Hi Dave, Thanks for your patches! On 1/16/25 18:43, Dave Stevenson wrote: > The driver was using reverse engineered pixel rates, and had different > values for different link frequencies. > In common with the other Starvis sensors (eg imx290), this isn't > actually the situation, and the pixel array runs off a different > PLL to the MIPI block, and there is a FIFO between the two. > > It's not quite so simple as HMAX is said to be in units of INCK, > not pixel clocks. Working through the various modes that appears that > even that is slightly wrong as it is units of a scaled INCK of > either 72MHz (for INCK = 24 or 72MHz) or 74.25MHz (for INCK = 27, > 37.125, or 74.25MHz). > > Rework the configuration so that the pixel rate is fixed, with the > different link frequencies adjusting the minimum hmax value so that > the FIFO doesn't overflow. > > Switching between 2 and 4 data lanes also only changes the MIPI data > rate, so also can be handled by altering the minimum HMAX. > > Once you've got HMAX / V4L2_CID_HBLANK represented sensibly, then > frame rate control through V4L2_CID_HBLANK and V4L2_CID_VBLANK is > trivial, so add in frame rate control too. > Exposure is set in lines (as usual), so amending VBLANK changes the > range for the exposure control. > > This has been tested on a Pi5 with Waveshare "IMX415-98 IR-CUT Camera" > module (SKU 28524). That uses a 24MHz clock, so only the 360MHz and > 720MHz link frequencies have been tested (other frequencies require > a 27, 37.125, or 74.25MHz clock input. > > It'd be nice to add support for 12bit readout and windowed mode readout, > but those are a job for another day. > > Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> Reviewed-by: Michael Riesch <michael.riesch@xxxxxxxxxxxxxx> Regards, Michael > --- > Changes in v2: > - Fixed VBLANK fall-through for setting the exposure correctly > - Sorted the checkpatch complaint over using fallthrough; vs commenting > why we're falling through. > - Corrected HMAX for 891Mbit/s mode. I now have a module with 37.125MHz > clock, and have validated that. > - Link to v1: https://lore.kernel.org/r/20250109-media-imx415-v1-0-366ba6a234ab@xxxxxxxxxxxxxxx > > --- > Dave Stevenson (3): > media: i2c: imx415: Add read/write control of VBLANK > media: i2c: imx415: Make HBLANK controllable and in consistent units > media: i2c: imx415: Link frequencies are not exclusive to num lanes > > drivers/media/i2c/imx415.c | 182 +++++++++++++++++++++++---------------------- > 1 file changed, 93 insertions(+), 89 deletions(-) > --- > base-commit: 94794b5ce4d90ab134b0b101a02fddf6e74c437d > change-id: 20250107-media-imx415-2df67ae21107 > > Best regards,
