diff mbox series

[v3,1/4] dt-bindings: display: mediatek: add property to control mipi tx drive current

Message ID 20200311074032.119481-2-jitao.shi@mediatek.com (mailing list archive)
State New, archived
Headers show
Series Config mipi tx drive current and impedance | expand

Commit Message

Jitao Shi March 11, 2020, 7:40 a.m. UTC
Add a property to control mipi tx drive current:
"drive-strength-microamp"

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 .../devicetree/bindings/display/mediatek/mediatek,dsi.txt     | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Rob Herring (Arm) March 23, 2020, 10 p.m. UTC | #1
On Wed, Mar 11, 2020 at 03:40:29PM +0800, Jitao Shi wrote:
> Add a property to control mipi tx drive current:
> "drive-strength-microamp"
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  .../devicetree/bindings/display/mediatek/mediatek,dsi.txt     | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt b/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
> index a19a6cc375ed..d501f9ff4b1f 100644
> --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
> +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
> @@ -33,6 +33,9 @@ Required properties:
>  - #clock-cells: must be <0>;
>  - #phy-cells: must be <0>.
>  
> +Optional properties:
> +- drive-strength-microamp: adjust driving current, should be 1 ~ 0xF

TBC, 1-0xf is in units of microamps? So a max drive strength of 15uA? 
Seems a bit low.

> +
>  Example:
>  
>  mipi_tx0: mipi-dphy@10215000 {
> @@ -42,6 +45,7 @@ mipi_tx0: mipi-dphy@10215000 {
>  	clock-output-names = "mipi_tx0_pll";
>  	#clock-cells = <0>;
>  	#phy-cells = <0>;
> +	drive-strength-microamp = <0x8>;
>  };
>  
>  dsi0: dsi@1401b000 {
> -- 
> 2.21.0
Jitao Shi March 31, 2020, 7:09 a.m. UTC | #2
On Mon, 2020-03-23 at 16:00 -0600, Rob Herring wrote:
> On Wed, Mar 11, 2020 at 03:40:29PM +0800, Jitao Shi wrote:
> > Add a property to control mipi tx drive current:
> > "drive-strength-microamp"
> > 
> > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> > ---
> >  .../devicetree/bindings/display/mediatek/mediatek,dsi.txt     | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt b/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
> > index a19a6cc375ed..d501f9ff4b1f 100644
> > --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
> > +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
> > @@ -33,6 +33,9 @@ Required properties:
> >  - #clock-cells: must be <0>;
> >  - #phy-cells: must be <0>.
> >  
> > +Optional properties:
> > +- drive-strength-microamp: adjust driving current, should be 1 ~ 0xF
> 
> TBC, 1-0xf is in units of microamps? So a max drive strength of 15uA? 
> Seems a bit low.
> 

The minimum amp is 3000 macroamps,  step is 200macroamps.
So the drive current is 3000 + 200 * drive-strength-microamp amps.

I will update "drive-strength-microamp" define next version.

BR
Jitao
> > +
> >  Example:
> >  
> >  mipi_tx0: mipi-dphy@10215000 {
> > @@ -42,6 +45,7 @@ mipi_tx0: mipi-dphy@10215000 {
> >  	clock-output-names = "mipi_tx0_pll";
> >  	#clock-cells = <0>;
> >  	#phy-cells = <0>;
> > +	drive-strength-microamp = <0x8>;
> >  };
> >  
> >  dsi0: dsi@1401b000 {
> > -- 
> > 2.21.0
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt b/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
index a19a6cc375ed..d501f9ff4b1f 100644
--- a/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
+++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt
@@ -33,6 +33,9 @@  Required properties:
 - #clock-cells: must be <0>;
 - #phy-cells: must be <0>.
 
+Optional properties:
+- drive-strength-microamp: adjust driving current, should be 1 ~ 0xF
+
 Example:
 
 mipi_tx0: mipi-dphy@10215000 {
@@ -42,6 +45,7 @@  mipi_tx0: mipi-dphy@10215000 {
 	clock-output-names = "mipi_tx0_pll";
 	#clock-cells = <0>;
 	#phy-cells = <0>;
+	drive-strength-microamp = <0x8>;
 };
 
 dsi0: dsi@1401b000 {