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1d149edd SG |
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 | |
1d149edd SG |
21 | serial_xuartlite.c |
22 | usbtty.c | |
23 | ||
24 | You should complete this by the end of January 2016. | |
25 | ||
26 | Here is a suggested approach for converting your serial driver over to driver | |
27 | model. Please feel free to update this file with your ideas and suggestions. | |
28 | ||
29 | - #ifdef out all your own serial driver code (#ifndef CONFIG_DM_SERIAL) | |
30 | - Define CONFIG_DM_SERIAL for your board, vendor or architecture | |
31 | - If the board does not already use driver model, you need CONFIG_DM also | |
32 | - Your board should then build, but will not boot since there will be no serial | |
33 | driver | |
34 | - Add the U_BOOT_DRIVER piece at the end (e.g. copy serial_s5p.c for example) | |
35 | - Add a private struct for the driver data - avoid using static variables | |
36 | - Implement each of the driver methods, perhaps by calling your old methods | |
37 | - You may need to adjust the function parameters so that the old and new | |
38 | implementations can share most of the existing code | |
39 | - If you convert all existing users of the driver, remove the pre-driver-model | |
40 | code | |
41 | ||
42 | In terms of patches a conversion series typically has these patches: | |
43 | - clean up / prepare the driver for conversion | |
44 | - add driver model code | |
45 | - convert at least one existing board to use driver model serial | |
46 | - (if no boards remain that don't use driver model) remove the old code | |
47 | ||
48 | This may be a good time to move your board to use device tree also. Mostly | |
49 | this involves these steps: | |
50 | ||
51 | - define CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE | |
52 | - add your device tree files to arch/<arch>/dts | |
53 | - update the Makefile there | |
54 | - Add stdout-path to your /chosen device tree node if it is not already there | |
55 | - build and get u-boot-dtb.bin so you can test it | |
56 | - Your drivers can now use device tree | |
57 | - For device tree in SPL, define CONFIG_SPL_OF_CONTROL |