doc/driver-model/serial-howto.txt

   1 How to port a serial driver to driver model
   2 ===========================================
   3
   4 About 16 of 33 serial drivers have been converted as at September 2015. It
   5 is time for maintainers to start converting over the remaining serial drivers:
   6
   7    altera_jtag_uart.c
   8    altera_uart.c
   9    arm_dcc.c
  10    lpc32xx_hsuart.c
  11    mcfuart.c
  12    mxs_auart.c
  13    opencores_yanu.c
  14    serial_bfin.c
  15    serial_imx.c
  16    serial_lpuart.c
  17    serial_max3100.c
  18    serial_pxa.c
  19    serial_s3c24x0.c
  20    serial_sa1100.c
  21    serial_stm32.c
  22    serial_xuartlite.c
  23    usbtty.c
  24
  25 You should complete this by the end of January 2016.
  26
  27 Here is a suggested approach for converting your serial driver over to driver
  28 model. Please feel free to update this file with your ideas and suggestions.
  29
  30 - #ifdef out all your own serial driver code (#ifndef CONFIG_DM_SERIAL)
  31 - Define CONFIG_DM_SERIAL for your board, vendor or architecture
  32 - If the board does not already use driver model, you need CONFIG_DM also
  33 - Your board should then build, but will not boot since there will be no serial
  34     driver
  35 - Add the U_BOOT_DRIVER piece at the end (e.g. copy serial_s5p.c for example)
  36 - Add a private struct for the driver data - avoid using static variables
  37 - Implement each of the driver methods, perhaps by calling your old methods
  38 - You may need to adjust the function parameters so that the old and new
  39     implementations can share most of the existing code
  40 - If you convert all existing users of the driver, remove the pre-driver-model
  41     code
  42
  43 In terms of patches a conversion series typically has these patches:
  44 - clean up / prepare the driver for conversion
  45 - add driver model code
  46 - convert at least one existing board to use driver model serial
  47 - (if no boards remain that don't use driver model) remove the old code
  48
  49 This may be a good time to move your board to use device tree also. Mostly
  50 this involves these steps:
  51
  52 - define CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE
  53 - add your device tree files to arch/<arch>/dts
  54 - update the Makefile there
  55 - Add stdout-path to your /chosen device tree node if it is not already there
  56 - build and get u-boot-dtb.bin so you can test it
  57 - Your drivers can now use device tree
  58 - For device tree in SPL, define CONFIG_SPL_OF_CONTROL