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 45