Hi Bingbu,
On Tue, 2023-10-24 at 19:29 +0800, bingbu.cao@xxxxxxxxx wrote:
> From: Bingbu Cao <bingbu.cao@xxxxxxxxx>
>
> Input system CSI2 receiver is exposed as a v4l2 sub-device.
> Each CSI2 sub-device represent one single CSI2 hardware port
> which be linked with external sub-device such camera sensor
> by linked with ISYS CSI2's sink pad. CSI2 source pad is linked
> to the sink pad of video capture device.
>
> Signed-off-by: Bingbu Cao <bingbu.cao@xxxxxxxxx>
> ---
> drivers/media/pci/intel/ipu6/ipu6-isys-csi2.c | 654
> ++++++++++++++++++
> drivers/media/pci/intel/ipu6/ipu6-isys-csi2.h | 81 +++
> .../media/pci/intel/ipu6/ipu6-isys-subdev.c | 379 ++++++++++
> .../media/pci/intel/ipu6/ipu6-isys-subdev.h | 58 ++
> .../intel/ipu6/ipu6-platform-isys-csi2-reg.h | 187 +++++
> 5 files changed, 1359 insertions(+)
> create mode 100644 drivers/media/pci/intel/ipu6/ipu6-isys-csi2.c
> create mode 100644 drivers/media/pci/intel/ipu6/ipu6-isys-csi2.h
> create mode 100644 drivers/media/pci/intel/ipu6/ipu6-isys-subdev.c
> create mode 100644 drivers/media/pci/intel/ipu6/ipu6-isys-subdev.h
> create mode 100644 drivers/media/pci/intel/ipu6/ipu6-platform-isys-
> csi2-reg.h
>
> diff --git a/drivers/media/pci/intel/ipu6/ipu6-isys-csi2.c
> b/drivers/media/pci/intel/ipu6/ipu6-isys-csi2.c
> new file mode 100644
> index 000000000000..0dedf3f51850
> --- /dev/null
> +++ b/drivers/media/pci/intel/ipu6/ipu6-isys-csi2.c
...
>
> +
> +#define DIV_SHIFT 8
> +#define CSI2_ACCINV 8
> +
> +static u32 calc_timing(s32 a, s32 b, s64 link_freq, u32 accinv)
> +{
> + return accinv * a + (accinv * b * (500000000 >> DIV_SHIFT)
> + / (int32_t)(link_freq >> DIV_SHIFT));
> +}
I think accinv should be s32 here. When accinv is unsigned, the
expression (accinv * b) becomes unsigned, and thus negative values of b
gives incorrect results.
This is different from e.g. https://github.com/intel/ipu6-drivers.
/Andreas
