Message ID | 20250317-plat2faux_dev-v1-7-5fe67c085ad5@arm.com (mailing list archive) |
---|---|
State | New |
Delegated to: | Netdev Maintainers |
Headers | show |
Series | drivers: Transition to the faux device interface | expand |
On Mon, Mar 17, 2025 at 10:13:19AM +0000, Sudeep Holla wrote: > The net fixed phy driver does not require the creation of a platform > device. Originally, this approach was chosen for simplicity when the > driver was first implemented. > > With the introduction of the lightweight faux device interface, we now > have a more appropriate alternative. Migrate the driver to utilize the > faux bus, given that the platform device it previously created was not > a real one anyway. This will simplify the code, reducing its footprint > while maintaining functionality. > > Cc: Andrew Lunn <andrew@lunn.ch> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: netdev@vger.kernel.org > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > --- > drivers/net/phy/fixed_phy.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) 8 insertions, 8 deletions. How does this reduce its footprint? Seems like pointless churn to me. Unless there is a real advantage to faux bus you are not enumerating in your commit message. Andrew
On Mon, Mar 17, 2025 at 01:29:31PM +0100, Andrew Lunn wrote: > On Mon, Mar 17, 2025 at 10:13:19AM +0000, Sudeep Holla wrote: > > The net fixed phy driver does not require the creation of a platform > > device. Originally, this approach was chosen for simplicity when the > > driver was first implemented. > > > > With the introduction of the lightweight faux device interface, we now > > have a more appropriate alternative. Migrate the driver to utilize the > > faux bus, given that the platform device it previously created was not > > a real one anyway. This will simplify the code, reducing its footprint > > while maintaining functionality. > > > > Cc: Andrew Lunn <andrew@lunn.ch> > > Cc: "David S. Miller" <davem@davemloft.net> > > Cc: netdev@vger.kernel.org > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > --- > > drivers/net/phy/fixed_phy.c | 16 ++++++++-------- > > 1 file changed, 8 insertions(+), 8 deletions(-) > > 8 insertions, 8 deletions. How does this reduce its footprint? > > Seems like pointless churn to me. Unless there is a real advantage to > faux bus you are not enumerating in your commit message. It stops the abuse of using a platform device for something that is NOT a platform device. This file should have never used a platform device for this in the first place, and this change is fixing that design bug. thanks, greg k-h
On Mon, Mar 17, 2025 at 01:29:31PM +0100, Andrew Lunn wrote: > On Mon, Mar 17, 2025 at 10:13:19AM +0000, Sudeep Holla wrote: > > The net fixed phy driver does not require the creation of a platform > > device. Originally, this approach was chosen for simplicity when the > > driver was first implemented. > > > > With the introduction of the lightweight faux device interface, we now > > have a more appropriate alternative. Migrate the driver to utilize the > > faux bus, given that the platform device it previously created was not > > a real one anyway. This will simplify the code, reducing its footprint > > while maintaining functionality. > > > > Cc: Andrew Lunn <andrew@lunn.ch> > > Cc: "David S. Miller" <davem@davemloft.net> > > Cc: netdev@vger.kernel.org > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > --- > > drivers/net/phy/fixed_phy.c | 16 ++++++++-------- > > 1 file changed, 8 insertions(+), 8 deletions(-) > > 8 insertions, 8 deletions. How does this reduce its footprint? > I meant the use of struct faux_device vs struct platform_device. Yes it is not a big deal. > Seems like pointless churn to me. Unless there is a real advantage to > faux bus you are not enumerating in your commit message. > Greg has answered that, so will skip.
diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c index aef739c20ac4d5a271465a677a85ef7c18cfce70..ee7831a9849b3728ca9c541da35d17e089985da2 100644 --- a/drivers/net/phy/fixed_phy.c +++ b/drivers/net/phy/fixed_phy.c @@ -10,7 +10,7 @@ #include <linux/kernel.h> #include <linux/module.h> -#include <linux/platform_device.h> +#include <linux/device/faux.h> #include <linux/list.h> #include <linux/mii.h> #include <linux/phy.h> @@ -40,7 +40,7 @@ struct fixed_phy { struct gpio_desc *link_gpiod; }; -static struct platform_device *pdev; +static struct faux_device *fdev; static struct fixed_mdio_bus platform_fmb = { .phys = LIST_HEAD_INIT(platform_fmb.phys), }; @@ -337,9 +337,9 @@ static int __init fixed_mdio_bus_init(void) struct fixed_mdio_bus *fmb = &platform_fmb; int ret; - pdev = platform_device_register_simple("Fixed MDIO bus", 0, NULL, 0); - if (IS_ERR(pdev)) - return PTR_ERR(pdev); + fdev = faux_device_create("Fixed MDIO bus", NULL, NULL); + if (!fdev) + return -ENODEV; fmb->mii_bus = mdiobus_alloc(); if (fmb->mii_bus == NULL) { @@ -350,7 +350,7 @@ static int __init fixed_mdio_bus_init(void) 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 = &pdev->dev; + 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; @@ -364,7 +364,7 @@ static int __init fixed_mdio_bus_init(void) err_mdiobus_alloc: mdiobus_free(fmb->mii_bus); err_mdiobus_reg: - platform_device_unregister(pdev); + faux_device_destroy(fdev); return ret; } module_init(fixed_mdio_bus_init); @@ -376,7 +376,7 @@ static void __exit fixed_mdio_bus_exit(void) mdiobus_unregister(fmb->mii_bus); mdiobus_free(fmb->mii_bus); - platform_device_unregister(pdev); + faux_device_destroy(fdev); list_for_each_entry_safe(fp, tmp, &fmb->phys, node) { list_del(&fp->node);
The net fixed phy driver does not require the creation of a platform device. Originally, this approach was chosen for simplicity when the driver was first implemented. With the introduction of the lightweight faux device interface, we now have a more appropriate alternative. Migrate the driver to utilize the faux bus, given that the platform device it previously created was not a real one anyway. This will simplify the code, reducing its footprint while maintaining functionality. Cc: Andrew Lunn <andrew@lunn.ch> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> --- drivers/net/phy/fixed_phy.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)