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authorGabor Juhos <juhosg@openwrt.org>2008-07-21 17:08:14 +0000
committerGabor Juhos <juhosg@openwrt.org>2008-07-21 17:08:14 +0000
commitf529a3742043a23da4f715c3664d5a822b1f970c (patch)
treea4cdaee84e23765d98072df25883f365cbc0d66a /target/linux/generic-2.6/patches-2.6.25
parent3d9c4c9073deaf01d592d6940af21be81d92e88a (diff)
downloadupstream-f529a3742043a23da4f715c3664d5a822b1f970c.tar.gz
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upstream-f529a3742043a23da4f715c3664d5a822b1f970c.zip
surprise :p
SVN-Revision: 11894
Diffstat (limited to 'target/linux/generic-2.6/patches-2.6.25')
-rw-r--r--target/linux/generic-2.6/patches-2.6.25/910-m25p80_redboot_partitions.patch17
-rw-r--r--target/linux/generic-2.6/patches-2.6.25/920-backport-gpio-is-valid.patch18
-rw-r--r--target/linux/generic-2.6/patches-2.6.25/960-backport_gpiolib_better_rmmod_infrastructure.patch93
-rw-r--r--target/linux/generic-2.6/patches-2.6.25/961-backport_gpio_define_gpio_valid.patch136
-rw-r--r--target/linux/generic-2.6/patches-2.6.25/962-backport_gpiolib_dynamic_gpio_number_allocation.patch118
-rw-r--r--target/linux/generic-2.6/patches-2.6.25/963-backport_gpio_chip_reserve.patch116
-rw-r--r--target/linux/generic-2.6/patches-2.6.25/964-backport_gpiolib_fix_off_by_one_errors.patch48
7 files changed, 528 insertions, 18 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.25/910-m25p80_redboot_partitions.patch b/target/linux/generic-2.6/patches-2.6.25/910-m25p80_redboot_partitions.patch
new file mode 100644
index 0000000000..5f35f007fc
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.25/910-m25p80_redboot_partitions.patch
@@ -0,0 +1,17 @@
+diff -Nur a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
+--- a/drivers/mtd/devices/m25p80.c 2008-07-06 14:36:59.000000000 +0200
++++ b/drivers/mtd/devices/m25p80.c 2008-07-06 15:17:48.000000000 +0200
+@@ -631,12 +631,10 @@
+ struct mtd_partition *parts = NULL;
+ int nr_parts = 0;
+
+-#ifdef CONFIG_MTD_CMDLINE_PARTS
+- static const char *part_probes[] = { "cmdlinepart", NULL, };
++ static const char *part_probes[] = { "RedBoot", "cmdlinepart", NULL, };
+
+ nr_parts = parse_mtd_partitions(&flash->mtd,
+ part_probes, &parts, 0);
+-#endif
+
+ if (nr_parts <= 0 && data && data->parts) {
+ parts = data->parts;
diff --git a/target/linux/generic-2.6/patches-2.6.25/920-backport-gpio-is-valid.patch b/target/linux/generic-2.6/patches-2.6.25/920-backport-gpio-is-valid.patch
deleted file mode 100644
index 966270b78e..0000000000
--- a/target/linux/generic-2.6/patches-2.6.25/920-backport-gpio-is-valid.patch
+++ /dev/null
@@ -1,18 +0,0 @@
-Backport gpio_is_valid() for gpiolib from linux-2.6.26
-Index: linux-2.6.25.10/include/asm-generic/gpio.h
-===================================================================
---- linux-2.6.25.10.orig/include/asm-generic/gpio.h 2008-07-03 05:46:47.000000000 +0200
-+++ linux-2.6.25.10/include/asm-generic/gpio.h 2008-07-20 20:32:12.000000000 +0200
-@@ -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;
-
- /**
diff --git a/target/linux/generic-2.6/patches-2.6.25/960-backport_gpiolib_better_rmmod_infrastructure.patch b/target/linux/generic-2.6/patches-2.6.25/960-backport_gpiolib_better_rmmod_infrastructure.patch
new file mode 100644
index 0000000000..a6822fc14e
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.25/960-backport_gpiolib_better_rmmod_infrastructure.patch
@@ -0,0 +1,93 @@
+From: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
+Date: Mon, 28 Apr 2008 09:14:44 +0000 (-0700)
+Subject: gpiolib: better rmmod infrastructure
+X-Git-Tag: v2.6.26-rc1~851
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=438d8908b379b6322fc3b28d45c9ebdddf58bc20
+
+gpiolib: better rmmod infrastructure
+
+As long as one or more GPIOs on a gpio chip are used its driver should not be
+unloaded. The existing mechanism (gpiochip_remove failure) doesn't address
+that, since rmmod can no longer be made to fail by having the cleanup code
+report errors. Module usecounts are the solution.
+
+Assuming standard "initialize struct to zero" policies, this change won't
+affect SOC platform drivers. However, drivers for external chips (on I2C and
+SPI busses) should be updated if they can be built as modules.
