From a2be3931144b8fab73c3d876c148ada7a3c09066 Mon Sep 17 00:00:00 2001 From: Michael Hennerich Date: Wed, 4 Feb 2009 16:49:45 +0800 Subject: [PATCH] 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 Signed-off-by: Bryan Wu --- arch/blackfin/kernel/bfin_gpio.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) 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);