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Revert "net: phy: marvell 88e151x: Fix handling of bare RGMII interface type"

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This reverts commit 431be621c6.

Section 3.3 of Reduced Gigabit Media Independent Interface (RGMII)
Version 2.0 (4/1/2002) details that a PHYs using a ~2ns internal delay
are referred to as RGMII-ID. This internal delay is optional.

Page 147-148 of the Marvell Doc. No. MV-S107146-U0 Rev. F details
timings of the RX/TX delays. We see that with the TX/RX_CLK delay
enabled, our RX/TX_CTL signal is shifted w.r.t CLK to reflect the delay
added.

In 431be62 there is no timing difference between RGMII and RGMII-ID, and
so programmers wanting to explicitly set their PHY to RGMII will find
that delay added anyway. This could throw off timing if that internal
delay is undesired.

We should be handling all 4 possible RGMII cases of PHY_INTERFACE_MODE:
RGMII, RGMII_ID, RGMII_TXID, and RGMII_RXID. Reverting 431be62
implements this.

See also m88e1111_config_init_rgmii_delays in the equivalent driver in
Linux (drivers/net/phy/marvell.c), which does not set these delays in
RGMII mode.

68e6eca was tested out on an 88E1512 PHY in RGMII-ID mode. This
reversion has been tested by myself on an 88E1518 in RGMII-ID mode. This
patch affects boards using this driver in "rgmii" mode, as the internal
delay will no longer be enabled. Namely kikwood-nsa310s.

Signed-off-by: Rufus Segar <rhs@riseup.net>
This commit is contained in:
Rufus Segar 2024-12-04 13:34:30 +00:00 • committed by Tom Rini
parent 395ee74991
commit c5cda4ae4a
1 changed files with 1 additions and 2 deletions
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3
drivers/net/phy/marvell.c
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@ -461,8 +461,7 @@ static int m88e151x_config(struct phy_device *phydev)
reg = phy_read(phydev, MDIO_DEVAD_NONE, MIIM_88E151x_PHY_MSCR);
reg &= ~MIIM_88E151x_RGMII_RXTX_DELAY;
if (phydev->interface == PHY_INTERFACE_MODE_RGMII ||
phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
reg |= MIIM_88E151x_RGMII_RXTX_DELAY;
else if (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID)
reg |= MIIM_88E151x_RGMII_RX_DELAY;