The driver doesn't support clause 45 register access yet, but doesn't
check if the access is a c45 one either. This leads to spurious register
reads and writes. Add the check.

Fixes: 542671fe4d86 ("net: phy: mscc-miim: Add MDIO driver")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/mdio/mdio-mscc-miim.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/mdio/mdio-mscc-miim.c b/drivers/net/mdio/mdio-mscc-miim.c
index c483ba67c21f..582969751b4c 100644
--- a/drivers/net/mdio/mdio-mscc-miim.c
+++ b/drivers/net/mdio/mdio-mscc-miim.c
@@ -102,6 +102,9 @@ static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
 	u32 val;
 	int ret;
 
+	if (regnum & MII_ADDR_C45)
+		return -EOPNOTSUPP;
+
 	ret = mscc_miim_wait_pending(bus);
 	if (ret)
 		goto out;
@@ -145,6 +148,9 @@ static int mscc_miim_write(struct mii_bus *bus, int mii_id,
 	struct mscc_miim_dev *miim = bus->priv;
 	int ret;
 
+	if (regnum & MII_ADDR_C45)
+		return -EOPNOTSUPP;
+
 	ret = mscc_miim_wait_pending(bus);
 	if (ret < 0)
 		goto out;
-- 
2.30.2

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Tue,  5 Apr 2022 14:02:33 +0200 you wrote:
> The driver doesn't support clause 45 register access yet, but doesn't
> check if the access is a c45 one either. This leads to spurious register
> reads and writes. Add the check.
> 
> Fixes: 542671fe4d86 ("net: phy: mscc-miim: Add MDIO driver")
> Signed-off-by: Michael Walle <michael@walle.cc>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> 
> [...]

Here is the summary with links:
  - [net] net: phy: mscc-miim: reject clause 45 register accesses
    https://git.kernel.org/netdev/net/c/8d90991e5bf7

You are awesome, thank you!
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