Re: [PATCH 2/3] drm/msm/dsi: Use "ref" fw clock instead of global name for VCO parent

From: Marijn Suijten
Date: Sun Aug 29 2021 - 17:53:45 EST


Hi Dmitry,

On 8/29/21 10:39 PM, Dmitry Baryshkov wrote:
Hi,

On Sun, 29 Aug 2021 at 23:30, Marijn Suijten
<marijn.suijten@xxxxxxxxxxxxxx> wrote:

All DSI PHY/PLL drivers were referencing their VCO parent clock by a
global name, most of which don't exist or have been renamed. These
clock drivers seem to function fine without that except the 14nm driver
for the sdm6xx [1].

At the same time all DTs provide a "ref" clock as per the requirements
of dsi-phy-common.yaml, but the clock is never used. This patchset puts
that clock to use without relying on a global clock name, so that all
dependencies are explicitly defined in DT (the firmware) in the end.

msm8974 (28nm-hpm) does not define the "ref" clock. So you'd have to:
1) add ref clock to the dtsi (should come in a separate patch).


Thanks for double-checking and noticing this! I've queued up this patch for v2.

2) add .name = "xo" as a fallback to the 28nm driver (to be compatible
with older devices)


Are there msm8974 devices out there that might upgrade kernels, but not firmware (DT)? On other boards (sdm630) I'm removing these from various drivers as to not have any possibility of relying on global names, in favour of having the clock dependencies fully specified in the DT.

Other than that this looks good to me.


Any r-b/a-b/t-b I can pick up for the next round?

- Marijn