Re: [PATCH 08/23] media: i2c: imx258: Add support for 24MHz clock

Sakari Ailus
2024-03-28T08:09:55Z

Hi Luigi311,

Thank you for the patchset.

On Wed, Mar 27, 2024 at 05:16:54PM -0600, git@luigi311.com wrote:
> From: Dave Stevenson <dave.stevenson@raspberrypi.com>
>
> There's no reason why only a clock of 19.2MHz is supported.
> Indeed this isn't even a frequency listed in the datasheet.
>
> Add support for 24MHz as well.
> The PLL settings result in slightly different link frequencies,
> so parameterise those.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Signed-off-by: Luigi311 <git@luigi311.com>

Is Luigi311 your real name? As per
Documentation/process/submitting-patches.rst, anonymous (or pseudonym I'd
say as well) contributions are not an option.

> ---
> drivers/media/i2c/imx258.c | 133 +++++++++++++++++++++++++++++--------
> 1 file changed, 107 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
> index 351add1bc5d5..6ee7de079454 100644
> --- a/drivers/media/i2c/imx258.c
> +++ b/drivers/media/i2c/imx258.c
> @@ -76,9 +76,6 @@
> #define REG_CONFIG_MIRROR_FLIP 0x03
> #define REG_CONFIG_FLIP_TEST_PATTERN 0x02
>
> -/* Input clock frequency in Hz */
> -#define IMX258_INPUT_CLOCK_FREQ 19200000
> -
> struct imx258_reg {
> u16 address;
> u8 val;
> @@ -115,7 +112,9 @@ struct imx258_mode {
> };
>
> /* 4208x3120 needs 1267Mbps/lane, 4 lanes */
> -static const struct imx258_reg mipi_data_rate_1267mbps[] = {
> +static const struct imx258_reg mipi_1267mbps_19_2mhz[] = {
> + { 0x0136, 0x13 },
> + { 0x0137, 0x33 },
> { 0x0301, 0x05 },
> { 0x0303, 0x02 },
> { 0x0305, 0x03 },
> @@ -133,7 +132,29 @@ static const struct imx258_reg mipi_data_rate_1267mbps[] = {
> { 0x0823, 0xCC },
> };
>
> -static const struct imx258_reg mipi_data_rate_640mbps[] = {
> +static const struct imx258_reg mipi_1272mbps_24mhz[] = {
> + { 0x0136, 0x18 },
> + { 0x0137, 0x00 },
> + { 0x0301, 0x05 },
> + { 0x0303, 0x02 },
> + { 0x0305, 0x04 },
> + { 0x0306, 0x00 },
> + { 0x0307, 0xD4 },
> + { 0x0309, 0x0A },
> + { 0x030B, 0x01 },
> + { 0x030D, 0x02 },
> + { 0x030E, 0x00 },
> + { 0x030F, 0xD8 },
> + { 0x0310, 0x00 },
> + { 0x0820, 0x13 },
> + { 0x0821, 0x4C },
> + { 0x0822, 0xCC },
> + { 0x0823, 0xCC },
> +};
> +
> +static const struct imx258_reg mipi_640mbps_19_2mhz[] = {
> + { 0x0136, 0x13 },
> + { 0x0137, 0x33 },
> { 0x0301, 0x05 },
> { 0x0303, 0x02 },
> { 0x0305, 0x03 },
> @@ -151,9 +172,27 @@ static const struct imx258_reg mipi_data_rate_640mbps[] = {
> { 0x0823, 0x00 },
> };
>
> +static const struct imx258_reg mipi_642mbps_24mhz[] = {
> + { 0x0136, 0x18 },
> + { 0x0137, 0x00 },
> + { 0x0301, 0x05 },
> + { 0x0303, 0x02 },
> + { 0x0305, 0x04 },
> + { 0x0306, 0x00 },
> + { 0x0307, 0x6B },
> + { 0x0309, 0x0A },
> + { 0x030B, 0x01 },
> + { 0x030D, 0x02 },
> + { 0x030E, 0x00 },
> + { 0x030F, 0xD8 },
> + { 0x0310, 0x00 },
> + { 0x0820, 0x0A },
> + { 0x0821, 0x00 },
> + { 0x0822, 0x00 },
> + { 0x0823, 0x00 },
> +};
> +
> static const struct imx258_reg mode_common_regs[] = {
> - { 0x0136, 0x13 },
> - { 0x0137, 0x33 },
> { 0x3051, 0x00 },
> { 0x3052, 0x00 },
> { 0x4E21, 0x14 },
> @@ -313,10 +352,6 @@ static const char * const imx258_supply_name[] = {
>
> #define IMX258_NUM_SUPPLIES ARRAY_SIZE(imx258_supply_name)
>
> -/* Configurations for supported link frequencies */
> -#define IMX258_LINK_FREQ_634MHZ 633600000ULL
> -#define IMX258_LINK_FREQ_320MHZ 320000000ULL
> -
> enum {
> IMX258_LINK_FREQ_1267MBPS,
> IMX258_LINK_FREQ_640MBPS,
> @@ -335,25 +370,55 @@ static u64 link_freq_to_pixel_rate(u64 f)
> }
>
> /* Menu items for LINK_FREQ V4L2 control */
> -static const s64 link_freq_menu_items[] = {
> +/* Configurations for supported link frequencies */
> +#define IMX258_LINK_FREQ_634MHZ 633600000ULL
> +#define IMX258_LINK_FREQ_320MHZ 320000000ULL
> +
> +static const s64 link_freq_menu_items_19_2[] = {
> IMX258_LINK_FREQ_634MHZ,
> IMX258_LINK_FREQ_320MHZ,
> };
>
> +/* Configurations for supported link frequencies */
> +#define IMX258_LINK_FREQ_636MHZ 636000000ULL
> +#define IMX258_LINK_FREQ_321MHZ 321000000ULL

