# Re: \[RFC PATCH v1 5/9\] net: phy: micrel: ksz886x add MDI-X support

- From: Oleksij Rempel \<o.rempel@pengutronix.de\>
- Date: 2021-05-10 09:11:19 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/05/6362157
- Thread: https://ratatoskr.run/netdev/2021/05/6358120/t.md

```text
On Wed, May 05, 2021 at 02:37:35PM +0200, Andrew Lunn wrote:
> > +/* Device specific MII_BMCR (Reg 0) bits */
> > +/* 1 = HP Auto MDI/MDI-X mode, 0 = Microchip Auto MDI/MDI-X mode */
> > +#define KSZ886X_BMCR_HP_MDIX			BIT(5)
> > +/* 1 = Force MDI (transmit on RXP/RXM pins), 0 = Normal operation
> > + * (transmit on TXP/TXM pins)
> > + */
> > +#define KSZ886X_BMCR_FORCE_MDI			BIT(4)
> > +/* 1 = Disable auto MDI-X */
> > +#define KSZ886X_BMCR_DISABLE_AUTO_MDIX		BIT(3)
> > +#define KSZ886X_BMCR_DISABLE_FAR_END_FAULT	BIT(2)
> > +#define KSZ886X_BMCR_DISABLE_TRANSMIT		BIT(1)
> > +#define KSZ886X_BMCR_DISABLE_LED		BIT(0)
> 
> Do these have the same values as what you added in patch 1?

ACK, i'll move it

> > +static int ksz886x_config_mdix(struct phy_device *phydev, u8 ctrl)
> > +{
> > +	u16 val;
> > +
> > +	switch (ctrl) {
> > +	case ETH_TP_MDI:
> > +		val = KSZ886X_BMCR_DISABLE_AUTO_MDIX;
> > +		break;
> > +	case ETH_TP_MDI_X:
> > +		/* Note: The naming of the bit KSZ886X_BMCR_FORCE_MDI is bit
> > +		 * counter intuitive, the "-X" in "1 = Force MDI" in the data
> > +		 * sheet seems to be missing:
> > +		 * 1 = Force MDI (sic!) (transmit on RX+/RX- pins)
> > +		 * 0 = Normal operation (transmit on TX+/TX- pins)
> > +		 */
> > +		val = KSZ886X_BMCR_DISABLE_AUTO_MDIX | KSZ886X_BMCR_FORCE_MDI;
> > +		break;
> > +	case ETH_TP_MDI_AUTO:
> > +		val = 0;
> > +		break;
> > +	default:
> > +		return 0;
> > +	}
> > +
> > +	return phy_modify(phydev, MII_BMCR,
> > +			  KSZ886X_BMCR_HP_MDIX | KSZ886X_BMCR_FORCE_MDI |
> > +			  KSZ886X_BMCR_DISABLE_AUTO_MDIX,
> > +			  KSZ886X_BMCR_HP_MDIX | val);
> > +}
> 
> Maybe this will also work for the PHY driver embedded in ksz8795.c?
> Maybe as another patchset, see if that PHY driver can be moved out of the DSA driver,
> and share some code with this driver?

Hm, i'm sure it can be done, but right now i have no access to ksz8795
hardware. I'll keep it in mind.

Regards,
Oleksij
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```