[PATCH V2 2/2] mmc: mmci: Move ios_handler functionality into the driver

[Lee Jones]

On Fri, 14 Dec 2012, Russell King - ARM Linux wrote:

> On Fri, Dec 14, 2012 at 03:30:29PM +0100, Ulf Hansson wrote:
> > From: Lee Jones <lee.jones at linaro.org>
> > 
> > There are currently two instances of the ios_handler being used.
> > Both of which mearly toy with some regulator settings. Now there
> > is a GPIO regulator API, we can use that instead, and lessen the
> > per platform burden. By doing this, we also become more Device
> > Tree compatible.
> 
> Err, why is this needed?  What's wrong with using the 'vmmc' for this?

It's a different regulator. The core knows about 'vmmc', which is the
primary one, then there is a regulator called 'vqmmc' which is for I/O
voltage. Until now this was done in a very platform specific way.
Normally by doing gpio_set's. Now there is a regulator API which can
deal with GPIO controlled regulators and there is provision for it in
MMC core also, so it's time to move it to the driver.

> From what I read in the mmc core, vmmc handling via mmc_regulator_set_ocr()
> can cope with GPIO-based regulators, and if you have a single GPIO signal
> then you have a single supply (it's either on or off).  So what's wrong
> with using the existing regulator hooks for this which are already there?

In our case it's not a 'fixed' regulator (i.e. on/off). The new GPIO
regulator API can also control voltage selection using GPIOs too.

-- 
Lee Jones
Linaro ST-Ericsson Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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