On Wed, May 28, 2014 at 10:16 AM, Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> wrote: > Hello Stephen, > > On Tue, May 27, 2014 at 02:40:15PM -0700, Stephen Boyd wrote: >> On 05/24/14 05:48, Mark Brown wrote: >> > On Fri, May 23, 2014 at 12:57:17PM -0700, Stephen Boyd wrote: >> > >> >> Optional properties: >> >> -- vdd-supply: supply for Ethernet mac >> >> +- vdd-supply: analog 3.3V supply for Ethernet mac >> >> +- vdd-io-supply: digital 1.8V IO supply for Ethernet mac >> > So, according to the datasheet I managed to find this device has a >> > supply VDD_IO (so normally written vdd-io-supply here), some other >> > supplies which are tied to VDD_IO (so can probably be omitted) and a >> > supply VDD_A3.3 none of which are optional. There is an internal >> > regulator which can be used to drop a higher voltage VDD_IO down for >> > some of the supplies tied to it but that's essentially a noop from >> > software as far as I can tell. None of these supplies are obviously >> > optional, though I've not read the datasheet in detail so I may have >> > missed something here. > There is a difference between the supply being optional for the hardware > to work and the need to specify it in the device tree, isn't it? My > expectation is that when it's not specified there is just nothing the > the software needs to care for. Yes, agreed. Of course you could have cases where a supply at the h/w level is optional like if a supply can be powered externally or via an internal regulator. Those cases will have to be made clear in the binding, but a heading "Optional properties" in a binding doc means properties which are optional to specify in DT. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
