[FEATURE] Support for multiple frame buffer devices #17580
Description
Is your feature request related to a problem? Please describe.
Currently, the frame buffer driver only supports registering frame buffer devices via up_fbinitialize(), which is over-written by each frame buffer driver.
A user, for instance, may want to use both the RPI4B frame buffer driver (HDMI output) and also have a frame buffer driver for a connected LED matrix peripheral. Currently this is not possible.
Describe the solution you'd like
Change the frame buffer device registration to allow multiple frame buffer devices to be registered using their own respective registration functions. In the example given, something like
bcm2711_fbregister(int disp) and led_matrix_fbregister(int disp) which can be called in board init logic.
Describe alternatives you've considered
To keep the fb_register() API, each driver's registration method could allocate some "node" for a linked list, then add that node to the global list maintained by fb_register. The up_fbuninitialize would be replaced by removing the node from the linked list. With this method, it would be possible to add many frame buffer drivers to the same board while keeping the user-facing interface the same.
Verification
- I have verified before submitting the report.