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Message-ID: <6b7486a4-ed01-89ed-5756-d7aca08a836d@starfivetech.com>
Date:   Fri, 7 Apr 2023 14:30:17 +0800
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Subject: Re: [PATCH v3 6/9] media: cadence: Add operation on reset
Content-Language: en-US
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
CC:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Maxime Ripard <mripard@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Robert Foss <rfoss@kernel.org>,
        "Todor Tomov" <todor.too@gmail.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        "Ezequiel Garcia" <ezequiel@vanguardiasur.com.ar>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Eugen Hristev <eugen.hristev@collabora.com>,
        <linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <changhuang.liang@starfivetech.com>
References: <20230331121826.96973-1-jack.zhu@starfivetech.com>
 <20230331121826.96973-7-jack.zhu@starfivetech.com>
 <20230404050615.GN16648@pendragon.ideasonboard.com>
From:   Jack Zhu <jack.zhu@starfivetech.com>
In-Reply-To: <20230404050615.GN16648@pendragon.ideasonboard.com>
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On 2023/4/4 13:06, Laurent Pinchart wrote:
> Hi Jack,
> 
> Thank you for the patch.
> 
> On Fri, Mar 31, 2023 at 08:18:23PM +0800, Jack Zhu wrote:
>> Add operation on reset for Cadence MIPI-CSI2 RX Controller.
>> 
>> Signed-off-by: Jack Zhu <jack.zhu@starfivetech.com>
>> ---
>>  drivers/media/platform/cadence/cdns-csi2rx.c | 30 ++++++++++++++++++++
>>  1 file changed, 30 insertions(+)
>> 
>> diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
>> index cc3ebb0d96f6..a1555cedb349 100644
>> --- a/drivers/media/platform/cadence/cdns-csi2rx.c
>> +++ b/drivers/media/platform/cadence/cdns-csi2rx.c
>> @@ -13,6 +13,7 @@
>>  #include <linux/of_graph.h>
>>  #include <linux/phy/phy.h>
>>  #include <linux/platform_device.h>
>> +#include <linux/reset.h>
>>  #include <linux/slab.h>
>>  
>>  #include <media/v4l2-ctrls.h>
>> @@ -68,6 +69,9 @@ struct csi2rx_priv {
>>  	struct clk			*sys_clk;
>>  	struct clk			*p_clk;
>>  	struct clk			*pixel_clk[CSI2RX_STREAMS_MAX];
>> +	struct reset_control		*sys_rst;
>> +	struct reset_control		*p_rst;
>> +	struct reset_control		*pixel_rst[CSI2RX_STREAMS_MAX];
>>  	struct phy			*dphy;
>>  
>>  	u8				lanes[CSI2RX_LANES_MAX];
>> @@ -112,6 +116,7 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>>  	if (ret)
>>  		return ret;
>>  
>> +	reset_control_deassert(csi2rx->p_rst);
>>  	csi2rx_reset(csi2rx);
>>  
>>  	reg = csi2rx->num_lanes << 8;
>> @@ -154,6 +159,8 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>>  		if (ret)
>>  			goto err_disable_pixclk;
> 
> The loop after the err_disable_pixclk label should assert the
> pixel_rst[i] reset.
> 

OK, I will fix it.

>>  
>> +		reset_control_deassert(csi2rx->pixel_rst[i]);
>> +
>>  		writel(CSI2RX_STREAM_CFG_FIFO_MODE_LARGE_BUF,
>>  		       csi2rx->base + CSI2RX_STREAM_CFG_REG(i));
>>  
>> @@ -169,6 +176,7 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>>  	if (ret)
>>  		goto err_disable_pixclk;
>>  
>> +	reset_control_deassert(csi2rx->sys_rst);
>>  	clk_disable_unprepare(csi2rx->p_clk);
>>  
>>  	return 0;
>> @@ -188,14 +196,17 @@ static void csi2rx_stop(struct csi2rx_priv *csi2rx)
>>  	unsigned int i;
>>  
>>  	clk_prepare_enable(csi2rx->p_clk);
>> +	reset_control_assert(csi2rx->sys_rst);
>>  	clk_disable_unprepare(csi2rx->sys_clk);
>>  
>>  	for (i = 0; i < csi2rx->max_streams; i++) {
>>  		writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
>>  
>> +		reset_control_assert(csi2rx->pixel_rst[i]);
>>  		clk_disable_unprepare(csi2rx->pixel_clk[i]);
>>  	}
>>  
>> +	reset_control_assert(csi2rx->p_rst);
>>  	clk_disable_unprepare(csi2rx->p_clk);
>>  
>>  	if (v4l2_subdev_call(csi2rx->source_subdev, video, s_stream, false))
>> @@ -299,6 +310,17 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
>>  		return PTR_ERR(csi2rx->p_clk);
>>  	}
>>  
>> +	csi2rx->sys_rst =
>> +		devm_reset_control_get_optional_exclusive(&pdev->dev,
>> +							  "sys_rst");
> 
> You can write this on two lines:
> 
> 	csi2rx->sys_rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
> 								    "sys_rst");

OK, I will modify it.

>> +	if (IS_ERR(csi2rx->sys_rst))
>> +		return PTR_ERR(csi2rx->sys_rst);
>> +
>> +	csi2rx->p_rst =
>> +		devm_reset_control_get_optional_exclusive(&pdev->dev, "p_rst");
> 
> And here,
> 
> 	csi2rx->p_rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
> 								  "p_rst");
> 
> would be the same number of lines but more readable in my opinion.
> 

OK, I will modify it.

>> +	if (IS_ERR(csi2rx->p_rst))
>> +		return PTR_ERR(csi2rx->p_rst);
>> +
>>  	csi2rx->dphy = devm_phy_optional_get(&pdev->dev, "dphy");
>>  	if (IS_ERR(csi2rx->dphy)) {
>>  		dev_err(&pdev->dev, "Couldn't get external D-PHY\n");
>> @@ -350,6 +372,7 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
>>  
>>  	for (i = 0; i < csi2rx->max_streams; i++) {
>>  		char clk_name[16];
>> +		char rst_name[16];
> 
> You don't need two variables, you can rename clk_name to name, and use
> it for both clk and rst.
> 

OK, I will fix it.

> With these small issues addressed you can add my
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> in the next version.
>
OK. Thank you for your review.

>>  
>>  		snprintf(clk_name, sizeof(clk_name), "pixel_if%u_clk", i);
>>  		csi2rx->pixel_clk[i] = devm_clk_get(&pdev->dev, clk_name);
>> @@ -357,6 +380,13 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
>>  			dev_err(&pdev->dev, "Couldn't get clock %s\n", clk_name);
>>  			return PTR_ERR(csi2rx->pixel_clk[i]);
>>  		}
>> +
>> +		snprintf(rst_name, sizeof(rst_name), "pixel_if%u_rst", i);
>> +		csi2rx->pixel_rst[i] =
>> +			devm_reset_control_get_optional_exclusive(&pdev->dev,
>> +								  rst_name);
>> +		if (IS_ERR(csi2rx->pixel_rst[i]))
>> +			return PTR_ERR(csi2rx->pixel_rst[i]);
>>  	}
>>  
>>  	return 0;
>