[PATCH net-next v2 2/2] net: axienet: add a MODULE_ALIAS for platform instantiation

[Sagi Maimon]

The module is built as xilinx_emac.ko while the platform driver it
registers is named xilinx_axienet.  For a device tree instantiation that
mismatch does not matter, because the OF match table supplies the
modalias udev uses to load the module.

A device registered by name from another driver has no OF node and so no
OF modalias.  It advertises platform:xilinx_axienet, which matches
nothing, and the device is created but never bound.  ptp_ocp is going to
register the AXI Ethernet MAC of the ADVA TimeCard X2 this way, as a
child platform device described by a software node.

Add the corresponding MODULE_ALIAS so name-based instantiation can
autoload the driver, and give the name a define now that it is used in
more than one place.

Tested on the X2 with a local ptp_ocp change: with this patch the module
is loaded and binds when ptp_ocp registers the device; without it the
device stays unbound until xilinx_emac is loaded by hand.

Assisted-by: LLM sparse
Signed-off-by: Sagi Maimon <maimon.sagi@xxxxxxxxx>
---
 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 0f2170af9b10..ae8ed4495ea0 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -48,6 +48,7 @@
 #include "xilinx_axienet.h"
 
 /* Descriptors defines for Tx and Rx DMA */
+#define AXIENET_DRIVER_NAME		"xilinx_axienet"
 #define TX_BD_NUM_DEFAULT		128
 #define RX_BD_NUM_DEFAULT		1024
 #define TX_BD_NUM_MIN			(MAX_SKB_FRAGS + 1)
@@ -3223,7 +3224,7 @@ static struct platform_driver axienet_driver = {
 	.remove = axienet_remove,
 	.shutdown = axienet_shutdown,
 	.driver = {
-		 .name = "xilinx_axienet",
+		 .name = AXIENET_DRIVER_NAME,
 		 .pm = &axienet_pm_ops,
 		 .of_match_table = axienet_of_match,
 	},
@@ -3231,6 +3232,13 @@ static struct platform_driver axienet_driver = {
 
 module_platform_driver(axienet_driver);
 
+/* The module is named xilinx_emac, the platform driver xilinx_axienet.  A
+ * device registered by name rather than from firmware advertises a
+ * platform:xilinx_axienet modalias, which without this matches no module:
+ * udev cannot autoload the driver and the device stays unbound.
+ */
+MODULE_ALIAS("platform:" AXIENET_DRIVER_NAME);
+
 MODULE_DESCRIPTION("Xilinx Axi Ethernet driver");
 MODULE_AUTHOR("Xilinx");
 MODULE_LICENSE("GPL");
-- 
2.47.0