On Mon, Dec 14, 2020 at 4:05 AM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>
> Hi Adam,
>
> 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 the above proposal, the clock-names would only be necessary when
using the txc_refclk.
>
> > + 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
