Fixing the devicetree of Rock 5 Model B (and possibly others)

From: Pratham Patel <prathampatel@thefossguy.com>
To: "sebastian.reichel@collabora.com"
	<sebastian.reichel@collabora.com>,
	"saravanak@google.com" <saravanak@google.com>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-rockchip@lists.infradead.org"
	<linux-rockchip@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"regressions@lists.linux.dev" <regressions@lists.linux.dev>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Fixing the devicetree of Rock 5 Model B (and possibly others)
Date: Sat, 23 Mar 2024 17:02:19 +0000	[thread overview]
Message-ID: <tQ0L3-34g4t-mzfQIP6KDe5OYelGnEo6Udzq6Kb_nEcljppSQUXOktpE__nL-CdLOu9gW-4tIIbjtSbqrdCrjEkdhZLPiiHTqRcCB6WORuM=@thefossguy.com> (raw)

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Since the introduction of the `of: property: fw_devlink: Fix stupid bug in remote-endpoint parsing` patch, an issue with the device-tree of the Rock 5 Model B has been detected. All the stable kernels (6.7.y and 6.8.y) work on the Orange Pi 5, which has the Rockchip RK3588S SoC (same as the RK3588, but less I/O basically). So, being an owner of only two SBCs which use the RK3588* SoC, it appears that the Rock 5 Model B's DT is incorrect.

I looked at the patch and tried several things, neither resulted in anything that would point me to the core issue. Then I tried this:

```
$ grep -C 3 remote-endpoint arch/arm64/boot/dts/rockchip/rk3588-rock-5b.dts

                port {
                        es8316_p0_0: endpoint {
                                remote-endpoint = <&i2s0_8ch_p0_0>;
                        };
                };
        };
--
                i2s0_8ch_p0_0: endpoint {
                        dai-format = "i2s";
                        mclk-fs = <256>;
                        remote-endpoint = <&es8316_p0_0>;
                };
        };
};
```

So, from a cursory look, the issue seems to be related to either the DT node for the audio codec or related to the es8316's binding itself. Though I doubt that the later is the issue because if that were the issue, _someone_ with a Pine64 Pinebook Pro would've raised alarms. So far, this seems to be related to the `rk3588-rock-5b.dts` and possibly with the `rk3588s-rock-5a.dts` too.

I would **love** to help but I'm afraid I device-trees are not something that I am at-all familiar with. That said, I am open to methods of debugging this issue to provide a fix myself.

I would have replied to the patch's link but unfortunately, I haven't yet setup neomutt and my email provider's web UI doesn't have a [straightforward] way to reply using the 'In-Reply-To' header, hence a new thread. Apologies for the inconvenience caused.

  -- Pratham Patel

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