3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liu Gang <Gang.Liu@xxxxxxxxxxxxx> commit 1aeef303b5d9e243c41d5b80f8bb059366514a10 upstream. For MPC8572/MPC8536, the status of GPIOs defined as output cannot be determined by reading GPDAT register, so the code use shadow data register instead. But the code may give the wrong status of GPIOs defined as input under some scenarios: 1. If some pins were configured as inputs and were asserted high before booting the kernel, the shadow data has been initialized with those pin values. 2. Some pins have been configured as output first and have been set to the high value, then reconfigured as input. The above cases will make the shadow data for those input pins to be set to high. Then reading the pin status will always return high even if the actual pin status is low. The code should eliminate the effects of the shadow data to the input pins, and the status of those pins should be read directly from GPDAT. Acked-by: Scott Wood <scottwood@xxxxxxxxxxxxx> Acked-by: Anatolij Gustschin <agust@xxxxxxx> Signed-off-by: Liu Gang <Gang.Liu@xxxxxxxxxxxxx> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpio/gpio-mpc8xxx.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/gpio/gpio-mpc8xxx.c +++ b/drivers/gpio/gpio-mpc8xxx.c @@ -69,10 +69,14 @@ static int mpc8572_gpio_get(struct 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); + u32 out_mask, out_shadow; - val = in_be32(mm->regs + GPIO_DAT) & ~in_be32(mm->regs + GPIO_DIR); + out_mask = in_be32(mm->regs + GPIO_DIR); - return (val | mpc8xxx_gc->data) & mpc8xxx_gpio2mask(gpio); + val = in_be32(mm->regs + GPIO_DAT) & ~out_mask; + out_shadow = mpc8xxx_gc->data & out_mask; + + return (val | out_shadow) & mpc8xxx_gpio2mask(gpio); } static int mpc8xxx_gpio_get(struct gpio_chip *gc, unsigned int gpio) -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html