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u-boot/doc/develop/driver-model/i2c-howto.rst

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doc: driver-model: Convert i2c-howto.txt to reST Convert plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
2019-07-18 07:33:53 +00:00
.. SPDX-License-Identifier: GPL-2.0+
How to port an I2C driver to driver model
=========================================
dm: Add timeline and guide for porting I2C drivers 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> Acked-by: Heiko Schocher <hs@denx.de>
2016-11-23 13:34:45 +00:00
Over half of the I2C drivers have been converted as at November 2016. These
ones remain:
doc: driver-model: Convert i2c-howto.txt to reST Convert plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
2019-07-18 07:33:53 +00:00
* adi_i2c
* davinci_i2c
* fti2c010
* ihs_i2c
* kona_i2c
* lpc32xx_i2c
* pca9564_i2c
* ppc4xx_i2c
* rcar_i2c
* sh_i2c
* soft_i2c
* zynq_i2c
dm: Add timeline and guide for porting I2C drivers 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> Acked-by: Heiko Schocher <hs@denx.de>
2016-11-23 13:34:45 +00:00
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.
dm: i2c: use CONFIG_IS_ENABLED macro for DM_I2C/DM_I2C_GPIO Use CONFIG_IS_ENABLED() macro, which provides more convenient way to check $(SPL)DM_I2C/$(SPL)DM_I2C_GPIO configs for both SPL and U-Boot proper. CONFIG_IS_ENABLED(DM_I2C) expands to: - 1 if CONFIG_SPL_BUILD is undefined and CONFIG_DM_I2C is set to 'y', - 1 if CONFIG_SPL_BUILD is defined and CONFIG_SPL_DM_I2C is set to 'y', - 0 otherwise. All occurences were replaced automatically using these bash cmds: $ find . -type f -exec sed -i 's/ifndef CONFIG_DM_I2C/if !CONFIG_IS_ENABLED(DM_I2C)/g' {} + $ find . -type f -exec sed -i 's/ifdef CONFIG_DM_I2C/if CONFIG_IS_ENABLED(DM_I2C)/g' {} + $ find . -type f -exec sed -i 's/defined(CONFIG_DM_I2C)/CONFIG_IS_ENABLED(DM_I2C)/g' {} + $ find . -type f -exec sed -i 's/ifndef CONFIG_DM_I2C_GPIO/if !CONFIG_IS_ENABLED(DM_I2C_GPIO)/g' {} + $ find . -type f -exec sed -i 's/ifdef CONFIG_DM_I2C_GPIO/if CONFIG_IS_ENABLED(DM_I2C_GPIO)/g' {} + $ find . -type f -exec sed -i 's/defined(CONFIG_DM_I2C_GPIO)/CONFIG_IS_ENABLED(DM_I2C_GPIO)/g' {} + Reviewed-by: Heiko Schocher <hs@denx.de> Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io> Reviewed-by: Tom Rini <trini@konsulko.com> Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
2021-02-09 11:52:45 +00:00
- #ifdef out all your own I2C driver code (#if !CONFIG_IS_ENABLED(DM_I2C))
dm: Add timeline and guide for porting I2C drivers 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> Acked-by: Heiko Schocher <hs@denx.de>
2016-11-23 13:34:45 +00:00
- 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
doc: driver-model: Convert i2c-howto.txt to reST Convert plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
2019-07-18 07:33:53 +00:00
no I2C driver
dm: Add timeline and guide for porting I2C drivers 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> Acked-by: Heiko Schocher <hs@denx.de>
2016-11-23 13:34:45 +00:00
- 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
doc: driver-model: Convert i2c-howto.txt to reST Convert plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
2019-07-18 07:33:53 +00:00
implementations can share most of the existing code
dm: Add timeline and guide for porting I2C drivers 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> Acked-by: Heiko Schocher <hs@denx.de>
2016-11-23 13:34:45 +00:00
- If you convert all existing users of the driver, remove the pre-driver-model
doc: driver-model: Convert i2c-howto.txt to reST Convert plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
2019-07-18 07:33:53 +00:00
code
dm: Add timeline and guide for porting I2C drivers 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> Acked-by: Heiko Schocher <hs@denx.de>
2016-11-23 13:34:45 +00:00
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
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