Subject: Re: [PATCH v3 3/6] dt-bindings: devfreq: Add bindings for imx ddr controller

From: Rob Herring <[email-masked]>
Date: Tue, 5 Nov 2019 14:13:02 -0600

On Tue, Nov 05, 2019 at 07:25:57PM +0000, Leonard Crestez wrote:
> On 05.11.2019 00:21, Rob Herring wrote:
> > On Thu, Oct 31, 2019 at 11:50:24PM +0200, Leonard Crestez wrote:
> >> Add devicetree bindings for the i.MX DDR Controller on imx8m series
> >> chips. It supports dynamic frequency switching between multiple data
> >> rates and this is exposed to Linux via the devfreq subsystem.
> >>
> >> Signed-off-by: Leonard Crestez <[email-masked]>
> >> ---
> >>   .../devicetree/bindings/devfreq/imx-ddrc.yaml | 60 +++++++++++++++++++
> > 
> > .../bindings/memory-controllers/
> 
> Okay, but I'm not sure about the rules here. Usually there is a 1:1 
> mapping between subsystems and bindings directory but I guess devfreq is 
> odd since it's not really a physical class of device.

Mostly true, but it's not completely 1:1.

> I saw there is also a drivers/memory and there is already a 
> devfreq-using driver in there (EXYNOS5422_DMC).

Yeah, well it's been a while since I last tried to clean up locations of 
things. DDR controller bindings are not in the best shape.

> It's not clear if my driver fits in there; as far as I can see the only 
> "core" functionality in drivers/memory is parsing DDR timings from DTS 
> but for imx8m this is all controlled in firmware.

You shouldn't have to think about that. Bindings should be for DDR 
controllers regardless of whether there's a driver for devfreq, EDAC, 
perf, or ??? or all of those.

Rob

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