| 
									
										
										
										
											2007-02-12 00:53:11 -08:00
										 |  |  | #ifndef _ASM_GENERIC_GPIO_H
 | 
					
						
							|  |  |  | #define _ASM_GENERIC_GPIO_H
 | 
					
						
							|  |  |  | 
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										 |  |  | #include <linux/kernel.h>
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										 |  |  | #include <linux/types.h>
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										 |  |  | #include <linux/errno.h>
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										 |  |  | #include <linux/of.h>
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											2012-10-27 15:21:36 +05:30
										 |  |  | #include <linux/pinctrl/pinctrl.h>
 | 
					
						
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										 |  |  | 
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											2008-07-25 01:46:11 -07:00
										 |  |  | #ifdef CONFIG_GPIOLIB
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							| 
									
										
										
										
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										 |  |  | 
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										 |  |  | #include <linux/compiler.h>
 | 
					
						
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											2013-10-17 10:21:36 -07:00
										 |  |  | #include <linux/gpio/driver.h>
 | 
					
						
							|  |  |  | #include <linux/gpio/consumer.h>
 | 
					
						
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										 |  |  | 
 | 
					
						
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										 |  |  | /* 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 | 
					
						
							| 
									
										
										
										
											2008-07-26 15:22:26 -07:00
										 |  |  |  * smaller range 0..ARCH_NR_GPIOS-1. | 
					
						
							| 
									
										
										
										
											2010-09-09 16:38:03 -07:00
										 |  |  |  * | 
					
						
							|  |  |  |  * 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. | 
					
						
							| 
									
										
										
										
											2008-02-04 22:28:20 -08:00
										 |  |  |  */ | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #ifndef ARCH_NR_GPIOS
 | 
					
						
							| 
									
										
										
										
											2014-09-15 17:09:44 +03:00
										 |  |  | #define ARCH_NR_GPIOS		512
 | 
					
						
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										 |  |  | #endif
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							|  |  |  | 
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							| 
									
										
										
										
											2010-09-09 16:38:03 -07:00
										 |  |  | /*
 | 
					
						
							|  |  |  |  * "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. | 
					
						
							|  |  |  |  */ | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
											2011-05-10 16:23:07 -07:00
										 |  |  | static inline bool gpio_is_valid(int number) | 
					
						
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										 |  |  | { | 
					
						
							| 
									
										
										
										
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										 |  |  | 	return number >= 0 && number < ARCH_NR_GPIOS; | 
					
						
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										 |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
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										 |  |  | struct device; | 
					
						
							| 
									
										
										
										
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										 |  |  | struct gpio; | 
					
						
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										 |  |  | struct seq_file; | 
					
						
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										 |  |  | struct module; | 
					
						
							| 
									
										
										
										
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										 |  |  | struct device_node; | 
					
						
							| 
									
										
										
										
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										 |  |  | struct gpio_desc; | 
					
						
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										 |  |  | 
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											2013-10-17 10:21:36 -07:00
										 |  |  | /* caller holds gpio_lock *OR* gpio is marked as requested */ | 
					
						
							|  |  |  | static inline struct gpio_chip *gpio_to_chip(unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_to_chip(gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
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											2008-02-04 22:28:20 -08:00
										 |  |  | 
 | 
					
						
							|  |  |  | /* Always use the library code for GPIO management calls,
 | 
					
						
							|  |  |  |  * or when sleeping may be involved. | 
					
						
							|  |  |  |  */ | 
					
						
							| 
									
										
										
										
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										 |  |  | extern int gpio_request(unsigned gpio, const char *label); | 
					
						
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										 |  |  | extern void gpio_free(unsigned gpio); | 
					
						
							|  |  |  | 
 | 
					
						
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											2014-07-24 14:51:02 +09:00
										 |  |  | static inline int gpio_direction_input(unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_direction_input(gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | static inline int gpio_direction_output(unsigned gpio, int value) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_direction_output_raw(gpio_to_desc(gpio), value); | 
					
						
							|  |  |  | } | 
					
						
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											2008-02-04 22:28:20 -08:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2014-07-24 14:51:02 +09:00
										 |  |  | static inline int gpio_set_debounce(unsigned gpio, unsigned debounce) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_set_debounce(gpio_to_desc(gpio), debounce); | 
					
						
							|  |  |  | } | 
					
						
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											2010-05-26 14:42:23 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2013-10-17 10:21:36 -07:00
										 |  |  | static inline int gpio_get_value_cansleep(unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_get_raw_value_cansleep(gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | static inline void gpio_set_value_cansleep(unsigned gpio, int value) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_set_raw_value_cansleep(gpio_to_desc(gpio), value); | 
					
						
							|  |  |  | } | 
					
						
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											2008-02-04 22:28:20 -08:00
										 |  |  | 
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | /* 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. | 
					
						
							|  |  |  |  */ | 
					
						
							| 
									
										
										
