linux-kernel - Re: [PATCH 1/7] media: hantro: add support for reset lines

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Message-ID: <08e80e9e-f646-72e4-e4d4-f8e6310228f1@collabora.com>
Date:   Tue, 23 Nov 2021 12:09:03 +0100
From:   Andrzej Pietrasiewicz <andrzej.p@...labora.com>
To:     Jernej Skrabec <jernej.skrabec@...il.com>,
        linux-media@...r.kernel.org
Cc:     ezequiel@...guardiasur.com.ar, nicolas.dufresne@...labora.com,
        mchehab@...nel.org, robh+dt@...nel.org, mripard@...nel.org,
        wens@...e.org, p.zabel@...gutronix.de, gregkh@...uxfoundation.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
        linux-staging@...ts.linux.dev
Subject: Re: [PATCH 1/7] media: hantro: add support for reset lines

Hi Jernej,

Thanks for the patch.

W dniu 22.11.2021 o 19:46, Jernej Skrabec pisze:
> Some SoCs like Allwinner H6 use reset lines for resetting Hantro G2. Add
> support for them.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@...il.com>
> ---
>   drivers/staging/media/hantro/hantro.h     |  3 +++
>   drivers/staging/media/hantro/hantro_drv.c | 15 ++++++++++++++-
>   2 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/media/hantro/hantro.h b/drivers/staging/media/hantro/hantro.h
> index 7da23f7f207a..33eb3e092cc1 100644
> --- a/drivers/staging/media/hantro/hantro.h
> +++ b/drivers/staging/media/hantro/hantro.h
> @@ -16,6 +16,7 @@
>   #include <linux/videodev2.h>
>   #include <linux/wait.h>
>   #include <linux/clk.h>
> +#include <linux/reset.h>
>   
>   #include <media/v4l2-ctrls.h>
>   #include <media/v4l2-device.h>
> @@ -171,6 +172,7 @@ hantro_vdev_to_func(struct video_device *vdev)
>    * @dev:		Pointer to device for convenient logging using
>    *			dev_ macros.
>    * @clocks:		Array of clock handles.
> + * @resets:		Array of reset handles.
>    * @reg_bases:		Mapped addresses of VPU registers.
>    * @enc_base:		Mapped address of VPU encoder register for convenience.
>    * @dec_base:		Mapped address of VPU decoder register for convenience.
> @@ -190,6 +192,7 @@ struct hantro_dev {
>   	struct platform_device *pdev;
>   	struct device *dev;
>   	struct clk_bulk_data *clocks;
> +	struct reset_control *resets;
>   	void __iomem **reg_bases;
>   	void __iomem *enc_base;
>   	void __iomem *dec_base;
> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
> index ab2467998d29..8c3de31f51b3 100644
> --- a/drivers/staging/media/hantro/hantro_drv.c
> +++ b/drivers/staging/media/hantro/hantro_drv.c
> @@ -905,6 +905,10 @@ static int hantro_probe(struct platform_device *pdev)
>   			return PTR_ERR(vpu->clocks[0].clk);
>   	}
>   
> +	vpu->resets = devm_reset_control_array_get(&pdev->dev, false, true);
> +	if (IS_ERR(vpu->resets))
> +		return PTR_ERR(vpu->resets);
> +
>   	num_bases = vpu->variant->num_regs ?: 1;
>   	vpu->reg_bases = devm_kcalloc(&pdev->dev, num_bases,
>   				      sizeof(*vpu->reg_bases), GFP_KERNEL);
> @@ -978,10 +982,16 @@ static int hantro_probe(struct platform_device *pdev)
>   	pm_runtime_use_autosuspend(vpu->dev);
>   	pm_runtime_enable(vpu->dev);
>   
> +	ret = reset_control_deassert(vpu->resets);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to deassert resets\n");
> +		return ret;
> +	}
> +
>   	ret = clk_bulk_prepare(vpu->variant->num_clocks, vpu->clocks);
>   	if (ret) {
>   		dev_err(&pdev->dev, "Failed to prepare clocks\n");
> -		return ret;
> +		goto err_rst_assert;

Before your patch is applied if clk_bulk_prepare() fails, we
simply return on the spot. After the patch is applied not only
do you...

>   	}
>   
>   	ret = v4l2_device_register(&pdev->dev, &vpu->v4l2_dev);
> @@ -1037,6 +1047,8 @@ static int hantro_probe(struct platform_device *pdev)
>   	v4l2_device_unregister(&vpu->v4l2_dev);
>   err_clk_unprepare:
>   	clk_bulk_unprepare(vpu->variant->num_clocks, vpu->clocks);
> +err_rst_assert:
> +	reset_control_assert(vpu->resets);

...revert the effect of reset_control_deassert(), you also...

>   	pm_runtime_dont_use_autosuspend(vpu->dev);
>   	pm_runtime_disable(vpu->dev);

... do pm_*() stuff. Is there any reason why this is needed?

Andrzej

>   	return ret;
> @@ -1055,6 +1067,7 @@ static int hantro_remove(struct platform_device *pdev)
>   	v4l2_m2m_release(vpu->m2m_dev);
>   	v4l2_device_unregister(&vpu->v4l2_dev);
>   	clk_bulk_unprepare(vpu->variant->num_clocks, vpu->clocks);
> +	reset_control_assert(vpu->resets);
>   	pm_runtime_dont_use_autosuspend(vpu->dev);
>   	pm_runtime_disable(vpu->dev);
>   	return 0;
>