Re: [PATCH 2/2] gpio/mxc: implement reading output gpio value

[Fabio Estevam]

On Wed, Aug 5, 2015 at 4:46 PM, Eduardo Valentin <edubezval@xxxxxxxxx> wrote:

> OK. Then, what is the recommendation? Do we set this by default in the
> driver code or this is left for DTS pinmux configuration?

You just need to set the SION bit in the pad you need to read the output.

SION is bit 30 according to
Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt

> To me seams like a bug in the gpio driver still, as the possibility to
> read the value of an output gpio is missing/inconsistent.

No, it is not a bug.

The Reference Manual explains the need of setting the SION bit:

>From the mx6q reference manual:

"28.4.3.2 GPIO Write Mode
The programming sequence for driving output signals should be as follows:
1. Configure IOMUX to select GPIO mode (Via IOMUXC), also enable SION if need
to read loopback pad value through PSR"
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/