linux-kernel - Re: [PATCH v3 1/2] clk: mediatek: Introduce need_pm_runtime to mtk_clk

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Date: Fri, 23 Feb 2024 12:27:28 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: Pin-yen Lin <treapking@...omium.org>
Cc: Michael Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>, 
	Matthias Brugger <matthias.bgg@...il.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Weiyi Lu <weiyi.lu@...iatek.com>, 
	linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org, 
	linux-mediatek@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 1/2] clk: mediatek: Introduce need_pm_runtime to mtk_clk_desc

On Mon, Jan 8, 2024 at 4:18 PM Pin-yen Lin <treapking@...omium.org> wrote:
>
> Introduce a new need_pm_runtime variable to mtk_clk_desc to indicate
> this clock controller needs runtime PM for its operations.
> Also do a runtime PM get on the clock controller during the
> probing stage to workaround a possible deadlock.
>
> Signed-off-by: Pin-yen Lin <treapking@...omium.org>

Reviewed-by: Chen-Yu Tsai <wenst@...omium.org>

The patch itself looks fine.

Besides the MT8183 MFG clock issues, we do actually need this for the
MT8192 ADSP clock. Its power domain is not enabled by default.

> ---
>
> Changes in v3:
> - Update the commit message and the comments before runtime PM call
>
> Changes in v2:
> - Fix the order of error handling
> - Update the commit message and add a comment before the runtime PM call
>
>  drivers/clk/mediatek/clk-mtk.c | 19 +++++++++++++++++++
>  drivers/clk/mediatek/clk-mtk.h |  2 ++
>  2 files changed, 21 insertions(+)
>
> diff --git a/drivers/clk/mediatek/clk-mtk.c b/drivers/clk/mediatek/clk-mtk.c
> index 2e55368dc4d8..ba1d1c495bc2 100644
> --- a/drivers/clk/mediatek/clk-mtk.c
> +++ b/drivers/clk/mediatek/clk-mtk.c
> @@ -13,6 +13,7 @@
>  #include <linux/of.h>
>  #include <linux/of_address.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/slab.h>
>
>  #include "clk-mtk.h"
> @@ -494,6 +495,18 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev,
>                         return IS_ERR(base) ? PTR_ERR(base) : -ENOMEM;
>         }
>
> +
> +       if (mcd->need_runtime_pm) {
> +               devm_pm_runtime_enable(&pdev->dev);
> +               /*
> +                * Do a pm_runtime_resume_and_get() to workaround a possible
> +                * deadlock between clk_register() and the genpd framework.
> +                */
> +               r = pm_runtime_resume_and_get(&pdev->dev);
> +               if (r)
> +                       return r;
> +       }
> +
>         /* Calculate how many clk_hw_onecell_data entries to allocate */
>         num_clks = mcd->num_clks + mcd->num_composite_clks;
>         num_clks += mcd->num_fixed_clks + mcd->num_factor_clks;
> @@ -574,6 +587,9 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev,
>                         goto unregister_clks;
>         }
>
> +       if (mcd->need_runtime_pm)
> +               pm_runtime_put(&pdev->dev);
> +
>         return r;
>
>  unregister_clks:
> @@ -604,6 +620,9 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev,
>  free_base:
>         if (mcd->shared_io && base)
>                 iounmap(base);
> +
> +       if (mcd->need_runtime_pm)
> +               pm_runtime_put(&pdev->dev);
>         return r;
>  }
>
> diff --git a/drivers/clk/mediatek/clk-mtk.h b/drivers/clk/mediatek/clk-mtk.h
> index 22096501a60a..c17fe1c2d732 100644
> --- a/drivers/clk/mediatek/clk-mtk.h
> +++ b/drivers/clk/mediatek/clk-mtk.h
> @@ -237,6 +237,8 @@ struct mtk_clk_desc {
>
>         int (*clk_notifier_func)(struct device *dev, struct clk *clk);
>         unsigned int mfg_clk_idx;
> +
> +       bool need_runtime_pm;
>  };
>
>  int mtk_clk_pdev_probe(struct platform_device *pdev);
> --
> 2.43.0.472.g3155946c3a-goog
>