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Commit | Line | Data |
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6ccb4101 SG |
1 | How to port a serial driver to driver model |
2 | =========================================== | |
3 | ||
4 | Over half of the I2C drivers have been converted as at November 2016. These | |
5 | ones remain: | |
6 | ||
7 | adi_i2c | |
8 | davinci_i2c | |
9 | fti2c010 | |
10 | ihs_i2c | |
11 | kona_i2c | |
12 | lpc32xx_i2c | |
13 | pca9564_i2c | |
14 | ppc4xx_i2c | |
15 | rcar_i2c | |
16 | sh_i2c | |
17 | sh_sh7734_i2c | |
18 | soft_i2c | |
19 | tsi108_i2c | |
20 | zynq_i2c | |
21 | ||
22 | The deadline for this work is the end of June 2017. If no one steps | |
23 | forward to convert these, at some point there may come a patch to remove them! | |
24 | ||
25 | Here is a suggested approach for converting your I2C driver over to driver | |
26 | model. Please feel free to update this file with your ideas and suggestions. | |
27 | ||
28 | - #ifdef out all your own I2C driver code (#ifndef CONFIG_DM_I2C) | |
29 | - Define CONFIG_DM_I2C for your board, vendor or architecture | |
30 | - If the board does not already use driver model, you need CONFIG_DM also | |
31 | - Your board should then build, but will not work fully since there will be | |
32 | no I2C driver | |
33 | - Add the U_BOOT_DRIVER piece at the end (e.g. copy tegra_i2c.c for example) | |
34 | - Add a private struct for the driver data - avoid using static variables | |
35 | - Implement each of the driver methods, perhaps by calling your old methods | |
36 | - You may need to adjust the function parameters so that the old and new | |
37 | implementations can share most of the existing code | |
38 | - If you convert all existing users of the driver, remove the pre-driver-model | |
39 | code | |
40 | ||
41 | In terms of patches a conversion series typically has these patches: | |
42 | - clean up / prepare the driver for conversion | |
43 | - add driver model code | |
44 | - convert at least one existing board to use driver model serial | |
45 | - (if no boards remain that don't use driver model) remove the old code | |
46 | ||
47 | This may be a good time to move your board to use device tree also. Mostly | |
48 | this involves these steps: | |
49 | ||
50 | - define CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE | |
51 | - add your device tree files to arch/<arch>/dts | |
52 | - update the Makefile there | |
53 | - Add stdout-path to your /chosen device tree node if it is not already there | |
54 | - build and get u-boot-dtb.bin so you can test it | |
55 | - Your drivers can now use device tree | |
56 | - For device tree in SPL, define CONFIG_SPL_OF_CONTROL |