The ov9281 produced by vision-components does not support auto-incremented reads, so read the id in 2 separate steps to circumvent the error: kernel: ov9282 10-0060: chip id mismatch: 9281!=92ff kernel: ov9282 10-0060: failed to find sensor: -6 Signed-off-by: Max Schulze <max.schulze@xxxxxxxxx> Tested-by: Max Schulze <max.schulze@xxxxxxxxx> Suggested-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> --- This was tested on rpi cm4 with two ov9281 at the same time, one from vc, one from inno-maker. The rpi kernel supported ov9281 out-of-tree until kernel 6.1. It carried this change originally made by Dave to support the vc sensor. Switching to mainline now broke support for it. I could not find a single-commit for the original change to which I could link, only squashed ones, i.e. https://github.com/raspberrypi/linux/commit/eb00efc993d8cd835221255b44e9019a31708abe media: i2c: ov9281: Read chip ID via 2 reads Vision Components have made an OV9281 module which blocks reading back the majority of registers to comply with NDAs, and in doing so doesn't allow auto-increment register reading as used when reading the chip ID. --- drivers/media/i2c/ov9282.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c index 068c7449f50e..3b687f6d4581 100644 --- a/drivers/media/i2c/ov9282.c +++ b/drivers/media/i2c/ov9282.c @@ -1078,13 +1078,16 @@ static int ov9282_set_stream(struct v4l2_subdev *sd, int enable) static int ov9282_detect(struct ov9282 *ov9282) { int ret; - u32 val; + u32 val = 0, id_msb = 0; - ret = ov9282_read_reg(ov9282, OV9282_REG_ID, 2, &val); - if (ret) - return ret; + // some firmware limits auto-increment register writes, so do it separately + ret = ov9282_read_reg(ov9282, OV9282_REG_ID + 1, 1, &val); + if (!ret) + ret = ov9282_read_reg(ov9282, OV9282_REG_ID, 1, &id_msb); + + val |= (id_msb << 8); - if (val != OV9282_ID) { + if (ret || val != OV9282_ID) { dev_err(ov9282->dev, "chip id mismatch: %x!=%x", OV9282_ID, val); return -ENXIO; -- 2.30.2
