[1/4] media: i2c: imx415: Add get_mbus_config() pad operation support

Allow the driver to report static media bus configuration using
pad get_mbus_config() operation.

Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
---
 drivers/media/i2c/imx415.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

Hi Alexander

On Wed, 19 Feb 2025 at 09:48, Alexander Shiyan
<eagle.alexander923@gmail.com> wrote:
>
> Not all CSI configurations are suitable for both 2-lane and 4-lane mode.
> To solve this, let's use a zero value in the hmax_min[] field of the
> supported_modes[] structure to indicate which CSI configuration can not
> be used for 2-lane or 4-lane mode.
> Now that we have done that, let's add the remaining CSI configurations
> that can be used for 4-lane mode.
>
> Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
> ---
>  drivers/media/i2c/imx415.c | 46 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 46 insertions(+)
>
> diff --git a/drivers/media/i2c/imx415.c b/drivers/media/i2c/imx415.c
> index 83b7929455b2..5f18d3f38ded 100644
> --- a/drivers/media/i2c/imx415.c
> +++ b/drivers/media/i2c/imx415.c
> @@ -505,6 +505,19 @@ static const struct cci_reg_sequence imx415_linkrate_1440mbps[] = {
>         { IMX415_TLPX, 0x004F },
>  };
>
> +/* 1485 Mbps CSI configuration */
> +static const struct cci_reg_sequence imx415_linkrate_1485mbps[] = {
> +       { IMX415_TCLKPOST, 0x00A7 },
> +       { IMX415_TCLKPREPARE, 0x0057 },
> +       { IMX415_TCLKTRAIL, 0x005F },
> +       { IMX415_TCLKZERO, 0x0197 },
> +       { IMX415_THSPREPARE, 0x005F },
> +       { IMX415_THSZERO, 0x00AF },
> +       { IMX415_THSTRAIL, 0x005F },
> +       { IMX415_THSEXIT, 0x009F },
> +       { IMX415_TLPX, 0x004F },
> +};
> +
>  /* 1782 Mbps CSI configuration */
>  static const struct cci_reg_sequence imx415_linkrate_1782mbps[] = {
>         { IMX415_TCLKPOST, 0x00B7 },
> @@ -531,6 +544,19 @@ static const struct cci_reg_sequence imx415_linkrate_2079mbps[] = {
>         { IMX415_TLPX, 0x006F },
>  };
>
> +/* 2376 Mbps CSI configuration */
> +static const struct cci_reg_sequence imx415_linkrate_2376mbps[] = {
> +       { IMX415_TCLKPOST, 0x00E7 },
> +       { IMX415_TCLKPREPARE, 0x008F },
> +       { IMX415_TCLKTRAIL, 0x008F },
> +       { IMX415_TCLKZERO, 0x027F },
> +       { IMX415_THSPREPARE, 0x0097 },
> +       { IMX415_THSZERO, 0x010F },
> +       { IMX415_THSTRAIL, 0x0097 },
> +       { IMX415_THSEXIT, 0x00F7 },
> +       { IMX415_TLPX, 0x007F },
> +};
> +
>  struct imx415_mode_reg_list {
>         u32 num_of_regs;
>         const struct cci_reg_sequence *regs;
> @@ -576,6 +602,14 @@ static const struct imx415_mode supported_modes[] = {
>                         .regs = imx415_linkrate_1440mbps,
>                 },
>         },
> +       {
> +               .lane_rate = 1485000000,
> +               .hmax_min = { 0, 550 },
> +               .reg_list = {
> +                       .num_of_regs = ARRAY_SIZE(imx415_linkrate_1485mbps),
> +                       .regs = imx415_linkrate_1485mbps,
> +               },
> +       },
>         {
>                 .lane_rate = 1782000000,
>                 .hmax_min = { 1100, 550 },
> @@ -592,6 +626,14 @@ static const struct imx415_mode supported_modes[] = {
>                         .regs = imx415_linkrate_2079mbps,
>                 },
>         },
> +       {
> +               .lane_rate = 2376000000,
> +               .hmax_min = { 0, 366 },
> +               .reg_list = {
> +                       .num_of_regs = ARRAY_SIZE(imx415_linkrate_2376mbps),
> +                       .regs = imx415_linkrate_2376mbps,
> +               },
> +       },
>  };
>
>  static const char *const imx415_test_pattern_menu[] = {
> @@ -1375,9 +1417,13 @@ static int imx415_parse_hw_config(struct imx415 *sensor)
>                 }
>
>                 for (j = 0; j < ARRAY_SIZE(supported_modes); ++j) {
> +                       int lanes_idx = sensor->num_data_lanes == 2 ? 0 : 1;
> +
>                         if (bus_cfg.link_frequencies[i] * 2 !=
>                             supported_modes[j].lane_rate)
>                                 continue;
> +                       if (!supported_modes[j].hmax_min[lanes_idx])
> +                               continue;

You could lose the local variable by checking
if (!supported_modes[j].hmax_min[0] && sensor->num_data_lanes == 2)

Either way:

Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

I've checked the register settings against the datasheet, and they all
appear to match.

>                         sensor->cur_mode = j;
>                         break;
>                 }
> --
> 2.39.1
>
>

Hello Dave.

> > The imx415 sensor has one more register for setting the output
> > format (10/12 bit), which is currently not in the driver.
>
> The datasheet states it is the "internal A/D conversion bits" setting,
> not output format.
> Output format is set via MDBIT (reg 0x3032).
>
> The sensor may well happily truncate 12bit A/D readout to RAW10
> output, or left shift 10bit A/D values to RAW12 output.
>
> I'll defer to Wolfvision on this one as I would expect them as the
> original authors to have been given a register list by Sony for the
> readout modes that they were interested in. Sony may therefore have
> recommended this apparent mismatch in A/D depth vs output format.

As far as I can see from the datasheet, the "Operating mode" table (page 48)
clearly states that the AS-conversion and output bit width values are equal.

Thanks!