Hello, On Wed, 18 Jan 2017 01:10:00 +0800, Icenowy Zheng wrote: > > Add a new compatible for sun4i-i2s driver to handle some > > SoCs that have a reset line that must be asserted/deasserted. > > > > This new compatible, "allwinner,sun6i-a31-i2s", requires two > > properties: > > - resets: phandle to the reset line > > - reset-names: the name of the reset line ("rst"). > > Except these differences, the compatible is identical to previous one > > which will not handle a reset line. > > But I think the IP block is identical, right? > > Should a new compatible be added only for reset-line? Having a different compatible in this case allows to make some stricter error checking: the driver can make sure that if the compatible string is sun6i-a31-i2s there *IS* a reset line specified in the DT. Without a separate compatible value, such a check is not possible, and the reset line is just optional. This can lead to people being confused if they forget to specify the reset line. Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- 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