From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [RFC V2] OPP: Redefine bindings to overcome shortcomings Date: Fri, 23 Jan 2015 11:52:06 +0000 Message-ID: <20150123115206.GT21293@sirena.org.uk> References: <1422013154.29475.11.camel@pengutronix.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="GGxZz/e2pmGePzrA" Return-path: Content-Disposition: inline In-Reply-To: <1422013154.29475.11.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lucas Stach Cc: Viresh Kumar , Rafael Wysocki , arnd.bergmann-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, rob.herring-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org, linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, nm-l0cyMroinI0@public.gmane.org, Sudeep.Holla-5wv7dgnIgG8@public.gmane.org, sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, santosh.shilimkar-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, mike.turquette-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kesavan.abhilash-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, catalin.marinas-5wv7dgnIgG8@public.gmane.org, ta.omasab-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org List-Id: linux-pm@vger.kernel.org --GGxZz/e2pmGePzrA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jan 23, 2015 at 12:39:14PM +0100, Lucas Stach wrote: > > + Required properties: > > + - opp-khz: Frequency in kHz > > + - opp-microvolt: voltage in micro Volts > Each OPP voltage should be defined by the triplet of minimum, > nominal/typical, maximum. This lets you specify exact tolerances in each > direction and should cover most use-cases. > IMHO it would make sense to just define opp-microvolt as an array of > those 3 values, so the DT doesn't get bloated with a lot more > properties. > A typical value for a CPU could then look like this: > opp-microvolt = <800000 850000 1100000> I tend to agree that this is clearer. It might be nice to have variants for specifying directly as a percentage but I don't think it's really worth the complexity. > For devices without any tolerance you can just specify the same value > three times and be done with it: > opp-microvolt = <900000 900000 900000> If we change the binding to be typ/min/max rather than min/typ/max then we could also do this by allowing either one or three values to be specified. That might be more worth the complexity especially given... > > + Optional properties: > > + - turbo-mode: Marks the volt-freq pair as turbo pair. > > + - status: Marks the node enabled/disabled. > > + - voltage-tolerance: Specify the CPU voltage tolerance in percentage. > Please let's drop this. DT bindings are supposed to be stable, this means the code should accept old bindings and they should be documented as deprecated. --GGxZz/e2pmGePzrA Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJUwjXlAAoJECTWi3JdVIfQzVUH/39T4b5ZKuAE1Z45bJIZjXCz 8cbvKWEmF903edzvxMGsy+5ygUKM5ACfvt7CJ6ZQ3t5qlwy3KNqUgKUgGGWaVDmw n4gFaS/1QBu3328Qbd3+jZTtQuIaAZJEhF6ocZ/cfAZbg9VXEPxFVF0gh4hDstN2 cyoI6hbdjU7yZCCkM9ML5EFOohplymN0dFF3quOQ3MtVPP0B2b88qtp6SdYDC9HL l2eM2e/GTCOR/xK/32HTCasyhgmSlXyDJ/rk0eqRoVceNsZ0aZwSO6SK1ZxABU8Z Qi0XtfHkWVt17NMxVc2XlUEUTcl3PkO+wKBrNA4awBkDzERnJCTm/dqVWB6YpnU= =NY1Q -----END PGP SIGNATURE----- --GGxZz/e2pmGePzrA-- -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html