[PATCH 21/38] mmc: sdhci: hack up driver to make it more compliant with UHS-1

Russell King - ARM Linux linux at arm.linux.org.uk
Fri Apr 25 06:22:45 PDT 2014


On Fri, Apr 25, 2014 at 02:15:30PM +0100, Russell King - ARM Linux wrote:
> On Fri, Apr 25, 2014 at 03:08:49PM +0200, Markus Pargmann wrote:
> > I just tried the different parts of the patch. Without the following
> > change, emmc works:
> > 
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -1507,12 +1507,6 @@ static void sdhci_do_set_ios(struct sdhci_host *host, struct mmc_ios *ios)
> >  			host->ops->set_clock(host, host->clock);
> >  		}
> >  
> > -
> > -		/* Reset SD Clock Enable */
> > -		clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
> > -		clk &= ~SDHCI_CLOCK_CARD_EN;
> > -		sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> > -
> 
> So the bit which stops us violating the SD spec stops eMMC from working...
> that's... just great.
> 
> Okay, I'll look deeper at this and see what can be done, but I suspect it
> will turn out to require more patches and be more invasive.

In the mean time, here's the remainder (to patch 33) of the series with
this commit omitted.

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