[RFC 0/2] spi: aspeed: SPI1 mode control driver enabling sysfs control

[Kun Yi]

Thanks Andrew that was helpful! I will look into pinctrl and FMC driver
then.

Thanks,
Kun

On Mon, Oct 24, 2016 at 4:26 PM, Andrew Jeffery <andrew at aj.id.au> wrote:

> On Mon, 2016-10-24 at 14:22 -0700, Kun Yi wrote:
> > Hi Andrew,
> >
> > One question I have though: I think pinmux/pinctrl driver is supposed
> > to be a boot time static pin configure module and parses DT and
> > configures accordingly. Is it possible to use pinmux to dynamically
> > modify the pin states?
>
> Yes, see "Runtime pinmuxing" here (at the bottom of the document):
>
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/
> linux.git/tree/Documentation/pinctrl.txt
>
> So you'd need to patch the FMC driver that Milton and Cedric have been
> working on to (de)activate pin states, likely at probe() and remove()
> (this implies you'll need to somehow orchestrate a remove/switch,
> switch/probe dance). Alternatively, provide a way to suspend operations
> on the MTD and switch the pins between master and passthru in the FMC
> driver. Some complications are that this functionality is only
> available for SPI1, and you might need to do a bit of work to guarantee
> sensible outcomes for operations that might span the mode switch.
>
> Cheers,
>
> Andrew




-- 
Regards,
Kun
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