I have been looking into designing a SoM based Linux handheld with the form factor of a mobile phone and have been considering using the CM3 as my compute. Despite the lack of an open DSI spec, I'm considering the CM3 because of the wide availability of general HDMI -> MIPI DSI circuit designs and the rich RPi ecosystem. In my opinion, the availability of support, a large community, and great software availability is worth designing an HDMI -> MIPI DSI conversion circuit. I am mostly posting this to share my idea and discuss the feasibility of such a device.
So far I am designing a custom carrier board and researching solutions for power management and display interfacing to begin. I am looking at using a MIPI DSI display which will receive data via an HDMI to MIPI DSI converter IC (Toshiba TC358779XBG) since DSI is proprietary on the CM3. The touch input will be routed directly to CM3's gold fingers from the DSI connector. The DSI data and clock lanes will be routed from the connector to the converter IC and the HDMI lanes will be routed from the gold fingers to the converter IC. Considering correct impedance matching and proper routing, is this a feasible approach to driving a MIPI display using the CM3?
PS: I have access to the MIPI specification and will hunt down a display for which a comprehensive data sheet containing an initialization sequence exists. I believe that will be enough documentation to drive a display but am still just starting to research this process and am unsure on a lot of things. Correct me anywhere if I am wrong