On Mon, 28 Oct 2013 16:53:44 -0700 Mark Brown <broo...@kernel.org> wrote:
> On Mon, Oct 28, 2013 at 10:10:04PM +1100, NeilBrown wrote: > > > I agree that this power-up sequence should be a property of the device. > > However until the device has been powered up, Linux doesn't know about it. > > Neither a board file or a devicetree can (as far as I can tell), tell the > > MMC port that a particular card is attached. Rather the host probes the > > card > > to see what it is. > > So there isn't any way for the device driver to get control at the > > appropriate time to effect the proper sequencing. > > If it is a genuinely pluggable MMC slot then I'd expect the sequence to > be implementing whatever is required for standard MMC enumeration to > work. If the device is a soldered down one with extra control (as is > quite common) then there shouldn't be a problem describing it? Yes, the device is soldered down and has a reset line that needs to be pulsed low at about the same time that the MMC port enables the regulator. How do you propose that I describe this? Which driver should know about the reset GPIO, how to I tell it about the GPIO, and which function should do the pulsing? Thanks, NeilBrown
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