Hi! This series introduces i2c communication with the imx290 sensor during probe s.t. the v4l2 subdev is not initialized when the chip is not reachable. The datasheets show that INCKSEL* registers have a different default value after reset on imx290[1] and imx327[2], however I am not sure if this is a sufficient identification option - therefore I just removed the current CHIP_ID register for now. Thank you all for the feedback and the discussion, I updated the series to contain some of the ideas that came up. For now, I kept reading back the content of the STANDBY register, as suggested by Sakari and Alexander. If not wanted (as suggested by Laurent), I can re-add my "optional read" commit from the first version of this series instead. *Overview:* Patch 1/7 is a split from the old 1/2 which defines the values of the STANDBY register and uses them. Patch 2/7 is new and defines the whole supported range of the controls. Patch 3/7 is the old 2/2 to drop the CHIP_ID register. Patch 4+5/7 are new and target the avoidable communication during probe(). I decided to use a variant that also works on machines without runtime PM active, and falls back to the values of 2/7 instead. Additionally, imx290_runtime_suspend() is using v4l_subdev, and therefore depends on the subdevice. If we move the autosuspend stuff before the subdevice creation, we basically have a race between the delay and the subdevice creation. Although it is not very close, I don't think it is a good idea to potentially autosuspend before the subdev is created. Patch 6/7 is the old 1/2. Patch 7/7 is a new PoC to decide to check the availability based on the power state of the sensor during probe(). Note: dummy-regulators, which are used when no supplies are set in the DT, are always-on. Note2: The "off" mode is currently only active after probe(). If this approach is of interest, I would also ensure that it is active once streaming has stopped - need to dig deeper if it is necessary to store the "old current" before stopping, therefore only "initial" for now. thanks & regards Benjamin [1] https://static6.arrow.com/aropdfconversion/c0c7efde6571c768020a72f59b226308b9669e45/sony_imx290lqr-c_datasheet.pdf [2] https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/138/IMX327LQR_2D00_C_5F00_TechnicalDatasheet_5F00_E_5F00_Rev0.2.pdf --- Changes in v3: - probably better readable in the overview - 1/2 -> 1+6/7 - 2/2 -> 3/7 (added R-b - thx for that) - others are new based on the discussions/suggestions - Link to v2: https://lore.kernel.org/r/20240828-imx290-avail-v2-0-bd320ac8e8fa@xxxxxxxxxxx Changes in v2: - dropped 1/2 to ignore the read value in cci_read() (old 2/2 -> new 1/2) - 1/2: read-back standby mode instead and ensure that it is really in standby - new 2/2: drop chip_id register definition which seems to be incorrect - Link to v1: https://lore.kernel.org/r/20240807-imx290-avail-v1-0-666c130c7601@xxxxxxxxxxx --- Benjamin Bara (7): media: i2c: imx290: Define standby mode values media: i2c: imx290: Define absolute control ranges media: i2c: imx290: Remove CHIP_ID reg definition media: i2c: imx290: Introduce initial "off" mode & link freq media: i2c: imx290: Avoid communication during probe() media: i2c: imx290: Check for availability in probe() media: i2c: imx290: Implement a "privacy mode" for probe() drivers/media/i2c/imx290.c | 153 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 124 insertions(+), 29 deletions(-) --- base-commit: eec5d86d5bac6b3e972eb9c1898af3c08303c52d change-id: 20240807-imx290-avail-85795c27d988 Best regards, -- Benjamin Bara <benjamin.bara@xxxxxxxxxxx>
