1 files changed, 19 insertions, 2 deletions

diff --git a/drivers/gpio/timbgpio.c b/drivers/gpio/timbgpio.c
index ddd053108a13..45293662e950 100644
--- a/drivers/gpio/timbgpio.c
+++ b/drivers/gpio/timbgpio.c
@@ -47,6 +47,7 @@ struct timbgpio {
         spinlock_t              lock; /* mutual exclusion */
         struct gpio_chip        gpio;
         int                     irq_base;
+        unsigned long           last_ier;
 };
 
 static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index,
@@ -112,16 +113,24 @@ static void timbgpio_irq_disable(unsigned irq)
 {
         struct timbgpio *tgpio = get_irq_chip_data(irq);
         int offset = irq - tgpio->irq_base;
+        unsigned long flags;
 
-        timbgpio_update_bit(&tgpio->gpio, offset, TGPIO_IER, 0);
+        spin_lock_irqsave(&tgpio->lock, flags);
+        tgpio->last_ier &= ~(1 << offset);
+        iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
+        spin_unlock_irqrestore(&tgpio->lock, flags);
 }
 
 static void timbgpio_irq_enable(unsigned irq)
 {
         struct timbgpio *tgpio = get_irq_chip_data(irq);
         int offset = irq - tgpio->irq_base;
+        unsigned long flags;
 
-        timbgpio_update_bit(&tgpio->gpio, offset, TGPIO_IER, 1);
+        spin_lock_irqsave(&tgpio->lock, flags);
+        tgpio->last_ier |= 1 << offset;
+        iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
+        spin_unlock_irqrestore(&tgpio->lock, flags);
 }
 
 static int timbgpio_irq_type(unsigned irq, unsigned trigger)
@@ -194,8 +203,16 @@ static void timbgpio_irq(unsigned int irq, struct irq_desc *desc)
         ipr = ioread32(tgpio->membase + TGPIO_IPR);
         iowrite32(ipr, tgpio->membase + TGPIO_ICR);
 
+        /*
+         * Some versions of the hardware trash the IER register if more than
+         * one interrupt is received simultaneously.
+         */
+        iowrite32(0, tgpio->membase + TGPIO_IER);
+
         for_each_set_bit(offset, &ipr, tgpio->gpio.ngpio)
                 generic_handle_irq(timbgpio_to_irq(&tgpio->gpio, offset));
+
+        iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
 }
 
 static struct irq_chip timbgpio_irqchip = {