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Message-ID: <c7abfe94-5cf4-4490-854d-7a1a8c653820@ideasonboard.com>
Date: Wed, 6 Mar 2024 22:47:56 +0530
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Subject: Re: [PATCH 4/5] media: imx335: Fix active area height discrepency
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To: Kieran Bingham <kieran.bingham@ideasonboard.com>,
 linux-media@vger.kernel.org
Cc: Alexander Shiyan <eagle.alexander923@gmail.com>,
 Mauro Carvalho Chehab <mchehab@kernel.org>,
 Sakari Ailus <sakari.ailus@linux.intel.com>,
 open list <linux-kernel@vger.kernel.org>
References: <20240306081038.212412-1-umang.jain@ideasonboard.com>
 <20240306081038.212412-5-umang.jain@ideasonboard.com>
 <170974471357.362031.9683522744235199514@ping.linuxembedded.co.uk>
From: Umang Jain <umang.jain@ideasonboard.com>
In-Reply-To: <170974471357.362031.9683522744235199514@ping.linuxembedded.co.uk>
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Hi Kieran,

On 06/03/24 10:35 pm, Kieran Bingham wrote:
> Quoting Umang Jain (2024-03-06 08:10:37)
>> The imx335 reports a recommended pixel area of - 2592x1944.
>> The driver supported mode however limits it to height=1940.
> Hrm, I think I would convert widths and sizes to decimal as a patch
> before this patch so the effect is clearer in this diff.
>
>> Fix the height discrepency by correctly the value of height
>> (with updates to vblank and mode registers).
>>
>> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
>> ---
>>   drivers/media/i2c/imx335.c | 18 +++++++++---------
>>   1 file changed, 9 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/media/i2c/imx335.c b/drivers/media/i2c/imx335.c
>> index 6ea09933e47b..c00e0c2be3f3 100644
>> --- a/drivers/media/i2c/imx335.c
>> +++ b/drivers/media/i2c/imx335.c
>> @@ -246,13 +246,13 @@ static const int imx335_tpg_val[] = {
>>   };
>>   
>>   /* Sensor mode registers */
>> -static const struct cci_reg_sequence mode_2592x1940_regs[] = {
>> +static const struct cci_reg_sequence mode_2592x1944_regs[] = {
>>          {IMX335_REG_MODE_SELECT, 0x01},
>>          {IMX335_REG_MASTER_MODE, 0x00},
>> -       {IMX335_REG_WINMODE, 0x04},
>> -       {IMX335_REG_HTRIMMING_START, 0x0180},
>> +       {IMX335_REG_WINMODE, 0x00},
> What's the distinction of the winmode here. What is 0x04 vs 0x00?
>
> Is this something that could be a defined value? Or is that not worth
> the effort?

It can be split out as a define in later parts if we introduce more 
modes. currently this change fixes the sensor to be in 'all-pixel scan 
mode' hence you see the change in value of WINMODE.
>
>> +       {IMX335_REG_HTRIMMING_START, 0x30},
> HTRIMMING_START has moved a lot more than I would expect there.
> Is there a visual impact of any concern here?

Value as per mentioned in the datasheet
>
>>          {IMX335_REG_HNUM, 0x0a20},
>> -       {IMX335_REG_Y_OUT_SIZE, 0x0794},
>> +       {IMX335_REG_Y_OUT_SIZE, 0x0798},
> This bit looks expected ;-)
>
>>          {IMX335_REG_VCROP_POS, 0x00b0},
>>          {IMX335_REG_VCROP_SIZE, 0x0f58},
> 0x0f58 = 3928. Does that correspond to anything on the pixel array size?
> We're modifying the vertical size, so I'm curious if the 'vcrop' is or
> should be impacted?

Probably I have not named this correctly, as VCROP_

This register (0x3076) is denotes the size of cropping rectangle
Named as 'AREA3_WIDTH_1' with explaination 'cropping size designation 
(Vertical direction)'

The value 0x0f58 is as per mentioned in the datasheet. I don't find any 
relation except 3928 is twice the IMX335_NATIVE_HEIGHT
>
>>          {IMX335_REG_OPB_SIZE_V, 0x00},
>> @@ -403,14 +403,14 @@ static const u32 imx335_mbus_codes[] = {
>>   /* Supported sensor mode configurations */
>>   static const struct imx335_mode supported_mode = {
>>          .width = 2592,
>> -       .height = 1940,
>> +       .height = 1944,
>>          .hblank = 342,
>> -       .vblank = 2560,
>> -       .vblank_min = 2560,
>> +       .vblank = 2556,
>> +       .vblank_min = 2556,
>>          .vblank_max = 133060,
>>          .reg_list = {
>> -               .num_of_regs = ARRAY_SIZE(mode_2592x1940_regs),
>> -               .regs = mode_2592x1940_regs,
>> +               .num_of_regs = ARRAY_SIZE(mode_2592x1944_regs),
>> +               .regs = mode_2592x1944_regs,
>>          },
>>   };
>>   
>> -- 
>> 2.43.0
>>