[patch 1/2] imx51: fix gpiolib support

[Lothar Waßmann]

Hi,

> The gpiolib code is always returning 0 when reading pad values if the pads
> are configured as output. Using DR registers instead of PSR is fixing that.
> 
> Signed-off-by: Arnaud Patard <arnaud.patard at rtp-net.org>
> Index: linux-2.6-submit/arch/arm/plat-mxc/gpio.c
> ===================================================================
> --- linux-2.6-submit.orig/arch/arm/plat-mxc/gpio.c	2010-11-24 18:00:47.000000000 +0100
> +++ linux-2.6-submit/arch/arm/plat-mxc/gpio.c	2010-11-24 18:06:54.000000000 +0100
> @@ -276,6 +276,10 @@
>  {
>  	struct mxc_gpio_port *port =
>  		container_of(chip, struct mxc_gpio_port, chip);
> +	u32 l = __raw_readl(port->base + GPIO_GDIR);
> +
> +	if (cpu_is_mx51() && (l & (1 << offset)))
> +		return (__raw_readl(port->base + GPIO_DR) >> offset) & 1;
>  
>  	return (__raw_readl(port->base + GPIO_PSR) >> offset) & 1;
>  }
>
Now you are not reading the actual pin state as with GPIO_PSR, but the
value that has been programmed into the output register (thus you
would not be able to determine whether an Open Drain output that is
programmed to HIGH is driven LOW by an external device).

Note that for being able to read back the actual pin state of an
output, the SION bit in the MUX_CTL register of the corresponding pad
has to be asserted.


Lothar Waßmann
-- 
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