[PATCH] arm64: dts: zynqmp: Add power domain for the DisplayPort DMA controller

[Rajan Vaja]

Hi,

> -----Original Message-----
> From: Michal Simek <michal.simek at xilinx.com>
> Sent: Monday, March 8, 2021 2:09 AM
> To: Laurent Pinchart <laurent.pinchart at ideasonboard.com>; linux-arm-
> kernel at lists.infradead.org; Rajan Vaja <RAJANV at xilinx.com>
> Cc: Michal Simek <michals at xilinx.com>
> Subject: Re: [PATCH] arm64: dts: zynqmp: Add power domain for the DisplayPort
> DMA controller
> 
> Hi,
> 
> On 3/7/21 12:09 AM, Laurent Pinchart wrote:
> > The DisplayPort DMA controller (DPDMA) is located in the same power
> > domain as the DisplayPort Subsystem (DPSUB). Specify the power domain in
> > the device tree.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >
> > I'm actually not entirely sure about the truthfulness of the commit
> > message, as I haven't been able to located this information in the
> > reference manual. Nonetheless, without this patch, I get a clock enable
> > failure when starting the display:
> >
> > [   70.517104] zynqmp_pll_enable() clock enable failed for vpll_int, ret = -22
> > [   70.527552] zynqmp-dpsub fd4a0000.display: failed to enable a pixel clock
> >
> > I'm thus quite confident the patch is correct. If anyone has more
> > information and would like to reword the commit message, please feel
> > free to do so.
> >
> >  arch/arm64/boot/dts/xilinx/zynqmp.dtsi | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm64/boot/dts/xilinx/zynqmp.dtsi
> b/arch/arm64/boot/dts/xilinx/zynqmp.dtsi
> > index c113c76f360d..dc5c3a09c77e 100644
> > --- a/arch/arm64/boot/dts/xilinx/zynqmp.dtsi
> > +++ b/arch/arm64/boot/dts/xilinx/zynqmp.dtsi
> > @@ -749,6 +749,7 @@ zynqmp_dpdma: dma-controller at fd4c0000 {
> >  			interrupts = <0 122 4>;
> >  			interrupt-parent = <&gic>;
> >  			clock-names = "axi_clk";
> > +			power-domains = <&zynqmp_firmware PD_DP>;
> >  			#dma-cells = <1>;
> >  		};
> >
> >
> 
> Rajan: Can you please comment this?
[Rajan] Change looks fine to me. If power-domain entry is not present in device tree node, that device would not be requested and hence clock control would fail.

> 
> Thanks,
> Michal