linux-kernel - Re: [PATCH v3 03/46] media: sun6i-csi: Grab bus clock instead of passing it to regmap

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Date:   Tue, 15 Mar 2022 20:22:50 +0100
From:   Jernej Škrabec <jernej.skrabec@...il.com>
To:     linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
        Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Cc:     Yong Deng <yong.deng@...ewell.com>,
        Paul Kocialkowski <paul.kocialkowski@...tlin.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Samuel Holland <samuel@...lland.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v3 03/46] media: sun6i-csi: Grab bus clock instead of passing it to regmap

Hi Paul!

Dne petek, 11. marec 2022 ob 15:34:49 CET je Paul Kocialkowski napisal(a):
> Since the bus clock alone is not enough to get access to the registers,
> don't pass it to regmap and manage it instead just like the other
> clocks.
> 

Let me ask it in another way, is bus clock needed only for register access? If 
yes, it makes sense to keep it enabled only during register access.

Best regards,
Jernej

> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@...tlin.com>
> ---
>  drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c | 10 ++++++++--
>  drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h |  1 +
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c b/drivers/
media/platform/sunxi/sun6i-csi/sun6i_csi.c
> index 5fbaa1e99412..dc79f3c14336 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> @@ -827,13 +827,19 @@ static int sun6i_csi_resource_request(struct 
sun6i_csi_device *csi_dev,
>  	if (IS_ERR(io_base))
>  		return PTR_ERR(io_base);
>  
> -	csi_dev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "bus", 
io_base,
> -						    
&sun6i_csi_regmap_config);
> +	csi_dev->regmap = devm_regmap_init_mmio(&pdev->dev, io_base,
> +						
&sun6i_csi_regmap_config);
>  	if (IS_ERR(csi_dev->regmap)) {
>  		dev_err(&pdev->dev, "Failed to init register map\n");
>  		return PTR_ERR(csi_dev->regmap);
>  	}
>  
> +	csi_dev->clk_bus = devm_clk_get(&pdev->dev, "bus");
> +	if (IS_ERR(csi_dev->clk_bus)) {
> +		dev_err(&pdev->dev, "Unable to acquire bus clock\n");
> +		return PTR_ERR(csi_dev->clk_bus);
> +	}
> +
>  	csi_dev->clk_mod = devm_clk_get(&pdev->dev, "mod");
>  	if (IS_ERR(csi_dev->clk_mod)) {
>  		dev_err(&pdev->dev, "Unable to acquire csi clock\n");
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h b/drivers/
media/platform/sunxi/sun6i-csi/sun6i_csi.h
> index e4e7ac6c869f..356661b413f8 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h
> @@ -51,6 +51,7 @@ struct sun6i_csi_device {
>  	struct sun6i_video		video;
>  
>  	struct regmap			*regmap;
> +	struct clk			*clk_bus;
>  	struct clk			*clk_mod;
>  	struct clk			*clk_ram;
>  	struct reset_control		*reset;
> -- 
> 2.35.1
> 
>