From: Yong Wu <yong.wu@mediatek.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: James Liao <jamesjj.liao@mediatek.com>,
<devicetree@vger.kernel.org>,
"Mike Turquette" <mturquette@linaro.org>,
<srv_heupstream@mediatek.com>,
"Stephen Boyd" <sboyd@codeaurora.org>,
<linux-kernel@vger.kernel.org>,
Henry Chen <henryc.chen@mediatek.com>,
Ricky Liang <jcliang@chromium.org>,
Rob Herring <robh+dt@kernel.org>,
<linux-mediatek@lists.infradead.org>,
Sascha Hauer <kernel@pengutronix.de>,
Matthias Brugger <matthias.bgg@gmail.com>,
Yingjoe Chen <yingjoe.chen@mediatek.com>,
Eddie Huang <eddie.huang@mediatek.com>,
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 3/5] dt-bindings: ARM: Mediatek: Document devicetree bindings for clock controllers
Date: Wed, 27 May 2015 14:12:49 +0800 [thread overview]
Message-ID: <1432707169.721.81.camel@mhfsdcap03> (raw)
In-Reply-To: <20150526110819.GI6325@pengutronix.de>
On Tue, 2015-05-26 at 13:08 +0200, Sascha Hauer wrote:
> On Tue, May 26, 2015 at 04:55:36PM +0800, James Liao wrote:
> > Hi Sascha,
> >
> > On Tue, 2015-05-26 at 09:56 +0200, Sascha Hauer wrote:
> > > On Thu, May 21, 2015 at 03:12:54PM +0800, James Liao wrote:
> > > > This adds the binding documentation for the mmsys, imgsys, vdecsys,
> > > > vencsys and vencltsys controllers found on Mediatek SoCs.
> > > >
> > > > index 0000000..a5b94a7
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt
> > > > +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencltsys.txt
> > > > +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt
> > >
> > > Do these really become multiple drivers so that it's worth abstracting
> > > them in the clock framework?
> >
> > These clocks need to be controlled among several drivers. For example,
> > vdecsys clocks will be controlled by VDEC driver (not ready yet) and
> > MT8173 SMI driver [1]. That means these clocks need a mechanism to share
> > between these 2 drivers. CCF share clocks by using of reference count,
> > so I think it's suitable to implement these subsystem clocks.
> >
> > As I know SMI driver need to access clocks among mmsys, imgsys, vdecsys,
> > vencsys and vencltsys. So in this patch I added clocks of these
> > subsystems into CCF.
> >
> > [1]
> > http://lists.infradead.org/pipermail/linux-mediatek/2015-March/000058.html
>
> Looking at the 3.18 tree we have this:
>
> vdecsys: vdecsys@16000000 {
> compatible = "mediatek,mt8173-vdecsys", "syscon";
> reg = <0 0x16000000 0 0x1000>;
> #clock-cells = <1>;
> };
>
> larb1:larb@16010000 {
> compatible = "mediatek,mt8173-smi-larb";
> reg = <0 0x16010000 0 0x1000>;
> clocks = <&mmsys MM_SMI_COMMON>,
> <&vdecsys VDEC_CKEN>,
> <&vdecsys VDEC_LARB_CKEN>;
> clock-names = "larb_sub0", "larb_sub1", "larb_sub2";
> };
>
> I believe that the larb needs the MM_SMI_COMMON clock to modify the larb
> registers, but is it really necessary to enable VDEC_CKEN and
> VDEC_LARB_CKEN just to set the F_SMI_MMU_EN bit in the larb?
Yes. SMI need the two clock while smi work.
the lastest smi binding is [1].
smi need "apb" and "smi" clocks.
[1]http://lists.linuxfoundation.org/pipermail/iommu/2015-May/013025.html
>
> With the above we have the situation that the vdec driver calls into the
> iommu driver which then calls into the larb driver which calls back into
> the vdec driver via the clk API. This seems very suspicious.
iommu driver will call into the larb driver.
but I don't think the larb driver will call into the vdec driver. is it
right?
At the end of the latest smi driver[2].
smi has provide two interface. the multimedia HW could call it to enable
smi clock, then they can delete some node like <&vdecsys VDEC_CKEN>. in
their dtsi.
//=====
+int mtk_smi_larb_get(struct device *plarbdev);
+void mtk_smi_larb_put(struct device *plarbdev);
//=====
SMI only help control the smi relational clockes.
The other clocks of multimedia module also should control theirself.
[2]http://lists.linuxfoundation.org/pipermail/iommu/2015-May/013030.html
>
> Sascha
>
next prev parent reply other threads:[~2015-05-27 6:14 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-21 7:12 [PATCH 0/5] Add Mediatek MT8173 subsystem clocks support James Liao
2015-05-21 7:12 ` [PATCH 1/5] clk: mediatek: Fix apmixedsys clock registration James Liao
2015-05-26 7:42 ` Sascha Hauer
2015-06-04 21:07 ` Stephen Boyd
2015-05-21 7:12 ` [PATCH 2/5] clk: mediatek: mt8173: Fix enabling of critical clocks James Liao
2015-05-26 7:46 ` Sascha Hauer
2015-05-26 8:36 ` James Liao
2015-05-21 7:12 ` [PATCH 3/5] dt-bindings: ARM: Mediatek: Document devicetree bindings for clock controllers James Liao
2015-05-26 7:56 ` Sascha Hauer
2015-05-26 8:55 ` James Liao
2015-05-26 11:08 ` Sascha Hauer
2015-05-27 6:12 ` Yong Wu [this message]
2015-05-27 7:27 ` Sascha Hauer
2015-05-28 5:14 ` Yong Wu
2015-05-21 7:12 ` [PATCH 4/5] clk: mediatek: Add subsystem clocks of MT8173 James Liao
2015-05-22 4:22 ` Daniel Kurtz
2015-05-22 6:03 ` James Liao
2015-06-12 17:09 ` Matthias Brugger
2015-06-15 2:10 ` James Liao
2015-05-21 7:12 ` [PATCH 5/5] clk: mediatek: Add USB clock support in MT8173 APMIXEDSYS James Liao
2015-05-26 8:05 ` Sascha Hauer
2015-05-26 9:11 ` James Liao
2015-05-26 9:41 ` Sascha Hauer
2015-05-26 9:58 ` James Liao
2015-05-28 13:24 ` [PATCH 0/5] Add Mediatek MT8173 subsystem clocks support Sascha Hauer
2015-05-29 2:47 ` James Liao
2015-05-29 6:23 ` Sascha Hauer
2015-06-04 21:02 ` Stephen Boyd
2015-06-05 1:45 ` James Liao
2015-06-06 0:59 ` Stephen Boyd
2015-06-08 7:27 ` James Liao
2015-06-08 7:48 ` Sascha Hauer
2015-06-11 23:52 ` Stephen Boyd
2015-06-12 17:05 ` Matthias Brugger
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