[PATCH] net: stmmac: Fix build without PCS_LYNX

[Geert Uytterhoeven]

On Tue, Jun 6, 2023 at 10:27 AM Geert Uytterhoeven
<geert+renesas at glider.be> wrote:
> If STMMAC_ETH=y, but PCS_LYNX=n (e.g. shmobile_defconfig):
>
>     arm-linux-gnueabihf-ld: drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.o: in function `stmmac_mdio_unregister':
>     stmmac_mdio.c:(.text+0xfbc): undefined reference to `lynx_pcs_destroy'
>
> As pcs_lynx is used only on dwmac_socfpga, fix this by adding a check
> for PCS_LYNX to the cleanup path in the generic driver.
>
> Fixes: 5d1f3fe7d2d54d04 ("net: stmmac: dwmac-sogfpga: use the lynx pcs driver")
> Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> index c784a6731f08e108..53ed59d732210814 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> @@ -665,7 +665,7 @@ int stmmac_mdio_unregister(struct net_device *ndev)
>         if (priv->hw->xpcs)
>                 xpcs_destroy(priv->hw->xpcs);
>
> -       if (priv->hw->lynx_pcs)
> +       if (IS_ENABLED(CONFIG_PCS_LYNX) && priv->hw->lynx_pcs)
>                 lynx_pcs_destroy(priv->hw->lynx_pcs);
>
>         mdiobus_unregister(priv->mii);

As pointed out by Arnd, this doesn't work when PCS_LYNX is a loadable
module and STMMAC is built-in:
https://lore.kernel.org/r/11bd37e9-c62e-46ba-9456-8e3b353df28f@app.fastmail.com

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds