ARM: OMAP: GPIO: IRQSTATUS2 workaround for retention state

In OMAP2420, an incoming GPIO interrupt always sets both GPIO_IRQSTATUS1
and GPIO_IRQSTATUS2, even if the relevant bit is disabled in
GPIO_IRQENABLE1/2 and DSP doesn't use GPIO at all. GPIO_IRQSTATUS1
is for MPU and GPIO_IRQSTATUS2 is for DSP. If IRQSTATUS is set, this
will prevent the system from going to idle state. This patch also clears
IRQSTATUS2 to avoid the above situation.

Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/gpio.c

@@ -94,6 +94,8 @@
 #define OMAP24XX_GPIO_SYSCONFIG		0x0010
 #define OMAP24XX_GPIO_SYSSTATUS		0x0014
 #define OMAP24XX_GPIO_IRQSTATUS1	0x0018
+#define OMAP24XX_GPIO_IRQSTATUS2	0x0028
+#define OMAP24XX_GPIO_IRQENABLE2	0x002c
 #define OMAP24XX_GPIO_IRQENABLE1	0x001c
 #define OMAP24XX_GPIO_CTRL		0x0030
 #define OMAP24XX_GPIO_OE		0x0034
@@ -529,6 +531,10 @@ static void _clear_gpio_irqbank(struct gpio_bank *bank, int gpio_mask)
 		return;
 	}
 	__raw_writel(gpio_mask, reg);
+
+	/* Workaround for clearing DSP GPIO interrupts to allow retention */
+	if (cpu_is_omap2420())
+		__raw_writel(gpio_mask, bank->base + OMAP24XX_GPIO_IRQSTATUS2);
 }
 
 static inline void _clear_gpio_irqstatus(struct gpio_bank *bank, int gpio)