Re: [PATCH v3 2/3] drm/bridge: sii902x: Enable I/O and core VCC supplies if present

[Sam Ravnborg]

Hi Alexandru

On Tue, Oct 20, 2020 at 05:14:58PM -0500, Alexandru Gagniuc wrote:
> On the SII9022, the IOVCC and CVCC12 supplies must reach the correct
> voltage before the reset sequence is initiated. On most boards, this
> assumption is true at boot-up, so initialization succeeds.
> 
> However, when we try to initialize the chip with incorrect supply
> voltages, it will not respond to I2C requests. sii902x_probe() fails
> with -ENXIO.
> 
> To resolve this, look for the "iovcc" and "cvcc12" regulators, and
> make sure they are enabled before starting the reset sequence. If
> these supplies are not available in devicetree, then they will default
> to dummy-regulator. In that case everything will work like before.
> 
> This was observed on a STM32MP157C-DK2 booting in u-boot falcon mode.
> On this board, the supplies would be set by the second stage
> bootloader, which does not run in falcon mode.
> 
> Signed-off-by: Alexandru Gagniuc <mr.nuke.me@xxxxxxxxx>

Thanks, applied series to drm-misc-next. I fixed two
checkpatch --strict warnings while applying.

	Sam