[PATCH 1/4] net: phy: fixed: be compatible with live OF tree

[Bin Meng]

On Wed, Feb 17, 2021 at 6:48 AM Vladimir Oltean <olteanv at gmail.com> wrote:
>
> From: Vladimir Oltean <vladimir.oltean at nxp.com>
>
> On systems that use CONFIG_OF_LIVE, the "ofnode" type is defined as
> const struct device_node *np, while on the flat DT systems it is defined
> as a long of_offset into gd->fdt_blob.
>
> It is desirable that the fixed PHY driver uses the higher-level ofnode
> abstraction instead of parsing gd->fdt_blob directly, because that
> enables it to work on live OF systems.
>
> The fixed PHY driver has used a nastyyyyy hack since its introduction in
> commit db40c1aa1c10 ("drivers/net/phy: add fixed-phy / fixed-link support"),
> which is to pass the long gd->fdt_blob offset inside int phydev->addr
> (a value that normally holds the MDIO bus address at which the PHY
> responds). Even ignoring the fact that the types were already mismatched
> leading to a potential truncation (flat OF offset was supposed to be a
> long and not an int), we really cannot extend this hack any longer,
> because there's no way an int will hold the other representation of
> ofnode, the struct device_node *np.
>
> So we unfortunately need to do the right thing, which is to use the
> framework introduced by Grygorii Strashko in commit eef0b8a930d1 ("net:
> phy: add ofnode node to struct phy_device"). This will populate
> phydev->node for the fixed PHY.
>
> Note that phydev->node will not be valid in the probe function, since
> that is called synchronously from phy_device_create and we really have
> no way of passing the ofnode directly through the phy_device_create API.
> So we do what other drivers do too: we move the OF parsing logic from
> the .probe to the .config method of the PHY driver. The new function
> will be called at phy_config() time.
>
> I do believe I've converted all the possible call paths for creating a
> PHY with PHY_FIXED_ID, so there is really no reason to maintain
> compatibility with the old logic of retrieving a flat OF tree offset
> from phydev->addr. We just pass 0 to phydev->addr now.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
> ---
>  drivers/net/phy/fixed.c | 30 ++++++++++++++++++++++--------
>  drivers/net/phy/phy.c   | 30 +++++++++++++++---------------
>  2 files changed, 37 insertions(+), 23 deletions(-)
>

For the record,

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
Tested-by: Bin Meng <bmeng.cn at gmail.com>