										
											2013-10-17 10:21:36 -07:00
										 |  |  | static inline int __gpio_get_value(unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_get_raw_value(gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | static inline void __gpio_set_value(unsigned gpio, int value) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_set_raw_value(gpio_to_desc(gpio), value); | 
					
						
							|  |  |  | } | 
					
						
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											2008-02-04 22:28:20 -08:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2013-10-17 10:21:36 -07:00
										 |  |  | static inline int __gpio_cansleep(unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_cansleep(gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
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											2008-02-04 22:28:20 -08:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2013-10-17 10:21:36 -07:00
										 |  |  | static inline int __gpio_to_irq(unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_to_irq(gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
							| 
									
										
										
										
											2008-02-04 22:28:20 -08:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2011-01-13 17:26:46 -08:00
										 |  |  | extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); | 
					
						
							| 
									
										
										
										
											2011-05-25 16:20:31 -07:00
										 |  |  | extern int gpio_request_array(const struct gpio *array, size_t num); | 
					
						
							|  |  |  | extern void gpio_free_array(const struct gpio *array, size_t num); | 
					
						
							| 
									
										
										
										
											2010-03-05 13:44:35 -08:00
										 |  |  | 
 | 
					
						
							| 
									
										
											  
											
												gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
    /sys/class/gpio
    	/export ... asks the kernel to export a GPIO to userspace
    	/unexport ... to return a GPIO to the kernel
        /gpioN ... for each exported GPIO #N
	    /value ... always readable, writes fail for input GPIOs
	    /direction ... r/w as: in, out (default low); write high, low
	/gpiochipN ... for each gpiochip; #N is its first GPIO
	    /base ... (r/o) same as N
	    /label ... (r/o) descriptive, not necessarily unique
	    /ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
  echo 23 > /sys/class/gpio/export
	... will gpio_request(23, "sysfs") and gpio_export(23);
	use /sys/class/gpio/gpio-23/direction to (re)configure it,
	when that GPIO can be used as both input and output.
  echo 23 > /sys/class/gpio/unexport
	... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO.  The additional I-space
footprint is about two thirds of the current size of gpiolib (!).  Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
  * This adds a device pointer to "struct gpio_chip".  When GPIO
    providers initialize that, sysfs gpio class devices become children of
    that device instead of being "virtual" devices.
  * The (few) gpio_chip providers which have such a device node have
    been updated.
  * Some gpio_chip drivers also needed to update their module "owner"
    field ...  for which missing kerneldoc was added.
  * Some gpio_chips don't support input GPIOs.  Those GPIOs are now
    flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
											
										 
											2008-07-25 01:46:07 -07:00
										 |  |  | /*
 | 
					
						
							|  |  |  |  * A sysfs interface can be exported by individual drivers if they want, | 
					
						
							|  |  |  |  * but more typically is configured entirely from userspace. | 
					
						
							|  |  |  |  */ | 
					
						
							| 
									
										
										
										
											2013-10-17 10:21:36 -07:00
										 |  |  | static inline int gpio_export(unsigned gpio, bool direction_may_change) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_export(gpio_to_desc(gpio), direction_may_change); | 
					
						
							|  |  |  | } | 
					
						
							| 
									
										
											  
