Re: [PATCH net-next] net: dsa: mt7530: fix support for MT7531BE

From: "Arınç ÜNAL" <arinc.unal@arinc9.com>
To: Daniel Golle <daniel@makrotopia.org>,
	netdev@vger.kernel.org, linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Sean Wang <sean.wang@mediatek.com>,
	Landen Chao <Landen.Chao@mediatek.com>,
	DENG Qingfang <dqfext@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Paolo Abeni <pabeni@redhat.com>, Jakub Kicinski <kuba@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	Vladimir Oltean <olteanv@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>
Subject: Re: [PATCH net-next] net: dsa: mt7530: fix support for MT7531BE
Date: Tue, 11 Apr 2023 22:30:06 +0300	[thread overview]
Message-ID: <13aedaa6-6b7b-727e-e932-4a5139c54f39@arinc9.com> (raw)
In-Reply-To: <ZDSlm-0gyyDZXy_k@makrotopia.org>

On 11.04.2023 03:11, Daniel Golle wrote:
> There are two variants of the MT7531 switch IC which got different
> features (and pins) regarding port 5:
>   * MT7531AE: SGMII/1000Base-X/2500Base-X SerDes
>   * MT7531BE: RGMII
> 
> Moving the creation of the SerDes PCS from mt753x_setup to mt7530_probe
> with commit 6de285229773 ("net: dsa: mt7530: move SGMII PCS creation to
> mt7530_probe function") works fine for MT7531AE which got two instances
> of mtk-pcs-lynxi, however, MT7531BE requires mt7531_pll_setup to setup
> clocks before the single PCS on port 6 (usually used as CPU port)
> starts to work and hence the PCS creation failed on MT7531BE.
> 
> Fix this by introducing a pointer to mt7531_create_sgmii function in
> struct mt7530_priv and call it again at the end of mt753x_setup like it
> was before commit 6de285229773 ("net: dsa: mt7530: move SGMII PCS
> creation to mt7530_probe function").

If I understand correctly, this patch does two things.

Run mt7531_create_sgmii() from mt753x_setup(), after mt7531_setup() and 
mt7531_setup_common() is run so that PCS on MT7531BE works.

Run the PCS creation code inside the loop only once if 
mt7531_dual_sgmii_supported() is false so it doesn't set the nonexistent 
port 5 SGMII on MT7531BE.

Regarding the first part:
I was actually in the middle of moving the code until after 
mt7530_pll_setup() and mt7531_pll_setup() on mt7530_setup() and 
mt7531_setup() to mt7530_probe(). To me it makes more sense to run them 
on mt7530_probe() as there's a good amount of duplicate code on 
mt7530_setup() and mt7531_setup().

This will resolve the problem here, and make my future work regarding 
the PHY muxing feature on the MT7530 switch possible to do.

Regarding the second part:
I'll take your changes to my current RFC patch series while addressing 
Jesse's suggestion if this is fine by you.

Arınç

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