linux-kernel - Re: [PATCH v3 3/5] media: atmel-isc: Enable the clocks during probe

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Message-ID: <20170928212543.sltvd4rgswfowtcd@valkosipuli.retiisi.org.uk>
Date:   Fri, 29 Sep 2017 00:25:43 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Wenyou Yang <wenyou.yang@...rochip.com>
Cc:     Mauro Carvalho Chehab <mchehab@...pensource.com>,
        linux-kernel@...r.kernel.org,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Jonathan Corbet <corbet@....net>,
        Hans Verkuil <hverkuil@...all.nl>,
        linux-arm-kernel@...ts.infradead.org,
        Linux Media Mailing List <linux-media@...r.kernel.org>
Subject: Re: [PATCH v3 3/5] media: atmel-isc: Enable the clocks during probe

Hi Wenyou,

On Thu, Sep 28, 2017 at 04:18:26PM +0800, Wenyou Yang wrote:
> To meet the relationship, enable the HCLOCK and ispck during the
> device probe, "isc_pck frequency is less than or equal to isc_ispck,
> and isc_ispck is greater than or equal to HCLOCK."
> Meanwhile, call the pm_runtime_enable() in the right place.
> 
> Signed-off-by: Wenyou Yang <wenyou.yang@...rochip.com>
> ---
> 
> Changes in v3: None
> Changes in v2: None
> 
>  drivers/media/platform/atmel/atmel-isc.c | 31 +++++++++++++++++++++++++------
>  1 file changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/platform/atmel/atmel-isc.c b/drivers/media/platform/atmel/atmel-isc.c
> index 0b15dc1a3a0b..f092c95587c1 100644
> --- a/drivers/media/platform/atmel/atmel-isc.c
> +++ b/drivers/media/platform/atmel/atmel-isc.c
> @@ -1594,6 +1594,7 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
>  	struct isc_subdev_entity *sd_entity;
>  	struct video_device *vdev = &isc->video_dev;
>  	struct vb2_queue *q = &isc->vb2_vidq;
> +	struct device *dev = isc->dev;
>  	int ret;
>  
>  	ret = v4l2_device_register_subdev_nodes(&isc->v4l2_dev);
> @@ -1677,6 +1678,10 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
>  		return ret;
>  	}
>  
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +	pm_request_idle(dev);

Remember that the driver's async complete function could never get called.

What would be the reason to move it here?

> +
>  	return 0;
>  }
>  
> @@ -1856,25 +1861,37 @@ static int atmel_isc_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	ret = clk_prepare_enable(isc->hclock);
> +	if (ret) {
> +		dev_err(dev, "failed to enable hclock: %d\n", ret);
> +		return ret;
> +	}
> +
>  	ret = isc_clk_init(isc);
>  	if (ret) {
>  		dev_err(dev, "failed to init isc clock: %d\n", ret);
> -		goto clean_isc_clk;
> +		goto unprepare_hclk;
>  	}
>  
>  	isc->ispck = isc->isc_clks[ISC_ISPCK].clk;
>  
> +	ret = clk_prepare_enable(isc->ispck);
> +	if (ret) {
> +		dev_err(dev, "failed to enable ispck: %d\n", ret);
> +		goto unprepare_hclk;
> +	}
> +
>  	/* ispck should be greater or equal to hclock */
>  	ret = clk_set_rate(isc->ispck, clk_get_rate(isc->hclock));
>  	if (ret) {
>  		dev_err(dev, "failed to set ispck rate: %d\n", ret);
> -		goto clean_isc_clk;
> +		goto unprepare_clk;
>  	}
>  
>  	ret = v4l2_device_register(dev, &isc->v4l2_dev);
>  	if (ret) {
>  		dev_err(dev, "unable to register v4l2 device.\n");
> -		goto clean_isc_clk;
> +		goto unprepare_clk;
>  	}
>  
>  	ret = isc_parse_dt(dev, isc);
> @@ -1907,8 +1924,6 @@ static int atmel_isc_probe(struct platform_device *pdev)
>  			break;
>  	}
>  
> -	pm_runtime_enable(dev);
> -
>  	return 0;
>  
>  cleanup_subdev:
> @@ -1917,7 +1932,11 @@ static int atmel_isc_probe(struct platform_device *pdev)
>  unregister_v4l2_device:
>  	v4l2_device_unregister(&isc->v4l2_dev);
>  
> -clean_isc_clk:
> +unprepare_clk:
> +	clk_disable_unprepare(isc->ispck);
> +unprepare_hclk:
> +	clk_disable_unprepare(isc->hclock);

I think you're missing clk_disable_unprepare() in the driver's remove
callback.

> +
>  	isc_clk_cleanup(isc);
>  
>  	return ret;

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@....fi