target/linux/generic/patches-2.6.25/961-backport_gpio_define_gpio_valid.patch

   1 From: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
   2 Date: Mon, 28 Apr 2008 09:14:46 +0000 (-0700)
   3 Subject: gpio: define gpio_is_valid()
   4 X-Git-Tag: v2.6.26-rc1~849
   5 X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=e6de1808f8ebfeb7e49f3c5a30cb8f2032beb287
   6
   7 gpio: define gpio_is_valid()
   8
   9 Introduce a gpio_is_valid() predicate; use it in gpiolib.
  10
  11 Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
  12     [ use inline function; follow the gpio_* naming convention;
  13       work without gpiolib; all programming interfaces need docs ]
  14 Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
  15 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  16 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  17 ---
  18
  19 --- a/Documentation/gpio.txt
  20 +++ b/Documentation/gpio.txt
  21 @@ -107,6 +107,16 @@ type of GPIO controller, and on one part
  22  The numbers need not be contiguous; either of those platforms could also
  23  use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders.
  24
  25 +If you want to initialize a structure with an invalid GPIO number, use
  26 +some negative number (perhaps "-EINVAL"); that will never be valid.  To
  27 +test if a number could reference a GPIO, you may use this predicate:
  28 +
  29 +       int gpio_is_valid(int number);
  30 +
  31 +A number that's not valid will be rejected by calls which may request
  32 +or free GPIOs (see below).  Other numbers may also be rejected; for
  33 +example, a number might be valid but unused on a given board.
  34 +
  35  Whether a platform supports multiple GPIO controllers is currently a
  36  platform-specific implementation issue.
  37
  38 --- a/drivers/gpio/gpiolib.c
  39 +++ b/drivers/gpio/gpiolib.c
  40 @@ -99,7 +99,7 @@ int gpiochip_add(struct gpio_chip *chip)
  41          * dynamic allocation.  We don't currently support that.
  42          */
  43
  44 -       if (chip->base < 0 || (chip->base  + chip->ngpio) >= ARCH_NR_GPIOS) {
  45 +       if (chip->base < 0 || !gpio_is_valid(chip->base  + chip->ngpio)) {
  46                 status = -EINVAL;
  47                 goto fail;
  48         }
  49 @@ -174,7 +174,7 @@ int gpio_request(unsigned gpio, const ch
  50
  51         spin_lock_irqsave(&gpio_lock, flags);
  52
  53 -       if (gpio >= ARCH_NR_GPIOS)
  54 +       if (!gpio_is_valid(gpio))
  55                 goto done;
  56         desc = &gpio_desc[gpio];
  57         if (desc->chip == NULL)
  58 @@ -209,7 +209,7 @@ void gpio_free(unsigned gpio)
  59         unsigned long           flags;
  60         struct gpio_desc        *desc;
  61
  62 -       if (gpio >= ARCH_NR_GPIOS) {
  63 +       if (!gpio_is_valid(gpio)) {
  64                 WARN_ON(extra_checks);
  65                 return;
  66         }
  67 @@ -245,7 +245,7 @@ const char *gpiochip_is_requested(struct
  68  {
  69         unsigned gpio = chip->base + offset;
  70
  71 -       if (gpio >= ARCH_NR_GPIOS || gpio_desc[gpio].chip != chip)
  72 +       if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
  73                 return NULL;
  74         if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
  75                 return NULL;
  76 @@ -276,7 +276,7 @@ int gpio_direction_input(unsigned gpio)
  77
  78         spin_lock_irqsave(&gpio_lock, flags);
  79
  80 -       if (gpio >= ARCH_NR_GPIOS)
  81 +       if (!gpio_is_valid(gpio))
  82                 goto fail;
  83         chip = desc->chip;
  84         if (!chip || !chip->get || !chip->direction_input)
  85 @@ -314,7 +314,7 @@ int gpio_direction_output(unsigned gpio,
  86
  87         spin_lock_irqsave(&gpio_lock, flags);
  88
  89 -       if (gpio >= ARCH_NR_GPIOS)
  90 +       if (!gpio_is_valid(gpio))
  91                 goto fail;
  92         chip = desc->chip;
  93         if (!chip || !chip->set || !chip->direction_output)
  94 @@ -531,7 +531,7 @@ static int gpiolib_show(struct seq_file
  95
  96         /* REVISIT this isn't locked against gpio_chip removal ... */
  97
  98 -       for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
  99 +       for (gpio = 0; gpio_is_valid(gpio); gpio++) {
 100                 if (chip == gpio_desc[gpio].chip)
 101                         continue;
 102                 chip = gpio_desc[gpio].chip;
 103 --- a/include/asm-generic/gpio.h
 104 +++ b/include/asm-generic/gpio.h
 105 @@ -16,6 +16,12 @@
 106  #define ARCH_NR_GPIOS          256
 107  #endif
 108
 109 +static inline int gpio_is_valid(int number)
 110 +{
 111 +       /* only some non-negative numbers are valid */
 112 +       return ((unsigned)number) < ARCH_NR_GPIOS;
 113 +}
 114 +
 115  struct seq_file;
 116  struct module;
 117
 118 @@ -99,6 +105,16 @@ extern int __gpio_cansleep(unsigned gpio
 119
 120  #else
 121
 122 +static inline int __gpio_is_valid(int number)
 123 +{
 124 +       /* only non-negative numbers are valid */
 125 +       return number >= 0;
 126 +}
 127 +
 128 +#ifndef gpio_is_valid
 129 +#define gpio_is_valid  __gpio_is_valid
 130 +#endif
 131 +
 132  /* platforms that don't directly support access to GPIOs through I2C, SPI,
 133   * or other blocking infrastructure can use these wrappers.
 134   */