Hi Prabhakar,
On Tue, Jul 28, 2020 at 06:50:21PM +0100, Lad, Prabhakar wrote:
> Hi,
>
> I am currently investigating adding support for the BT656 format which
> is currently missing in the driver.
>
> The platform which I am currently testing can support both 8-bit DVP
> and BT656 modes.
> * Testing DVP mode capturing 320x240, 640x480 worked OK with random
> green lines in-between
>
> Following is the chunk of code which enables BT656 support, (for
> BT656 mode ov5640_set_dvp_pclk() is used), with the below changes I
> can get 640x480 working
>
> #define OV5640_REG_CCIR656_CTRL00 0x4730
>
> static int ov5640_set_stream_bt656(struct ov5640_dev *sensor, bool on)
> {
> int ret;
>
> ret = ov5640_write_reg(sensor,
> OV5640_REG_IO_MIPI_CTRL00, on ? 0x18: 0);
> if (ret)
> return ret;
>
> ret = ov5640_write_reg(sensor,
> OV5640_REG_PAD_OUTPUT_ENABLE01, 0x7f);
> if (ret)
> return ret;
>
> ret = ov5640_write_reg(sensor,
> OV5640_REG_PAD_OUTPUT_ENABLE02, 0xfc);
> if (ret)
> return ret;
>
> return ov5640_write_reg(sensor,
> OV5640_REG_CCIR656_CTRL00, on ? 0x1: 0x0);
> }
>
> As soon as I change the code to below to disable the data pads on
> stream OFF as below it stops working!
>
> static int ov5640_set_stream_bt656(struct ov5640_dev *sensor, bool on)
> {
> int ret;
>
> ret = ov5640_write_reg(sensor,
> OV5640_REG_IO_MIPI_CTRL00, on ? 0x18: 0);
> if (ret)
> return ret;
>
> ret = ov5640_write_reg(sensor,
> OV5640_REG_PAD_OUTPUT_ENABLE01, on ? 0x7f, 0);
s/,/:/ ? Is that a typo in your e-mail, or also in the code you've
tested ? I assume the former as the latter shouldn't compile.
> if (ret)
> return ret;
>
> ret = ov5640_write_reg(sensor,
> OV5640_REG_PAD_OUTPUT_ENABLE02, on ? 0xfc, 0);
> if (ret)
> return ret;
>
> return ov5640_write_reg(sensor,
> OV5640_REG_CCIR656_CTRL00, on ? 0x1: 0x0);
> }
>
> Looking at the datasheet [1] I don't find it wrong or is there any
> information missing in this freely available datasheet.
>
> Ideally BT656 mode should just work in DVP mode by setting 0x1 in
> 0x4730, but doesn work.
>
> Is there anything I'm missing here, any thoughts ?
>
> [1] https://cdn.sparkfun.com/datasheets/Sensors/LightImaging/OV5640_datasheet.pdf
--
Regards,
Laurent Pinchart
