[PATCH v3 0/4] media: qcom: camss: Report CAMSS hardware version via media controller

[Loic Poulain <loic.poulain@oss.qualcomm.com>]

This series lets user space discover the exact CAMSS hardware variant by
reporting the top-level CAMSS hardware version register through the media
controller (media_dev.hw_revision), queryable via media-ctl -p or
MEDIA_IOC_DEVICE_INFO. This helps identify the platform variant and adapt
behaviour accordingly, for example allowing libcamera to apply quirks or
enable features that cannot be discovered through standard V4L2 or
media-controller APIs.

The version register is exposed by some platforms through the top-level
"top" (or "cpas-top") reg region at offset 0. Accessing it requires the
AHB bus to be clocked. To make this possible at probe time, the series
first moves the shared CAMSS clocks (top_ahb, ahb, axi on QCM2290) into
the PM clock framework, so they are managed by runtime PM at the CAMSS
instance level rather than by each individual sub-block (VFE, CSID, ...).

For now, only Agatti is supported. But support for other platforms like
TITAN-based ones will be introduced in a follow-up series.

Reported media info on Agatti/CM2290 (Spectra 520):
Media Driver Info:
        Driver name      : qcom-camss
        Model            : Qualcomm Camera Subsystem
        Bus info         : platform:5c11000.camss
        Hardware revision: 0x00050200 (328192)

Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
---
Changes in v3:
- Guard the pm_clk_suspend()/pm_clk_resume() calls with CONFIG_PM_CLK
- Link to v2: https://lore.kernel.org/r/20260721-camss-version-v2-0-b2440d99085a@oss.qualcomm.com

Changes in v2:
- PM clock support: propagate pm_clk_add() failures (Bryan)
- make camss_read_version() return an int and propagate (Bryan)
- use pm_runtime_put() instead of pm_runtime_put_sync() (Konrad)
- Link to v1: https://lore.kernel.org/r/20260717-camss-version-v1-0-7ed71fea95e8@oss.qualcomm.com

---
Loic Poulain (4):
      media: qcom: camss: Add PM clock support and integrate with runtime PM
      media: qcom: camss: Add PM clock definitions for QCM2290
      media: qcom: camss: Drop top_ahb/ahb/axi from QCM2290 subdevice clocks
      media: qcom: camss: Report hardware version via media controller

 drivers/media/platform/qcom/camss/camss.c | 125 +++++++++++++++++++++++-------
 drivers/media/platform/qcom/camss/camss.h |   2 +
 2 files changed, 101 insertions(+), 26 deletions(-)
---
base-commit: 8c7fc7de3b6cc89e68f115ee5ffe28cb93d99e5b
change-id: 20260717-camss-version-a8ea61dfae5d

Best regards,
-- 
Loic Poulain <loic.poulain@oss.qualcomm.com>