[U-Boot] [PATCH V2] imx: mx25: Remove SION bit in all pin-mux that are safe
Fabio Estevam
festevam at gmail.com
Thu Jan 25 12:51:10 UTC 2018
On Thu, Jan 25, 2018 at 10:43 AM, Michael Trimarchi
<michael at amarulasolutions.com> wrote:
> SION bit should be used in the situation that we need
> to read back the value of a pin and should not be set by
> default macro.
>
> We get some mulfuction as raised by following thread
malfunction
>
> https://www.spinics.net/lists/linux-usb/msg162574.html
>
> As reported by this application note:
> https://www.nxp.com/docs/en/application-note/AN5078.pdf
>
> The software input on (SION) bit is an option to force an input
> path to be active regardless of the value driven by the
> corresponding module. It is used when the nature direction
> of a pin depending on selected alternative function is an output,
> but it is needed to read the real logic value on a pin.
>
> The SION bit can be used in:
> • Loopback: the module of a selected alternative function drives
> the pad and also receives the pad value as an input
> • GPIO capture: the module of a selected alternative function
> drives the pin and the value is captured by the GPIO
>
> SION pin is not necessary when the pin is configured as a peripheral
SION bit
Apart from these minor typos:
Reviewed-by: Fabio Estevam <fabio.estevam at nxp.com>
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