[PATCH 3/6] mmc: sdhci: add platform set_timeout hook

[Shawn Guo]

On Wed, Dec 11, 2013 at 01:03:43PM +0800, Dong Aisheng wrote:
> On Wed, Dec 11, 2013 at 11:48 AM, Shawn Guo <shawn.guo at linaro.org> wrote:
> > On Wed, Dec 11, 2013 at 11:35:17AM +0800, Dong Aisheng wrote:
> >> This actually is the register value, not the max timeout counter value.
> >> Then you may want define the API as:
> >> unsigned int    (*get_max_timeout_val)(struct sdhci_host *host);
> >
> > Yes, something like that.
> >
> >> But i don't think it's necessary to do the max timeout setting in two steps.
> >> First, deinfe a API to get the max timeout counter val,
> >> Second, write this val into register.
> >> Why not simply implement .set_timeout and handle the details in
> >> platform specific
> >> host driver respectively?
> >
> > Well, that's how sdhci host driver is structured.  Doing so leaves the
> > least details to platform driver, and calling sdhci_writeb() to access
> > SDHCI_TIMEOUT_CONTROL in sdhci-esdhc-imx seems a layer violation to me.
> >
> 
> The current sdhci-esdhci-imx already does something like that.
> You can search SDHCI_* in the code.
> It just reuses the register offset definition in sdhci,
> It's not the layer violation.

I do not understand why we have to do this SDHCI_TIMEOUT_CONTROL setup
in our sdhci-esdhc-imx driver, when sdhci driver is already structured
to do it in its way.  All we need is a hook to give the correct
max_timeout_val.

Shawn