On Thu, Aug 25, 2016 at 07:10:00PM +0100, Mark Rutland wrote: > On Thu, Aug 25, 2016 at 12:15:44PM -0500, Zach Brown wrote: > > On Thu, Aug 25, 2016 at 11:56:55AM +0100, Mark Rutland wrote: > > > On Wed, Aug 24, 2016 at 06:23:03PM -0500, Zach Brown wrote: > > > > +- fake-cd: On Zynq Devices the SDHCI Controller will not work without > > > > the cd > > > > + bit. When this option is set the driver will put the controller in > > > > test mode > > > > + and fake the cd bit so it will function. > > > > > > As Lars noted, the DT should describe the HW, and the policy of how to > > > deal > > > with that should be left to the kernel. So from a DT perspective the > > > above is > > > not correct. > > > > > > If I understand the linked documentation, this is slightly different to > > > typical > > > uses of broken-cd in that in the absence of a card detect signal the HW > > > will > > > not be able to access the SD card at all, even if requested to. Is that > > > correct? > > > > > > If so, perhaps a better option is to have the combination of broken-cd > > > and the > > > compatible string for this IP block imply that the test mode workaround is > > > required. Obviously that requires a fixup to the usual broken-cd binding > > > to > > > remove the implication that polling alone must be used. > > > > > > Thanks, > > > Mark. > > > > In cases where the card is non-removable then polling doesn't make sense. > > We have the non-removable property to describe that, so we can also look at > that. > > > So it doesn't make sense to tie the test mode workaround into the broken-cd > > property, even though I agree the nature of the defect fits under the notion > > of the CD being broken. > > Maybe not solely on broken-cd, but I think that we dont necessarily need a new > DT property. As above, broken-cd, non-removable, and the compatible string may > together give the kernel enough information to choose the right thing to do. > > Thanks, > Mark.
I'm not sure if I understand your suggestion completely. Are you suggesting setting both the broken-cd and non-removable properties? That would make sense, but my understanding was that the two properities are not meant to co-exist. In /Documentation/devicetree/bindings/mmc/mmc.txt it states that only one should be supplied. Don't the two properties conflict with each other?