+
+Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
+[ gpio_ensure_requested() needs to update module usecounts too ]
+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 d8db2f8..eb75d12 100644
+--- a/drivers/gpio/gpiolib.c
++++ b/drivers/gpio/gpiolib.c
+@@ -68,6 +68,9 @@ static void gpio_ensure_requested(struct gpio_desc *desc)
+ if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
+ pr_warning("GPIO-%d autorequested\n", (int)(desc - gpio_desc));
+ desc_set_label(desc, "[auto]");
++ if (!try_module_get(desc->chip->owner))
++ pr_err("GPIO-%d: module can't be gotten \n",
++ (int)(desc - gpio_desc));
+ }
+ }
+
+@@ -177,6 +180,9 @@ int gpio_request(unsigned gpio, const char *label)
+ if (desc->chip == NULL)
+ goto done;
+
++ if (!try_module_get(desc->chip->owner))
++ goto done;
++
+ /* NOTE: gpio_request() can be called in early boot,
+ * before IRQs are enabled.
+ */
+@@ -184,8 +190,10 @@ int gpio_request(unsigned gpio, const char *label)
+ if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
+ desc_set_label(desc, label ? : "?");
+ status = 0;
+- } else
++ } else {
+ status = -EBUSY;
++ module_put(desc->chip->owner);
++ }
+
+ done:
+ if (status)
+@@ -209,9 +217,10 @@ void gpio_free(unsigned gpio)
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ desc = &gpio_desc[gpio];
+- if (desc->chip && test_and_clear_bit(FLAG_REQUESTED, &desc->flags))
++ if (desc->chip && test_and_clear_bit(FLAG_REQUESTED, &desc->flags)) {
+ desc_set_label(desc, NULL);
+- else
++ module_put(desc->chip->owner);
++ } else
+ WARN_ON(extra_checks);
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
+index f29a502..7e77b6f 100644
+--- a/include/asm-generic/gpio.h
++++ b/include/asm-generic/gpio.h
+@@ -17,6 +17,7 @@
+ #endif
+
+ struct seq_file;
++struct module;
+
+ /**
+ * struct gpio_chip - abstract a GPIO controller
+@@ -48,6 +49,7 @@ struct seq_file;
+ */
+ struct gpio_chip {
+ char *label;
++ struct module *owner;
+
+ int (*direction_input)(struct gpio_chip *chip,
+ unsigned offset);
diff --git a/target/linux/generic-2.6/patches-2.6.25/961-backport_gpio_define_gpio_valid.patch b/target/linux/generic-2.6/patches-2.6.25/961-backport_gpio_define_gpio_valid.patch
new file mode 100644
index 0000000000..2e826d43f4
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.25/961-backport_gpio_define_gpio_valid.patch
@@ -0,0 +1,136 @@
+From: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
+Date: Mon, 28 Apr 2008 09:14:46 +0000 (-0700)
+Subject: gpio: define gpio_is_valid()
+X-Git-Tag: v2.6.26-rc1~849
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=e6de1808f8ebfeb7e49f3c5a30cb8f2032beb287
+
+gpio: define gpio_is_valid()
+
+Introduce a gpio_is_valid() predicate; use it in gpiolib.
+
+Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
+ [ use inline function; follow the gpio_* naming convention;
+ work without gpiolib; all programming interfaces need docs ]
+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/Documentation/gpio.txt b/Documentation/gpio.txt
+index 5463009..c35ca9e 100644
+--- a/Documentation/gpio.txt
++++ b/Documentation/gpio.txt
+@@ -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.
+
+diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
+index eb75d12..623fcd9 100644
+--- a/drivers/gpio/gpiolib.c
++++ b/drivers/gpio/gpiolib.c
+@@ -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;
+diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
+index 7e77b6f..464c5b3 100644
+--- a/include/asm-generic/gpio.h
++++ b/include/asm-generic/gpio.h
+@@ -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.
+ */
diff --git a/target/linux/generic-2.6/patches-2.6.25/962-backport_gpiolib_dynamic_gpio_number_allocation.patch b/target/linux/generic-2.6/patches-2.6.25/962-backport_gpiolib_dynamic_gpio_number_allocation.patch
new file mode 100644
index 0000000000..0007423223
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.25/962-backport_gpiolib_dynamic_gpio_number_allocation.patch
@@ -0,0 +1,118 @@
+From: Anton Vorontsov <avorontsov@ru.mvista.com>
+Date: Mon, 28 Apr 2008 09:14:46 +0000 (-0700)
+Subject: gpiolib: dynamic gpio number allocation
+X-Git-Tag: v2.6.26-rc1~848
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=8d0aab2f16c4fa170f32e7a74a52cd0122bbafef
+
+gpiolib: dynamic gpio number allocation
+
+If gpio_chip->base is negative during registration, gpiolib performs dynamic
+base allocation. This is useful for devices that aren't always present, such
+as GPIOs on hotplugged devices rather than mainboards. (This behavior was
+previously specified but not implemented.)
