linux-kernel - Re: [PATCH v2 21/66] media: sun6i-csi: Always set exclusive module clock rate

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Date:   Mon, 7 Feb 2022 10:14:43 +0100
From:   Maxime Ripard <maxime@...no.tech>
To:     Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Cc:     linux-media@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
        linux-kernel@...r.kernel.org, linux-phy@...ts.infradead.org,
        linux-clk@...r.kernel.org, linux-staging@...ts.linux.dev,
        Yong Deng <yong.deng@...ewell.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Helen Koike <helen.koike@...labora.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v2 21/66] media: sun6i-csi: Always set exclusive module
 clock rate

On Sat, Feb 05, 2022 at 07:53:44PM +0100, Paul Kocialkowski wrote:
> In some situations the default rate of the module clock is not the
> required one for operation (for example when reconfiguring the clock
> tree to use a different parent). As a result, always set the correct
> rate for the clock (and take care of cleanup).
> 
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@...tlin.com>
> ---
>  .../platform/sunxi/sun6i-csi/sun6i_csi.c      | 54 ++++++++++++++-----
>  1 file changed, 41 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> index 8155e9560164..2355088fdc37 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> @@ -154,9 +154,6 @@ int sun6i_csi_set_power(struct sun6i_csi_device *csi_dev, bool enable)
>  		regmap_update_bits(regmap, CSI_EN_REG, CSI_EN_CSI_EN, 0);
>  
>  		clk_disable_unprepare(csi_dev->clk_ram);
> -		if (of_device_is_compatible(dev->of_node,
> -					    "allwinner,sun50i-a64-csi"))
> -			clk_rate_exclusive_put(csi_dev->clk_mod);
>  		clk_disable_unprepare(csi_dev->clk_mod);
>  		reset_control_assert(csi_dev->reset);
>  		return 0;
> @@ -168,9 +165,6 @@ int sun6i_csi_set_power(struct sun6i_csi_device *csi_dev, bool enable)
>  		return ret;
>  	}
>  
> -	if (of_device_is_compatible(dev->of_node, "allwinner,sun50i-a64-csi"))
> -		clk_set_rate_exclusive(csi_dev->clk_mod, 300000000);
> -
>  	ret = clk_prepare_enable(csi_dev->clk_ram);
>  	if (ret) {
>  		dev_err(csi_dev->dev, "Enable clk_dram_csi clk err %d\n", ret);
> @@ -190,8 +184,6 @@ int sun6i_csi_set_power(struct sun6i_csi_device *csi_dev, bool enable)
>  clk_ram_disable:
>  	clk_disable_unprepare(csi_dev->clk_ram);
>  clk_mod_disable:
> -	if (of_device_is_compatible(dev->of_node, "allwinner,sun50i-a64-csi"))
> -		clk_rate_exclusive_put(csi_dev->clk_mod);
>  	clk_disable_unprepare(csi_dev->clk_mod);
>  	return ret;
>  }
> @@ -819,6 +811,7 @@ static int sun6i_csi_resources_setup(struct sun6i_csi_device *csi_dev,
>  				     struct platform_device *platform_dev)
>  {
>  	struct device *dev = csi_dev->dev;
> +	unsigned long clk_mod_rate;
>  	void __iomem *io_base;
>  	int ret;
>  	int irq;
> @@ -856,28 +849,53 @@ static int sun6i_csi_resources_setup(struct sun6i_csi_device *csi_dev,
>  		return PTR_ERR(csi_dev->clk_ram);
>  	}
>  
> +	if (of_device_is_compatible(dev->of_node, "allwinner,sun50i-a64-csi"))
> +		clk_mod_rate = 300000000;
> +	else
> +		clk_mod_rate = 297000000;
> +
> +	ret = clk_set_rate_exclusive(csi_dev->clk_mod, clk_mod_rate);
> +	if (ret) {
> +		dev_err(dev, "failed to set mod clock rate\n");
> +		return ret;
> +	}
> +
>  	/* Reset */
>  
>  	csi_dev->reset = devm_reset_control_get_shared(dev, NULL);
>  	if (IS_ERR(csi_dev->reset)) {
>  		dev_err(dev, "failed to acquire reset\n");
> -		return PTR_ERR(csi_dev->reset);
> +		ret = PTR_ERR(csi_dev->reset);
> +		goto error_clk_rate_exclusive;
>  	}
>  
>  	/* Interrupt */
>  
>  	irq = platform_get_irq(platform_dev, 0);
> -	if (irq < 0)
> -		return -ENXIO;
> +	if (irq < 0) {
> +		dev_err(dev, "failed to get interrupt\n");
> +		ret = -ENXIO;
> +		goto error_clk_rate_exclusive;
> +	}
>  
>  	ret = devm_request_irq(dev, irq, sun6i_csi_isr, 0, SUN6I_CSI_NAME,
>  			       csi_dev);
>  	if (ret) {
>  		dev_err(dev, "failed to request interrupt\n");
> -		return ret;
> +		goto error_clk_rate_exclusive;
>  	}
>  
>  	return 0;
> +
> +error_clk_rate_exclusive:
> +	clk_rate_exclusive_put(csi_dev->clk_mod);
> +
> +	return ret;
> +}
> +
> +static void sun6i_csi_resources_cleanup(struct sun6i_csi_device *csi_dev)
> +{
> +	clk_rate_exclusive_put(csi_dev->clk_mod);
>  }

If you're going to have that function anyway, let's use
devm_add_action_or_reset, it'll simplify the rest of the patch.

Maxime

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