Re: [RFC] ravb: Add support for optional txc_refclk
From: Geert Uytterhoeven
Date: Mon Dec 14 2020 - 05:06:52 EST
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.
> + 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().
[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