| Simon Glass | 1d149ed | 2015-11-20 10:48:47 -0700 | [diff] [blame^] | 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 |