[PATCH] powerpc/85xx: Workaround MPC8536 GPIO 1 errata.

[Felix Radensky]

On MPC8536 Rev 1.0 the status of GPIO pins configured
as output cannot be determined by reading GPDAT register.
Workaround by reading the status of input pins from GPDAT
and the status of output pins from a shadow register.

Signed-off-by: Felix Radensky <felix at embedded-sol.com>
---
 arch/powerpc/sysdev/mpc8xxx_gpio.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/sysdev/mpc8xxx_gpio.c b/arch/powerpc/sysdev/mpc8xxx_gpio.c
index 103eace..0b996f3 100644
--- a/arch/powerpc/sysdev/mpc8xxx_gpio.c
+++ b/arch/powerpc/sysdev/mpc8xxx_gpio.c
@@ -56,9 +56,13 @@ static void mpc8xxx_gpio_save_regs(struct of_mm_gpio_chip *mm)
 
 static int mpc8xxx_gpio_get(struct gpio_chip *gc, unsigned int gpio)
 {
+	u32 val;
 	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
+	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
+	
+	val = in_be32(mm->regs + GPIO_DAT) && ~in_be32(mm->regs + GPIO_DIR);
 
-	return in_be32(mm->regs + GPIO_DAT) & mpc8xxx_gpio2mask(gpio);
+	return (val | mpc8xxx_gc->data) & mpc8xxx_gpio2mask(gpio);
 }
 
 static void mpc8xxx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
-- 
1.5.4.3