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Commit e6de1808 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Linus Torvalds
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gpio: define gpio_is_valid() 



Introduce a gpio_is_valid() predicate; use it in gpiolib.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@pengutronix.de>
    [ use inline function; follow the gpio_* naming convention;
      work without gpiolib; all programming interfaces need docs ]
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d72cbed0

Documentation/gpio.txt

+10 −0
Original line number Diff line number Diff line
@@ -107,6 +107,16 @@ type of GPIO controller, and on one particular board 80-95 with an FPGA. 
The numbers need not be contiguous; either of those platforms could also

use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders.



If you want to initialize a structure with an invalid GPIO number, use

some negative number (perhaps "-EINVAL"); that will never be valid.  To

test if a number could reference a GPIO, you may use this predicate:



	int gpio_is_valid(int number);



A number that's not valid will be rejected by calls which may request

or free GPIOs (see below).  Other numbers may also be rejected; for

example, a number might be valid but unused on a given board.



Whether a platform supports multiple GPIO controllers is currently a

platform-specific implementation issue.

drivers/gpio/gpiolib.c

+7 −7
Original line number Diff line number Diff line
@@ -99,7 +99,7 @@ int gpiochip_add(struct gpio_chip *chip) 
	 * dynamic allocation.  We don't currently support that.

	 */



	if (chip->base < 0 || (chip->base  + chip->ngpio) >= ARCH_NR_GPIOS) {

	if (chip->base < 0 || !gpio_is_valid(chip->base  + chip->ngpio)) {

		status = -EINVAL;

		goto fail;

	}
@@ -174,7 +174,7 @@ int gpio_request(unsigned gpio, const char *label) 


	spin_lock_irqsave(&gpio_lock, flags);



	if (gpio >= ARCH_NR_GPIOS)

	if (!gpio_is_valid(gpio))

		goto done;

	desc = &gpio_desc[gpio];

	if (desc->chip == NULL)
@@ -209,7 +209,7 @@ void gpio_free(unsigned gpio) 
	unsigned long		flags;

	struct gpio_desc	*desc;



	if (gpio >= ARCH_NR_GPIOS) {

	if (!gpio_is_valid(gpio)) {

		WARN_ON(extra_checks);

		return;

	}
@@ -245,7 +245,7 @@ const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset) 
{

	unsigned gpio = chip->base + offset;



	if (gpio >= ARCH_NR_GPIOS || gpio_desc[gpio].chip != chip)

	if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)

		return NULL;

	if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)

		return NULL;
@@ -276,7 +276,7 @@ int gpio_direction_input(unsigned gpio) 


	spin_lock_irqsave(&gpio_lock, flags);



	if (gpio >= ARCH_NR_GPIOS)

	if (!gpio_is_valid(gpio))

		goto fail;

	chip = desc->chip;

	if (!chip || !chip->get || !chip->direction_input)
@@ -314,7 +314,7 @@ int gpio_direction_output(unsigned gpio, int value) 


	spin_lock_irqsave(&gpio_lock, flags);



	if (gpio >= ARCH_NR_GPIOS)

	if (!gpio_is_valid(gpio))

		goto fail;

	chip = desc->chip;

	if (!chip || !chip->set || !chip->direction_output)
@@ -531,7 +531,7 @@ static int gpiolib_show(struct seq_file *s, void *unused) 


	/* REVISIT this isn't locked against gpio_chip removal ... */



	for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {

	for (gpio = 0; gpio_is_valid(gpio); gpio++) {

		if (chip == gpio_desc[gpio].chip)

			continue;

		chip = gpio_desc[gpio].chip;

include/asm-generic/gpio.h

+12 −0
Original line number Diff line number Diff line
@@ -16,6 +16,12 @@ 
#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;
@@ -99,6 +105,12 @@ 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.

 */