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Subject: Re: [PATCH 4/5] media: mt9p031: Make pixel clock polarity
 configurable by DT
To:     Sakari Ailus <sakari.ailus@linux.intel.com>
Cc:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Christian Hemp <c.hemp@phytec.de>
References: <20200925075029.32181-1-s.riedmueller@phytec.de>
 <20200925075029.32181-4-s.riedmueller@phytec.de>
 <20200925200741.GW26842@paasikivi.fi.intel.com>
From:   =?UTF-8?Q?Stefan_Riedm=c3=bcller?= <s.riedmueller@phytec.de>
Message-ID: <9e4c70ec-a359-bbcd-5650-b68ea5f0b312@phytec.de>
Date:   Wed, 30 Sep 2020 09:58:00 +0200
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Hi Sakari,

thanks for your review.

On 25.09.20 22:07, Sakari Ailus wrote:
> Hi Stefan,
> 
> Thanks for the patchset.
> 
> On Fri, Sep 25, 2020 at 09:50:28AM +0200, Stefan Riedmueller wrote:
>> From: Christian Hemp <c.hemp@phytec.de>
>>
>> Evaluate the desired pixel clock polarity from the device tree.
>>
>> Signed-off-by: Christian Hemp <c.hemp@phytec.de>
>> Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
>> ---
>>   drivers/media/i2c/Kconfig   |  1 +
>>   drivers/media/i2c/mt9p031.c | 19 ++++++++++++++++++-
>>   include/media/i2c/mt9p031.h |  1 +
>>   3 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
>> index c7ba76fee599..7c026daeacf0 100644
>> --- a/drivers/media/i2c/Kconfig
>> +++ b/drivers/media/i2c/Kconfig
>> @@ -1103,6 +1103,7 @@ config VIDEO_MT9P031
>>   	select MEDIA_CONTROLLER
>>   	select VIDEO_V4L2_SUBDEV_API
>>   	select VIDEO_APTINA_PLL
>> +	select V4L2_FWNODE
>>   	help
>>   	  This is a Video4Linux2 sensor driver for the Aptina
>>   	  (Micron) mt9p031 5 Mpixel camera.
>> diff --git a/drivers/media/i2c/mt9p031.c b/drivers/media/i2c/mt9p031.c
>> index f5d6a7890c47..8f8ee37a2dd2 100644
>> --- a/drivers/media/i2c/mt9p031.c
>> +++ b/drivers/media/i2c/mt9p031.c
>> @@ -27,6 +27,7 @@
>>   #include <media/v4l2-async.h>
>>   #include <media/v4l2-ctrls.h>
>>   #include <media/v4l2-device.h>
>> +#include <media/v4l2-fwnode.h>
>>   #include <media/v4l2-subdev.h>
>>   
>>   #include "aptina-pll.h"
>> @@ -399,6 +400,14 @@ static int __mt9p031_set_power(struct mt9p031 *mt9p031, bool on)
>>   		return ret;
>>   	}
>>   
>> +	/* Configure the pixel clock polarity */
>> +	if (mt9p031->pdata && mt9p031->pdata->pixclk_pol) {
>> +		ret = mt9p031_write(client, MT9P031_PIXEL_CLOCK_CONTROL,
>> +				MT9P031_PIXEL_CLOCK_INVERT);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>>   	return v4l2_ctrl_handler_setup(&mt9p031->ctrls);
>>   }
>>   
>> @@ -1062,7 +1071,8 @@ static const struct v4l2_subdev_internal_ops mt9p031_subdev_internal_ops = {
>>   static struct mt9p031_platform_data *
>>   mt9p031_get_pdata(struct i2c_client *client)
>>   {
>> -	struct mt9p031_platform_data *pdata;
>> +	struct mt9p031_platform_data *pdata = NULL;
>> +	struct v4l2_fwnode_endpoint endpoint;
> 
> Could you initialise the bus_type field to a valid value? I suppose this
> sensor only supports one of them? That way you'll also initialise the rest
> of the struct fields to zero.

Yes, I'll do that and send a v2.

Thanks,
Stefan

> 
>>   	struct device_node *np;
>>   
>>   	if (!IS_ENABLED(CONFIG_OF) || !client->dev.of_node)
>> @@ -1072,6 +1082,10 @@ mt9p031_get_pdata(struct i2c_client *client)
>>   	if (!np)
>>   		return NULL;
>>   
>> +	endpoint.bus_type = V4L2_MBUS_UNKNOWN;
>> +	if (v4l2_fwnode_endpoint_parse(of_fwnode_handle(np), &endpoint) < 0)
>> +		goto done;
>> +
>>   	pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
>>   	if (!pdata)
>>   		goto done;
>> @@ -1079,6 +1093,9 @@ mt9p031_get_pdata(struct i2c_client *client)
>>   	of_property_read_u32(np, "input-clock-frequency", &pdata->ext_freq);
>>   	of_property_read_u32(np, "pixel-clock-frequency", &pdata->target_freq);
>>   
>> +	pdata->pixclk_pol = !!(endpoint.bus.parallel.flags &
>> +			       V4L2_MBUS_PCLK_SAMPLE_RISING);
>> +
>>   done:
>>   	of_node_put(np);
>>   	return pdata;
>> diff --git a/include/media/i2c/mt9p031.h b/include/media/i2c/mt9p031.h
>> index 7c29c53aa988..f933cd0be8e5 100644
>> --- a/include/media/i2c/mt9p031.h
>> +++ b/include/media/i2c/mt9p031.h
>> @@ -10,6 +10,7 @@ struct v4l2_subdev;
>>    * @target_freq: Pixel clock frequency
>>    */
>>   struct mt9p031_platform_data {
>> +	unsigned int pixclk_pol:1;
>>   	int ext_freq;
>>   	int target_freq;
>>   };
>