linux-kernel - Re: [PATCH v9 3/9] soc: mediatek: Add basic_clk_id to scp_power

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Date:   Mon, 16 Dec 2019 15:01:31 +0800
From:   Nicolas Boichat <drinkcat@...omium.org>
To:     Weiyi Lu <weiyi.lu@...iatek.com>
Cc:     Matthias Brugger <matthias.bgg@...il.com>,
        Rob Herring <robh@...nel.org>,
        James Liao <jamesjj.liao@...iatek.com>,
        Fan Chen <fan.chen@...iatek.com>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        lkml <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        srv_heupstream <srv_heupstream@...iatek.com>,
        Yong Wu <yong.wu@...iatek.com>
Subject: Re: [PATCH v9 3/9] soc: mediatek: Add basic_clk_id to scp_power_data

On Tue, Dec 10, 2019 at 2:47 PM Weiyi Lu <weiyi.lu@...iatek.com> wrote:
>
> Try to stop extending the clk_id or clk_names if there are
> more and more new BASIC clocks. To get its own clocks by the
> basic_clk_id of each power domain.

Looking at this a bit more, I'm not sure why we make this an option...

The easiest way to make this consistent with non-MT8183 scpsys drivers
is to add your missing clocks to "enum clk_id" and clk_names, but I
understand it's not desired (number of clocks would blow up).

Can we, instead, convert all existing scpsys drivers to use "char *"
clock names instead?
I made an attempt here and it seems simple enough:
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1969103

>
> Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>
> ---
>  drivers/soc/mediatek/mtk-scpsys.c | 29 +++++++++++++++++++++--------
>  1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
> index f669d37..915d635 100644
> --- a/drivers/soc/mediatek/mtk-scpsys.c
> +++ b/drivers/soc/mediatek/mtk-scpsys.c
> @@ -117,6 +117,8 @@ enum clk_id {
>   * @sram_pdn_ack_bits: The mask for sram power control acked bits.
>   * @bus_prot_mask: The mask for single step bus protection.
>   * @clk_id: The basic clocks required by this power domain.
> + * @basic_clk_id: provide the same purpose with field "clk_id"
> + *                by declaring basic clock prefix name rather than clk_id.

Actually, I prefer the name clk_name, not sure why I pushed you in
that direction...

>   * @caps: The flag for active wake-up action.
>   */
>  struct scp_domain_data {
> @@ -127,6 +129,7 @@ struct scp_domain_data {
>         u32 sram_pdn_ack_bits;
>         u32 bus_prot_mask;
>         enum clk_id clk_id[MAX_CLKS];
> +       const char *basic_clk_id[MAX_CLKS];
>         u8 caps;
>  };
>
> @@ -493,16 +496,26 @@ static struct scp *init_scp(struct platform_device *pdev,
>
>                 scpd->data = data;
>
> -               for (j = 0; j < MAX_CLKS && data->clk_id[j]; j++) {
> -                       struct clk *c = clk[data->clk_id[j]];
> +               if (data->clk_id[0]) {
> +                       WARN_ON(data->basic_clk_id[0]);
>
> -                       if (IS_ERR(c)) {
> -                               dev_err(&pdev->dev, "%s: clk unavailable\n",
> -                                       data->name);
> -                               return ERR_CAST(c);
> -                       }
> +                       for (j = 0; j < MAX_CLKS && data->clk_id[j]; j++) {
> +                               struct clk *c = clk[data->clk_id[j]];
> +
> +                               if (IS_ERR(c)) {
> +                                       dev_err(&pdev->dev,
> +                                               "%s: clk unavailable\n",
> +                                               data->name);
> +                                       return ERR_CAST(c);
> +                               }
>
> -                       scpd->clk[j] = c;
> +                               scpd->clk[j] = c;
> +                       }
> +               } else if (data->basic_clk_id[0]) {
> +                       for (j = 0; j < MAX_CLKS &&
> +                                       data->basic_clk_id[j]; j++)
> +                               scpd->clk[j] = devm_clk_get(&pdev->dev,
> +                                               data->basic_clk_id[j]);
>                 }
>
>                 genpd->name = data->name;
> --
> 1.8.1.1.dirty