Re: [PATCH net-next v1 1/5] net: phy: realtek: add support for dummy phy

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

On 6/3/26 08:59, javen wrote:
> From: Javen Xu <javen_xu@realsil.com.cn>
> 
> Add support for rtl8116af dummy phy driver, match phy id and read link
> speed from MII_BMCR.
> 
> Signed-off-by: Javen Xu <javen_xu@realsil.com.cn>

Can you elaborate more on why this is needed ?

The cover says :
"
In this mode, the driver
needs a dummy PHY ID so that phylib can attach to a dummy Realtek PHY driver,
while selected standard PHY registers are handled through the SerDes register.
"

Why can't you use the SerDes registers for your PHY driver ? The phrase above
suggests that the "SerDes registers" have the typical C22/45 layout. There are PHYs
and PCSs out there that aren't accessed through regular MDIO with regmap being
used to translate the mdio accesses done by phylib into the actual register
access method used.

Maxime

> ---
>  drivers/net/phy/realtek/realtek_main.c | 54 ++++++++++++++++++++++++++
>  include/net/phy/realtek_phy.h          |  1 +
>  2 files changed, 55 insertions(+)
> 
> diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
> index 27268811f564..9b92828c49d9 100644
> --- a/drivers/net/phy/realtek/realtek_main.c
> +++ b/drivers/net/phy/realtek/realtek_main.c
> @@ -2659,6 +2659,47 @@ static int rtlgen_sfp_get_features(struct phy_device *phydev)
>  	return 0;
>  }
>  
> +static int rtl8116af_sfp_get_features(struct phy_device *phydev)
> +{
> +	linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
> +			 phydev->supported);
> +
> +	phydev->speed = SPEED_1000;
> +	phydev->duplex = DUPLEX_FULL;
> +
> +	phydev->port = PORT_FIBRE;
> +
> +	return 0;
> +}
> +
> +static int rtl8116af_sfp_read_status(struct phy_device *phydev)
> +{
> +	int val, err;
> +
> +	err = genphy_update_link(phydev);
> +	if (err)
> +		return err;
> +
> +	if (!phydev->link)
> +		return 0;
> +
> +	val = phy_read(phydev, MII_BMCR);
> +	if (val < 0)
> +		return val;
> +
> +	if (val & BMCR_SPEED1000)
> +		phydev->speed = SPEED_1000;
> +	else if (val & BMCR_SPEED100)
> +		phydev->speed = SPEED_100;
> +
> +	if (val & BMCR_FULLDPLX)
> +		phydev->duplex = DUPLEX_FULL;
> +	else
> +		phydev->duplex = DUPLEX_HALF;
> +
> +	return 0;
> +}
> +
>  static int rtlgen_sfp_read_status(struct phy_device *phydev)
>  {
>  	int val, err;
> @@ -2947,6 +2988,19 @@ static struct phy_driver realtek_drvs[] = {
>  		.write_page	= rtl821x_write_page,
>  		.read_mmd	= rtl822x_read_mmd,
>  		.write_mmd	= rtl822x_write_mmd,
> +	}, {
> +		PHY_ID_MATCH_EXACT(PHY_ID_RTL8116AF_DUMMY),
> +		.name		= "RTL8116af PHY Mode",
> +		.flags		= PHY_IS_INTERNAL,
> +		.get_features	= rtl8116af_sfp_get_features,
> +		.config_aneg	= rtlgen_sfp_config_aneg,
> +		.read_status	= rtl8116af_sfp_read_status,
> +		.suspend	= genphy_suspend,
> +		.resume		= rtlgen_resume,
> +		.read_page	= rtl821x_read_page,
> +		.write_page	= rtl821x_write_page,
> +		.read_mmd	= rtl822x_read_mmd,
> +		.write_mmd	= rtl822x_write_mmd,
>  	}, {
>  		PHY_ID_MATCH_EXACT(0x001ccad0),
>  		.name		= "RTL8224 2.5Gbps PHY",
> diff --git a/include/net/phy/realtek_phy.h b/include/net/phy/realtek_phy.h
> index d683bc1b0659..cbf91af0ead6 100644
> --- a/include/net/phy/realtek_phy.h
> +++ b/include/net/phy/realtek_phy.h
> @@ -3,5 +3,6 @@
>  #define _REALTEK_PHY_H
>  
>  #define	PHY_ID_RTL_DUMMY_SFP	0x001ccbff
> +#define PHY_ID_RTL8116AF_DUMMY  0x001ccbfe
>  
>  #endif /* _REALTEK_PHY_H */