Re: [PATCH v4 net 1/3] net: mediatek: sgmii: ensure the SGMII PHY is powered down on configuration

[Simon Horman <simon.horman@corigine.com>]

On Wed, Jan 25, 2023 at 07:16:00PM +0100, Bjørn Mork wrote:
> From: Alexander Couzens <lynxis@fe80.eu>
> 
> The code expect the PHY to be in power down which is only true after reset.
> Allow changes of the SGMII parameters more than once.
> 
> Only power down when reconfiguring to avoid bouncing the link when there's
> no reason to - based on code from Russell King.
> 
> There are cases when the SGMII_PHYA_PWD register contains 0x9 which
> prevents SGMII from working. The SGMII still shows link but no traffic
> can flow. Writing 0x0 to the PHYA_PWD register fix the issue. 0x0 was
> taken from a good working state of the SGMII interface.
> 
> Fixes: 42c03844e93d ("net-next: mediatek: add support for MediaTek MT7622 SoC")
> Suggested-by: Russell King (Oracle) <linux@armlinux.org.uk>
> Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
> [ bmork: rebased and squashed into one patch ]
> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> Signed-off-by: Bjørn Mork <bjorn@mork.no>
> ---
>  drivers/net/ethernet/mediatek/mtk_eth_soc.h |  2 ++
>  drivers/net/ethernet/mediatek/mtk_sgmii.c   | 39 +++++++++++++++------
>  2 files changed, 30 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> index 18a50529ce7b..b299a7df3c30 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> @@ -1037,10 +1037,12 @@ struct mtk_soc_data {
>   *                     SGMII modes
>   * @ana_rgc3:          The offset refers to register ANA_RGC3 related to regmap
>   * @pcs:               Phylink PCS structure
> + * @interface:         Currently configured interface mode

nit: @interface should probably be above @pcs

>   */
>  struct mtk_pcs {
>  	struct regmap	*regmap;
>  	u32             ana_rgc3;
> +	phy_interface_t	interface;
>  	struct phylink_pcs pcs;
>  };

Thanks for tweaking the location of the interface field so
there is no hole in mtk_pcs. Looks good (on x86_64).