Re: [PATCH 01/12] mmc: dt-bindings: update Mediatek MMC bindings

[Chaotian Jing]

On Wed, 2017-09-27 at 00:33 +0200, Ulf Hansson wrote:
> On 14 September 2017 at 04:10, Chaotian Jing <chaotian.jing@xxxxxxxxxxxx> wrote:
> > On Wed, 2017-09-13 at 09:10 -0500, Rob Herring wrote:
> >> On Tue, Sep 12, 2017 at 05:07:41PM +0800, Chaotian Jing wrote:
> >> > Change the comptiable for support of multi-platform
> >> > Add description for reg
> >> > Add description for source_cg
> >> > Add description for mediatek,latch-ck
> >>
> >> This is at least the 3rd patch with exactly the same vague subject.
> >> Please make the subject somewhat unique.
> >>
> > Thx, will change the subject at next version
> >> >
> >> > Signed-off-by: Chaotian Jing <chaotian.jing@xxxxxxxxxxxx>
> >> > ---
> >> >  Documentation/devicetree/bindings/mmc/mtk-sd.txt | 13 ++++++++++---
> >> >  1 file changed, 10 insertions(+), 3 deletions(-)
> >> >
> >> > diff --git a/Documentation/devicetree/bindings/mmc/mtk-sd.txt b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> >> > index 4182ea3..405cd06 100644
> >> > --- a/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> >> > +++ b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> >> > @@ -7,10 +7,15 @@ This file documents differences between the core properties in mmc.txt
> >> >  and the properties used by the msdc driver.
> >> >
> >> >  Required properties:
> >> > -- compatible: Should be "mediatek,mt8173-mmc","mediatek,mt8135-mmc"
> >> > +- compatible: value should be either of the following.
> >> > +   "mediatek,mt8135-mmc": for mmc host ip compatible with mt8135
> >> > +   "mediatek,mt8173-mmc": for mmc host ip compatible with mt8173
> >> > +   "mediatek,mt2701-mmc": for mmc host ip compatible with mt2701
> >> > +   "mediatek,mt2712-mmc": for mmc host ip compatible with mt2712
> >> > +- reg: physical base address of the controller and length
> >> >  - interrupts: Should contain MSDC interrupt number
> >> > -- clocks: MSDC source clock, HCLK
> >> > -- clock-names: "source", "hclk"
> >> > +- clocks: MSDC source clock, HCLK, source_cg
> >> > +- clock-names: "source", "hclk", "source_cg"
> >>
> >> All chips support source_cg? That's not backwards compatible for
> >> existing compatible strings if the driver requires it.
> > Not all chips support source_cg, for chips which do not support
> > source_cg, no need source_cg here, and the driver will parse it
> > to know if current chip support it.
> 
> In such case you must not add add a required binding for it. I think
> that is what Rob is trying to point out for you.
> 
> [...]
> 
> Kind regards
> Uffe
The source_cg is required(MUST) at MT2712 and future SoCs, but not
required(do not have it) at previous SoCs, so that put it at required
properties, let the driver to handle it.