On 3 August 2015 at 08:19, Simon Glass sjg@chromium.org wrote:
Add a new I2C_MUX uclass. Devices in this class can multiplex between several I2C buses, selecting them one at a time for use by the system. The multiplexing mechanism is left to the driver to decide - it may be controlled by GPIOs, for example.
The uclass supports only two methods: select() and deselect().
The current mux state is expected to be stored in the mux itself since it is the only thing that knows how to make things work. The mux can record the current state and then avoid switching unless it is necessary. So select() can be skipped if the mux is already in the correct state. Also deselect() can be made a nop if required.
Signed-off-by: Simon Glass sjg@chromium.org
Changes in v2:
- Update commit message and header file to better explain select()/deselect()
doc/device-tree-bindings/i2c/i2c-mux.txt | 60 ++++++++++ drivers/i2c/Kconfig | 2 + drivers/i2c/Makefile | 2 + drivers/i2c/muxes/Kconfig | 8 ++ drivers/i2c/muxes/Makefile | 6 + drivers/i2c/muxes/i2c-mux-uclass.c | 198 +++++++++++++++++++++++++++++++ include/dm/uclass-id.h | 1 + include/i2c.h | 39 ++++++ 8 files changed, 316 insertions(+) create mode 100644 doc/device-tree-bindings/i2c/i2c-mux.txt create mode 100644 drivers/i2c/muxes/Kconfig create mode 100644 drivers/i2c/muxes/Makefile create mode 100644 drivers/i2c/muxes/i2c-mux-uclass.c
Applied to u-boot-dm.