RE: [PATCH] net/phy: Micrel KSZ8061 PHY link failure after cable connect

[Onnasch, Alexander (EXT)]

Hi Andrew

thanks for your feedback. I was on holiday, thus just delayed, not forgotten...
Sorry for top-posting - odd company default mail setup.
I checked again phy_write_mmd(), you are right ! 
Patch with changed implementation will follow.

Best regards, Alex


-----Original Message-----
From: Andrew Lunn <andrew@xxxxxxx> 
Sent: Dienstag, 19. Juni 2018 17:29
To: Onnasch, Alexander (EXT) <Alexander.Onnasch@xxxxxxxxxxxxx>
Cc: Florian Fainelli <f.fainelli@xxxxxxxxx>; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] net/phy: Micrel KSZ8061 PHY link failure after cable connect

On Tue, Jun 19, 2018 at 02:23:41PM +0000, Onnasch, Alexander (EXT) wrote:
> Hi Andrew
> thanks for the hint. But actually I cannot confirm - or I don't see it yet. 
> 
> Without having tested, just from the code, the struct phy_driver instance for PHY_ID_KSZ8061 in micrel.c does not have a .write_mmd function assigned, thus phy_write_mmd should evaluate to its else-clause (see below) and not to mdiobus_write (as in phy_write).
> 
> Also the ksz8061_extended_write() function which I have added uses the same principle as already existing HW-specific functions in micrel.c for simular reasons (kszphy_extended_write and ksz9031_extended_write).
> They use phy_write all over the place in that file and never phy_write_mmd - for whatever reason they had.
> Thus I thought it would be a good idea ...

Hi Alexander

Please don't top post. And wrap your lines at around 75 characters 

> 		struct mii_bus *bus = phydev->mdio.bus;
> 		int phy_addr = phydev->mdio.addr;
> 
> 		mutex_lock(&bus->mdio_lock);
> 		mmd_phy_indirect(bus, phy_addr, devad, regnum);
> 
> 		/* Write the data into MMD's selected register */
> 		bus->write(bus, phy_addr, MII_MMD_DATA, val);
> 		mutex_unlock(&bus->mdio_lock);


> > +static int ksz8061_extended_write(struct phy_device *phydev,
> > +				  u8 mode, u32 dev_addr, u32 regnum, u16 val) {
> > +	phy_write(phydev, MII_KSZ8061RN_MMD_CTRL_REG, dev_addr);
> > +	phy_write(phydev, MII_KSZ8061RN_MMD_REGDATA_REG, regnum);
> > +	phy_write(phydev, MII_KSZ8061RN_MMD_CTRL_REG, (mode << 14) | dev_addr);
> > +	return phy_write(phydev, MII_KSZ8061RN_MMD_REGDATA_REG, val); }
> 
> Hi Alexander
> 
> This looks a lot like phy_write_mmd().

Look closely at the two implementations. Look at what
mmd_phy_indirect() does. I _think_ these are identical. So don't add your own helper, please use the core code.

     Andrew