1 How to port a serial driver to driver model
2 ===========================================
4 Almost all of the serial drivers have been converted as at January 2016. These
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!
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.
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
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
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
35 This may be a good time to move your board to use device tree also. Mostly
36 this involves these steps:
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