[PATCH] NOT TO BE MERGED: ARM: dts: bcm2711: Add support for PiFi DAC+ v2.0/Hifiberry DAC+

Stefan Wahren stefan.wahren at i2se.com
Mon Jun 29 11:56:52 EDT 2020


Am 29.06.20 um 15:38 schrieb Nicolas Saenz Julienne:
> Hi Stefan,
> On Thu, 2020-06-25 at 18:56 +0200, Stefan Wahren wrote:
>> Hi Nicolas,
>> Am 19.06.20 um 19:34 schrieb Nicolas Saenz Julienne:
>>> };
>>> +
>>> +&i2s {
>>> + #sound-dai-cells = <0>;
>>> + pinctrl-names = "default";
>>> + pinctrl-0 = <&pcm_gpio18>;
>>> + dmas = <&dma 2>, <&dma 3>;
>>> + dma-names = "tx", "rx";
>> Since both DMA channels are dedicated for PCM. I think it's worth to
>> merge these 2 lines into bcm2711.dtsi for upstream.
> I see that the i2s dma channels are defined in "bcm2835-common.dtsi" for the
> rest of RPis to use. Do you recall was this wasn't enabled on RPi4? Maybe just
> lack of documentation/testing?

there were two reasons for keeping them separate. First was the lack of
documentation and second one is the fact that the BCM2711 supports 40
bit DMA channels with all the possible consequences to the devicetree.

As long as we don't know which channels are identical and which who not,
i thought it would be better to have them all in a separate file.


>  If so I'll just move it into "bcm283x.dtsi".
> Actually I now see that there is a different dma node for bcm2711 (one
> available in bcm2711.dtsi the other in bcm2835-common.dtsi). Do you think we
> could merge them and just override the interrupt properties for bcm2711? It
> feels cleaner to me, but I might be missing something.
> Regards,
> Nicolas

More information about the linux-rpi-kernel mailing list