Commit 169b6a7a6e91e1ea32136681b475cbaf2074bf35
Committed by
Linus Torvalds
Linus Torvalds
1 parent
8d0aab2f16
Exists in
master
and in
7 other branches
gpiochip_reserve()
Add a new function gpiochip_reserve() to reserve ranges of gpios that platform code has pre-allocated. That is, this marks gpio numbers which will be claimed by drivers that haven't yet been loaded, and thus are not available for dynamic gpio number allocation. [akpm@linux-foundation.org: remove unneeded __must_check] [david-b@pacbell.net: don't export gpiochip_reserve (section fix)] Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 2 changed files with 48 additions and 3 deletions Side-by-side Diff
drivers/gpio/gpiolib.c
| ... | ... | @@ -43,6 +43,7 @@ |
| 43 | 43 | /* flag symbols are bit numbers */ |
| 44 | 44 | #define FLAG_REQUESTED 0 |
| 45 | 45 | #define FLAG_IS_OUT 1 |
| 46 | +#define FLAG_RESERVED 2 | |
| 46 | 47 | |
| 47 | 48 | #ifdef CONFIG_DEBUG_FS |
| 48 | 49 | const char *label; |
| 49 | 50 | |
| ... | ... | @@ -88,9 +89,10 @@ |
| 88 | 89 | int base = -ENOSPC; |
| 89 | 90 | |
| 90 | 91 | for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) { |
| 91 | - struct gpio_chip *chip = gpio_desc[i].chip; | |
| 92 | + struct gpio_desc *desc = &gpio_desc[i]; | |
| 93 | + struct gpio_chip *chip = desc->chip; | |
| 92 | 94 | |
| 93 | - if (!chip) { | |
| 95 | + if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) { | |
| 94 | 96 | spare++; |
| 95 | 97 | if (spare == ngpio) { |
| 96 | 98 | base = i; |
| 97 | 99 | |
| ... | ... | @@ -98,13 +100,55 @@ |
| 98 | 100 | } |
| 99 | 101 | } else { |
| 100 | 102 | spare = 0; |
| 101 | - i -= chip->ngpio - 1; | |
| 103 | + if (chip) | |
| 104 | + i -= chip->ngpio - 1; | |
| 102 | 105 | } |
| 103 | 106 | } |
| 104 | 107 | |
| 105 | 108 | if (gpio_is_valid(base)) |
| 106 | 109 | pr_debug("%s: found new base at %d\n", __func__, base); |
| 107 | 110 | return base; |
| 111 | +} | |
| 112 | + | |
| 113 | +/** | |
| 114 | + * gpiochip_reserve() - reserve range of gpios to use with platform code only | |
| 115 | + * @start: starting gpio number | |
| 116 | + * @ngpio: number of gpios to reserve | |
| 117 | + * Context: platform init, potentially before irqs or kmalloc will work | |
| 118 | + * | |
| 119 | + * Returns a negative errno if any gpio within the range is already reserved | |
| 120 | + * or registered, else returns zero as a success code. Use this function | |
| 121 | + * to mark a range of gpios as unavailable for dynamic gpio number allocation, | |
| 122 | + * for example because its driver support is not yet loaded. | |
| 123 | + */ | |
| 124 | +int __init gpiochip_reserve(int start, int ngpio) | |
| 125 | +{ | |
| 126 | + int ret = 0; | |
| 127 | + unsigned long flags; | |
| 128 | + int i; | |
| 129 | + | |
| 130 | + if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio)) | |
| 131 | + return -EINVAL; | |
| 132 | + | |
| 133 | + spin_lock_irqsave(&gpio_lock, flags); | |
| 134 | + | |
| 135 | + for (i = start; i < start + ngpio; i++) { | |
| 136 | + struct gpio_desc *desc = &gpio_desc[i]; | |
| 137 | + | |
| 138 | + if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) { | |
| 139 | + ret = -EBUSY; | |
| 140 | + goto err; | |
| 141 | + } | |
| 142 | + | |
| 143 | + set_bit(FLAG_RESERVED, &desc->flags); | |
| 144 | + } | |
| 145 | + | |
| 146 | + pr_debug("%s: reserved gpios from %d to %d\n", | |
| 147 | + __func__, start, start + ngpio - 1); | |
| 148 | +err: | |
| 149 | + spin_unlock_irqrestore(&gpio_lock, flags); | |
| 150 | + | |
| 151 | + return ret; | |
| 108 | 152 | } |
| 109 | 153 | |
| 110 | 154 | /** |
include/asm-generic/gpio.h