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From:   Evan Green <evgreen@chromium.org>
Date:   Mon, 25 Feb 2019 15:56:29 -0800
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Subject: Re: [PATCH 11/13] iommu/mediatek: Use builtin_platform_driver
To:     Yong Wu <yong.wu@mediatek.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Tomasz Figa <tfiga@google.com>,
        Will Deacon <will.deacon@arm.com>,
        linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        linux-arm-kernel@lists.infradead.org,
        iommu@lists.linux-foundation.org, Arnd Bergmann <arnd@arndb.de>,
        yingjoe.chen@mediatek.com, youlin.pei@mediatek.com,
        Nicolas Boichat <drinkcat@chromium.org>
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On Mon, Dec 31, 2018 at 8:53 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> MediaTek IOMMU should wait for smi larb which need wait for the
> power domain(mtk-scpsys.c) and the multimedia ccf who both are
> module init. Thus, subsys_initcall for MediaTek IOMMU is not helpful.
> Switch to builtin_platform_driver.
>
> Meanwhile, the ".remove" can be removed. Move its content to
> ".shutdown".
>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
>  drivers/iommu/mtk_iommu.c    | 23 ++---------------------
>  drivers/iommu/mtk_iommu_v1.c | 16 ++--------------
>  2 files changed, 4 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 735ae8d..2798b12 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -690,7 +690,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
>         return component_master_add_with_match(dev, &mtk_iommu_com_ops, match);
>  }
>
> -static int mtk_iommu_remove(struct platform_device *pdev)
> +static void mtk_iommu_shutdown(struct platform_device *pdev)
>  {
>         struct mtk_iommu_data *data = platform_get_drvdata(pdev);
>
> @@ -703,12 +703,6 @@ static int mtk_iommu_remove(struct platform_device *pdev)
>         clk_disable_unprepare(data->bclk);
>         devm_free_irq(&pdev->dev, data->irq, data);
>         component_master_del(&pdev->dev, &mtk_iommu_com_ops);
> -       return 0;
> -}
> -
> -static void mtk_iommu_shutdown(struct platform_device *pdev)
> -{
> -       mtk_iommu_remove(pdev);

Is there a reason all these things are happening in shutdown()? Don't
we normally just not clean things up and let the machine turn off?
Normally I'm a big advocate of proper symmetric teardown, so it hurts
a little to ask.