											
												gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
    /sys/class/gpio
    	/export ... asks the kernel to export a GPIO to userspace
    	/unexport ... to return a GPIO to the kernel
        /gpioN ... for each exported GPIO #N
	    /value ... always readable, writes fail for input GPIOs
	    /direction ... r/w as: in, out (default low); write high, low
	/gpiochipN ... for each gpiochip; #N is its first GPIO
	    /base ... (r/o) same as N
	    /label ... (r/o) descriptive, not necessarily unique
	    /ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
  echo 23 > /sys/class/gpio/export
	... will gpio_request(23, "sysfs") and gpio_export(23);
	use /sys/class/gpio/gpio-23/direction to (re)configure it,
	when that GPIO can be used as both input and output.
  echo 23 > /sys/class/gpio/unexport
	... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO.  The additional I-space
footprint is about two thirds of the current size of gpiolib (!).  Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
  * This adds a device pointer to "struct gpio_chip".  When GPIO
    providers initialize that, sysfs gpio class devices become children of
    that device instead of being "virtual" devices.
  * The (few) gpio_chip providers which have such a device node have
    been updated.
  * Some gpio_chip drivers also needed to update their module "owner"
    field ...  for which missing kerneldoc was added.
  * Some gpio_chips don't support input GPIOs.  Those GPIOs are now
    flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
											
										 
											2008-07-25 01:46:07 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2013-10-17 10:21:36 -07:00
										 |  |  | static inline int gpio_export_link(struct device *dev, const char *name, | 
					
						
							|  |  |  | 				   unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_export_link(dev, name, gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | static inline int gpio_sysfs_set_active_low(unsigned gpio, int value) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value); | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | static inline void gpio_unexport(unsigned gpio) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	gpiod_unexport(gpio_to_desc(gpio)); | 
					
						
							|  |  |  | } | 
					
						
							| 
									
										
											  
											
												gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
    /sys/class/gpio
    	/export ... asks the kernel to export a GPIO to userspace
    	/unexport ... to return a GPIO to the kernel
        /gpioN ... for each exported GPIO #N
	    /value ... always readable, writes fail for input GPIOs
	    /direction ... r/w as: in, out (default low); write high, low
	/gpiochipN ... for each gpiochip; #N is its first GPIO
	    /base ... (r/o) same as N
	    /label ... (r/o) descriptive, not necessarily unique
	    /ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
  echo 23 > /sys/class/gpio/export
	... will gpio_request(23, "sysfs") and gpio_export(23);
	use /sys/class/gpio/gpio-23/direction to (re)configure it,
	when that GPIO can be used as both input and output.
  echo 23 > /sys/class/gpio/unexport
	... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO.  The additional I-space
footprint is about two thirds of the current size of gpiolib (!).  Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
  * This adds a device pointer to "struct gpio_chip".  When GPIO
    providers initialize that, sysfs gpio class devices become children of
    that device instead of being "virtual" devices.
  * The (few) gpio_chip providers which have such a device node have
    been updated.
  * Some gpio_chip drivers also needed to update their module "owner"
    field ...  for which missing kerneldoc was added.
  * Some gpio_chips don't support input GPIOs.  Those GPIOs are now
    flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
											
										 
											2008-07-25 01:46:07 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2013-01-17 22:03:22 +08:00
										 |  |  | #ifdef CONFIG_PINCTRL
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | /**
 | 
					
						
							|  |  |  |  * struct gpio_pin_range - pin range controlled by a gpio chip | 
					
						
							|  |  |  |  * @head: list for maintaining set of pin ranges, used internally | 
					
						
							|  |  |  |  * @pctldev: pinctrl device which handles corresponding pins | 
					
						
							|  |  |  |  * @range: actual range of pins controlled by a gpio controller | 
					
						
							|  |  |  |  */ | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | struct gpio_pin_range { | 
					
						
							|  |  |  | 	struct list_head node; | 
					
						
							|  |  |  | 	struct pinctrl_dev *pctldev; | 
					
						
							|  |  |  | 	struct pinctrl_gpio_range range; | 
					
						
							|  |  |  | }; | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name, | 
					
						
							|  |  |  | 			   unsigned int gpio_offset, unsigned int pin_offset, | 
					
						
							|  |  |  | 			   unsigned int npins); | 
					
						
							| 
									
										
										
										
											2013-10-15 15:37:54 +02:00
										 |  |  | int gpiochip_add_pingroup_range(struct gpio_chip *chip, | 
					
						
							|  |  |  | 			struct pinctrl_dev *pctldev, | 
					
						
							|  |  |  | 			unsigned int gpio_offset, const char *pin_group); | 
					
						
							| 
									
										
										
