,
	65	unsigned offset);
	66	int (get)(struct gpio_chip chip,
	67	unsigned offset);
	68	int (direction_output)(struct gpio_chip chip,
	69	unsigned offset, int value);
	70	void (set)(struct gpio_chip chip,
	71	unsigned offset, int value);
	72	void (dbg_show)(struct seq_file s,
	73	struct gpio_chip *chip);
	74	int base;
	75	u16 ngpio;
	76	unsigned can_sleep:1;
	77	};
	78
	79	extern const char gpiochip_is_requested(struct gpio_chip chip,
	80	unsigned offset);
6ea0205b	81	extern int __must_check gpiochip_reserve(int start, int ngpio);
d2876d08 DB	82
	83	/* add/remove chips */
	84	extern int gpiochip_add(struct gpio_chip *chip);
	85	extern int __must_check gpiochip_remove(struct gpio_chip *chip);
	86
	87
	88	/* Always use the library code for GPIO management calls,
	89	* or when sleeping may be involved.
	90	*/
	91	extern int gpio_request(unsigned gpio, const char *label);
	92	extern void gpio_free(unsigned gpio);
	93
	94	extern int gpio_direction_input(unsigned gpio);
	95	extern int gpio_direction_output(unsigned gpio, int value);
	96
	97	extern int gpio_get_value_cansleep(unsigned gpio);
	98	extern void gpio_set_value_cansleep(unsigned gpio, int value);
	99
	100
	101	/* A platform's <asm/gpio.h> code may want to inline the I/O calls when
	102	* the GPIO is constant and refers to some always-present controller,
	103	* giving direct access to chip registers and tight bitbanging loops.
	104	*/
	105	extern int __gpio_get_value(unsigned gpio);
	106	extern void __gpio_set_value(unsigned gpio, int value);
	107
	108	extern int __gpio_cansleep(unsigned gpio);
	109
	110
	111	#else
	112
e6de1808 GL	113	static inline int gpio_is_valid(int number)
	114	{
	115	/* only non-negative numbers are valid */
	116	return number >= 0;
	117	}
	118
4c20386c DB	119	/* platforms that don't directly support access to GPIOs through I2C, SPI,
	120	* or other blocking infrastructure can use these wrappers.
	121	*/
	122
	123	static inline int gpio_cansleep(unsigned gpio)
	124	{
	125	return 0;
	126	}
	127
	128	static inline int gpio_get_value_cansleep(unsigned gpio)
	129	{
	130	might_sleep();
	131	return gpio_get_value(gpio);
	132	}
	133
	134	static inline void gpio_set_value_cansleep(unsigned gpio, int value)
	135	{
	136	might_sleep();
	137	gpio_set_value(gpio, value);
	138	}
	139
d2876d08 DB	140	#endif
d2876d08 DB	141
4c20386c	142	#endif /* _ASM_GENERIC_GPIO_H */