diff mbox

[3/5] dt-bindings: ARM: Mediatek: Document devicetree bindings for clock controllers

Message ID 1432192376-6712-4-git-send-email-jamesjj.liao@mediatek.com
State Superseded, archived
Headers show

Commit Message

James Liao May 21, 2015, 7:12 a.m. UTC 
This adds the binding documentation for the mmsys, imgsys, vdecsys,
vencsys and vencltsys controllers found on Mediatek SoCs.

Signed-off-by: James Liao <jamesjj.liao@mediatek.com>
---
 .../bindings/arm/mediatek/mediatek,imgsys.txt      | 22 ++++++++++++++++++++++
 .../bindings/arm/mediatek/mediatek,mmsys.txt       | 22 ++++++++++++++++++++++
 .../bindings/arm/mediatek/mediatek,vdecsys.txt     | 22 ++++++++++++++++++++++
 .../bindings/arm/mediatek/mediatek,vencltsys.txt   | 22 ++++++++++++++++++++++
 .../bindings/arm/mediatek/mediatek,vencsys.txt     | 22 ++++++++++++++++++++++
 5 files changed, 110 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt
 create mode 100644 Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt
 create mode 100644 Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt
 create mode 100644 Documentation/devicetree/bindings/arm/mediatek/mediatek,vencltsys.txt
 create mode 100644 Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt

Comments

Sascha Hauer May 26, 2015, 7:56 a.m. UTC | #1 
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?

Sascha
James Liao May 26, 2015, 8:55 a.m. UTC | #2 
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


Best regards,

James


--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Sascha Hauer May 26, 2015, 11:08 a.m. UTC | #3 
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?

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.

Sascha
Yong Wu (吴勇) May 27, 2015, 6:12 a.m. UTC | #4 
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
> 


--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Sascha Hauer May 27, 2015, 7:27 a.m. UTC | #5 
On Wed, May 27, 2015 at 02:12:49PM +0800, Yong Wu wrote:
> 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?

When the larb has clocks from the vdec like in the above example from
the 3.18 kernel then the larb indirectly via the clk API writes to the
vdec register space.
In the latest code you referenced the vdec clocks are no longer assigned
to the larbs. This means we no longer need the vdec clocks abstracted in
CCF.

Sascha
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt
new file mode 100644
index 0000000..7612bac
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt
@@ -0,0 +1,22 @@ 
+Mediatek imgsys controller
+============================
+
+The Mediatek imgsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-imgsys", "syscon"
+- #clock-cells: Must be 1
+
+The imgsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+imgsys: imgsys@15000000 {
+	compatible = "mediatek,mt8173-imgsys", "syscon";
+	reg = <0 0x15000000 0 0x1000>;
+	#clock-cells = <1>;
+};
diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt
new file mode 100644
index 0000000..b51e417
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt
@@ -0,0 +1,22 @@ 
+Mediatek mmsys controller
+============================
+
+The Mediatek mmsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-mmsys", "syscon"
+- #clock-cells: Must be 1
+
+The mmsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+mmsys: mmsys@14000000 {
+	compatible = "mediatek,mt8173-mmsys", "syscon";
+	reg = <0 0x14000000 0 0x1000>;
+	#clock-cells = <1>;
+};
diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt
new file mode 100644
index 0000000..a5b94a7
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt
@@ -0,0 +1,22 @@ 
+Mediatek vdecsys controller
+============================
+
+The Mediatek vdecsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-vdecsys", "syscon"
+- #clock-cells: Must be 1
+
+The vdecsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+vdecsys: vdecsys@16000000 {
+	compatible = "mediatek,mt8173-vdecsys", "syscon";
+	reg = <0 0x16000000 0 0x1000>;
+	#clock-cells = <1>;
+};
diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencltsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencltsys.txt
new file mode 100644
index 0000000..3d4e8d8
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencltsys.txt
@@ -0,0 +1,22 @@ 
+Mediatek vencltsys controller
+============================
+
+The Mediatek vencltsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-vencltsys", "syscon"
+- #clock-cells: Must be 1
+
+The vencltsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+vencltsys: vencltsys@19000000 {
+	compatible = "mediatek,mt8173-vencltsys", "syscon";
+	reg = <0 0x19000000 0 0x1000>;
+	#clock-cells = <1>;
+};
diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt
new file mode 100644
index 0000000..e5b72f5
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt
@@ -0,0 +1,22 @@ 
+Mediatek vencsys controller
+============================
+
+The Mediatek vencsys controller provides various clocks to the system.
+
+Required Properties:
+
+- compatible: Should be:
+	- "mediatek,mt8173-vencsys", "syscon"
+- #clock-cells: Must be 1
+
+The vencsys controller uses the common clk binding from
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+The available clocks are defined in dt-bindings/clock/mt*-clk.h.
+
+Example:
+
+vencsys: vencsys@18000000 {
+	compatible = "mediatek,mt8173-vencsys", "syscon";
+	reg = <0 0x18000000 0 0x1000>;
+	#clock-cells = <1>;
+};