[PATCH] net: macb: ignore tx_clk if MII is used

Michael Walle
2021-01-20T19:48:48Z

If the MII interface is used, the PHY is the clock master, thus don't
set the clock rate. On Zynq-7000, this will prevent the following
warning:
macb e000b000.ethernet eth0: unable to generate target frequency: 25000000 Hz

Signed-off-by: Michael Walle <michael@walle.cc>
---
drivers/net/ethernet/cadence/macb_main.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 814a5b10141d..472bf8f220bc 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -470,6 +470,10 @@ static void macb_set_tx_clk(struct macb *bp, int speed)
if (!bp->tx_clk || (bp->caps & MACB_CAPS_CLK_HW_CHG))
return;

+ /* In case of MII the PHY is the clock master */
+ if (bp->phy_interface == PHY_INTERFACE_MODE_MII)
+ return;
+
switch (speed) {
case SPEED_10:
rate = 2500000;
--
2.20.1