Re: [PATCH net-next 06/11] net: dsa: rzn1-a5psw: Add support for optional timestamp clock

[Geert Uytterhoeven]

Hi Prabhakar,

On Fri, 21 Nov 2025 at 12:36, Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
>
> Add support for an optional "ts" (timestamp) clock to the RZN1 A5PSW
> driver. Some SoC variants provide a dedicated clock source for
> timestamping or time synchronization features within the Ethernet
> switch IP.
>
> Request and enable this clock during probe if defined in the device tree.
> If the clock is not present, the driver continues to operate normally.
>
> This change prepares the driver for Renesas RZ/T2H and RZ/N2H SoCs, where
> the Ethernet switch includes a timestamp clock input.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

Thanks for your patch!


> --- a/drivers/net/dsa/rzn1_a5psw.c
> +++ b/drivers/net/dsa/rzn1_a5psw.c
> @@ -1243,6 +1243,13 @@ static int a5psw_probe(struct platform_device *pdev)
>                 goto free_pcs;
>         }
>
> +       a5psw->ts = devm_clk_get_optional_enabled(dev, "ts");
> +       if (IS_ERR(a5psw->ts)) {
> +               dev_err(dev, "failed get ts clock\n");

I think the error can be -EPROBE_DEFER, so this should use
dev_err_probe() instead. Same for the existing calls.

> +               ret = PTR_ERR(a5psw->ts);
> +               goto free_pcs;
> +       }
> +
>         reset = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL);
>         if (IS_ERR(reset)) {
>                 ret = PTR_ERR(reset);

> --- a/drivers/net/dsa/rzn1_a5psw.h
> +++ b/drivers/net/dsa/rzn1_a5psw.h
> @@ -236,6 +236,7 @@ union lk_data {
>   * @base: Base address of the switch
>   * @hclk: hclk_switch clock
>   * @clk: clk_switch clock
> + * @ts: Timestamp clock
>   * @dev: Device associated to the switch
>   * @mii_bus: MDIO bus struct
>   * @mdio_freq: MDIO bus frequency requested
> @@ -251,6 +252,7 @@ struct a5psw {
>         void __iomem *base;
>         struct clk *hclk;
>         struct clk *clk;
> +       struct clk *ts;

"ts" is only used inside a5psw_probe(), so it can be a local variable.

>         struct device *dev;
>         struct mii_bus  *mii_bus;
>         struct phylink_pcs *pcs[A5PSW_PORTS_NUM - 1];

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