These values aren't used outside the array below and the macro names are
imprecise anyway. Could you put the numerical values to the array instead?

> +
> +static const s64 link_freq_menu_items_24[] = {
> + IMX258_LINK_FREQ_636MHZ,
> + IMX258_LINK_FREQ_321MHZ,
> +};
> +
> /* Link frequency configs */
> -static const struct imx258_link_freq_config link_freq_configs[] = {
> +static const struct imx258_link_freq_config link_freq_configs_19_2[] = {
> [IMX258_LINK_FREQ_1267MBPS] = {
> .pixels_per_line = IMX258_PPL_DEFAULT,
> .reg_list = {
> - .num_of_regs = ARRAY_SIZE(mipi_data_rate_1267mbps),
> - .regs = mipi_data_rate_1267mbps,
> + .num_of_regs = ARRAY_SIZE(mipi_1267mbps_19_2mhz),
> + .regs = mipi_1267mbps_19_2mhz,
> }
> },
> [IMX258_LINK_FREQ_640MBPS] = {
> .pixels_per_line = IMX258_PPL_DEFAULT,
> .reg_list = {
> - .num_of_regs = ARRAY_SIZE(mipi_data_rate_640mbps),
> - .regs = mipi_data_rate_640mbps,
> + .num_of_regs = ARRAY_SIZE(mipi_640mbps_19_2mhz),
> + .regs = mipi_640mbps_19_2mhz,
> + }
> + },
> +};
> +
> +static const struct imx258_link_freq_config link_freq_configs_24[] = {
> + [IMX258_LINK_FREQ_1267MBPS] = {
> + .pixels_per_line = IMX258_PPL_DEFAULT,
> + .reg_list = {
> + .num_of_regs = ARRAY_SIZE(mipi_1272mbps_24mhz),
> + .regs = mipi_1272mbps_24mhz,
> + }
> + },
> + [IMX258_LINK_FREQ_640MBPS] = {
> + .pixels_per_line = IMX258_PPL_DEFAULT,
> + .reg_list = {
> + .num_of_regs = ARRAY_SIZE(mipi_642mbps_24mhz),
> + .regs = mipi_642mbps_24mhz,
> }
> },
> };
> @@ -410,6 +475,9 @@ struct imx258 {
> /* Current mode */
> const struct imx258_mode *cur_mode;
>
> + const struct imx258_link_freq_config *link_freq_configs;
> + const s64 *link_freq_menu_items;
> +
> /*
> * Mutex for serialized access:
> * Protect sensor module set pad format and start/stop streaming safely.
> @@ -713,7 +781,7 @@ static int imx258_set_pad_format(struct v4l2_subdev *sd,
> imx258->cur_mode = mode;
> __v4l2_ctrl_s_ctrl(imx258->link_freq, mode->link_freq_index);
>
> - link_freq = link_freq_menu_items[mode->link_freq_index];
> + link_freq = imx258->link_freq_menu_items[mode->link_freq_index];
> pixel_rate = link_freq_to_pixel_rate(link_freq);
> __v4l2_ctrl_s_ctrl_int64(imx258->pixel_rate, pixel_rate);
> /* Update limits and set FPS to default */
> @@ -727,7 +795,7 @@ static int imx258_set_pad_format(struct v4l2_subdev *sd,
> vblank_def);
> __v4l2_ctrl_s_ctrl(imx258->vblank, vblank_def);
> h_blank =
> - link_freq_configs[mode->link_freq_index].pixels_per_line
> + imx258->link_freq_configs[mode->link_freq_index].pixels_per_line
