Re: [PATCH net-next v3] net: ethernet: stmmac: dwmac-rk: Make the clk_phy could be used for external phy

[Chaoyi Chen]

Hi Russell,

On 8/25/2025 9:37 PM, Russell King (Oracle) wrote:
> On Mon, Aug 25, 2025 at 12:53:37PM +0200, Marek Szyprowski wrote:
> > On 25.08.2025 11:57, Chaoyi Chen wrote:
> > > On 8/25/2025 3:23 PM, Marek Szyprowski wrote:
> > > > On 15.08.2025 04:35, Chaoyi Chen wrote:
> > > > > From: Chaoyi Chen <chaoyi.chen@xxxxxxxxxxxxxx>
> > > > >
> > > > > For external phy, clk_phy should be optional, and some external phy
> > > > > need the clock input from clk_phy. This patch adds support for setting
> > > > > clk_phy for external phy.
> > > > >
> > > > > Signed-off-by: David Wu <david.wu@xxxxxxxxxxxxxx>
> > > > > Signed-off-by: Chaoyi Chen <chaoyi.chen@xxxxxxxxxxxxxx>
> > > > > ---
> > > > >
> > > > > Changes in v3:
> > > > > - Link to V2:
> > > > > https://lore.kernel.org/netdev/20250812012127.197-1-kernel@xxxxxxxxxx/
> > > > > - Rebase to net-next/main
> > > > >
> > > > > Changes in v2:
> > > > > - Link to V1:
> > > > > https://lore.kernel.org/netdev/20250806011405.115-1-kernel@xxxxxxxxxx/
> > > > > - Remove get clock frequency from DT prop
> > > > >
> > > > >     drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c | 11 +++++++----
> > > > >     1 file changed, 7 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > > > > b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > > > > index ac8288301994..5d921e62c2f5 100644
> > > > > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > > > > @@ -1412,12 +1412,15 @@ static int rk_gmac_clk_init(struct
> > > > > plat_stmmacenet_data *plat)
> > > > >             clk_set_rate(plat->stmmac_clk, 50000000);
> > > > >         }
> > > > >     -    if (plat->phy_node && bsp_priv->integrated_phy) {
> > > > > +    if (plat->phy_node) {
> > > > >             bsp_priv->clk_phy = of_clk_get(plat->phy_node, 0);
> > > > >             ret = PTR_ERR_OR_ZERO(bsp_priv->clk_phy);
> > > > > -        if (ret)
> > > > > -            return dev_err_probe(dev, ret, "Cannot get PHY clock\n");
> > > > > -        clk_set_rate(bsp_priv->clk_phy, 50000000);
> > > > > +        /* If it is not integrated_phy, clk_phy is optional */
> > > > > +        if (bsp_priv->integrated_phy) {
> > > > > +            if (ret)
> > > > > +                return dev_err_probe(dev, ret, "Cannot get PHY
> > > > > clock\n");
> > > > > +            clk_set_rate(bsp_priv->clk_phy, 50000000);
> > > > > +        }
> > > I think  we should set bsp_priv->clk_phy to NULL here if we failed to
> > > get the clock.
> > >
> > > Could you try this on your board? Thank you.
> > Right, the following change also fixes this issue:
> >
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > index 9fc41207cc45..2d19d48be01f 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> > @@ -1415,6 +1415,8 @@ static int rk_gmac_clk_init(struct
> > plat_stmmacenet_data *plat)
> >           if (plat->phy_node) {
> >                   bsp_priv->clk_phy = of_clk_get(plat->phy_node, 0);
> >                   ret = PTR_ERR_OR_ZERO(bsp_priv->clk_phy);
> > +               if (ret)
> > +                       bsp_priv->clk_phy = NULL;
> Or just:
>
> 		clk = of_clk_get(plat->phy_node, 0);
> 		if (clk == ERR_PTR(-EPROBE_DEFER))

Do we actually need this? Maybe other devm_clk_get() before it would fail in advance.


> 			...
> 		else if (!IS_ERR)
> 			bsp_priv->clk_phy = clk;
>
> I don't have a free terminal to work out what "..." should be.