Re: [PATCH v2 1/2] net: phy: realtek: Add rtl8211e rx/tx delays config

Andrew Lunn
2019-04-26T21:40:58Z

On Sat, Apr 27, 2019 at 12:21:11AM +0300, Serge Semin wrote:
> There are two chip pins named TXDLY and RXDLY which actually adds the 2ns
> delays to TXC and RXC for TXD/RXD latching. Alas this is the only
> documented info regarding the RGMII timing control configurations the PHY
> provides. It turns out the same settings can be setup via MDIO registers
> hidden in the extension pages layout. Particularly the extension page 0xa4
> provides a register 0x1c, which bits 1 and 2 control the described delays.
> They are used to implement the "rgmii-{id,rxid,txid}" phy-mode.
>
> The hidden RGMII configs register utilization was found in the rtl8211e
> U-boot driver:
> https://elixir.bootlin.com/u-boot/v2019.01/source/drivers/net/phy/realtek.c#L99
>
> There is also a freebsd-folks discussion regarding this register:
> https://reviews.freebsd.org/D13591
>
> It confirms that the register bits field must control the so called
> configuration pins described in the table 12-13 of the official PHY
> datasheet:
> 8:6 = PHY Address
> 5:4 = Auto-Negotiation
> 3 = Interface Mode Select
> 2 = RX Delay
> 1 = TX Delay
> 0 = SELRGV
>
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

Hi Serge

Next time please include a patch 0 containing a cover note explaining
the who series.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Andrew