> - imx258->cur_mode->width;
> __v4l2_ctrl_modify_range(imx258->hblank, h_blank,
> h_blank, 1, h_blank);
> @@ -747,7 +815,7 @@ static int imx258_start_streaming(struct imx258 *imx258)
>
> /* Setup PLL */
> link_freq_index = imx258->cur_mode->link_freq_index;
> - reg_list = &link_freq_configs[link_freq_index].reg_list;
> + reg_list = &imx258->link_freq_configs[link_freq_index].reg_list;
> ret = imx258_write_regs(imx258, reg_list->regs, reg_list->num_of_regs);
> if (ret) {
> dev_err(&client->dev, "%s failed to set plls\n", __func__);
> @@ -946,9 +1014,9 @@ static int imx258_init_controls(struct imx258 *imx258)
> imx258->link_freq = v4l2_ctrl_new_int_menu(ctrl_hdlr,
> &imx258_ctrl_ops,
> V4L2_CID_LINK_FREQ,
> - ARRAY_SIZE(link_freq_menu_items) - 1,
> + ARRAY_SIZE(link_freq_menu_items_19_2) - 1,
> 0,
> - link_freq_menu_items);
> + imx258->link_freq_menu_items);
>
> if (imx258->link_freq)
> imx258->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> @@ -964,8 +1032,10 @@ static int imx258_init_controls(struct imx258 *imx258)
> if (vflip)
> vflip->flags |= V4L2_CTRL_FLAG_READ_ONLY;
>
> - pixel_rate_max = link_freq_to_pixel_rate(link_freq_menu_items[0]);
> - pixel_rate_min = link_freq_to_pixel_rate(link_freq_menu_items[1]);
> + pixel_rate_max =
> + link_freq_to_pixel_rate(imx258->link_freq_menu_items[0]);
> + pixel_rate_min =
> + link_freq_to_pixel_rate(imx258->link_freq_menu_items[1]);

The arrays currently have two entries so this works but it'd nice to have a
bit more robust way to handle differences between the two arrays. Could you
maintain e.g. the number of entries in the array in a struct field perhaps?

> /* By default, PIXEL_RATE is read only */
> imx258->pixel_rate = v4l2_ctrl_new_std(ctrl_hdlr, &imx258_ctrl_ops,
> V4L2_CID_PIXEL_RATE,
> @@ -1086,8 +1156,19 @@ static int imx258_probe(struct i2c_client *client)
> } else {
> val = clk_get_rate(imx258->clk);
> }
> - if (val != IMX258_INPUT_CLOCK_FREQ) {
> - dev_err(&client->dev, "input clock frequency not supported\n");
> +
> + switch (val) {
> + case 19200000:
> + imx258->link_freq_configs = link_freq_configs_19_2;
> + imx258->link_freq_menu_items = link_freq_menu_items_19_2;
> + break;
> + case 24000000:
> + imx258->link_freq_configs = link_freq_configs_24;
> + imx258->link_freq_menu_items = link_freq_menu_items_24;
> + break;
> + default:
> + dev_err(&client->dev, "input clock frequency of %u not supported\n",
> + val);
> return -EINVAL;
> }
>

--
Kind regards,

Sakari Ailus