Re: [PATCH 21/27] arm64: dts: rockchip: rk356x: Add HDMI nodes

Peter Geis
2022-01-26T18:44:25Z

On Wed, Jan 26, 2022 at 12:56 PM Robin Murphy <robin.murphy@arm.com> wrote:
>
> On 2022-01-26 16:04, Peter Geis wrote:
> > On Wed, Jan 26, 2022 at 9:58 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
> >>
> >> Add support for the HDMI port found on RK3568.
> >>
> >> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> >> ---
> >> arch/arm64/boot/dts/rockchip/rk356x.dtsi | 37 +++++++++++++++++++++++-
> >> 1 file changed, 36 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/arch/arm64/boot/dts/rockchip/rk356x.dtsi b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> >> index 4008bd666d01..e38fb223e9b8 100644
> >> --- a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> >> +++ b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> >> @@ -10,7 +10,6 @@
> >> #include <dt-bindings/pinctrl/rockchip.h>
> >> #include <dt-bindings/power/rk3568-power.h>
> >> #include <dt-bindings/soc/rockchip,boot-mode.h>
> >> -#include <dt-bindings/soc/rockchip,vop2.h>
> >> #include <dt-bindings/thermal/thermal.h>
> >>
> >> / {
> >> @@ -502,6 +501,42 @@ vop_mmu: iommu@fe043e00 {
> >> status = "disabled";
> >> };
> >>
> >> + hdmi: hdmi@fe0a0000 {
> >> + compatible = "rockchip,rk3568-dw-hdmi";
> >> + reg = <0x0 0xfe0a0000 0x0 0x20000>;
> >> + interrupts = <GIC_SPI 45 IRQ_TYPE_LEVEL_HIGH>;
> >> + clocks = <&cru PCLK_HDMI_HOST>,
> >> + <&cru CLK_HDMI_SFR>,
> >> + <&cru CLK_HDMI_CEC>,
> >> + <&pmucru CLK_HDMI_REF>,
> >> + <&cru HCLK_VOP>;
> >> + clock-names = "iahb", "isfr", "cec", "ref", "hclk";
> >> + pinctrl-names = "default";
> >> + pinctrl-0 = <&hdmitx_scl &hdmitx_sda &hdmitxm0_cec>;
> >
> > I looked into CEC support here, and it seems that it does work with one change.
> > Please add the two following lines to your patch:
> > assigned-clocks = <&cru CLK_HDMI_CEC>;
> > assigned-clock-rates = <32768>;
> >
> > The issue is the clk_rtc32k_frac clock that feeds clk_rtc_32k which
> > feeds clk_hdmi_cec is 24mhz at boot, which is too high for CEC to
> > function.
>
> Wouldn't it make far more sense to just stick a suitable clk_set_rate()
> call in the driver? AFAICS it's already explicitly aware of the CEC clock.

This is handled purely in the
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c driver, so I'm hesitant to
touch it there as it would affect all users, not just Rockchip.

Could someone familiar with the dw-hdmi IP weigh in on the minimum and
maximum clock rate the CEC block can handle?

>
> Robin.
>
> >> + power-domains = <&power RK3568_PD_VO>;
> >> + reg-io-width = <4>;
> >> + rockchip,grf = <&grf>;
> >> + #sound-dai-cells = <0>;
> >> + status = "disabled";
> >> +
> >> + ports {
> >> + #address-cells = <1>;
> >> + #size-cells = <0>;
> >> +
> >> + hdmi_in: port@0 {
> >> + reg = <0>;
> >> + #address-cells = <1>;
> >> + #size-cells = <0>;
> >> + };
> >> +
> >> + hdmi_out: port@1 {
> >> + reg = <1>;
> >> + #address-cells = <1>;
> >> + #size-cells = <0>;
> >> + };
> >> + };
> >> + };
> >> +
> >> qos_gpu: qos@fe128000 {
> >> compatible = "rockchip,rk3568-qos", "syscon";
> >> reg = <0x0 0xfe128000 0x0 0x20>;
> >> --
> >> 2.30.2
> >>
> >
> > _______________________________________________
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