Re: [PATCH] arm64: dts: ti: k3-am625-sk: Add support for WL1837 module onboard

From: Nishanth Menon <nm@ti.com>
To: Tony Lindgren <tony@atomide.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>,
	<devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	sukrut bellary <sukrut.bellary@gmail.com>
Subject: Re: [PATCH] arm64: dts: ti: k3-am625-sk: Add support for WL1837 module onboard
Date: Sun, 3 Dec 2023 08:07:10 -0600	[thread overview]
Message-ID: <20231203140710.irc7mmwff2b5voak@observant> (raw)
In-Reply-To: <20231129083433.GT5169@atomide.com>

On 10:34-20231129, Tony Lindgren wrote:
> * Nishanth Menon <nm@ti.com> [231123 07:10]:
> > On 14:24-20231121, Tony Lindgren wrote:
> > > From: Vignesh Raghavendra <vigneshr@ti.com>
> > > 
> > > WL1837 WLAN card is present on the original AM625 SK board. It
> > > communicates with the SoC using 4 bit SDIO through the second instance of
> > > MMCSD.
> > > 
> > > Starting with SK-AM62B, there is a M.2 WLAN device connector instead of
> > 
> > We support AM62B-SK.
> 
> Is that with k3-am62-lp-sk.dts though? Wondering if they should have separate
> dts files for the M.2.

It has been the same dts. Separating the wlan out of the dts sounds
correct.

> 
> > > the integrated WL1837 WLAN. The M.2 connector should be handled separately
> > > in the k3-am62a.dtsi and k3-am62b.dtsi files as needed.
> > 
> > Should this rather be an overlay instead of integrated dts fixup? M2
> > connector allows for various options including the newer 33xx family[2].
> 
> Not sure if an overlay makes sense for an integrated device.. It sure makes
> sense for plug in boards though.

overlay works for both variant of devices (please see additional comment
below).

> 
> > It makes sense for the regulator etc to be on the main dts file, but I
> > am not convinced about it being integrated as part of the dts.
> 
> Yeah if AM62B-SK is supported with the same dts. My vote would be for
> separate dts files for the integrated variant to keep things simple :)

we can handle it via dtb itself

dts can remain common, the m2 is a dtso, we generate a dtbo and the
original will be an additional dtb? I think this can work out without
dts/dtsi duplication.

arch/arm64/boot/dts/ti/Makefile has previous examples of the form.

> 
> > Should we use mmc-pwrseq ?
> 
> Yes probably, I think there was some issue earlier with that but sounds like
> it's been solved already.
> 
> > Looks like we have run into an issue in BeaglePlay with wlan_en
> > being always on for loading firmware. so is there a need to keep the
> > wlan on while suspended?
> 
> If the wlan irq was on the first gpio bank, wake-up path would work for
> the wlan. But I think it's wired to a gpio bank with no wake-up capability,
> and the padconf wake related patches are still pending. So no need to keep
> the wlan enabled so far AFAIK.

I believe the issue was around the wlan firmware load itself, but i
think the mmc-pwrseq will probably help resolve it.
-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D

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