Re: [PATCH] net: ravb: Add additional refclk

[Ramon Fried <rfried.dev@gmail.com>]

On Tue, May 25, 2021 at 8:52 PM Adam Ford <aford173@gmail.com> wrote:
>
> The ethernet requires an external reference clock, and the driver
> currently assumes the clock is always running.  For devices using
> a programmable clock, this may not be true.  Add an optional clock
> called 'refclk' to open and enable the refclk for hardware running
> with programmable clocks.
>
> Signed-off-by: Adam Ford <aford173@gmail.com>
> ---
> This was also done in the Linux kernel, see:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/ethernet/renesas/ravb_main.c?id=8ef7adc6beb2ef0bce83513dc9e4505e7b21e8c2
>
> diff --git a/drivers/net/ravb.c b/drivers/net/ravb.c
> index 6953b7286a..ced80485de 100644
> --- a/drivers/net/ravb.c
> +++ b/drivers/net/ravb.c
> @@ -130,6 +130,7 @@ struct ravb_priv {
>         struct mii_dev          *bus;
>         void __iomem            *iobase;
>         struct clk              clk;
> +       struct clk              *refclk;
>         struct gpio_desc        reset_gpio;
>  };
>
> @@ -489,6 +490,8 @@ static int ravb_probe(struct udevice *dev)
>         if (ret < 0)
>                 goto err_mdio_alloc;
>
> +       eth->refclk = devm_clk_get_optional(dev, "refclk");
> +
>         ret = dev_read_phandle_with_args(dev, "phy-handle", NULL, 0, 0, &phandle_args);
>         if (!ret) {
>                 gpio_request_by_name_nodev(phandle_args.node, "reset-gpios", 0,
> @@ -522,6 +525,10 @@ static int ravb_probe(struct udevice *dev)
>         if (ret)
>                 goto err_mdio_register;
>
> +       ret = clk_enable(eth->refclk);
> +       if (ret)
> +               goto err_disable_clk;
> +
>         ret = ravb_reset(dev);
>         if (ret)
>                 goto err_mdio_reset;
> @@ -533,6 +540,8 @@ static int ravb_probe(struct udevice *dev)
>         return 0;
>
>  err_mdio_reset:
> +       clk_disable(eth->refclk);
> +err_disable_clk:
>         clk_disable(&eth->clk);
>  err_mdio_register:
>         mdio_free(mdiodev);
> @@ -545,6 +554,7 @@ static int ravb_remove(struct udevice *dev)
>  {
>         struct ravb_priv *eth = dev_get_priv(dev);
>
> +       clk_disable(eth->refclk);
>         clk_disable(&eth->clk);
>
>         free(eth->phydev);
> --
> 2.25.1
>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>