On Wed, 2020-03-25 at 16:24 +0100, Heiner Kallweit wrote:
> On 25.03.2020 16:03, Philippe Schenker wrote:
> > The KSZ9131 provides DLL controlled delays on RXC and TXC lines.
> > This
> > patch makes use of those delays. The information which delays should
> > be enabled or disabled comes from the interface names, documented in
> > ethernet-controller.yaml:
> >
> > rgmii: Disable RXC and TXC delays
> > rgmii-id: Enable RXC and TXC delays
> > rgmii-txid: Enable only TXC delay, disable RXC delay
> > rgmii-rxid: Enable onlx RXC delay, disable TXC delay
> >
> > Signed-off-by: Philippe Schenker <philippe.schenker@xxxxxxxxxxx>
> > ---
> >
> > drivers/net/phy/micrel.c | 45
> > ++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 45 insertions(+)
> >
> > diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> > index 63dedec0433d..d3ad09774847 100644
> > --- a/drivers/net/phy/micrel.c
> > +++ b/drivers/net/phy/micrel.c
> > @@ -704,6 +704,48 @@ static int ksz9131_of_load_skew_values(struct
> > phy_device *phydev,
> > return phy_write_mmd(phydev, 2, reg, newval);
> > }
> >
> > +/* MMD Address 0x2 */
> > +#define KSZ9131RN_RXC_DLL_CTRL 76
> > +#define KSZ9131RN_TXC_DLL_CTRL 77
> > +#define KSZ9131RN_DLL_CTRL_BYPASS BIT_MASK(12)
> > +#define KSZ9131RN_DLL_ENABLE_DELAY 0
> > +#define KSZ9131RN_DLL_DISABLE_DELAY BIT(12)
> > +
> > +static int ksz9131_config_rgmii_delay(struct phy_device *phydev)
> > +{
> > + int ret;
> > + u16 rxcdll_val, txcdll_val;
> > +
>
> Reverse xmas tree order please.
>
> > + switch (phydev->interface) {
> > + case PHY_INTERFACE_MODE_RGMII:
> > + rxcdll_val = KSZ9131RN_DLL_DISABLE_DELAY;
> > + txcdll_val = KSZ9131RN_DLL_DISABLE_DELAY;
> > + break;
> > + case PHY_INTERFACE_MODE_RGMII_ID:
> > + rxcdll_val = KSZ9131RN_DLL_ENABLE_DELAY;
> > + txcdll_val = KSZ9131RN_DLL_ENABLE_DELAY;
> > + break;
> > + case PHY_INTERFACE_MODE_RGMII_RXID:
> > + rxcdll_val = KSZ9131RN_DLL_ENABLE_DELAY;
> > + txcdll_val = KSZ9131RN_DLL_DISABLE_DELAY;
> > + break;
> > + case PHY_INTERFACE_MODE_RGMII_TXID:
> > + rxcdll_val = KSZ9131RN_DLL_DISABLE_DELAY;
> > + txcdll_val = KSZ9131RN_DLL_ENABLE_DELAY;
> > + break;
> > + default:
> > + return 0;
> > + }
> > +
> > + ret = phy_modify_mmd_changed(phydev, 2, KSZ9131RN_RXC_DLL_CTRL,
> > + KSZ9131RN_DLL_CTRL_BYPASS,
> > rxcdll_val);
> > + if (ret < 0)
> > + return ret;
> > +
> > + return phy_modify_mmd_changed(phydev, 2, KSZ9131RN_TXC_DLL_CTRL,
> > + KSZ9131RN_DLL_CTRL_BYPASS,
> > txcdll_val);
>
> phy_modify_mmd_changed() returns 1 if the register value was changed,
> and that's not what you want here. Simply use phy_modify_mmd() in both
> occurrences. And your function has a return value, but it's not used
> by
> the caller.
Thanks for your feedback, I'll send a v2 with those fixes.
>
> > +}
> > +
> > static int ksz9131_config_init(struct phy_device *phydev)
> > {
> > const struct device *dev = &phydev->mdio.dev;
> > @@ -730,6 +772,9 @@ static int ksz9131_config_init(struct phy_device
> > *phydev)
> > if (!of_node)
> > return 0;
> >
> > + if (phy_interface_is_rgmii(phydev))
> > + ksz9131_config_rgmii_delay(phydev);
> > +
> > ret = ksz9131_of_load_skew_values(phydev, of_node,
> > MII_KSZ9031RN_CLK_PAD_SKEW, 5,
> > clk_skews, 2);
> >
