[8.09] kernel: refresh patches
[openwrt/svn-archive/archive.git] / target / linux / generic-2.6 / 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 */