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authorMichael Hennerich <michael.hennerich@analog.com>2009-02-04 16:49:45 +0800
committerBryan Wu <cooloney@kernel.org>2009-02-04 16:49:45 +0800
commita2be3931144b8fab73c3d876c148ada7a3c09066 (patch)
tree9a69e48cfa69c2b1191299e3493a3b2416753ed3 /arch
parent5e7bb132bbed2088b8b103e410d143b341dcb837 (diff)
downloadlinux-a2be3931144b8fab73c3d876c148ada7a3c09066.tar.bz2
Blackfin arch: reset POLAR setting when acquiring a gpio for the first time
when requesting a GPIO for the first time, the POLAR setting is not set to a sane state. this can lead to indeterminate behavior that cannot be resolved without an explicit write to the Blackfin port POLAR register. when requesting a GPIO for the first time via gpio_request(), the POLAR setting for the GPIO in question should be set to sane state. this should occur if the GPIO has not been allocated in any other way. some examples: - when doing something like "request_irq(); gpio_request();" on the same GPIO, the POLAR setting should not be reset. - when doing "gpio_request(); gpio_request();" on the same GPIO, the POLAR setting should be reset only the first time and not the second. Signed-off-by: Michael Hennerich <michael.hennerich@analog.com> Signed-off-by: Bryan Wu <cooloney@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/blackfin/kernel/bfin_gpio.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/blackfin/kernel/bfin_gpio.c b/arch/blackfin/kernel/bfin_gpio.c
index ea67ae5b033e..0c4fc31029c2 100644
--- a/arch/blackfin/kernel/bfin_gpio.c
+++ b/arch/blackfin/kernel/bfin_gpio.c
@@ -1053,9 +1053,15 @@ int bfin_gpio_request(unsigned gpio, const char *label)
local_irq_restore_hw(flags);
return -EBUSY;
}
- if (unlikely(reserved_gpio_irq_map[gpio_bank(gpio)] & gpio_bit(gpio)))
+ if (unlikely(reserved_gpio_irq_map[gpio_bank(gpio)] & gpio_bit(gpio))) {
printk(KERN_NOTICE "bfin-gpio: GPIO %d is already reserved as gpio-irq!"
" (Documentation/blackfin/bfin-gpio-notes.txt)\n", gpio);
+ }
+#ifndef BF548_FAMILY
+ else { /* Reset POLAR setting when acquiring a gpio for the first time */
+ set_gpio_polar(gpio, 0);
+ }
+#endif
reserved_gpio_map[gpio_bank(gpio)] |= gpio_bit(gpio);
set_label(gpio, label);