[U-Boot] [PATCH v2 0/7] Align U-Boot I2C DM bus ID handling with Linux

[Heiko Schocher]

Hello Michal,

Am 05.02.2019 um 08:57 schrieb Michal Simek:
> Hi Simon,
> 
> On 02. 02. 19 15:10, Simon Glass wrote:
>> Hi Michal,
>>
>> On Thu, 31 Jan 2019 at 08:31, Michal Simek <michal.simek at xilinx.com> wrote:
>>>
>>> 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.
>>>
>>> Removing setting up aliases from i2c mux code and unifying it in the
>>> same code ensures that numbering schema is proper if no alias is
>>> specified.
>>>
>>> ZynqMP> i2c bus
>>> Bus 0:  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 1:  i2c at ff020000->i2c-mux at 75->i2c at 0
>>> Bus 2:  i2c at ff020000->i2c-mux at 75->i2c at 1
>>> Bus 3:  i2c at ff020000->i2c-mux at 75->i2c at 2
>>> Bus 4:  i2c at ff030000  (active 4)
>>>     74: i2c-mux at 74, offset len 1, flags 0
>>>     75: i2c-mux at 75, offset len 1, flags 0
>>> Bus 5:  i2c at ff030000->i2c-mux at 74->i2c at 0  (active 5)
>>>     54: eeprom at 54, offset len 1, flags 0
>>> Bus 6:  i2c at ff030000->i2c-mux at 74->i2c at 1
>>> Bus 7:  i2c at ff030000->i2c-mux at 74->i2c at 2
>>> Bus 8:  i2c at ff030000->i2c-mux at 74->i2c at 3
>>> Bus 9:  i2c at ff030000->i2c-mux at 74->i2c at 4
>>> Bus 10: i2c at ff030000->i2c-mux at 75->i2c at 0
>>> Bus 11: i2c at ff030000->i2c-mux at 75->i2c at 1
>>> Bus 12: i2c at ff030000->i2c-mux at 75->i2c at 2
>>> Bus 13: i2c at ff030000->i2c-mux at 75->i2c at 3
>>> Bus 14: i2c at ff030000->i2c-mux at 75->i2c at 4
>>> Bus 15: i2c at ff030000->i2c-mux at 75->i2c at 5
>>> Bus 16: i2c at ff030000->i2c-mux at 75->i2c at 6
>>> Bus 17: i2c at ff030000->i2c-mux at 75->i2c at 7
>>>
>>> Thanks,
>>> Michal
>>>
>>> Changes in v2:
>>> - Update kernel-doc binding
>>> - Return -1 in case of error. -1 means that the next free alias is 0.
>>> - New patch
>>> - New patch
>>> - Use dev_read_alias_highest_id()
>>> - Use uclass private data
>>> - Use private uclass data
>>> - Fix headers
>>> - Change patch description to focus only on bus name
>>
>> I don't have strong objections to this series, but I'd still like to
>> try a bit harder on the existing req_seq/seq stuff.
>>
>> I don't think we necessarily need to set the 'seq' before probe,
>> although I suppose we could.
>>
>> But is there anything to stop us moving some of the logic which sets
>> seq to setting req_seq? We could check the aliases and then set
>> req_seq during bind(), perhaps?
> 
> Let me put this to my TODO list. But it is not a task which you know
> will be done in some hours. It requires to study the whole logic if this
> works for all cases.

For me it is okay to do this in a second step.

@Simon: Can you give the patcheseries a formal Reviewed-by?

>> This would be better for code size since it would help all subsystems.
> 
> This approach is used in the linux kernel that's why there is no way to
> get rid of dev_read_alias_highest_id() as function.
> It means only i2c_uclass_init() and little code in i2c_post_bind() could
> be removed. That's why I don't think we will improve size a lot.
> If this is copied to other subsystems then yes it will be more useful.
> If we have just one now we can't save a lot.
> 
> Heiko: Can you please take a look at this series? I have another 7
> patches on the top of this series which depends on it which cleanup all
> zynq/zynqmp platforms and I would like to close this to be able to move.

ASAP as I was ill the last 2 weeks ... sorry, give me some time.


bye,
Heiko
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