Re: [PATCH net v2] net: phy: realtek: add support for RTL8366S Gigabit PHY

[Maxime Chevallier]

Hello Mark,

On Thu, 25 Jul 2024 16:41:44 -0400
Mark Mentovai <mark@xxxxxxxxxxxx> wrote:

> The PHY built in to the Realtek RTL8366S switch controller was
> previously supported by genphy_driver. This PHY does not implement MMD
> operations. Since commit 9b01c885be36 ("net: phy: c22: migrate to
> genphy_c45_write_eee_adv()"), MMD register reads have been made during
> phy_probe to determine EEE support. For genphy_driver, these reads are
> transformed into 802.3 annex 22D clause 45-over-clause 22
> mmd_phy_indirect operations that perform MII register writes to
> MII_MMD_CTRL and MII_MMD_DATA. This overwrites those two MII registers,
> which on this PHY are reserved and have another function, rendering the
> PHY unusable while so configured.
> 
> Proper support for this PHY is restored by providing a phy_driver that
> declares MMD operations as unsupported by using the helper functions
> provided for that purpose, while remaining otherwise identical to
> genphy_driver.
> 
> Fixes: 9b01c885be36 ("net: phy: c22: migrate to genphy_c45_write_eee_adv()")
> Reported-by: Russell Senior <russell@xxxxxxxxxxxxxxxxx>
> Closes: https://github.com/openwrt/openwrt/issues/15981
> Link: https://github.com/openwrt/openwrt/issues/15739
> Signed-off-by: Mark Mentovai <mark@xxxxxxxxxxxx>

This looks correct to me.

Reviewed-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>

Thanks,

Maxime