linux-kernel - Re: [PATCH 2/3] usb: renesas_usbhs: Enable support for more than two clks

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Date:   Thu, 1 Jul 2021 11:07:25 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Adam Ford <aford173@...il.com>
Cc:     USB list <linux-usb@...r.kernel.org>,
        Adam Ford-BE <aford@...conembedded.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Magnus Damm <magnus.damm@...il.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH 2/3] usb: renesas_usbhs: Enable support for more than two clks

Hi Adam,

Thanks for your patch!

On Wed, Jun 30, 2021 at 7:30 PM Adam Ford <aford173@...il.com> wrote:
> The RZ/G2 boards expect there to be an external clock reference for
> USBHS controller, but this could be set by a programmable clock.
> For those devices using a programmable clock, there need to be two
> additional clocks beyond the internal reference clocks:
>
> rcar-usb2-clock-sel to specify we using an external clock, and
> the external reference clock itself.

Something is missing in the above sentence?

>
> Make this driver dynamically enable all the clocks assigned to it
> instead of only enabling the first one or two clocks.
>
> Signed-off-by: Adam Ford <aford173@...il.com>
>
> diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
> index 3af91b2b8f76..255e4bd68ed3 100644
> --- a/drivers/usb/renesas_usbhs/common.c
> +++ b/drivers/usb/renesas_usbhs/common.c
> @@ -297,6 +297,8 @@ static bool usbhsc_is_multi_clks(struct usbhs_priv *priv)
>
>  static int usbhsc_clk_get(struct device *dev, struct usbhs_priv *priv)
>  {
> +       unsigned int i;
> +
>         if (!usbhsc_is_multi_clks(priv))
>                 return 0;
>
> @@ -309,11 +311,13 @@ static int usbhsc_clk_get(struct device *dev, struct usbhs_priv *priv)
>          * To backward compatibility with old DT, this driver checks the return
>          * value if it's -ENOENT or not.
>          */
> -       priv->clks[1] = of_clk_get(dev_of_node(dev), 1);
> -       if (PTR_ERR(priv->clks[1]) == -ENOENT)
> -               priv->clks[1] = NULL;
> -       else if (IS_ERR(priv->clks[1]))
> -               return PTR_ERR(priv->clks[1]);
> +       for (i = 1; i < ARRAY_SIZE(priv->clks); i++) {
> +               priv->clks[1] = of_clk_get(dev->of_node, i);
> +               if (PTR_ERR(priv->clks[i]) == -ENOENT)
> +                       priv->clks[i] = NULL;
> +               else if (IS_ERR(priv->clks[i]))
> +                       return PTR_ERR(priv->clks[i]);
> +       }

This is identical to the current code, as ARRAY_SIZE(priv->clks) == 2.
Probably you wanted to increase usbhs_priv.clks[], too?

Does it make sense to start using the clk_bulk*() API?

>
>         return 0;
>  }

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

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