powerpc/85xx: Workaround MPC8572/MPC8536 GPIO 1 errata.

[mv-sheeva.git] / arch / powerpc / sysdev / mpc8xxx_gpio.c

diff --git a/arch/powerpc/sysdev/mpc8xxx_gpio.c b/arch/powerpc/sysdev/mpc8xxx_gpio.c
index 103eace361946a65ed5cdb28f59b7afa6ed9e1ac..ee1c0e1cf4a7d814d99788c0c6520fb18bfcd3bf 100644 (file)
--- a/arch/powerpc/sysdev/mpc8xxx_gpio.c
+++ b/arch/powerpc/sysdev/mpc8xxx_gpio.c
@@ -54,6 +54,22 @@ static void mpc8xxx_gpio_save_regs(struct of_mm_gpio_chip *mm)
        mpc8xxx_gc->data = in_be32(mm->regs + GPIO_DAT);
 }
 
+/* Workaround GPIO 1 errata on MPC8572/MPC8536. The status of GPIOs
+ * defined as output cannot be determined by reading GPDAT register,
+ * so we use shadow data register instead. The status of input pins
+ * is determined by reading GPDAT register.
+ */
+static int mpc8572_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 (val | mpc8xxx_gc->data) & mpc8xxx_gpio2mask(gpio);
+}
+
 static int mpc8xxx_gpio_get(struct gpio_chip *gc, unsigned int gpio)
 {
        struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
@@ -136,7 +152,10 @@ static void __init mpc8xxx_add_controller(struct device_node *np)
        gc->ngpio = MPC8XXX_GPIO_PINS;
        gc->direction_input = mpc8xxx_gpio_dir_in;
        gc->direction_output = mpc8xxx_gpio_dir_out;
-       gc->get = mpc8xxx_gpio_get;
+       if (of_device_is_compatible(np, "fsl,mpc8572-gpio"))
+               gc->get = mpc8572_gpio_get;
+       else
+               gc->get = mpc8xxx_gpio_get;
        gc->set = mpc8xxx_gpio_set;
 
        ret = of_mm_gpiochip_add(np, mm_gc);