| Bin Meng | e1bed0a | 2019-07-18 00:33:59 -0700 | [diff] [blame] | 1 | .. SPDX-License-Identifier: GPL-2.0+ |
| 2 | |
| Simon Glass | 12c420c | 2015-11-20 10:48:47 -0700 | [diff] [blame] | 3 | How to port a serial driver to driver model |
| 4 | =========================================== |
| 5 | |
| Simon Glass | 90f437f | 2016-01-31 09:16:17 -0700 | [diff] [blame] | 6 | Almost all of the serial drivers have been converted as at January 2016. These |
| 7 | ones remain: |
| Simon Glass | 12c420c | 2015-11-20 10:48:47 -0700 | [diff] [blame] | 8 | |
| Bin Meng | e1bed0a | 2019-07-18 00:33:59 -0700 | [diff] [blame] | 9 | * serial_bfin.c |
| 10 | * serial_pxa.c |
| Simon Glass | 12c420c | 2015-11-20 10:48:47 -0700 | [diff] [blame] | 11 | |
| Simon Glass | 90f437f | 2016-01-31 09:16:17 -0700 | [diff] [blame] | 12 | The deadline for this work was the end of January 2016. If no one steps |
| 13 | forward to convert these, at some point there may come a patch to remove them! |
| Simon Glass | 12c420c | 2015-11-20 10:48:47 -0700 | [diff] [blame] | 14 | |
| 15 | Here is a suggested approach for converting your serial driver over to driver |
| 16 | model. Please feel free to update this file with your ideas and suggestions. |
| 17 | |
| 18 | - #ifdef out all your own serial driver code (#ifndef CONFIG_DM_SERIAL) |
| 19 | - Define CONFIG_DM_SERIAL for your board, vendor or architecture |
| 20 | - If the board does not already use driver model, you need CONFIG_DM also |
| 21 | - Your board should then build, but will not boot since there will be no serial |
| Bin Meng | e1bed0a | 2019-07-18 00:33:59 -0700 | [diff] [blame] | 22 | driver |
| Simon Glass | 12c420c | 2015-11-20 10:48:47 -0700 | [diff] [blame] | 23 | - Add the U_BOOT_DRIVER piece at the end (e.g. copy serial_s5p.c for example) |
| 24 | - Add a private struct for the driver data - avoid using static variables |
| 25 | - Implement each of the driver methods, perhaps by calling your old methods |
| 26 | - You may need to adjust the function parameters so that the old and new |
| Bin Meng | e1bed0a | 2019-07-18 00:33:59 -0700 | [diff] [blame] | 27 | implementations can share most of the existing code |
| Simon Glass | 12c420c | 2015-11-20 10:48:47 -0700 | [diff] [blame] | 28 | - If you convert all existing users of the driver, remove the pre-driver-model |
| Bin Meng | e1bed0a | 2019-07-18 00:33:59 -0700 | [diff] [blame] | 29 | code |
| Simon Glass | 12c420c | 2015-11-20 10:48:47 -0700 | [diff] [blame] | 30 | |
| 31 | In terms of patches a conversion series typically has these patches: |
| 32 | - clean up / prepare the driver for conversion |
| 33 | - add driver model code |
| 34 | - convert at least one existing board to use driver model serial |
| 35 | - (if no boards remain that don't use driver model) remove the old code |
| 36 | |
| 37 | This may be a good time to move your board to use device tree also. Mostly |
| 38 | this involves these steps: |
| 39 | |
| 40 | - define CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE |
| 41 | - add your device tree files to arch/<arch>/dts |
| 42 | - update the Makefile there |
| 43 | - Add stdout-path to your /chosen device tree node if it is not already there |
| 44 | - build and get u-boot-dtb.bin so you can test it |
| 45 | - Your drivers can now use device tree |
| 46 | - For device tree in SPL, define CONFIG_SPL_OF_CONTROL |