Re: [PATCH RESEND 0/4] media: i2c: imx214: Problem with CCS PLL calculator

From: André Apitzsch
Date: Mon Apr 14 2025 - 16:36:49 EST

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Am Montag, dem 07.04.2025 um 21:10 +0200 schrieb André Apitzsch:
> Am Montag, dem 10.03.2025 um 23:35 +0100 schrieb André Apitzsch:
> > Hi Sakari,
> >
> > Am Montag, dem 10.03.2025 um 11:11 +0000 schrieb Sakari Ailus:
> > > Hi André,
> > >
> > > On Sat, Mar 08, 2025 at 10:47:54PM +0100, André Apitzsch via B4
> > > Relay
> > > wrote:
> > > > The imx214 driver currently supports only a 24MHz external
> > > > clock.
> > > > But
> > > > there are devices, like Qualcomm-MSM8916-based phones, which
> > > > cannot
> > > > provide this frequency. To make the sensor usable by those
> > > > devices,
> > > > add
> > > > support for 23.88MHz clock.
> > > >
> > > > Signed-off-by: André Apitzsch <git@xxxxxxxxxxx>
> > > > ---
> > > > André Apitzsch (4):
> > > >       media: i2c: imx214: Calculate link bit rate from clock
> > > > frequency
> > > >       media: i2c: imx214: Prepare for variable clock frequency
> > > >       media: i2c: imx214: Read clock frequency from device tree
> > > >       media: i2c: imx214: Add support for 23.88MHz clock
> > > >
> > > > drivers/media/i2c/imx214.c | 188
> > > > +++++++++++++++++++++++++++++++++++----------
> > > > 1 file changed, 146 insertions(+), 42 deletions(-)
> > >
> > > Thanks for the patches.
> > >
> > > Do you think the driver could use the CCS PLL calculator? The PLL
> > > appears to be compliant. The AR0234 driver will do the same. (The
> > > sensor might just work with the CCS driver, too, but that's
> > > another
> > > discussion.)
> > >
> > Using the CCS PLL calculator seems quite complicated compared to
> > switching to the CCS driver. That's why I looked at the later
> > first.
> > But for it to work, quirks already need to be applied in
> > ccs_power_on(), to disable writing to COMPRESSION_MODE, and in
> > ccs_identify_module(), to change the MODULE_MANUFACTURER_ID
> > register.
> >
> > I'll check if CCS PLL calculator could be used.
> >
> > Best regards,
> > André
>
> Hi Sakari,
>
> the CCS PLL calculator seems to work (up to one problem) and to be a
> more elegant way forward.
> The problem is, that the pixel rate is too small by a factor of 10
> and I cannot figure out why. Any help would be appreciated.
>
> My devices uses a clock-frequency of 24000000 and a link-frequency of
> 600000000. There are four data lanes.
> The calculator returns a pixel rate of 480.000.000. The expected
> value is 4800.000.000.

Hi,

Everything works as expected.

For some reason, I assumed the unit of pixel rate to be bits per
second. But to get the bits per second, the pixel rate needs to be
multiplied by bits per pixel (here: 10), which gives the expected value
of 4,800,000,000.

I'll send my patches in the coming days.

