[PATCH] ARM: dts: am335x-bone* enable pmic-shutdown-controller

Pantelis Antoniou pantelis.antoniou at konsulko.com
Mon May 18 11:01:26 PDT 2015

Hi Tony,

> On May 18, 2015, at 20:03 , Tony Lindgren <tony at atomide.com> wrote:
> * Robert Nelson <robertcnelson at gmail.com> [150518 09:51]:
>> On Mon, May 18, 2015 at 11:29 AM, Tony Lindgren <tony at atomide.com> wrote:
>>> * Robert Nelson <robertcnelson at gmail.com> [150518 09:15]:
>>>> On Mon, May 18, 2015 at 10:21 AM, Tony Lindgren <tony at atomide.com> wrote:
>>>> All the rev information is in the board's eeprom:
>>>> hexdump -e '8/1 "%c"' /sys/bus/i2c/devices/0-0050/eeprom -s 12 -n 4
>>>> Rev A5B
>>>> 0A5B
>>>> Rev C
>>>> 000C
>>>> Just another default qwerk to add to Pantelis' bone_capemgr. ;)
>>> It seems we should not even instantiate some devices on BBB
>>> until the EEPROM is parsed.. So maybe something like this:
>>> 1. The problem devices are initially set with status = "disabled"
>>>   in the dts
>>> 2. We set up drivers/*/bbb-eeprom.c that parses the board
>>>   revision at module_init time, and then flips the selected
>>>   devices to have status = "enabled" and populates the revision
>>>   info based on the eeprom and SoC revision passed in pdata.
>>>   Then those devices get their struct device created and
>>>   probed, but at a much later time.
>>> So rather than trying to init all that early, let's just
>>> init them much later when we have the proper I2C driver
>>> running?
>> I see that working just fine.  We (beagleboard.org) enforce the eeprom
>> data, as all the official images require a proper baseboard eeprom.
> OK
>> We just have to be very careful to limit the scope, otherwise we will
>> end up with Pantelis' rejected capebus from the v3.2.x days...
> Naturally I was thinking #2 above would use Pantelis' code for
> CONFIG_OF_OVERLAY in mainline. But instead of the earlier patches,
> we can make things happen much later on to avoid the detect of
> EEPROM early on.

Already been taken care of:


The patchset works, but it still needs some review eyeballs.
There might be a rename to variants or something.

You were part of that thread too :)

I think it’s best if we go this path instead of twiddling with the
status properties manually. Conceptually the idea is similar to
the detection of the white/black, with the added joy of revision

Ain’t hardware designers a fun bunch or what?

> Regards,
> Tony


— Pantelis

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