1*4882a593SmuzhiyunHow to port a serial driver to driver model 2*4882a593Smuzhiyun=========================================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunOver half of the I2C drivers have been converted as at November 2016. These 5*4882a593Smuzhiyunones remain: 6*4882a593Smuzhiyun 7*4882a593Smuzhiyun adi_i2c 8*4882a593Smuzhiyun davinci_i2c 9*4882a593Smuzhiyun fti2c010 10*4882a593Smuzhiyun ihs_i2c 11*4882a593Smuzhiyun kona_i2c 12*4882a593Smuzhiyun lpc32xx_i2c 13*4882a593Smuzhiyun pca9564_i2c 14*4882a593Smuzhiyun ppc4xx_i2c 15*4882a593Smuzhiyun rcar_i2c 16*4882a593Smuzhiyun sh_i2c 17*4882a593Smuzhiyun sh_sh7734_i2c 18*4882a593Smuzhiyun soft_i2c 19*4882a593Smuzhiyun tsi108_i2c 20*4882a593Smuzhiyun zynq_i2c 21*4882a593Smuzhiyun 22*4882a593SmuzhiyunThe deadline for this work is the end of June 2017. If no one steps 23*4882a593Smuzhiyunforward to convert these, at some point there may come a patch to remove them! 24*4882a593Smuzhiyun 25*4882a593SmuzhiyunHere is a suggested approach for converting your I2C driver over to driver 26*4882a593Smuzhiyunmodel. Please feel free to update this file with your ideas and suggestions. 27*4882a593Smuzhiyun 28*4882a593Smuzhiyun- #ifdef out all your own I2C driver code (#ifndef CONFIG_DM_I2C) 29*4882a593Smuzhiyun- Define CONFIG_DM_I2C for your board, vendor or architecture 30*4882a593Smuzhiyun- If the board does not already use driver model, you need CONFIG_DM also 31*4882a593Smuzhiyun- Your board should then build, but will not work fully since there will be 32*4882a593Smuzhiyun no I2C driver 33*4882a593Smuzhiyun- Add the U_BOOT_DRIVER piece at the end (e.g. copy tegra_i2c.c for example) 34*4882a593Smuzhiyun- Add a private struct for the driver data - avoid using static variables 35*4882a593Smuzhiyun- Implement each of the driver methods, perhaps by calling your old methods 36*4882a593Smuzhiyun- You may need to adjust the function parameters so that the old and new 37*4882a593Smuzhiyun implementations can share most of the existing code 38*4882a593Smuzhiyun- If you convert all existing users of the driver, remove the pre-driver-model 39*4882a593Smuzhiyun code 40*4882a593Smuzhiyun 41*4882a593SmuzhiyunIn terms of patches a conversion series typically has these patches: 42*4882a593Smuzhiyun- clean up / prepare the driver for conversion 43*4882a593Smuzhiyun- add driver model code 44*4882a593Smuzhiyun- convert at least one existing board to use driver model serial 45*4882a593Smuzhiyun- (if no boards remain that don't use driver model) remove the old code 46*4882a593Smuzhiyun 47*4882a593SmuzhiyunThis may be a good time to move your board to use device tree also. Mostly 48*4882a593Smuzhiyunthis involves these steps: 49*4882a593Smuzhiyun 50*4882a593Smuzhiyun- define CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE 51*4882a593Smuzhiyun- add your device tree files to arch/<arch>/dts 52*4882a593Smuzhiyun- update the Makefile there 53*4882a593Smuzhiyun- Add stdout-path to your /chosen device tree node if it is not already there 54*4882a593Smuzhiyun- build and get u-boot-dtb.bin so you can test it 55*4882a593Smuzhiyun- Your drivers can now use device tree 56*4882a593Smuzhiyun- For device tree in SPL, define CONFIG_SPL_OF_CONTROL 57