On 05/28/14 10:12, Mark Brown wrote: > On Wed, May 28, 2014 at 05:16:46PM +0200, Uwe Kleine-König wrote: >> On Tue, May 27, 2014 at 02:40:15PM -0700, Stephen Boyd wrote: >>> On 05/24/14 05:48, Mark Brown wrote: >>>> 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. > If the supply must always be physically present the bindings should be > specified as it being mandatory and the code written in that fashion; as > an extension Linux will put a dummy in but this is attempting to handle > incorrect DTs. This means we have functional error handling in cases > where there is something to worry about and simplifies the code using > the regulator. Ok, you're saying the opposite of Rob. Should it be required or optional in the DT binding? > > regulator_get_optional() should *only* be used if the supply may be > omitted from the physical design and should generally always be > accompanied by code which does something substantially different such as > using an internal regulator or changing the source for a reference > voltage instead. > > Ok. Dave M has already picked up all these patches so I'll send a patch to replace regulator_get_optional() with regulator_get() and fix up the error handling unless I hear otherwise. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- 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
