This patch serie aims to reduce parallel port rate according to maximum pixel clock frequency admissible by camera interface in front of the sensor. This allows to support any resolutions/framerate requests by decreasing the framerate according to maximum camera interface capabilities. This allows typically to enable 5Mp YUV/RGB frame capture even if 15fps framerate could not be reached by platform.
This work is based on OV5640 Maxime Ripard's runtime clock computing serie [1] which allows to adapt the clock tree registers according to maximum pixel clock. Then the first patch adds handling of pclk divider registers DVP_PCLK_DIVIDER (0x3824) and VFIFO_CTRL0C (0x460c) in order to correlate the rate to the effective pixel clock output on parallel interface. A new devicetree property "pclk-max-frequency" is introduced in order to inform sensor of the camera interface maximum admissible pixel clock. This new devicetree property handling is added to V4L2 core. Then OV5640 ov5640_set_dvp_pclk() is modified to clip rate according to optional maximum pixel clock property. References: [1] [PATCH v3 00/12] media: ov5640: Misc cleanup and improvements https://www.mail-archive.com/linux-media@vger.kernel.org/msg131655.html Hugues Fruchet (4): media: ov5640: move parallel port pixel clock divider out of registers set media: v4l2-core: add pixel clock max frequency parallel port property media: dt-bindings: media: Document pclk-max-frequency property media: ov5640: reduce rate according to maximum pixel clock frequency .../devicetree/bindings/media/video-interfaces.txt | 2 + drivers/media/i2c/ov5640.c | 78 ++++++++++++++++------ drivers/media/v4l2-core/v4l2-fwnode.c | 3 + include/media/v4l2-fwnode.h | 2 + 4 files changed, 65 insertions(+), 20 deletions(-) -- 2.7.4
