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From:   Nicolas Boichat <drinkcat@chromium.org>
Date:   Tue, 15 Dec 2020 21:42:22 +0800
Message-ID: <CANMq1KBu4Ft49CUgGMxYdsv6ymWzVWK+eNBhn1t+oEN0ZwP0YA@mail.gmail.com>
Subject: Re: [PATCH v2, 14/17] soc: mediatek: mmsys: Use function call for
 setting mmsys ovl mout register
To:     Yongqiang Niu <yongqiang.niu@mediatek.com>
Cc:     CK Hu <ck.hu@mediatek.com>, Philipp Zabel <p.zabel@pengutronix.de>,
        Rob Herring <robh+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Devicetree List <devicetree@vger.kernel.org>,
        David Airlie <airlied@linux.ie>,
        lkml <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>
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On Sat, Dec 12, 2020 at 12:13 PM Yongqiang Niu
<yongqiang.niu@mediatek.com> wrote:
>
> Use function call for setting mmsys ovl mout register
>
> Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
> ---
>  drivers/soc/mediatek/mmsys/mtk-mmsys.c | 18 ++++++++++++++++++
>  include/linux/soc/mediatek/mtk-mmsys.h |  3 +++
>  2 files changed, 21 insertions(+)
>
> diff --git a/drivers/soc/mediatek/mmsys/mtk-mmsys.c b/drivers/soc/mediatek/mmsys/mtk-mmsys.c
> index cb76e64..2558b42 100644
> --- a/drivers/soc/mediatek/mmsys/mtk-mmsys.c
> +++ b/drivers/soc/mediatek/mmsys/mtk-mmsys.c
> @@ -78,6 +78,15 @@ void mtk_mmsys_ddp_connect(struct device *dev,
>                 reg = readl_relaxed(mmsys->regs + addr) | value;
>                 writel_relaxed(reg, mmsys->regs + addr);
>         }
> +
> +       if (!funcs->ovl_mout_en)
> +               return;
> +
> +       value = funcs->ovl_mout_en(cur, next, &addr);
> +       if (value) {
> +               reg = readl_relaxed(mmsys->regs + addr) | value;
> +               writel_relaxed(reg, mmsys->regs + addr);
> +       }

This is technically correct, but I'm afraid this may become and issue
later if we have another function like ovl_mout_en.

So maybe it's better to do:
if (funcs->ovl_mout_en) {
  value = funcs->ovl_mout_en(cur, next, &addr);
  ...
}

Or another option: Create a new function
static unsigned int mtk_mmsys_ovl_mout_en(...) {
   if (!funcs->ovl_mout_en)
      return 0;
}

and call that, following the same pattern as
mtk_mmsys_ddp_mout_en/mtk_mmsys_ddp_sel_in?

>  }
>  EXPORT_SYMBOL_GPL(mtk_mmsys_ddp_connect);
>
> @@ -103,6 +112,15 @@ void mtk_mmsys_ddp_disconnect(struct device *dev,
>                 reg = readl_relaxed(mmsys->regs + addr) & ~value;
>                 writel_relaxed(reg, mmsys->regs + addr);
>         }
> +
> +       if (!funcs->ovl_mout_en)
> +               return;
> +
> +       value = funcs->ovl_mout_en(cur, next, &addr);
> +       if (value) {
> +               reg = readl_relaxed(mmsys->regs + addr) & ~value;
> +               writel_relaxed(reg, mmsys->regs + addr);
> +       }
>  }
>  EXPORT_SYMBOL_GPL(mtk_mmsys_ddp_disconnect);
>
> diff --git a/include/linux/soc/mediatek/mtk-mmsys.h b/include/linux/soc/mediatek/mtk-mmsys.h
> index aa4f60e..220203d 100644
> --- a/include/linux/soc/mediatek/mtk-mmsys.h
> +++ b/include/linux/soc/mediatek/mtk-mmsys.h
> @@ -49,6 +49,9 @@ struct mtk_mmsys_conn_funcs {
>         u32 (*mout_en)(enum mtk_ddp_comp_id cur,
>                        enum mtk_ddp_comp_id next,
>                        unsigned int *addr);
> +       u32 (*ovl_mout_en)(enum mtk_ddp_comp_id cur,
> +                          enum mtk_ddp_comp_id next,
> +                          unsigned int *addr);
>         u32 (*sel_in)(enum mtk_ddp_comp_id cur,
>                       enum mtk_ddp_comp_id next,
>                       unsigned int *addr);
> --
> 1.8.1.1.dirty
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