Messages in this thread | | | Subject | Re: [PATCH 1/2] drm/bridge: sii902x: Enable I/O and core VCC supplies if present | From | "Alex G." <> | Date | Mon, 28 Sep 2020 12:35:01 -0500 |
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On 9/26/20 1:49 PM, Sam Ravnborg wrote: > Hi Alexandru > > On Thu, Sep 24, 2020 at 03:05:05PM -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@gmail.com> > > One nitpick here. The binding should be present in the tree before > you start using it. So this patch should be applied after the binding.
It is :) * arch/arm/boot/dts/stm32mp15xx-dkx.dtsi
Alex
> One detail below - I think others have already commented on the rest. [snip]
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