[PATCH net-next] net: phy: fixed: remove usage of a faux device

[PATCH net-next] net: phy: fixed: remove usage of a faux device

[Heiner Kallweit]

A struct mii_bus doesn't need a parent, so we can simplify the code and
remove using a faux device. Only difference is the following in sysfs
under /sys/class/mdio_bus:

old: fixed-0 -> '../../devices/faux/Fixed MDIO bus/mdio_bus/fixed-0'
new: fixed-0 -> ../../devices/virtual/mdio_bus/fixed-0

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/net/phy/fixed_phy.c | 22 +++-------------------
 1 file changed, 3 insertions(+), 19 deletions(-)

diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c
index 033656d57..7f4fc4df6 100644
--- a/drivers/net/phy/fixed_phy.c
+++ b/drivers/net/phy/fixed_phy.c
@@ -10,7 +10,6 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/device/faux.h>
 #include <linux/list.h>
 #include <linux/mii.h>
 #include <linux/phy.h>
@@ -40,7 +39,6 @@ struct fixed_phy {
 	struct gpio_desc *link_gpiod;
 };
 
-static struct faux_device *fdev;
 static struct fixed_mdio_bus platform_fmb = {
 	.phys = LIST_HEAD_INIT(platform_fmb.phys),
 };
@@ -317,34 +315,21 @@ static int __init fixed_mdio_bus_init(void)
 	struct fixed_mdio_bus *fmb = &platform_fmb;
 	int ret;
 
-	fdev = faux_device_create("Fixed MDIO bus", NULL, NULL);
-	if (!fdev)
-		return -ENODEV;
-
 	fmb->mii_bus = mdiobus_alloc();
-	if (fmb->mii_bus == NULL) {
-		ret = -ENOMEM;
-		goto err_mdiobus_reg;
-	}
+	if (!fmb->mii_bus)
+		return -ENOMEM;
 
 	snprintf(fmb->mii_bus->id, MII_BUS_ID_SIZE, "fixed-0");
 	fmb->mii_bus->name = "Fixed MDIO Bus";
 	fmb->mii_bus->priv = fmb;
-	fmb->mii_bus->parent = &fdev->dev;
 	fmb->mii_bus->read = &fixed_mdio_read;
 	fmb->mii_bus->write = &fixed_mdio_write;
 	fmb->mii_bus->phy_mask = ~0;
 
 	ret = mdiobus_register(fmb->mii_bus);
 	if (ret)
-		goto err_mdiobus_alloc;
+		mdiobus_free(fmb->mii_bus);
 
-	return 0;
-
-err_mdiobus_alloc:
-	mdiobus_free(fmb->mii_bus);
-err_mdiobus_reg:
-	faux_device_destroy(fdev);
 	return ret;
 }
 module_init(fixed_mdio_bus_init);
@@ -356,7 +341,6 @@ static void __exit fixed_mdio_bus_exit(void)
 
 	mdiobus_unregister(fmb->mii_bus);
 	mdiobus_free(fmb->mii_bus);
-	faux_device_destroy(fdev);
 
 	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
 		list_del(&fp->node);
-- 
2.50.1

Re: [PATCH net-next] net: phy: fixed: remove usage of a faux device

[Jakub Kicinski]

On Mon, 11 Aug 2025 21:45:49 +0200 Heiner Kallweit wrote:
>  	ret = mdiobus_register(fmb->mii_bus);
>  	if (ret)
> -		goto err_mdiobus_alloc;
> +		mdiobus_free(fmb->mii_bus);
>  
> -	return 0;
> -
> -err_mdiobus_alloc:
> -	mdiobus_free(fmb->mii_bus);
> -err_mdiobus_reg:
> -	faux_device_destroy(fdev);
>  	return ret;
>  }

nit: would you mind leaving the mdiobus_free() where it is?
Feels a little more idiomatic.