Gentle ping. Still waiting for any [2/2] review. Should I resend? On 2022-07-12 at 17:19 +03, Mikhail Rudenko <mike.rudenko@xxxxxxxxx> wrote: > Hello, > > this series implements support for Omnivision OV4689 image > sensor. The Omnivision OV4689 is a high performance, 1/3-inch, 4 > megapixel image sensor. Ihis chip supports high frame rate speeds up > to 90 fps at 2688x1520 resolution. It is programmable through an I2C > interface, and sensor output is sent via 1/2/4 lane MIPI CSI-2 > connection. > > The driver is based on Rockchip BSP kernel [1]. It implements 4-lane CSI-2 > and single 2688x1520 @ 30 fps mode. The driver was tested on Rockchip > 3399-based FriendlyElec NanoPi M4 board with MCAM400 camera module. > > While porting the driver, I stumbled upon two issues: > > (1) In the original driver, horizontal total size (HTS) was set to a > value (2584) lower then the frame width (2688), resulting in negative > hblank. In this driver, I increased HTS to 2688, but fps dropped from > 29.88 to 28.73. What is the preferred way to handle this? > > (2) The original driver exposes analog gain range 0x0 - 0x7ff, but the > gain is not linear across that range. Instead, it is piecewise linear > (and discontinuous). 0x0-0xff register values result in 0x-2x gain, > 0x100-0x1ff to 0x-4x, 0x300-0x3ff to 0x-8x, and 0x700-0x7ff to 0x-16x, > with more linear segments in between. Rockchip's camera engine code > chooses one of the above segments depenging on the desired gain > value. The question is, how should we proceed keeping in mind > libcamera use case? Should the whole 0x0-0x7ff be exposed as-is and > libcamera will do the mapping, or the driver will do the mapping > itself and expose some logical gain units not tied to the actual gain > register value? Meanwhile, this driver conservatively exposes only > 0x0-0xf8 gain register range. > > [1] https://github.com/rockchip-linux/kernel/blob/develop-4.19/drivers/media/i2c/ov4689.c > > Mikhail Rudenko (2): > media: dt-bindings: media: i2c: document OV4689 DT bindings > media: i2c: add support for ov4689 > > .../bindings/media/i2c/ovti,ov4689.yaml | 122 +++ > MAINTAINERS | 8 + > drivers/media/i2c/Kconfig | 14 + > drivers/media/i2c/Makefile | 1 + > drivers/media/i2c/ov4689.c | 899 ++++++++++++++++++ > 5 files changed, 1044 insertions(+) > create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov4689.yaml > create mode 100644 drivers/media/i2c/ov4689.c -- Best regards, Mikhail Rudenko
