[PATCH v4 0/2] imx8mq-evk and ov5640: Add overlay-based camera support with shared reset handling

[robby.cai@oss.nxp.com]

From: Robby Cai <robby.cai@nxp.com>

This series enables OV5640 camera support on the i.MX8MQ EVK using
device tree overlays, including single- and dual-camera configurations.

The DT overlays describe two OV5640 sensors connected to different
MIPI CSI-2 interfaces:

  - OV5640 (I2C2) -> MIPI CSI1 -> CSI1 bridge
  - OV5640 (I2C1) -> MIPI CSI2 -> CSI2 bridge

On this platform, both sensors share a common reset GPIO line, while
each has an independent powerdown (PWDN) GPIO. Due to this hardware
constraint, proper handling of the shared reset line is required when
both cameras are present.

To address this, the OV5640 driver is updated to use the reset controller
framework, allowing it to correctly support shared reset lines. Legacy
reset-gpios support is retained as a fallback when no reset controller
is defined, ensuring compatibility with existing device tree
descriptions without requiring changes.

Note:
1) With commit 8f040b5c5e3a ("leds: class: Use firmware nodes for device lookup"),
the OV5640 driver reports the following errors:

  [   11.373844] ov5640 0-003c: error -EINVAL: getting privacy LED
  [   11.376442] ov5640 0-003c: probe with driver ov5640 failed with error -22
  [   11.906977] ov5640 1-003c: error -EINVAL: getting privacy LED
  [   11.909793] ov5640 1-003c: probe with driver ov5640 failed with error -22

This issue has been reported and discussed in [1] and related threads.
As a temporary workaround for testing OV5640, the patch can be reverted.

Link [1]: https://lore.kernel.org/all/aignTNlK5kCLmQ2A@tom-desktop/

2) The patch at:
     https://lore.kernel.org/imx/20260619073115.3778313-1-robby.cai@oss.nxp.com/
   is also required for OV5640 to function properly on the i.MX8MQ EVK.




Changes in v4:
- Switch EVK camera support to DT overlays for CSI1/CSI2/dual configurations (Kieran Bingham)
- Convert OV5640 driver to use reset controller framework with GPIO fallback (sashiko)
- Ensure correct handling of reset line (sashiko)

Link to v3: https://lore.kernel.org/imx/20260529132334.3333294-1-robby.cai@nxp.com/

Changes in v3:
- Add OV5640 driver changes to use reset control framework for shared reset
- Drop GPIO hog for reset in DTS

Link to v2: https://lore.kernel.org/imx/20260515111143.2980956-1-robby.cai@nxp.com/

Changes in v2:
- Address comments on MIPI clock configuration (Frank, Sebastian):
  drop the first patch and consolidate the correct clock configuration
  into the second patch
- Address comments from sashiko:
  * Use MEDIA_BUS_TYPE_CSI2_DPHY instead of a literal value
  * Fix a probe-order dependency related to reset handling. Switch to
    software reset, as the shared hardware reset line prevents
    independent reset when both cameras are enabled due to a board
    design limitation
  * Fix incorrect voltage value in the reg_2v8 node

Link to v1: https://lore.kernel.org/imx/20260417110200.753678-1-robby.cai@nxp.com/


Signed-off-by: Robby Cai <robby.cai@nxp.com>

Robby Cai (2):
  arm64: dts: imx8mq-evk: Add OV5640 camera support via overlays
  media: i2c: ov5640: Add reset controller support with GPIO fallback

 arch/arm64/boot/dts/freescale/Makefile        |  7 ++
 .../dts/freescale/imx8mq-evk-ov5640-csi1.dtso | 69 ++++++++++++++++
 .../dts/freescale/imx8mq-evk-ov5640-csi2.dtso | 65 +++++++++++++++
 arch/arm64/boot/dts/freescale/imx8mq-evk.dts  | 50 ++++++++++++
 drivers/media/i2c/ov5640.c                    | 80 ++++++++++++++++---
 5 files changed, 261 insertions(+), 10 deletions(-)
 create mode 100644 arch/arm64/boot/dts/freescale/imx8mq-evk-ov5640-csi1.dtso
 create mode 100644 arch/arm64/boot/dts/freescale/imx8mq-evk-ov5640-csi2.dtso

-- 
2.50.1