From mboxrd@z Thu Jan 1 00:00:00 1970 From: tixy@linaro.org (Jon Medhurst (Tixy)) Date: Tue, 15 Sep 2015 17:31:29 +0100 Subject: [PATCH v3 1/5] Documentation: add DT bindings for ARM SCPI sensors In-Reply-To: <9hheghzvfbz.fsf@e105922-lin.cambridge.arm.com> References: <1442235619-4029-1-git-send-email-punit.agrawal@arm.com> <1442235619-4029-2-git-send-email-punit.agrawal@arm.com> <20150914131448.GC7002@leverpostej> <9hhh9mxf7lg.fsf@e105922-lin.cambridge.arm.com> <20150914134949.GE7002@leverpostej> <9hhk2rtdq1f.fsf@e105922-lin.cambridge.arm.com> <1442251092.2850.53.camel@linaro.org> <9hhy4g89g64.fsf@e105922-lin.cambridge.arm.com> <1442313962.2917.25.camel@linaro.org> <9hheghzvfbz.fsf@e105922-lin.cambridge.arm.com> Message-ID: <1442334689.4040.68.camel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 2015-09-15 at 17:04 +0100, Punit Agrawal wrote: > "Jon Medhurst (Tixy)" writes: > > > On Tue, 2015-09-15 at 10:37 +0100, Punit Agrawal wrote: > >> "Jon Medhurst (Tixy)" writes: > >> > >> > On Mon, 2015-09-14 at 15:38 +0100, Punit Agrawal wrote: > >> >> Mark Rutland writes: > >> >> > > [...] > >> >> The way the SCP interface is defined, the sensor identifiers are > >> >> contiguous, > >> > > >> > Is there any documentation other than DUI0922A? [1] From what I can seen > >> > that just says it's a 16-bit value and doesn't put any particular > >> > constraints on its value. > >> > >> Although not explicitly stated, if you look at the Get Sensor Capability > >> [2] and Get Sensor Info [3] commands you can indirectly infer that the > >> Sensor IDs are contiguous. > > > > I personally wouldn't even indirectly infer they are contiguous from > > what the document says. If I were implementing the firmware I would feel > > quite in my rights to, for example, use the top 8 bits of the ID for a > > sensor type and the bottom 8 for an index, if that made dispatching of > > requests more efficient. Or if some optional hardware was detected as > > missing, leaving some holes in ID space. > > True. And without a command to convey the list of valid IDs, the > consumer of the API would have to iterate over the entire 16bit space to > locate valid IDs. Or get IDs from device-tree :-) Anyway, I'm not arguing that the IDs shouldn't be 0..N-1, just that it should explicitly documented in the SCPI doc, which we're are in agreement on. -- Tixy