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

From: Luigi311
Date: Thu Mar 28 2024 - 13:55:45 EST

On 3/28/24 02:09, Sakari Ailus wrote:
> Hi Luigi311,
>
> Thank you for the patchset.
>
> On Wed, Mar 27, 2024 at 05:16:54PM -0600, git@xxxxxxxxxxxx wrote:
>> From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
>>
>> 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@xxxxxxxxxxxxxxx>
>> Signed-off-by: Luigi311 <git@xxxxxxxxxxxx>
>
> 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.

Luigi311 is not my real name but it would be a lot easier to find me if
it was. My real name is Luis Garcia which is a super common name so its
actually way easier to find me and all my work using my online name of
Luigi311. I can go ahead and swap over to Luis Garcia if required but a
name like that would provide no value in contacting/finding me since I'm
not famous like all the other Luis Garcia's that appear on google.

>
>> ---
>> 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?

Ok I've removed the defines and just threw the values into 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?

Would it make more sense to do something like default to index 0 and then use
ARRAY_SIZE to iterate through the array and do a comparison to get the min and
max size so it would always choose the correct value no matter how many entries
there are?

>
>> /* 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;
>> }
>>
>