Hi Adam,
CC devicetree
On Mon, Dec 28, 2020 at 2:49 PM Adam Ford <aford173@xxxxxxxxx> wrote:
> On Mon, Dec 14, 2020 at 4:05 AM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> > On Sun, Dec 13, 2020 at 5:18 PM Adam Ford <aford173@xxxxxxxxx> wrote:
> > > The SoC expects the txv_refclk is provided, but if it is provided
> > > by a programmable clock, there needs to be a way to get and enable
> > > this clock to operate. It needs to be optional since it's only
> > > necessary for those with programmable clocks.
> > >
> > > Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/net/ethernet/renesas/ravb.h
> > > +++ b/drivers/net/ethernet/renesas/ravb.h
> > > @@ -994,6 +994,7 @@ struct ravb_private {
> > > struct platform_device *pdev;
> > > void __iomem *addr;
> > > struct clk *clk;
> > > + struct clk *ref_clk;
> > > struct mdiobb_ctrl mdiobb;
> > > u32 num_rx_ring[NUM_RX_QUEUE];
> > > u32 num_tx_ring[NUM_TX_QUEUE];
> > > diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> > > index bd30505fbc57..4c3f95923ef2 100644
> > > --- a/drivers/net/ethernet/renesas/ravb_main.c
> > > +++ b/drivers/net/ethernet/renesas/ravb_main.c
> > > @@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
> > > goto out_release;
> > > }
> > >
> > > + priv->ref_clk = devm_clk_get(&pdev->dev, "txc_refclk");
> >
> > Please also update the DT bindings[1], to document the optional
> > presence of the clock.
>
> I am not all that familiar with the YAML syntax, but right now, the
> clock-names property isn't in the binding, and the driver doesn't use
> a name when requesting the single clock it's expecting.
> Since the txc_refclk is optional, can the clock-names property allow
> for 0-2 names while the number of clocks be 1-2?
>
> clocks:
> minItems: 1
> maxItems: 2
>
> clock-names:
> minItems: 0
> maxItems: 2
> items:
> enum:
> - fck # AVB functional clock (optional if it is the only clock)
> - txc_refclk # TXC reference clock
With "enum", it accepts any order. But for compatibility, we want to force
"fck" first.
Something like:
clocks:
minItems: 1
items:
- description: AVB functional clock
- description: Optional TXC reference clock
clock-names:
items:
- const: fck
- const: txc_refclk
> With the above proposal, the clock-names would only be necessary when
> using the txc_refclk.
I think that's difficult to express: either make clock-names optional (i.e.
don't list it under "required"), or make it required in all cases (which need
fixups for the existing users, and "minItems: 1" for "clock-names", too).
> > > + if (IS_ERR(priv->ref_clk)) {
> > > + if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
> > > + /* for Probe defer return error */
> > > + error = PTR_ERR(priv->ref_clk);
> > > + goto out_release;
> > > + }
> > > + /* Ignore other errors since it's optional */
> > > + } else {
> > > + (void)clk_prepare_enable(priv->ref_clk);
> >
> > This can fail.
> > Does this clock need to be enabled all the time?
> > At least it should be disabled in the probe failure path, and in
> > ravb_remove().
>
> I'll do that for the next rev.
>
> thanks,
>
> adam
> >
> > [1] Documentation/devicetree/bindings/net/renesas,etheravb.yaml
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
