Hello Simon,
Am 23.11.2016 um 14:34 schrieb Simon Glass:
Add a README with a brief guide to porting i2c drivers over to use driver model.
Add a timeline also. All I2C drivers should be converted by the end of June 2017.
Signed-off-by: Simon Glass sjg@chromium.org
doc/driver-model/i2c-howto.txt | 56 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 doc/driver-model/i2c-howto.txt
Thanks!
Acked-by: Heiko Schocher hs@denx.de
bye, Heiko
diff --git a/doc/driver-model/i2c-howto.txt b/doc/driver-model/i2c-howto.txt new file mode 100644 index 0000000..605d3ef --- /dev/null +++ b/doc/driver-model/i2c-howto.txt @@ -0,0 +1,56 @@ +How to port a serial driver to driver model +===========================================
+Over half of the I2C drivers have been converted as at November 2016. These +ones remain:
- adi_i2c
- davinci_i2c
- fti2c010
- ihs_i2c
- kona_i2c
- lpc32xx_i2c
- pca9564_i2c
- ppc4xx_i2c
- rcar_i2c
- sh_i2c
- sh_sh7734_i2c
- soft_i2c
- tsi108_i2c
- zynq_i2c
+The deadline for this work is the end of June 2017. If no one steps +forward to convert these, at some point there may come a patch to remove them!
+Here is a suggested approach for converting your I2C driver over to driver +model. Please feel free to update this file with your ideas and suggestions.
+- #ifdef out all your own I2C driver code (#ifndef CONFIG_DM_I2C) +- Define CONFIG_DM_I2C for your board, vendor or architecture +- If the board does not already use driver model, you need CONFIG_DM also +- Your board should then build, but will not work fully since there will be
- no I2C driver
+- Add the U_BOOT_DRIVER piece at the end (e.g. copy tegra_i2c.c for example) +- Add a private struct for the driver data - avoid using static variables +- Implement each of the driver methods, perhaps by calling your old methods +- You may need to adjust the function parameters so that the old and new
- implementations can share most of the existing code
+- If you convert all existing users of the driver, remove the pre-driver-model
- code
+In terms of patches a conversion series typically has these patches: +- clean up / prepare the driver for conversion +- add driver model code +- convert at least one existing board to use driver model serial +- (if no boards remain that don't use driver model) remove the old code
+This may be a good time to move your board to use device tree also. Mostly +this involves these steps:
+- define CONFIG_OF_CONTROL and CONFIG_OF_SEPARATE +- add your device tree files to arch/<arch>/dts +- update the Makefile there +- Add stdout-path to your /chosen device tree node if it is not already there +- build and get u-boot-dtb.bin so you can test it +- Your drivers can now use device tree +- For device tree in SPL, define CONFIG_SPL_OF_CONTROL