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From:   Evan Green <evgreen@chromium.org>
Date:   Mon, 25 Feb 2019 15:54:50 -0800
Message-ID: <CAE=gft71J+5ui_FFm4D+62uSy6KHYzT7wru_NNdPsvrCDV3ekw@mail.gmail.com>
Subject: Re: [PATCH 05/13] memory: mtk-smi: Add device-link between smi-larb
 and smi-common
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 8:52 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> Normally, If the smi-larb HW need work, we should enable the smi-common
> HW power and clock firstly.
> This patch adds device-link between the smi-larb dev and the smi-common
> dev. then If pm_runtime_get_sync(smi-larb-dev), the pm_runtime_get_sync
> (smi-common-dev) will be called automatically.
>
> Since smi is built-in driver like IOMMU and never unbound,
> DL_FLAG_AUTOREMOVE_* is not needed.
>
> CC: Matthias Brugger <matthias.bgg@gmail.com>
> Suggested-by: Tomasz Figa <tfiga@chromium.org>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
>  drivers/memory/mtk-smi.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index 9688341..30930e4 100644
> --- a/drivers/memory/mtk-smi.c
> +++ b/drivers/memory/mtk-smi.c
> @@ -271,6 +271,7 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
>         struct device *dev = &pdev->dev;
>         struct device_node *smi_node;
>         struct platform_device *smi_pdev;
> +       struct device_link *link;
>
>         larb = devm_kzalloc(dev, sizeof(*larb), GFP_KERNEL);
>         if (!larb)
> @@ -310,6 +311,12 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
>                 if (!platform_get_drvdata(smi_pdev))
>                         return -EPROBE_DEFER;
>                 larb->smi_common_dev = &smi_pdev->dev;
> +               link = device_link_add(dev, larb->smi_common_dev,
> +                                      DL_FLAG_PM_RUNTIME);

Doesn't this need to be torn down in remove()? You mention that it's
built-in and never removed, but it does seem to have a remove()
function that tears down everything else, so it seemed a shame to
start leaking now. Maybe the AUTOREMOVE flag would do it.