From: Stefano Radaelli <stefano.radaelli21@gmail•com>
To: Frank Li <Frank.li@nxp•com>
Cc: linux-kernel@vger•kernel.org, devicetree@vger•kernel.org,
imx@lists•linux.dev, pierluigi.p@variscite•com,
Stefano Radaelli <stefano.r@variscite•com>,
Rob Herring <robh@kernel•org>,
Krzysztof Kozlowski <krzk+dt@kernel•org>,
Conor Dooley <conor+dt@kernel•org>,
Sascha Hauer <s.hauer@pengutronix•de>,
Pengutronix Kernel Team <kernel@pengutronix•de>,
Fabio Estevam <festevam@gmail•com>,
linux-arm-kernel@lists•infradead.org
Subject: Re: [PATCH v1 1/1] arm64: dts: imx91-var-som-symphony: fix RGB_SEL handling
Date: Wed, 3 Jun 2026 11:12:16 +0200 [thread overview]
Message-ID: <ah_v8E78aV3n1TZx@Lord-Beerus.station> (raw)
In-Reply-To: <ah3uuIeZ4Z6BMwfi@lizhi-Precision-Tower-5810>
Hi Frank,
On Mon, Jun 01, 2026 at 04:42:32PM -0400, Frank Li wrote:
> On Fri, May 29, 2026 at 03:48:50PM +0200, Stefano Radaelli wrote:
> > From: Stefano Radaelli <stefano.r@variscite•com>
> >
> > RGB_SEL is a board-level signal driven by the PCAL6408 GPIO expander on
> > the Symphony carrier board.
> >
> > The signal needs to be driven high on the i.MX91 variant to keep the
> > board in the expected display configuration. Move the handling of this
> > line from a fixed regulator tied to the PCAL6408 supply to a GPIO hog on
> > the correct GPIO expander.
>
> Look like this can't resolve your problem. gpio driver may probe later
> than display, so gpio-hog may not set correct when display setup.
>
> Frank
> >
thanks for looking at this.
The main issue I am trying to fix here is that the current upstream DT
describes RGB_SEL on the wrong GPIO expander.
The existing DT drives RGB_SEL from pca9534 GPIO 7 and also uses it as a
fake supply for the pca6408. That is not correct for this board. RGB_SEL
is actually connected to pca6408 GPIO 7, so the current description does
not drive the intended line at all.
With this change, RGB_SEL is driven by the correct GPIO controller and
this fixes the hardware configuration issue I am seeing on the i.MX91
Symphpony board, making it working now as expected.
Best Regards,
Stefano
next prev parent reply other threads:[~2026-06-03 9:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-29 13:48 [PATCH v1 1/1] arm64: dts: imx91-var-som-symphony: fix RGB_SEL handling Stefano Radaelli
2026-06-01 20:42 ` Frank Li
2026-06-03 9:12 ` Stefano Radaelli [this message]
2026-06-03 18:03 ` Frank.Li
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