On 04/24/2018 09:09 AM, Alexandre Belloni wrote:
> Some MDIO busses will error out when trying to read a phy address with no
> phy present at that address. In that case, probing the bus will fail
> because __mdiobus_register() is scanning the bus for all possible phys
> addresses.
>
> In case MII_PHYSID1 returns -EIO or -ENODEV, consider there is no phy at
> this address and set the phy ID to 0xffffffff which is then properly
> handled in get_phy_device().
Humm, why not have your MDIO bus implementation do the scanning itself
in a reset() callback, which happens before probing the bus, and based
on the results, set phy_mask accordingly such that only PHYs present are
populated?
My only concern with your change is that we are having a special
treatment for EIO and ENODEV, so we must make sure MDIO bus drivers are
all conforming to that.
>
> Suggested-by: Andrew Lunn <and...@lunn.ch>
> Signed-off-by: Alexandre Belloni <alexandre.bell...@bootlin.com>
> ---
> drivers/net/phy/phy_device.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index ac23322a32e1..9e4ba8e80a18 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -535,8 +535,17 @@ static int get_phy_id(struct mii_bus *bus, int addr, u32
> *phy_id,
>
> /* Grab the bits from PHYIR1, and put them in the upper half */
> phy_reg = mdiobus_read(bus, addr, MII_PHYSID1);
> - if (phy_reg < 0)
> + if (phy_reg < 0) {
> + /* if there is no device, return without an error so scanning
> + * the bus works properly
> + */
> + if (phy_reg == -EIO || phy_reg == -ENODEV) {
> + *phy_id = 0xffffffff;
> + return 0;
> + }
> +
> return -EIO;
> + }
>
> *phy_id = (phy_reg & 0xffff) << 16;
>
>
--
Florian
