Subject: [PATCH] net: dsa: microchip: really look for phy-mode in port nodes

From: Helmut Grohne <[email-masked]>
Date: Thu, 24 Sep 2020 10:37:47 +0200

The previous implementation failed to account for the "ports" node. The
actual port nodes are not child nodes of the switch node, but a "ports"
node sits in between.

Fixes: edecfa98f602 ("net: dsa: microchip: look for phy-mode in port nodes")
Signed-off-by: Helmut Grohne <[email-masked]>
---
 drivers/net/dsa/microchip/ksz_common.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

I am very sorry that I need to send a fixup. It turned out that my
testing methodology was flawed. When I reintegrated Linus' master
branch, I noticed that it didn't work. It turned out that our hardware
now correctly implements hardware reset. As a consequence, the correct
setting of the phy-mode now became essential to operating the device.

I'm also looking forward to see "net: dsa: microchip: Improve phy mode
message" (from net-next) being merged. That would have helped me spot
this earlier.

Helmut

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 8e755b50c9c1..c796d42730ba 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -387,8 +387,8 @@ EXPORT_SYMBOL(ksz_switch_alloc);
 int ksz_switch_register(struct ksz_device *dev,
 			const struct ksz_dev_ops *ops)
 {
+	struct device_node *port, *ports;
 	phy_interface_t interface;
-	struct device_node *port;
 	unsigned int port_num;
 	int ret;
 
@@ -429,13 +429,17 @@ int ksz_switch_register(struct ksz_device *dev,
 		ret = of_get_phy_mode(dev->dev->of_node, &interface);
 		if (ret == 0)
 			dev->compat_interface = interface;
-		for_each_available_child_of_node(dev->dev->of_node, port) {
-			if (of_property_read_u32(port, "reg", &port_num))
-				continue;
-			if (port_num >= dev->port_cnt)
-				return -EINVAL;
-			of_get_phy_mode(port, &dev->ports[port_num].interface);
-		}
+		ports = of_get_child_by_name(dev->dev->of_node, "ports");
+		if (ports)
+			for_each_available_child_of_node(ports, port) {
+				if (of_property_read_u32(port, "reg",
+							 &port_num))
+					continue;
+				if (port_num >= dev->port_cnt)
+					return -EINVAL;
+				of_get_phy_mode(port,
+						&dev->ports[port_num].interface);
+			}
 		dev->synclko_125 = of_property_read_bool(dev->dev->of_node,
 							 "microchip,synclko-125");
 	}
-- 
2.20.1