Re: [PATCH] net: phy: realtek: fix rtl8211e rx/tx delay config

From: Andrew Lunn
Date: Mon Sep 21 2020 - 11:12:51 EST

On Mon, Sep 21, 2020 at 07:00:00AM +0000, 劉偉權 wrote:
> Hi Andrew,

> I removed below register layout descriptions because these
> descriptions did not match register definitions for rtl8211e
> extension page 164 reg 0x1c at all.
> 8:6 = PHY Address
> 5:4 = Auto-Negotiation
> 3 = Mode
> 2 = RXD
> 1 = TXD
> 0 = SELRGV1

> I think it is a misunderstanding. These definitions are mapped from
> datasheet rtl8211e table13" Configuration Register
> Definition". However this table should be HW pin configurations not
> register descriptions.

So these are just how the device is strapped. So lets add that to the
description, rather than remove it.

> Users can config RXD/TXD via register setting(extension page 164 reg
> 0x1c). But bit map for these two settings should be below:
> 13 = Force Tx RX Delay controlled by bit12 bit11,
> 12 = RX Delay, 11 = TX Delay

> Hi Sergey,

> I saw the summary from This
> patch is to reconfigure the RTL8211E used to force off TXD/RXD (RXD
> is defaulting to on, in my checks) and turn on some bits in the
> configuration register for this PHY that are undocumented.

> The default value for "extension pg 0xa4 reg 0x1c" is 0x8148, and
> bit1-2 should be 0. In my opinion, this patch should be worked based
> on the magic number (0xb400).

Magic numbers are always bad. Please document what these bits mean.