On 23 September 2016 at 22:01, Zach Brown <[email protected]> wrote: > Certain board configurations can make highspeed malfunction due to > timing issues. In these cases a way is needed to force the controller > and card into standard speed even if they otherwise appear to be capable > of highspeed. > > The sd-broken-highspeed property will let the sdhci driver know that > highspeed will not work. > > Signed-off-by: Zach Brown <[email protected]> > --- > Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt > b/Documentation/devicetree/bindings/mmc/mmc.txt > index 8a37782..59332ea 100644 > --- a/Documentation/devicetree/bindings/mmc/mmc.txt > +++ b/Documentation/devicetree/bindings/mmc/mmc.txt > @@ -52,6 +52,8 @@ Optional properties: > - no-sdio: controller is limited to send sdio cmd during initialization > - no-sd: controller is limited to send sd cmd during initialization > - no-mmc: controller is limited to send mmc cmd during initialization > +- sd-broken-highspeed: Highspeed is broken, even if the controller and card > + themselves claim they support highspeed.
Regarding a broken card, that is managed via the card quirks and not in DT. If this is about a controller limitation, we already have the option to describe what it supports, so we don't need an option to tell what it *not* supports. For example "cap-sd-highspeed" tells whether the controller supports SD high-speed, please use that instead. > > *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers > line > polarity properties, we have to fix the meaning of the "normal" and > "inverted" > -- > 2.7.4 > Kind regards Uffe
