[PATCH 5.10 1/5] net: dsa: microchip: Fix probing KSZ87xx switch with DT node for host port

Ben Hutchings
2021-08-16T18:09:19Z

The ksz8795 and ksz9477 drivers differ in the way they count ports.
For ksz8795, ksz_device::port_cnt does not include the host port
whereas for ksz9477 it does. This inconsistency was fixed in Linux
5.11 by a series of changes, but remains in 5.10-stable.

When probing, the common code treats a port device node with an
address >= dev->port_cnt as a fatal error. As a minimal fix, change
it to compare again dev->mib_port_cnt. This is the length of the
dev->ports array that the port number will be used to index, and
always includes the host port.

Cc: Woojung Huh <woojung.huh@microchip.com>
Cc: Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
Cc: Michael Grzeschik <m.grzeschik@pengutronix.de>
Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
---
drivers/net/dsa/microchip/ksz_common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index d4a64dbde315..88fa0779e0bc 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -432,7 +432,7 @@ int ksz_switch_register(struct ksz_device *dev,
if (of_property_read_u32(port, "reg",
&port_num))
continue;
- if (port_num >= dev->port_cnt)
+ if (port_num >= dev->mib_port_cnt)
return -EINVAL;
of_get_phy_mode(port,
&dev->ports[port_num].interface);
--
2.20.1