Best regards,
André

>
> You can find the PLL input parameters in [1] and the generated debug
> output below.
>
> Best regards,
> André
>
> [1]
> https://github.com/a-andre/linux/blob/58e10a814985f700579847ac7c99468a65cb55bb/drivers/media/i2c/imx214.c#L1116-L1196
>
> $ dmesg | grep imx
> [   17.851215] imx214 4-0010: vt_lanes: 4
> [   17.851245] imx214 4-0010: op_lanes: 4
> [   17.851254] imx214 4-0010: binning: 1x1
> [   17.851262] imx214 4-0010: min / max op_pre_pll_clk_div: 1 / 15
> [   17.851272] imx214 4-0010: pre-pll check: min / max
> op_pre_pll_clk_div: 1 / 15
> [   17.851281] imx214 4-0010: mul 50 / div 1
> [   17.851290] imx214 4-0010: pll_op check: min / max
> op_pre_pll_clk_div: 1 / 15
> [   17.851300] imx214 4-0010: op_pre_pll_clk_div 1
> [   17.851308] imx214 4-0010: more_mul_max: max_op_pll_multiplier
> check: 24
> [   17.851317] imx214 4-0010: more_mul_max: max_pll_op_clk_freq_hz
> check: 1
> [   17.851325] imx214 4-0010: more_mul_max: max_op_sys_clk_div check:
> 1
> [   17.851333] imx214 4-0010: more_mul_max: min_pll_multiplier check:
> 1
> [   17.851341] imx214 4-0010: more_mul_min: min_op_pll_op_clk_freq_hz
> check: 1
> [   17.851349] imx214 4-0010: more_mul_min: min_op_pll_multiplier
> check: 1
> [   17.851357] imx214 4-0010: more_mul_factor: 1
> [   17.851365] imx214 4-0010: more_mul_factor: min_op_sys_clk_div: 1
> [   17.851373] imx214 4-0010: final more_mul: 1
> [   17.851381] imx214 4-0010: op_sys_clk_div: 1
> [   17.851389] imx214 4-0010: op_pix_clk_div: 10
> [   17.851398] imx214 4-0010: min_vt_div: 10
> [   17.851406] imx214 4-0010: min_vt_div: max_vt_pix_clk_freq_hz: 10
> [   17.851414] imx214 4-0010: min_vt_div: min_vt_clk_div: 10
> [   17.851422] imx214 4-0010: max_vt_div: 40
> [   17.851486] imx214 4-0010: max_vt_div: min_vt_pix_clk_freq_hz: 40
> [   17.851502] imx214 4-0010: min_sys_div: 2
> [   17.851510] imx214 4-0010: min_sys_div: max_vt_pix_clk_div: 2
> [   17.851518] imx214 4-0010: min_sys_div: max_pll_op_clk_freq_hz: 2
> [   17.851526] imx214 4-0010: min_sys_div: one or even: 2
> [   17.851534] imx214 4-0010: max_sys_div: 4
> [   17.851541] imx214 4-0010: max_sys_div: min_vt_pix_clk_div: 4
> [   17.851549] imx214 4-0010: max_sys_div: min_vt_pix_clk_freq_hz: 4
> [   17.851557] imx214 4-0010: pix_div 3 too small or too big (5--10)
> [   17.851568] imx214 4-0010: ext_clk_freq_hz 24000000
> [   17.851578] imx214 4-0010: vt_pre_pll_clk_div 1
> [   17.851587] imx214 4-0010: vt_pll_multiplier 50
> [   17.851595] imx214 4-0010: vt_pll_ip_clk_freq_hz 24000000
> [   17.851603] imx214 4-0010: vt_pll_op_clk_freq_hz 1200000000
> [   17.851612] imx214 4-0010: vt_sys_clk_div 2
> [   17.851620] imx214 4-0010: vt_pix_clk_div 5
> [   17.851629] imx214 4-0010: vt_sys_clk_freq_hz 600000000
> [   17.851637] imx214 4-0010: vt_pix_clk_freq_hz 120000000
> [   17.851645] imx214 4-0010: op_sys_clk_div 1
> [   17.851653] imx214 4-0010: op_pix_clk_div 10
> [   17.851661] imx214 4-0010: op_sys_clk_freq_hz 1200000000
> [   17.851669] imx214 4-0010: op_pix_clk_freq_hz 120000000
> [   17.851677] imx214 4-0010: pixel rate in pixel
> array: 480000000
