diff options
Diffstat (limited to 'target/linux/generic-2.6/patches-2.6.25/963-backport_gpio_chip_reserve.patch')
| -rw-r--r-- | target/linux/generic-2.6/patches-2.6.25/963-backport_gpio_chip_reserve.patch | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.25/963-backport_gpio_chip_reserve.patch b/target/linux/generic-2.6/patches-2.6.25/963-backport_gpio_chip_reserve.patch new file mode 100644 index 000000000..306fb0a16 --- /dev/null +++ b/target/linux/generic-2.6/patches-2.6.25/963-backport_gpio_chip_reserve.patch @@ -0,0 +1,116 @@ +From: Anton Vorontsov <avorontsov@ru.mvista.com> +Date: Mon, 28 Apr 2008 09:14:47 +0000 (-0700) +Subject: gpiochip_reserve() +X-Git-Tag: v2.6.26-rc1~847 +X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=169b6a7a6e91e1ea32136681b475cbaf2074bf35 + +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> +--- + +diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c +index 2ba6127..24c62b8 100644 +--- a/drivers/gpio/gpiolib.c ++++ b/drivers/gpio/gpiolib.c +@@ -43,6 +43,7 @@ struct gpio_desc { + /* flag symbols are bit numbers */ + #define FLAG_REQUESTED 0 + #define FLAG_IS_OUT 1 ++#define FLAG_RESERVED 2 + + #ifdef CONFIG_DEBUG_FS + const char *label; +@@ -88,9 +89,10 @@ static int gpiochip_find_base(int ngpio) + int base = -ENOSPC; + + for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) { +- struct gpio_chip *chip = gpio_desc[i].chip; ++ struct gpio_desc *desc = &gpio_desc[i]; ++ struct gpio_chip *chip = desc->chip; + +- if (!chip) { ++ if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) { + spare++; + if (spare == ngpio) { + base = i; +@@ -98,7 +100,8 @@ static int gpiochip_find_base(int ngpio) + } + } else { + spare = 0; +- i -= chip->ngpio - 1; ++ if (chip) ++ i -= chip->ngpio - 1; + } + } + +@@ -108,6 +111,47 @@ static int gpiochip_find_base(int ngpio) + } + + /** ++ * gpiochip_reserve() - reserve range of gpios to use with platform code only ++ * @start: starting gpio number ++ * @ngpio: number of gpios to reserve ++ * Context: platform init, potentially before irqs or kmalloc will work ++ * ++ * Returns a negative errno if any gpio within the range is already reserved ++ * or registered, else returns zero as a success code. Use this function ++ * to mark a range of gpios as unavailable for dynamic gpio number allocation, ++ * for example because its driver support is not yet loaded. ++ */ ++int __init gpiochip_reserve(int start, int ngpio) ++{ ++ int ret = 0; ++ unsigned long flags; ++ int i; ++ ++ if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio)) ++ return -EINVAL; ++ ++ spin_lock_irqsave(&gpio_lock, flags); ++ ++ for (i = start; i < start + ngpio; i++) { ++ struct gpio_desc *desc = &gpio_desc[i]; ++ ++ if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) { ++ ret = -EBUSY; ++ goto err; ++ } ++ ++ set_bit(FLAG_RESERVED, &desc->flags); ++ } ++ ++ pr_debug("%s: reserved gpios from %d to %d\n", ++ __func__, start, start + ngpio - 1); ++err: ++ spin_unlock_irqrestore(&gpio_lock, flags); ++ ++ return ret; ++} ++ ++/** + * gpiochip_add() - register a gpio_chip + * @chip: the chip to register, with chip->base initialized + * Context: potentially before irqs or kmalloc will work +diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h +index 464c5b3..ecf675a 100644 +--- a/include/asm-generic/gpio.h ++++ b/include/asm-generic/gpio.h +@@ -74,6 +74,7 @@ struct gpio_chip { + + extern const char *gpiochip_is_requested(struct gpio_chip *chip, + unsigned offset); ++extern int __init __must_check gpiochip_reserve(int start, int ngpio); + + /* add/remove chips */ + extern int gpiochip_add(struct gpio_chip *chip); |