On 21 August 2012 20:33, Rob Herring <robherring2@xxxxxxxxx> wrote: > On 08/21/2012 09:48 AM, Chris Ball wrote: >> Hi, adding Shawn and Wolfram, > > snip... > >> Rob Herring said: >>> This makes the most sense to me. However, I prefer broken-cd over >>> cd-internal. The binding should add properties for exceptions, not SDHCI >>> spec compliant implementations. >> >> Agreed, I was going to say the same thing. Putting it all together, it >> sounds like we want: >> >> no extra properties: the CD pin on the host just works. >> broken-cd: the CD pin on the host is broken; use polling. >> cd-gpios: the GPIO listed is the CD pin on the host being >> brought out directly to a GPIO. >> cd-external: when used with cd-gpios, specifies that the GPIO >> in cd-gpios is external to the CD pin on the host. >> >> cd-gpios and cd-external can be present on the same node. if broken-cd >> is present, it must be the only one of these nodes used. > > I don't see the point of cd-external. Either you just use the CD > interrupt defined within the SDHCI or you have a gpio line independent > of the SDHCI and use cd-gpios. There should be way to distinguish between the two types of 'cd-gpios' value. (A) a 'cd-gpios' line that connects the card-detect pin of the mmc physical slot to the card-detect pad to the mmc host controller. (B) a 'cd-gpios' line that is connected to the card-detect pin of the slot but not to the card-detect pad of the mmc host controller (used either as gpio interrupt or polled gpio line). So the binding 'cd-external' can act as an additional qualifier to value of 'cd-gpios' to represent the second type. Hence, the bindings proposed by Chris does support all the possible combinations of card-detection used by the Samsung sdhci controller driver. Thanks, Thomas. > > Rob > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
