Re: [PATCH v2] arm64: dts: rockchip: add SPDIF node for rk3399-rockpro64

[Katsuhiro Suzuki]

Hello Heiko,

On 2020/08/31 4:08, Heiko Stuebner wrote:
> Hi,
>
> Am Montag, 10. August 2020, 11:16:19 CEST schrieb Katsuhiro Suzuki:
> > This patch adds 'disabled' SPDIF sound node and related settings
> > for rk3399-rockpro64.
> >
> > There are 2 reasons:
> >    - All RK3399 dma-bus channels have been already used by I2S0/1/2
> >    - RockPro64 does not have SPDIF optical nor coaxial connector,
> >      just have 3pins
>
> I don't really understand what you mean here.
>
> Like is there spdif on the board or not? Because you call it "disabled"
> and also indicate that no i2s is available anymore, yet you mention 3 pins.
> What do they do then?

RockPro64 has output pins for SPDIF Tx. But RK3399 does not have enough DMA
channel for enabling SPDIF tx. Current settings are:

  - I2S0     (Req number 0, 1): Enabled  : Output to 40pin headers (CON40)
  - I2S1     (Req number 2, 3): Enabled  : Output to ES8316 on board
  - I2S2     (Req number 4, 5): Enabled  : Output to internal HDMI core
  - SPDIF Tx (Req number 7)   : Disabled : Output to other connector (J10)

If we want to enable ALL sound I/Os, we need 7 DMA channels for it.
But... Unfortunately, RK3399 has only 6 DMA channels for sounds, PWM and SPIs.

So users of RockPro64 have to choose from the following:

  - Disable one of I2S (Ex. I2S0) and enable SPDIF tx
  - Keep enable I2S0/1/2 and disable SPDIF tx

> Thanks
> Heiko

Best Regards,
Katsuhiro Suzuki


> > Signed-off-by: Katsuhiro Suzuki <katsuhiro@xxxxxxxxxxxxx>
> >
> > ---
> >
> > Changes in v2:
> >    - Remove redundant status property
> > ---
> >   .../boot/dts/rockchip/rk3399-rockpro64.dtsi   | 27 +++++++++++++++++++
> >   1 file changed, 27 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi
> > index 6e553ff47534..58097245994a 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi
> > +++ b/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi
> > @@ -76,6 +76,23 @@ sound {
> >   		dais = <&i2s1_p0>;
> >   	};
> >   
> > +	sound-dit {
> > +		compatible = "audio-graph-card";
> > +		label = "rockchip,rk3399";
> > +		dais = <&spdif_p0>;
> > +	};
> > +
> > +	spdif-dit {
> > +		compatible = "linux,spdif-dit";
> > +		#sound-dai-cells = <0>;
> > +
> > +		port {
> > +			dit_p0_0: endpoint {
> > +				remote-endpoint = <&spdif_p0_0>;
> > +			};
> > +		};
> > +	};
> > +
> >   	vcc12v_dcin: vcc12v-dcin {
> >   		compatible = "regulator-fixed";
> >   		regulator-name = "vcc12v_dcin";
> > @@ -698,6 +715,16 @@ &sdhci {
> >   	status = "okay";
> >   };
> >   
> > +&spdif {
> > +	pinctrl-0 = <&spdif_bus_1>;
> > +
> > +	spdif_p0: port {
> > +		spdif_p0_0: endpoint {
> > +			remote-endpoint = <&dit_p0_0>;
> > +		};
> > +	};
> > +};
> > +
> >   &spi1 {
> >   	status = "okay";
> >