Re: [PATCH] net: phy: marvell: Add errata section 5.1 for Alaska PHY

["Marek Behún" <kabel@kernel.org>]

On Tue, 15 Mar 2022 08:48:27 +0100
Stefan Roese <sr@denx.de> wrote:

> From: Leszek Polak <lpolak@arri.de>
> 
> As per Errata Section 5.1, if EEE is intended to be used, some register
> writes must be done once after every hardware reset. This patch now adds
> the necessary register writes as listed in the Marvell errata.
> 
> Without this fix we experience ethernet problems on some of our boards
> equipped with a new version of this ethernet PHY (different supplier).
> 
> The fix applies to Marvell Alaska 88E1510/88E1518/88E1512/88E1514
> Rev. A0.
> 
> Signed-off-by: Leszek Polak <lpolak@arri.de>
> Signed-off-by: Stefan Roese <sr@denx.de>
> Cc: Andrew Lunn <andrew@lunn.ch>
> Cc: Heiner Kallweit <hkallweit1@gmail.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: David S. Miller <davem@davemloft.net>
> ---
>  drivers/net/phy/marvell.c | 42 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> index 2429db614b59..0f4a3ab4a415 100644
> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -1179,6 +1179,48 @@ static int m88e1510_config_init(struct phy_device *phydev)
>  {
>  	int err;
>  
> +	/* As per Marvell Release Notes - Alaska 88E1510/88E1518/88E1512/
> +	 * 88E1514 Rev A0, Errata Section 5.1:
> +	 * If EEE is intended to be used, the following register writes
> +	 * must be done once after every hardware reset.
> +	 */
> +	err = marvell_set_page(phydev, 0x00FF);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 17, 0x214B);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 16, 0x2144);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 17, 0x0C28);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 16, 0x2146);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 17, 0xB233);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 16, 0x214D);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 17, 0xCC0C);
> +	if (err < 0)
> +		return err;
> +	err = phy_write(phydev, 16, 0x2159);
> +	if (err < 0)
> +		return err;

Can you please create a static const struct and then do this in a for
cycle? Somethign like this

static const struct { u16 reg17, reg16; } errata_vals = {
  { 0x214B, 0x2144 }, ...
};

for (i = 0; i < ARRAY_SIZE(errata_vals); ++i) {
  err = phy_write(phydev, 17, errata_vals[i].reg17);
  if (err)
    return err;
  err = phy_write(phydev, 16, errata_vals[i].reg16);
  if (err)
    return err;
}