[U-Boot] [PATCH 0/4] Align U-Boot I2C DM bus ID handling with Linux

[Michal Simek]

U-Boot with I2C_DM enabled is not capable to list i2c busses connected
to i2c mux. For getting this work there is a need to find out highest
alias ID and use this uniq number for new buses connected to I2C mux.
This series is making this happen.

There is only one missing piece which is that also i2c controllers which
are not listed in DT are not using this feature.
For getting this work it would be necessary to setup dev->req_seq in
pre_bind function.

int i2c_pre_bind(struct udevice *dev)
{
	if (dev->req_seq == -1) {
		dev->req_seq = ++i2c_highest_id;
	}
	return 0;
}

It can be done also in post_bind but it looks quite weird that
controller has highest ID then i2c-mux sub-buses connected to it.
For example:
ZynqMP> i2c bus
Bus 3:	i2c at ff020000
   20: gpio at 20, offset len 1, flags 0
   21: gpio at 21, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus 0:	i2c at ff020000->i2c-mux at 75->i2c at 0
Bus 1:	i2c at ff020000->i2c-mux at 75->i2c at 1
Bus 2:	i2c at ff020000->i2c-mux at 75->i2c at 2
Bus 17:	i2c at ff030000
   74: i2c-mux at 74, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus 4:	i2c at ff030000->i2c-mux at 74->i2c at 0
Bus 5:	i2c at ff030000->i2c-mux at 74->i2c at 1
Bus 6:	i2c at ff030000->i2c-mux at 74->i2c at 2
Bus 7:	i2c at ff030000->i2c-mux at 74->i2c at 3
...

That's why I think it would be better to introduce pre_bind hooks and
call it in device_bind_common() before binding childs.

Thanks,
Michal


Michal Simek (4):
  dm: core: Add of_alias_get_highest_id()
  fdt: Introduce fdtdec_get_alias_highest_id()
  i2c: dm: Record maximum id of devices before probing devices
  i2c: mux: Add support for not listed sub-buses

 drivers/core/of_access.c           | 18 ++++++++++++++++++
 drivers/i2c/i2c-uclass.c           | 19 +++++++++++++++++++
 drivers/i2c/muxes/i2c-mux-uclass.c | 35 +++++++++++++++++++++++++++++++++--
 include/dm/of_access.h             |  9 +++++++++
 include/fdtdec.h                   | 13 +++++++++++++
 include/i2c.h                      |  3 +++
 lib/fdtdec.c                       | 33 +++++++++++++++++++++++++++++++++
 7 files changed, 128 insertions(+), 2 deletions(-)

-- 
1.9.1