From: Mark Brown <broonie@opensource.wolfsonmicro.com> To: linux-arm-kernel@lists.infradead.org Subject: Re: Device tree binding for DVFS table Date: Thu, 12 Jul 2012 17:15:29 +0000 [thread overview] Message-ID: <20120712171528.GK7256@opensource.wolfsonmicro.com> (raw) In-Reply-To: <20120712171016.GL2772@gmail.com> [-- Attachment #1: Type: text/plain, Size: 1266 bytes --] On Thu, Jul 12, 2012 at 10:10:16AM -0700, Mike Turquette wrote: > On 20120712-17:10, Peter De Schrijver wrote: > > + power rail constraints (eg voltage difference limit between 2 rails) > This should come from regulator DT data and not anything DVFS-specific, > correct? Currently the regulator API will only constrain individual rails (and shortly likely parent/child relationships). It will not do anything to constrain between different rails, this has been left to the consumers. For this stuff it may still make sense to do that if we've got a set of operating points defined which apply over multiple inputs (like clock and frequency) - we'll naturally impose these constraints by virtue of selecting the operating point. > > + clock constraints (eg. clock x frequency must be a fixed ratio of clock y > > frequency) > Yeah, after sending my email above yesterday I instantly regretted it. > It is true that *functional* clock dependencies are really the purview > of the device driver. E.g. for Device X to operate at FAST_SPEED, scale > functional_clk up to 200MHz and l3_ddr_clk up to 100MHz. On OMAP our > display subsystem block also has clock ratio rules that must be honored, > but it just open-coded. This is similar to the regulator thing. [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 836 bytes --]
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From: broonie@opensource.wolfsonmicro.com (Mark Brown) To: linux-arm-kernel@lists.infradead.org Subject: Device tree binding for DVFS table Date: Thu, 12 Jul 2012 18:15:29 +0100 [thread overview] Message-ID: <20120712171528.GK7256@opensource.wolfsonmicro.com> (raw) In-Reply-To: <20120712171016.GL2772@gmail.com> On Thu, Jul 12, 2012 at 10:10:16AM -0700, Mike Turquette wrote: > On 20120712-17:10, Peter De Schrijver wrote: > > + power rail constraints (eg voltage difference limit between 2 rails) > This should come from regulator DT data and not anything DVFS-specific, > correct? Currently the regulator API will only constrain individual rails (and shortly likely parent/child relationships). It will not do anything to constrain between different rails, this has been left to the consumers. For this stuff it may still make sense to do that if we've got a set of operating points defined which apply over multiple inputs (like clock and frequency) - we'll naturally impose these constraints by virtue of selecting the operating point. > > + clock constraints (eg. clock x frequency must be a fixed ratio of clock y > > frequency) > Yeah, after sending my email above yesterday I instantly regretted it. > It is true that *functional* clock dependencies are really the purview > of the device driver. E.g. for Device X to operate at FAST_SPEED, scale > functional_clk up to 200MHz and l3_ddr_clk up to 100MHz. On OMAP our > display subsystem block also has clock ratio rules that must be honored, > but it just open-coded. This is similar to the regulator thing. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: Digital signature URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20120712/161e4acc/attachment.sig>
next prev parent reply other threads:[~2012-07-12 17:15 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-07-11 12:56 Device tree binding for DVFS table Prashant Gaikwad 2012-07-11 13:08 ` Prashant Gaikwad 2012-07-11 14:03 ` Rob Herring 2012-07-11 14:03 ` Rob Herring 2012-07-11 14:44 ` Mark Brown 2012-07-11 14:44 ` Mark Brown 2012-07-11 20:04 ` Mike Turquette 2012-07-11 20:04 ` Mike Turquette 2012-07-12 4:14 ` Prashant Gaikwad 2012-07-12 4:26 ` Prashant Gaikwad 2012-07-12 14:10 ` Peter De Schrijver 2012-07-12 14:10 ` Peter De Schrijver 2012-07-12 17:10 ` Mike Turquette 2012-07-12 17:10 ` Mike Turquette 2012-07-12 17:15 ` Mark Brown [this message] 2012-07-12 17:15 ` Mark Brown 2012-07-13 10:34 ` Peter De Schrijver 2012-07-13 10:34 ` Peter De Schrijver 2012-07-13 17:25 ` Mike Turquette 2012-07-13 17:25 ` Mike Turquette 2012-07-12 4:17 ` Prashant Gaikwad 2012-07-12 4:29 ` Prashant Gaikwad 2012-07-12 15:23 ` Mark Brown 2012-07-12 15:23 ` Mark Brown 2012-07-12 17:01 ` Mike Turquette 2012-07-12 17:01 ` Mike Turquette 2012-07-12 8:19 ` Peter De Schrijver 2012-07-12 8:19 ` Peter De Schrijver 2012-07-12 4:08 ` Prashant Gaikwad 2012-07-12 4:20 ` Prashant Gaikwad 2012-07-13 18:30 ` Prashant Gaikwad 2012-07-13 18:42 ` Prashant Gaikwad 2012-07-15 21:40 ` Mark Brown 2012-07-15 21:40 ` Mark Brown 2012-07-15 23:42 ` Rob Herring 2012-07-15 23:42 ` Rob Herring 2012-07-16 18:36 ` Turquette, Mike 2012-07-16 18:36 ` Turquette, Mike 2012-07-17 12:37 ` Prashant Gaikwad 2012-07-17 12:49 ` Prashant Gaikwad 2012-07-17 13:20 ` Mark Brown 2012-07-17 13:20 ` Mark Brown 2012-07-17 14:22 ` Prashant Gaikwad 2012-07-17 14:34 ` Prashant Gaikwad 2012-07-17 14:37 ` Mark Brown 2012-07-17 14:37 ` Mark Brown 2012-07-18 12:46 ` Prashant Gaikwad 2012-07-18 12:58 ` Prashant Gaikwad 2012-07-18 21:19 ` Mark Brown 2012-07-18 21:19 ` Mark Brown 2012-07-18 17:08 ` Shawn Guo 2012-07-18 17:08 ` Shawn Guo 2012-07-11 13:08 함명주 2012-07-11 13:08 ` 함명주 2012-07-11 13:49 ` Peter De Schrijver 2012-07-11 13:49 ` Peter De Schrijver 2012-07-11 13:49 ` Peter De Schrijver 2012-07-11 13:49 ` Peter De Schrijver 2012-07-12 4:22 ` Prashant Gaikwad 2012-07-12 4:34 ` Prashant Gaikwad
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