> [   17.851685] imx214 4-0010: pixel rate on CSI-2 bus: 480000000
> [   17.851694] imx214 4-0010: flags lane-speed
> [   17.869313] imx214 4-0010: vt_lanes: 4
> [   17.869342] imx214 4-0010: op_lanes: 4
> [   17.869352] imx214 4-0010: binning: 1x1
> [   17.869361] imx214 4-0010: min / max op_pre_pll_clk_div: 1 / 15
> [   17.869372] imx214 4-0010: pre-pll check: min / max
> op_pre_pll_clk_div: 1 / 15
> [   17.869382] imx214 4-0010: mul 50 / div 1
> [   17.869391] imx214 4-0010: pll_op check: min / max
> op_pre_pll_clk_div: 1 / 15
> [   17.869400] imx214 4-0010: op_pre_pll_clk_div 1
> [   17.869409] imx214 4-0010: more_mul_max: max_op_pll_multiplier
> check: 24
> [   17.869417] imx214 4-0010: more_mul_max: max_pll_op_clk_freq_hz
> check: 1
> [   17.869426] imx214 4-0010: more_mul_max: max_op_sys_clk_div check:
> 1
> [   17.869435] imx214 4-0010: more_mul_max: min_pll_multiplier check:
> 1
> [   17.869443] imx214 4-0010: more_mul_min: min_op_pll_op_clk_freq_hz
> check: 1
> [   17.869451] imx214 4-0010: more_mul_min: min_op_pll_multiplier
> check: 1
> [   17.869460] imx214 4-0010: more_mul_factor: 1
> [   17.869468] imx214 4-0010: more_mul_factor: min_op_sys_clk_div: 1
> [   17.869476] imx214 4-0010: final more_mul: 1
> [   17.869483] imx214 4-0010: op_sys_clk_div: 1
> [   17.869491] imx214 4-0010: op_pix_clk_div: 10
> [   17.869501] imx214 4-0010: min_vt_div: 10
> [   17.869509] imx214 4-0010: min_vt_div: max_vt_pix_clk_freq_hz: 10
> [   17.869517] imx214 4-0010: min_vt_div: min_vt_clk_div: 10
> [   17.869525] imx214 4-0010: max_vt_div: 40
> [   17.869533] imx214 4-0010: max_vt_div: min_vt_pix_clk_freq_hz: 40
> [   17.869541] imx214 4-0010: min_sys_div: 2
> [   17.869549] imx214 4-0010: min_sys_div: max_vt_pix_clk_div: 2
> [   17.869557] imx214 4-0010: min_sys_div: max_pll_op_clk_freq_hz: 2
> [   17.869565] imx214 4-0010: min_sys_div: one or even: 2
> [   17.869572] imx214 4-0010: max_sys_div: 4
> [   17.869580] imx214 4-0010: max_sys_div: min_vt_pix_clk_div: 4
> [   17.869588] imx214 4-0010: max_sys_div: min_vt_pix_clk_freq_hz: 4
> [   17.869596] imx214 4-0010: pix_div 3 too small or too big (5--10)
> [   17.869607] imx214 4-0010: ext_clk_freq_hz 24000000
> [   17.869616] imx214 4-0010: vt_pre_pll_clk_div 1
> [   17.869624] imx214 4-0010: vt_pll_multiplier 50
> [   17.869633] imx214 4-0010: vt_pll_ip_clk_freq_hz 24000000
> [   17.869642] imx214 4-0010: vt_pll_op_clk_freq_hz 1200000000
> [   17.869651] imx214 4-0010: vt_sys_clk_div 2
> [   17.869659] imx214 4-0010: vt_pix_clk_div 5
> [   17.869667] imx214 4-0010: vt_sys_clk_freq_hz 600000000
> [   17.869675] imx214 4-0010: vt_pix_clk_freq_hz 120000000
> [   17.869684] imx214 4-0010: op_sys_clk_div 1
> [   17.869692] imx214 4-0010: op_pix_clk_div 10
> [   17.869699] imx214 4-0010: op_sys_clk_freq_hz 1200000000
> [   17.869707] imx214 4-0010: op_pix_clk_freq_hz 120000000
> [   17.869716] imx214 4-0010: pixel rate in pixel
> array: 480000000
> [   17.869724] imx214 4-0010: pixel rate on CSI-2 bus: 480000000
> [   17.869732] imx214 4-0010: flags lane-speed

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