GPIO: OMAP: add locking around calls to _set_gpio_triggering

_set_gpio_triggering uses read-modify-write on bank registers,
lock bank->lock around all calls to it to prevent register
corruption if two cpus access gpios in the same bank at the
same time.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 5ad827a..01f74a8 100644 (file)
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -1126,8 +1126,11 @@ static void gpio_irq_shutdown(struct irq_data *d)
 {
        unsigned int gpio = d->irq - IH_GPIO_BASE;
        struct gpio_bank *bank = irq_data_get_irq_chip_data(d);
+       unsigned long flags;
 
+       spin_lock_irqsave(&bank->lock, flags);
        _reset_gpio(bank, gpio);
+       spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 static void gpio_ack_irq(struct irq_data *d)
@@ -1142,9 +1145,12 @@ static void gpio_mask_irq(struct irq_data *d)
 {
        unsigned int gpio = d->irq - IH_GPIO_BASE;
        struct gpio_bank *bank = irq_data_get_irq_chip_data(d);
+       unsigned long flags;
 
+       spin_lock_irqsave(&bank->lock, flags);
        _set_gpio_irqenable(bank, gpio, 0);
        _set_gpio_triggering(bank, get_gpio_index(gpio), IRQ_TYPE_NONE);
+       spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 static void gpio_unmask_irq(struct irq_data *d)
@@ -1153,7 +1159,9 @@ static void gpio_unmask_irq(struct irq_data *d)
        struct gpio_bank *bank = irq_data_get_irq_chip_data(d);
        unsigned int irq_mask = 1 << get_gpio_index(gpio);
        u32 trigger = irqd_get_trigger_type(d);
+       unsigned long flags;
 
+       spin_lock_irqsave(&bank->lock, flags);
        if (trigger)
                _set_gpio_triggering(bank, get_gpio_index(gpio), trigger);
 
@@ -1165,6 +1173,7 @@ static void gpio_unmask_irq(struct irq_data *d)
        }
 
        _set_gpio_irqenable(bank, gpio, 1);
+       spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 static struct irq_chip gpio_irq_chip = {