linux-kernel - Re: [PATCH v6 1/9] mtk-mdp: propagate errors from clock

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Message-ID: <8fe5ac46-a9db-710e-a6d1-856805ab2773@collabora.com>
Date:   Thu, 5 Aug 2021 08:06:07 +0200
From:   Dafna Hirschfeld <dafna.hirschfeld@...labora.com>
To:     Eizan Miyamoto <eizan@...omium.org>, linux-kernel@...r.kernel.org
Cc:     wenst@...omium.org, houlong.wei@...iatek.com, yong.wu@...iatek.com,
        enric.balletbo@...labora.com, devicetree@...r.kernel.org,
        chunkuang.hu@...nel.org,
        Andrew-CT Chen <andrew-ct.chen@...iatek.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Minghsiu Tsai <minghsiu.tsai@...iatek.com>,
        linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH v6 1/9] mtk-mdp: propagate errors from clock_on



On 02.08.21 14:12, Eizan Miyamoto wrote:
> Up until this change, many errors were logged but ignored when powering
> on clocks inside mtk_mdp_core. This change tries to do a better job at
> propagating errors back to the power management framework.
> 
> Signed-off-by: Eizan Miyamoto <eizan@...omium.org>
> ---
> 
> (no changes since v1)
> 
>   drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 25 ++++++++++++-----
>   drivers/media/platform/mtk-mdp/mtk_mdp_comp.h |  2 +-
>   drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 27 ++++++++++++++-----
>   3 files changed, 39 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> index b3426a551bea..76e295c8d9bc 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> @@ -13,10 +13,9 @@
>   
>   #include "mtk_mdp_comp.h"
>   
> -
> -void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
> +int mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
>   {
> -	int i, err;
> +	int i, err, status;
>   
>   	if (comp->larb_dev) {
>   		err = mtk_smi_larb_get(comp->larb_dev);
> @@ -30,11 +29,23 @@ void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
>   		if (IS_ERR(comp->clk[i]))
>   			continue;
>   		err = clk_prepare_enable(comp->clk[i]);
> -		if (err)
> -			dev_err(dev,
> -			"failed to enable clock, err %d. type:%d i:%d\n",
> -				err, comp->type, i);
> +		if (err) {
> +			status = err;
> +			dev_err(dev, "failed to enable clock, err %d. i:%d\n", err, i);
> +			goto err_clk_prepare_enable;
> +		}
> +	}
> +
> +	return 0;
> +
> +err_clk_prepare_enable:
> +	for (--i; i >= 0; i--) {
> +		if (IS_ERR(comp->clk[i]))
> +			continue;
> +		clk_disable_unprepare(comp->clk[i]);
>   	}
> +
> +	return status;

There is an API function clk_bulk_prepare_enable to prepare and enable an array of clks
so you can just use it.

>   }
>   
>   void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp)
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> index 7897766c96bb..92ab5249bcad 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> @@ -41,7 +41,7 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
>   		      struct mtk_mdp_comp *comp,
>   		      enum mtk_mdp_comp_type comp_type);
>   void mtk_mdp_comp_deinit(struct device *dev, struct mtk_mdp_comp *comp);
> -void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp);
> +int mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp);
>   void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp);
>   
>   
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> index 976aa1f4829b..412bbec0f735 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> @@ -52,13 +52,28 @@ static const struct of_device_id mtk_mdp_of_ids[] = {
>   };
>   MODULE_DEVICE_TABLE(of, mtk_mdp_of_ids);
>   
> -static void mtk_mdp_clock_on(struct mtk_mdp_dev *mdp)
> +static int mtk_mdp_clock_on(struct mtk_mdp_dev *mdp)
>   {
> -	struct device *dev = &mdp->pdev->dev;
>   	struct mtk_mdp_comp *comp_node;
> +	int status;
> +	struct device *dev = &mdp->pdev->dev;
> +	int err;
>   
> -	list_for_each_entry(comp_node, &mdp->comp_list, node)
> -		mtk_mdp_comp_clock_on(dev, comp_node);
> +	list_for_each_entry(comp_node, &mdp->comp_list, node) {
> +		err = mtk_mdp_comp_clock_on(dev, comp_node);
> +		if (err) {
> +			status = err;

You can get rid of the new var 'status' and just return ret in case of error

> +			goto err_mtk_mdp_comp_clock_on;
> +		}
> +	}
> +
> +	return 0;
> +
> +err_mtk_mdp_comp_clock_on:
> +	list_for_each_entry_continue_reverse(comp_node, &mdp->comp_list, node)
> +		mtk_mdp_comp_clock_off(dev, comp_node);
> +
> +	return status;
>   }
>   
>   static void mtk_mdp_clock_off(struct mtk_mdp_dev *mdp)
> @@ -274,9 +289,7 @@ static int __maybe_unused mtk_mdp_pm_resume(struct device *dev)
>   {
>   	struct mtk_mdp_dev *mdp = dev_get_drvdata(dev);
>   
> -	mtk_mdp_clock_on(mdp);
> -
> -	return 0;
> +	return mtk_mdp_clock_on(mdp);
>   }
>   
>   static int __maybe_unused mtk_mdp_suspend(struct device *dev)
>