Re: [PATCH v2] media: ov5640: fix support of BT656 bus mode

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Hi Jacopo,

On 10/12/20 5:48 PM, Jacopo Mondi wrote:
> Hi Hugues,
> 
> On Mon, Oct 12, 2020 at 04:51:43PM +0200, Hugues Fruchet wrote:
>> Fix PCLK polarity not being taken into account.
>> Add comments about BT656 register control.
>> Remove useless ov5640_set_stream_bt656() function.
>> Refine comments about MIPI IO register control.
>>
>> Fixes: 4039b03720f7 ("media: i2c: ov5640: Add support for BT656 mode")
>> Signed-off-by: Hugues Fruchet <hugues.fruchet@xxxxxx>
>> ---
>>   drivers/media/i2c/ov5640.c | 77 +++++++++++++++++++++++++++-------------------
>>   1 file changed, 45 insertions(+), 32 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
>> index 8d0254d..c0ebf4c 100644
>> --- a/drivers/media/i2c/ov5640.c
>> +++ b/drivers/media/i2c/ov5640.c
>> @@ -1216,20 +1216,6 @@ static int ov5640_set_autogain(struct ov5640_dev *sensor, bool on)
>>   			      BIT(1), on ? 0 : BIT(1));
>>   }
>>
>> -static int ov5640_set_stream_bt656(struct ov5640_dev *sensor, bool on)
>> -{
>> -	int ret;
>> -
>> -	ret = ov5640_write_reg(sensor, OV5640_REG_CCIR656_CTRL00,
>> -			       on ? 0x1 : 0x00);
>> -	if (ret)
>> -		return ret;
>> -
>> -	return ov5640_write_reg(sensor, OV5640_REG_SYS_CTRL0, on ?
>> -				OV5640_REG_SYS_CTRL0_SW_PWUP :
>> -				OV5640_REG_SYS_CTRL0_SW_PWDN);
>> -}
>> -
>>   static int ov5640_set_stream_dvp(struct ov5640_dev *sensor, bool on)
>>   {
>>   	return ov5640_write_reg(sensor, OV5640_REG_SYS_CTRL0, on ?
>> @@ -1994,6 +1980,7 @@ static int ov5640_set_power_mipi(struct ov5640_dev *sensor, bool on)
>>   static int ov5640_set_power_dvp(struct ov5640_dev *sensor, bool on)
>>   {
>>   	unsigned int flags = sensor->ep.bus.parallel.flags;
>> +	bool bt656 = sensor->ep.bus_type == V4L2_MBUS_BT656;
>>   	u8 pclk_pol = 0;
>>   	u8 hsync_pol = 0;
>>   	u8 vsync_pol = 0;
>> @@ -2001,6 +1988,7 @@ static int ov5640_set_power_dvp(struct ov5640_dev *sensor, bool on)
>>
>>   	if (!on) {
>>   		/* Reset settings to their default values. */
>> +		ov5640_write_reg(sensor, OV5640_REG_CCIR656_CTRL00, 0x00);
>>   		ov5640_write_reg(sensor, OV5640_REG_IO_MIPI_CTRL00, 0x58);
>>   		ov5640_write_reg(sensor, OV5640_REG_POLARITY_CTRL00, 0x20);
>>   		ov5640_write_reg(sensor, OV5640_REG_PAD_OUTPUT_ENABLE01, 0x00);
>> @@ -2024,23 +2012,51 @@ static int ov5640_set_power_dvp(struct ov5640_dev *sensor, bool on)
>>   	 * - VSYNC:	active high
>>   	 * - HREF:	active low
>>   	 * - PCLK:	active low
>> +	 *
>> +	 * VSYNC & HREF are not configured if BT656 bus mode is selected
>>   	 */
>> +
>>   	/*
>> -	 * configure parallel port control lines polarity
>> +	 * BT656 embedded synchronization configuration
>>   	 *
>> -	 * POLARITY CTRL0
>> -	 * - [5]:	PCLK polarity (0: active low, 1: active high)
>> -	 * - [1]:	HREF polarity (0: active low, 1: active high)
>> -	 * - [0]:	VSYNC polarity (mismatch here between
>> -	 *		datasheet and hardware, 0 is active high
>> -	 *		and 1 is active low...)
>> +	 * CCIR656 CTRL00
>> +	 * - [7]:	SYNC code selection (0: auto generate sync code,
>> +	 *		1: sync code from regs 0x4732-0x4735)
>> +	 * - [6]:	f value in CCIR656 SYNC code when fixed f value
>> +	 * - [5]:	Fixed f value
>> +	 * - [4:3]:	Blank toggle data options (00: data=1'h040/1'h200,
>> +	 *		01: data from regs 0x4736-0x4738, 10: always keep 0)
>> +	 * - [1]:	Clip data disable
>> +	 * - [0]:	CCIR656 mode enable
>> +	 *
>> +	 * Default CCIR656 SAV/EAV mode with default codes
>> +	 * SAV=0xff000080 & EAV=0xff00009d is enabled here with settings:
>> +	 * - CCIR656 mode enable
>> +	 * - auto generation of sync codes
>> +	 * - blank toggle data 1'h040/1'h200
>> +	 * - clip reserved data (0x00 & 0xff changed to 0x01 & 0xfe)
>>   	 */
>> -	if (sensor->ep.bus_type == V4L2_MBUS_PARALLEL) {
>> +	ret = ov5640_write_reg(sensor, OV5640_REG_CCIR656_CTRL00,
>> +			       bt656 ? 0x01 : 0x00);
>> +	if (ret)
>> +		return ret;
> 
> All good so far
> 
>> +
>> +	if (on) {
> 
> But don't you have retained
>          if (!on)
> at the beginning of the function ?
> 
> I would reflow this as:
> 
> static int ov5640_set_power_dvp(struct ov5640_dev *sensor, bool on) {
>          if (!on) {
>                  ...
>          }
> 
>          uint8_t polarities = 0;
>          if (!bt656) {
>                  if (flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
>          	        polarities |= BIT(1);
>                  if (flags & V4L2_MBUS_VSYNC_ACTIVE_LOW)
> 	                polarities |= BIT(0);
>          }
>          if (flags & V4L2_MBUS_PCLK_SAMPLE_RISING)
> 	        polarities |= BIT(5);
> 
> 	ret = ov5640_write_reg(sensor, OV5640_REG_POLARITY_CTRL00,
>                                 polarities);
>          if (ret)
>                  return ret;
> 
>          if (bt656) {
>                  write_reg(CCIR656);
>          }
> 
>          ....
> 
> To make it more readable. What do you think ?

