doc/driver-model/serial-howto.txt

   1 How to port a serial driver to driver model
   2 ===========================================
   3
   4 Almost all of the serial drivers have been converted as at January 2016. These
   5 ones remain:
   6
   7    serial_bfin.c
   8    serial_pxa.c
   9
  10 The deadline for this work was the end of January 2016. If no one steps
  11 forward to convert these, at some point there may come a patch to remove them!
  12
  13 Here is a suggested approach for converting your serial driver over to driver
  14 model. Please feel free to update this file with your ideas and suggestions.
  15
  16 - #ifdef out all your own serial driver code (#ifndef CONFIG_DM_SERIAL)
  17 - Define CONFIG_DM_SERIAL for your board, vendor or architecture
  18 - If the board does not already use driver model, you need CONFIG_DM also
  19 - Your board should then build, but will not boot since there will be no serial
  20     driver
  21 - Add the U_BOOT_DRIVER piece at the end (e.g. copy serial_s5p.c for example)
  22 - Add a private struct for the driver data - avoid using static variables
  23 - Implement each of the driver methods, perhaps by calling your old methods
  24 - You may need to adjust the function parameters so that the old and new
  25     implementations can share most of the existing code
  26 - If you convert all existing users of the driver, remove the pre-driver-model
  27     code
  28
  29 In terms of patches a conversion series typically has these patches:
  30 - clean up / prepare the driver for conversion
  31 - add driver model code
  32 - convert at least one existing board to use driver model serial
  33 - (if no boards remain that don't use driver model) remove the old code
  34
  35 This may be a good time to move your board to use device tree also. Mostly
  36 this involves these steps:
  37
  38 - define CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE
  39 - add your device tree files to arch/<arch>/dts
  40 - update the Makefile there
  41 - Add stdout-path to your /chosen device tree node if it is not already there
  42 - build and get u-boot-dtb.bin so you can test it
  43 - Your drivers can now use device tree
  44 - For device tree in SPL, define CONFIG_SPL_OF_CONTROL