+
+To avoid using any numbers that may have been explicitly assigned but not yet
+registered, this dynamic allocation assigns GPIO numbers from the biggest
+number on down, instead of from the smallest on up.
+
+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 623fcd9..2ba6127 100644
+--- a/drivers/gpio/gpiolib.c
++++ b/drivers/gpio/gpiolib.c
+@@ -80,6 +80,33 @@ static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
+ return gpio_desc[gpio].chip;
+ }
+
++/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
++static int gpiochip_find_base(int ngpio)
++{
++ int i;
++ int spare = 0;
++ int base = -ENOSPC;
++
++ for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
++ struct gpio_chip *chip = gpio_desc[i].chip;
++
++ if (!chip) {
++ spare++;
++ if (spare == ngpio) {
++ base = i;
++ break;
++ }
++ } else {
++ spare = 0;
++ i -= chip->ngpio - 1;
++ }
++ }
++
++ if (gpio_is_valid(base))
++ pr_debug("%s: found new base at %d\n", __func__, base);
++ return base;
++}
++
+ /**
+ * gpiochip_add() - register a gpio_chip
+ * @chip: the chip to register, with chip->base initialized
+@@ -88,38 +115,49 @@ static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
+ * Returns a negative errno if the chip can't be registered, such as
+ * because the chip->base is invalid or already associated with a
+ * different chip. Otherwise it returns zero as a success code.
++ *
++ * If chip->base is negative, this requests dynamic assignment of
++ * a range of valid GPIOs.
+ */
+ int gpiochip_add(struct gpio_chip *chip)
+ {
+ unsigned long flags;
+ int status = 0;
+ unsigned id;
++ int base = chip->base;
+
+- /* NOTE chip->base negative is reserved to mean a request for
+- * dynamic allocation. We don't currently support that.
+- */
+-
+- if (chip->base < 0 || !gpio_is_valid(chip->base + chip->ngpio)) {
++ if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio))
++ && base >= 0) {
+ status = -EINVAL;
+ goto fail;
+ }
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
++ if (base < 0) {
++ base = gpiochip_find_base(chip->ngpio);
++ if (base < 0) {
++ status = base;
++ goto fail_unlock;
++ }
++ chip->base = base;
++ }
++
+ /* these GPIO numbers must not be managed by another gpio_chip */
+- for (id = chip->base; id < chip->base + chip->ngpio; id++) {
++ for (id = base; id < base + chip->ngpio; id++) {
+ if (gpio_desc[id].chip != NULL) {
+ status = -EBUSY;
+ break;
+ }
+ }
+ if (status == 0) {
+- for (id = chip->base; id < chip->base + chip->ngpio; id++) {
++ for (id = base; id < base + chip->ngpio; id++) {
+ gpio_desc[id].chip = chip;
+ gpio_desc[id].flags = 0;
+ }
+ }
+
++fail_unlock:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ fail:
+ /* failures here can mean systems won't boot... */
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 0000000000..306fb0a169
--- /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);
diff --git a/target/linux/generic-2.6/patches-2.6.25/964-backport_gpiolib_fix_off_by_one_errors.patch b/target/linux/generic-2.6/patches-2.6.25/964-backport_gpiolib_fix_off_by_one_errors.patch
new file mode 100644
index 0000000000..715f9abbbf
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.25/964-backport_gpiolib_fix_off_by_one_errors.patch
@@ -0,0 +1,48 @@
+From: Trent Piepho <xyzzy@speakeasy.org>
+Date: Fri, 23 May 2008 20:04:44 +0000 (-0700)
+Subject: gpiolib: fix off by one errors
+X-Git-Tag: v2.6.26-rc4~31
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=bff5fda972dc23bd1806a47c2098ae173585d013
+
+gpiolib: fix off by one errors
+
+The last gpio belonging to a chip is chip->base + chip->ngpios - 1. Some
+places in the code, but not all, forgot the critical minus one.
+
+Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
+Acked-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 7f138c6..beaf6b3 100644
+--- a/drivers/gpio/gpiolib.c
++++ b/drivers/gpio/gpiolib.c
+@@ -127,7 +127,7 @@ int __init gpiochip_reserve(int start, int ngpio)
+ unsigned long flags;
+ int i;
+
+- if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio))
++ if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1))
+ return -EINVAL;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+@@ -170,7 +170,7 @@ int gpiochip_add(struct gpio_chip *chip)
+ unsigned id;
+ int base = chip->base;
+
+- if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio))
++ if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
+ && base >= 0) {
+ status = -EINVAL;
+ goto fail;
+@@ -207,7 +207,7 @@ fail:
+ /* failures here can mean systems won't boot... */
+ if (status)
+ pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n",
+- chip->base, chip->base + chip->ngpio,
++ chip->base, chip->base + chip->ngpio - 1,
+ chip->label ? : "generic");
+ return status;
+ }