Fully agree.

> 
>> +		/*
>> +		 * configure parallel port control lines polarity
>> +		 *
>> +		 * POLARITY CTRL0
>> +		 * - [5]:	PCLK polarity (0: active low, 1: active high)
>> +		 * - [1]:	HREF polarity (0: active low, 1: active high)
>> +		 * - [0]:	VSYNC polarity (mismatch here between
>> +		 *		datasheet and hardware, 0 is active high
>> +		 *		and 1 is active low...)
>> +		 */
>>   		if (flags & V4L2_MBUS_PCLK_SAMPLE_RISING)
>>   			pclk_pol = 1;
>> -		if (flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
>> +		if (!bt656 && flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
>>   			hsync_pol = 1;
>> -		if (flags & V4L2_MBUS_VSYNC_ACTIVE_LOW)
>> +		if (!bt656 && flags & V4L2_MBUS_VSYNC_ACTIVE_LOW)
>>   			vsync_pol = 1;
>>
>>   		ret = ov5640_write_reg(sensor, OV5640_REG_POLARITY_CTRL00,
>> @@ -2052,12 +2068,12 @@ static int ov5640_set_power_dvp(struct ov5640_dev *sensor, bool on)
>>   	}
>>
> 
> The part here below looks good!
> 
>>   	/*
>> -	 * powerdown MIPI TX/RX PHY & disable MIPI
>> +	 * powerdown MIPI TX/RX PHY & enable DVP
>>   	 *
>>   	 * MIPI CONTROL 00
>> -	 * 4:	 PWDN PHY TX
>> -	 * 3:	 PWDN PHY RX
>> -	 * 2:	 MIPI enable
>> +	 * [4] = 1	: Power down MIPI HS Tx
>> +	 * [3] = 1	: Power down MIPI LS Rx
>> +	 * [2] = 0	: DVP enable (MIPI disable)
>>   	 */
>>   	ret = ov5640_write_reg(sensor, OV5640_REG_IO_MIPI_CTRL00, 0x18);
>>   	if (ret)
>> @@ -2074,8 +2090,7 @@ static int ov5640_set_power_dvp(struct ov5640_dev *sensor, bool on)
>>   	 * - [3:0]:	D[9:6] output enable
>>   	 */
>>   	ret = ov5640_write_reg(sensor, OV5640_REG_PAD_OUTPUT_ENABLE01,
>> -			       sensor->ep.bus_type == V4L2_MBUS_PARALLEL ?
>> -			       0x7f : 0x1f);
>> +			       bt656 ? 0x1f : 0x7f);
>>   	if (ret)
>>   		return ret;
>>
>> @@ -2925,8 +2940,6 @@ static int ov5640_s_stream(struct v4l2_subdev *sd, int enable)
>>
>>   		if (sensor->ep.bus_type == V4L2_MBUS_CSI2_DPHY)
>>   			ret = ov5640_set_stream_mipi(sensor, enable);
>> -		else if (sensor->ep.bus_type == V4L2_MBUS_BT656)
>> -			ret = ov5640_set_stream_bt656(sensor, enable);
>>   		else
>>   			ret = ov5640_set_stream_dvp(sensor, enable);
>>
>> --
>> 2.7.4
>>

BR,
Hugues.




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