netdev - Re: [PATCH RFC 3/7] net: phy: clean up PHY ID reading

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Message-ID: <20200526154655.GD1551@shell.armlinux.org.uk>
Date:   Tue, 26 May 2020 16:46:55 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Jeremy Linton <jeremy.linton@....com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org
Subject: Re: [PATCH RFC 3/7] net: phy: clean up PHY ID reading

On Tue, May 26, 2020 at 10:38:31AM -0500, Jeremy Linton wrote:
> Hi,
> 
> On 5/26/20 9:31 AM, Russell King wrote:
> > Rearrange the code to read the PHY IDs, so we don't call get_phy_id()
> > only to immediately call get_phy_c45_ids().  Move that logic into
> > get_phy_device(), which results in better readability.
> > 
> > Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
> > ---
> >   drivers/net/phy/phy_device.c | 25 +++++++++----------------
> >   1 file changed, 9 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> > index e04284c4ebf8..0d6b6ca66216 100644
> > --- a/drivers/net/phy/phy_device.c
> > +++ b/drivers/net/phy/phy_device.c
> > @@ -756,29 +756,18 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id,
> >   }
> >   /**
> > - * get_phy_id - reads the specified addr for its ID.
> > + * get_phy_c22_id - reads the specified addr for its clause 22 ID.
> >    * @bus: the target MII bus
> >    * @addr: PHY address on the MII bus
> >    * @phy_id: where to store the ID retrieved.
> > - * @is_c45: If true the PHY uses the 802.3 clause 45 protocol
> > - * @c45_ids: where to store the c45 ID information.
> > - *
> > - * Description: In the case of a 802.3-c22 PHY, reads the ID registers
> > - *   of the PHY at @addr on the @bus, stores it in @phy_id and returns
> > - *   zero on success.
> > - *
> > - *   In the case of a 802.3-c45 PHY, get_phy_c45_ids() is invoked, and
> > - *   its return value is in turn returned.
> >    *
> > + * Read the 802.3 clause 22 PHY ID from the PHY at @addr on the @bus.
> > + * Return the PHY ID read from the PHY in @phy_id on successful access.
> >    */
> > -static int get_phy_id(struct mii_bus *bus, int addr, u32 *phy_id,
> > -		      bool is_c45, struct phy_c45_device_ids *c45_ids)
> > +static int get_phy_c22_id(struct mii_bus *bus, int addr, u32 *phy_id)
> >   {
> >   	int phy_reg;
> > -	if (is_c45)
> > -		return get_phy_c45_ids(bus, addr, phy_id, c45_ids);
> > -
> >   	/* Grab the bits from PHYIR1, and put them in the upper half */
> >   	phy_reg = mdiobus_read(bus, addr, MII_PHYSID1);
> >   	if (phy_reg < 0) {
> > @@ -817,7 +806,11 @@ struct phy_device *get_phy_device(struct mii_bus *bus, int addr, bool is_c45)
> >   	c45_ids.devices_in_package = 0;
> >   	memset(c45_ids.device_ids, 0xff, sizeof(c45_ids.device_ids));
> > -	r = get_phy_id(bus, addr, &phy_id, is_c45, &c45_ids);
> > +	if (is_c45)
> > +		r = get_phy_c45_ids(bus, addr, &phy_id, &c45_ids);
> > +	else
> > +		r = get_phy_c22_id(bus, addr, &phy_id);
> > +
> >   	if (r)
> >   		return ERR_PTR(r);
> > 
> 
> I see this, and the c22 regs detection, but I don't see how your choosing to
> use the c22 regs if the 45's aren't responding. Which was one of the primary
> purposes of that other set.

You are entirely correct, but I am not aiming for that in this series.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up