										
											2013-01-17 22:03:22 +08:00
										 |  |  | void gpiochip_remove_pin_ranges(struct gpio_chip *chip); | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #else
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | static inline int | 
					
						
							|  |  |  | gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name, | 
					
						
							|  |  |  | 		       unsigned int gpio_offset, unsigned int pin_offset, | 
					
						
							|  |  |  | 		       unsigned int npins) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return 0; | 
					
						
							|  |  |  | } | 
					
						
							| 
									
										
										
										
											2013-10-15 15:37:54 +02:00
										 |  |  | static inline int | 
					
						
							|  |  |  | gpiochip_add_pingroup_range(struct gpio_chip *chip, | 
					
						
							|  |  |  | 			struct pinctrl_dev *pctldev, | 
					
						
							|  |  |  | 			unsigned int gpio_offset, const char *pin_group) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	return 0; | 
					
						
							|  |  |  | } | 
					
						
							| 
									
										
										
										
											2013-01-17 22:03:22 +08:00
										 |  |  | 
 | 
					
						
							|  |  |  | static inline void | 
					
						
							|  |  |  | gpiochip_remove_pin_ranges(struct gpio_chip *chip) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | #endif /* CONFIG_PINCTRL */
 | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
											2010-10-27 15:33:16 -07:00
										 |  |  | #else	/* !CONFIG_GPIOLIB */
 | 
					
						
							| 
									
										
										
										
											2008-02-04 22:28:20 -08:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2011-05-10 16:23:07 -07:00
										 |  |  | static inline bool gpio_is_valid(int number) | 
					
						
							| 
									
										
										
										
											2008-04-28 02:14:46 -07:00
										 |  |  | { | 
					
						
							|  |  |  | 	/* only non-negative numbers are valid */ | 
					
						
							|  |  |  | 	return number >= 0; | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
											2007-02-12 00:53:11 -08:00
										 |  |  | /* 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(); | 
					
						
							| 
									
										
										
										
											2011-10-21 09:38:32 +08:00
										 |  |  | 	return __gpio_get_value(gpio); | 
					
						
							| 
									
										
										
										
											2007-02-12 00:53:11 -08:00
										 |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | static inline void gpio_set_value_cansleep(unsigned gpio, int value) | 
					
						
							|  |  |  | { | 
					
						
							|  |  |  | 	might_sleep(); | 
					
						
							| 
									
										
										
										
											2011-10-21 09:38:32 +08:00
										 |  |  | 	__gpio_set_value(gpio, value); | 
					
						
							| 
									
										
										
										
											2007-02-12 00:53:11 -08:00
										 |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
											2010-10-27 15:33:16 -07:00
										 |  |  | #endif /* !CONFIG_GPIOLIB */
 | 
					
						
							| 
									
										
											  
											
												gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
    /sys/class/gpio
    	/export ... asks the kernel to export a GPIO to userspace
    	/unexport ... to return a GPIO to the kernel
        /gpioN ... for each exported GPIO #N
	    /value ... always readable, writes fail for input GPIOs
	    /direction ... r/w as: in, out (default low); write high, low
	/gpiochipN ... for each gpiochip; #N is its first GPIO
	    /base ... (r/o) same as N
	    /label ... (r/o) descriptive, not necessarily unique
	    /ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
  echo 23 > /sys/class/gpio/export
	... will gpio_request(23, "sysfs") and gpio_export(23);
	use /sys/class/gpio/gpio-23/direction to (re)configure it,
	when that GPIO can be used as both input and output.
  echo 23 > /sys/class/gpio/unexport
	... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO.  The additional I-space
footprint is about two thirds of the current size of gpiolib (!).  Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
  * This adds a device pointer to "struct gpio_chip".  When GPIO
    providers initialize that, sysfs gpio class devices become children of
    that device instead of being "virtual" devices.
  * The (few) gpio_chip providers which have such a device node have
    been updated.
  * Some gpio_chip drivers also needed to update their module "owner"
    field ...  for which missing kerneldoc was added.
  * Some gpio_chips don't support input GPIOs.  Those GPIOs are now
    flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
											
										 
											2008-07-25 01:46:07 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2007-02-12 00:53:11 -08:00
										 |  |  | #endif /* _ASM_GENERIC_GPIO_H */
 |