[RFC,2/3] net: phy: call mdiobus_scan() after adding a fixed PHY

The fixed_phy_add() function allows to register a fixed PHY. However,
when this function gets called *after* fixed_mdio_bus_init() (which
gets called at the module_init stage), then the fixed PHY is not
registered into the phylib.

In order to address this, we add a call to mdiobus_scan() in
fixed_phy_add() to ensure that the PHY indeed gets registered into the
phylib, even if the fixed_phy_add() is called after
fixed_mdio_bus_init().

This is needed because until now, the only code that was calling the
fixed_add_phy() function was PowerPC-specific platform code, which
could ensure that such fixed PHYs get registered before
fixed_mdio_bus_init() is called.

However, with the new of_phy_register_fixed_link() function, device
drivers can parse their 'fixed-link' property and register a fixed PHY
at ->probe() time, which may happen after fixed_mdio_bus_init() is
called.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 drivers/net/phy/fixed.c | 2 ++
 1 file changed, 2 insertions(+)

Hello Thomas,

2013/7/15 Thomas Petazzoni <thomas.petazzoni@free-electrons.com>:
> The fixed_phy_add() function allows to register a fixed PHY. However,
> when this function gets called *after* fixed_mdio_bus_init() (which
> gets called at the module_init stage), then the fixed PHY is not
> registered into the phylib.
>
> In order to address this, we add a call to mdiobus_scan() in
> fixed_phy_add() to ensure that the PHY indeed gets registered into the
> phylib, even if the fixed_phy_add() is called after
> fixed_mdio_bus_init().
>
> This is needed because until now, the only code that was calling the
> fixed_add_phy() function was PowerPC-specific platform code, which
> could ensure that such fixed PHYs get registered before
> fixed_mdio_bus_init() is called.

arch/mips/ar7/platform.c also calls fixed_phy_add() early enough as
well to ensure that we do not need to rescan the MDIO bus. There is
also another user: arch/m68k/platform/coldfire/m5272.c

>
> However, with the new of_phy_register_fixed_link() function, device
> drivers can parse their 'fixed-link' property and register a fixed PHY
> at ->probe() time, which may happen after fixed_mdio_bus_init() is
> called.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: Florian Fainelli <florian@openwrt.org>

> ---
>  drivers/net/phy/fixed.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/phy/fixed.c b/drivers/net/phy/fixed.c
> index ba55adf..bd1e67a 100644
> --- a/drivers/net/phy/fixed.c
> +++ b/drivers/net/phy/fixed.c
> @@ -195,6 +195,8 @@ int fixed_phy_add(unsigned int irq, int phy_id,
>
>         list_add_tail(&fp->node, &fmb->phys);
>
> +       mdiobus_scan(fmb->mii_bus, phy_id);
> +
>         return 0;
>
>  err_regs:
> --
> 1.8.1.2
>



--
Florian
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