Message-ID: <7e207725-3eb9-4549-8fdf-3d2ddd12e36e@luigi311.com>
Date: Thu, 28 Mar 2024 17:03:15 -0600
From: Luigi311 <git@...gi311.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: linux-media@...r.kernel.org, dave.stevenson@...pberrypi.com,
 jacopo.mondi@...asonboard.com, mchehab@...nel.org, robh@...nel.org,
 krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org, shawnguo@...nel.org,
 s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com,
 devicetree@...r.kernel.org, imx@...ts.linux.dev,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 08/23] media: i2c: imx258: Add support for 24MHz clock

On 3/28/24 11:55, Luigi311 wrote:
> 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@...gi311.com wrote:
>>> From: Dave Stevenson <dave.stevenson@...pberrypi.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@...pberrypi.com>
>>> Signed-off-by: Luigi311 <git@...gi311.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.
> 
> 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?
> 

Actually down the patch series 15/23 set pixel_rate range to the same as the value,
changes the logic and removes those two lines all together

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

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