Re: [PATCH RFC net-next v2 08/12] net: ethernet: freescale: xgmac: Separate C22 and C45 transactions for xgmac

From: Vladimir Oltean <olteanv@gmail.com>
To: Michael Walle <michael@walle.cc>
Cc: Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Jose Abreu <Jose.Abreu@synopsys.com>,
	Sergey Shtylyov <s.shtylyov@omp.ru>, Wei Fang <wei.fang@nxp.com>,
	Shenwei Wang <shenwei.wang@nxp.com>,
	Clark Wang <xiaoning.wang@nxp.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Sean Wang <sean.wang@mediatek.com>,
	Landen Chao <Landen.Chao@mediatek.com>,
	DENG Qingfang <dqfext@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, Andrew Lunn <andrew@lunn.ch>,
	Geert Uytterhoeven <geert+renesas@glider.be>
Subject: Re: [PATCH RFC net-next v2 08/12] net: ethernet: freescale: xgmac: Separate C22 and C45 transactions for xgmac
Date: Tue, 3 Jan 2023 15:55:19 +0200	[thread overview]
Message-ID: <20230103135519.oai43rj3waigqi54@skbuf> (raw)
In-Reply-To: <20221227-v6-2-rc1-c45-seperation-v2-8-ddb37710e5a7@walle.cc>

Commit message can be: "net/fsl: xgmac_mdio: Separate C22 and C45 transactions".

On Wed, Dec 28, 2022 at 12:07:24AM +0100, Michael Walle wrote:
> From: Andrew Lunn <andrew@lunn.ch>
> 
> The xgmac MDIO bus driver can perform both C22 and C45 transfers.
> Create separate functions for each and register the C45 versions using
> the new API calls where appropriate.
> 
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Michael Walle <michael@walle.cc>
> ---
> v2:
>  - [al] Move the masking of regnum into the variable declarations
>  - [al] Remove a couple of blank lines

Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>

>  
> -/*
> - * Reads from register regnum in the PHY for device dev, returning the value.
> +/* Reads from register regnum in the PHY for device dev, returning the value.
>   * Clears miimcom first.  All PHY configuration has to be done through the
>   * TSEC1 MIIM regs.
>   */

I have some reservations regarding the utility of the comments in this
driver. It's surely not worth duplicating them between C22 and C45.
It might also be more productive to just delete them, because:

 - miimcom is a register accessed by fsl_pq_mdio.c, not by xgmac_mdio.c
 - "device dev" doesn't really refer to anything (maybe "dev_addr").
 - I don't understand what is meant by the comment "All PHY configuration
   has to be done through the TSEC1 MIIM regs". Or rather said, I think I
   understand, but it is irrelevant to the driver for 2 reasons:
    * TSEC devices use the fsl_pq_mdio.c driver, not this one
    * It doesn't matter to this driver whose TSEC registers are used for
      MDIO access. The driver just works with the registers it's given,
      which is a concern for the device tree.
 - barring the above, the rest just describes the MDIO bus API, which is
   superfluous