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