linux-kernel - Re: [PATCH net-next 2/3] net: mdio: mscc-miim: replace magic numbers for the bus reset

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Message-ID: <Yi4FHDz+ya8VZZDq@lunn.ch>
Date:   Sun, 13 Mar 2022 15:52:12 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Michael Walle <michael@...le.cc>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next 2/3] net: mdio: mscc-miim: replace magic numbers
 for the bus reset

On Sun, Mar 13, 2022 at 02:17:55AM +0100, Michael Walle wrote:
> Am 2022-03-13 01:51, schrieb Andrew Lunn:
> > > diff --git a/drivers/net/mdio/mdio-mscc-miim.c
> > > b/drivers/net/mdio/mdio-mscc-miim.c
> > > index 64fb76c1e395..7773d5019e66 100644
> > > --- a/drivers/net/mdio/mdio-mscc-miim.c
> > > +++ b/drivers/net/mdio/mdio-mscc-miim.c
> > > @@ -158,18 +158,18 @@ static int mscc_miim_reset(struct mii_bus *bus)
> > >  {
> > >  	struct mscc_miim_dev *miim = bus->priv;
> > >  	int offset = miim->phy_reset_offset;
> > > +	int mask = PHY_CFG_PHY_ENA | PHY_CFG_PHY_COMMON_RESET |
> > > +		   PHY_CFG_PHY_RESET;
> > 
> > > -		ret = regmap_write(miim->phy_regs,
> > > -				   MSCC_PHY_REG_PHY_CFG + offset, 0x1ff);
> > > +		ret = regmap_write(miim->phy_regs, offset, mask);
> > 
> > Is mask the correct name? It is not being used in the typical way for
> > a mask.
> 
> It is the mask of all the reset bits, see also patch 3/3. Either all
> these bits are set or none.

Yes, it is you just don't use it in the typical way for a mask

	foo = bar & mask;

The name mask made me look for a read-modify-write or similar. And
that then makes me thing of race conditions.

> Do you haave any suggestion?

value everywhere? Or phy_reset_bits?

      Andrew