Re: [PATCH v2 2/2] net: phy: realtek: Change TX-delay setting for RGMII modes only

Andrew Lunn
2019-04-26T21:46:38Z

On Sat, Apr 27, 2019 at 12:21:12AM +0300, Serge Semin wrote:
> It's prone to problems if delay is cleared out for other than RGMII
> modes. So lets set/clear the TX-delay in the config register only
> if actually RGMII-like interface mode is requested.
>
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
>
> ---
> drivers/net/phy/realtek.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> index ab567a1923ad..a18cb01158f9 100644
> --- a/drivers/net/phy/realtek.c
> +++ b/drivers/net/phy/realtek.c
> @@ -163,16 +163,24 @@ static int rtl8211c_config_init(struct phy_device *phydev)
> static int rtl8211f_config_init(struct phy_device *phydev)
> {
> int ret;
> - u16 val = 0;
> + u16 val;
>
> ret = genphy_config_init(phydev);
> if (ret < 0)
> return ret;
>
> - /* enable TX-delay for rgmii-id and rgmii-txid, otherwise disable it */
> - if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
> - phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID)
> + /* enable TX-delay for rgmii-id/rgmii-txid, and disable it for rgmii */
> + switch (phydev->interface) {
> + case PHY_INTERFACE_MODE_RGMII:
> + val = 0;
> + break;
> + case PHY_INTERFACE_MODE_RGMII_ID:
> + case PHY_INTERFACE_MODE_RGMII_TXID:
> val = RTL8211F_TX_DELAY;
> + break;
> + default: /* the rest of the modes imply leaving delay as is. */
> + return 0;
> + }

So there is no control of the RX delay?

That means PHY_INTERFACE_MODE_RGMII_ID and
PHY_INTERFACE_MODE_RGMII_RXID are not supported, and you should return
-EINVAL.

This is where we get into interesting backwards compatibility
issues. Are there any broken DT blobs with rgmii-id or rgmii-rxid,
which will break with such a change?

Andrew