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Message-ID: <23196dd7ad4eacbee3ad7f4f29b94917a5451450.camel@pengutronix.de>
Subject: Re: [PATCH] reset: microchip-sparx5: allow building as a module
From:   Philipp Zabel <p.zabel@pengutronix.de>
To:     Michael Walle <michael@walle.cc>
Cc:     Steen.Hegelund@microchip.com, UNGLinuxDriver@microchip.com,
        allan.nielsen@microchip.com, clement.leger@bootlin.com,
        horatiu.vultur@microchip.com, lars.povlsen@microchip.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        thomas.petazzoni@bootlin.com
Date:   Wed, 13 Jul 2022 10:56:14 +0200
In-Reply-To: <20220712125836.2676525-1-michael@walle.cc>
References: <99cba2d231c5971525ec976611e66f86259dd1e0.camel@pengutronix.de>
         <20220712125836.2676525-1-michael@walle.cc>
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Hi Michael,

On Di, 2022-07-12 at 14:58 +0200, Michael Walle wrote:
> Hi,
> 
> > On Fr, 2022-06-17 at 12:37 +0200, Clément Léger wrote:
> > > Set RESET_MCHP_SPARX5 as a tristate and add MODULE_DEVICE_TABLE() to
> > > allow building this driver as a module.
> > > 
> > > Signed-off-by: Clément Léger <clement.leger@bootlin.com>
> > 
> > Thank you, applied to reset/next.
> 
> Unfortunately, this is breaking ethernet on my board
> (lan966x-kontron-kswitch-d10-mmt-6g-2gs, see dts in arch/arm/).
> 
> I suspect this is because the postcore_initcall() was called earlier
> in the kernel startup. Now, somehow the MDIO controller isn't working
> anymore.
> 
> For a bit of a background, on the LAN9668 (I guess this is also true
> on most other microchip switch platforms), there is a global switch
> reset which is shared among most subsystems, i.e GPIO, SGPIO and
> switch core. The switch driver will use this reset as there is no other
> reset available (e.g. one which only reset the switching core). But when
> it asserts the reset it will also reset other devices on the SoC. This
> was for example the case for the GPIO, see commit 453200af8a85 ("pinctrl:
> ocelot: add optional shared reset"). It seems like the MIIM is also
> affected by this global reset, thus it needs the same fix.
> 
> I tried the obvious by adding the reset to the MIIM, but that didn't
> help for all broken interfaces. I have to dig deeper into that.
> 
> In the meantime I'd appreciate it if this commit can be reverted until
> the other fixes (at least the missing MIIM reset) will be merged.

Thank you for catching this so quickly, I've sent a revert [1].
I'll add that to reset/next, please let me know when this is fixed.

[1] https://lore.kernel.org/all/20220713084010.168720-1-p.zabel@pengutronix.de/

regards
Philipp