Hi Tony, > On May 18, 2015, at 20:03 , Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > * Robert Nelson <robertcnelson@xxxxxxxxx> [150518 09:51]: >> On Mon, May 18, 2015 at 11:29 AM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: >>> * Robert Nelson <robertcnelson@xxxxxxxxx> [150518 09:15]: >>>> On Mon, May 18, 2015 at 10:21 AM, Tony Lindgren <tony@xxxxxxxxxxx> 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: https://lkml.org/lkml/2015/2/18/258 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 detection. Ain’t hardware designers a fun bunch or what? > Regards, > > Tony Regards — Pantelis -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
