On 5 May 2015 at 11:04, Lars-Peter Clausen <lars@xxxxxxxxxx> wrote: > On 05/05/2015 10:36 AM, Ulf Hansson wrote: > [...] >>> >>> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt >>> b/Documentation/devicetree/bindings/mmc/mmc.txt >>> index 438899e..b068549 100644 >>> --- a/Documentation/devicetree/bindings/mmc/mmc.txt >>> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt >>> @@ -21,6 +21,7 @@ Optional properties: >>> below for the case, when a GPIO is used for the CD line >>> - wp-inverted: when present, polarity on the WP line is inverted. See >>> the note >>> below for the case, when a GPIO is used for the WP line >>> +- disable-wp: When set no physical WP line is present >> >> >> This requires some additional explanation, I believe. I assume this >> property is only relevant for those controllers that have internal >> logic to handle WP!? > > > Yes, currently drivers for controllers that have a built-in WP detection > logic typically assume that if no WP GPIO is specified the built-in WP logic > should be used. But for some of them the value returned by the internal > detection logic will be bogus if there is no WP signal connected. So we need > a way to specify that that there is no WP signal and the internal detection > logic shouldn't be used either. > >> >> For those that uses GPIO, this can't ever be a correct configuration. >> Right? > > > It wouldn't make much sense to use it with a GPIO based detection logic, > since you simply don't specify the wp-gpio property if it is not present. > One the other hand it wouldn't cause any harm to specify it in addition to > not specifying the wp-gpios property. > > How about: > > - disable-wp: When set no physical WP line is present. This property should > only be specified when the controller has a dedicated write-protect > detection logic. If a GPIO is used for write-protect detection logic is used Remove the last "is used". > it is sufficient to not specify wp-gpios property in the absence of a WP > line. Looks good! Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
