Re: [PATCH v3] media: ov5640: fix support of BT656 bus mode

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Hi Jacopo,

On 10/13/20 2:01 PM, Jacopo Mondi wrote:
> Hi Hugues,
> 
> On Tue, Oct 13, 2020 at 11:02:23AM +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>
>> ---
>> version 3:
>>    - reformat code as per Jacopo's comments
>> version 2:
>>    - keep reset to default without error check at power off
>>
>>   drivers/media/i2c/ov5640.c | 82 +++++++++++++++++++++++++---------------------
>>   1 file changed, 45 insertions(+), 37 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
>> index 8d0254d..8f0812e 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 ?
>> @@ -1994,13 +1980,13 @@ 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;
>> -	u8 pclk_pol = 0;
>> -	u8 hsync_pol = 0;
>> -	u8 vsync_pol = 0;
>> +	bool bt656 = sensor->ep.bus_type == V4L2_MBUS_BT656;
>> +	u8 polarities = 0;
>>   	int ret;
>>
>>   	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);
>> @@ -2024,7 +2010,35 @@ 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
>>   	 */
>> +
>> +	/*
>> +	 * BT656 embedded synchronization configuration
>> +	 *
>> +	 * 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)
>> +	 */
>> +	ret = ov5640_write_reg(sensor, OV5640_REG_CCIR656_CTRL00,
>> +			       bt656 ? 0x01 : 0x00);
>> +	if (ret)
>> +		return ret;
>> +
>>   	/*
>>   	 * configure parallel port control lines polarity
>>   	 *
>> @@ -2035,29 +2049,26 @@ static int ov5640_set_power_dvp(struct ov5640_dev *sensor, bool on)
>>   	 *		datasheet and hardware, 0 is active high
>>   	 *		and 1 is active low...)
>>   	 */
>> -	if (sensor->ep.bus_type == V4L2_MBUS_PARALLEL) {
>> -		if (flags & V4L2_MBUS_PCLK_SAMPLE_RISING)
>> -			pclk_pol = 1;
>> +	if (!bt656) {
>>   		if (flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
>> -			hsync_pol = 1;
>> +			polarities |= BIT(1);
>>   		if (flags & V4L2_MBUS_VSYNC_ACTIVE_LOW)
>> -			vsync_pol = 1;
> 
> Ups, this doesn't match what's reported in the manual version I have
> (version 2.03, page 134) I read:
> 
> VSYNC polarity  0: Active low
>                  1: Active high
> 
> Was this a bug already present in the code ? >
 > Anyway, this has not been introduced by this patch, but might be a
 > good occasion to fix it.

Code is good, this is a "manual bug" that was documented by me when 
submitting DVP support few lines above ;):
	 * - [0]:	VSYNC polarity (mismatch here between
	 *		datasheet and hardware, 0 is active high
	 *		and 1 is active low...)

> 
> Reviewed-by: Jacopo Mondi <jacopo@xxxxxxxxxx>
> 
> Thanks
>    j
> 
>> -
>> -		ret = ov5640_write_reg(sensor, OV5640_REG_POLARITY_CTRL00,
>> -				       (pclk_pol << 5) | (hsync_pol << 1) |
>> -				       vsync_pol);
>> -
>> -		if (ret)
>> -			return ret;
>> +			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;
>>
>>   	/*
>> -	 * 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 +2085,7 @@ 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 +2935,6 @@ 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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