BBB/I2C: Read PMIC data

[Sulev-Madis Silber (ketas)]

On 2014-05-02 23:46, Winston Smith wrote:
> On Fri, May 2, 2014 at 11:30 AM, Warner Losh <imp at bsdimp.com> wrote:
>> Only if the kernel is actively accessing them so your transactions are messed up.
>> In the kernel, all the bridge knows about is transactions of one flavor or another.
>> This may indicate a more fundamental issue going on, either in your belief that
>> it is at 24, or in the address (which is 7 bits) gets translated to 8 bits. Try a left
>> shift 1 bit.
> 
> Alright, figured it out. The "dummy" write that precedes the read is
> not a dummy, you're sending a command to the I2C device.  For a
> EEPROM, you send it a 2 byte address of where to read.  For the PMIC,
> you need to send it a *1-byte* register ID!
> 
> I've updated the tool and renamed it `bbb_sysutil.c`:
> 
> http://pastebin.com/NhMy9D7d
> 
> Here's the output (still working on the "interrupt storm" issue!):
> 
> root at beaglebone:~ # ./bbb_sysutil
> TPS65217 PMIC @ address 24:
> ChipID: E2 TPS65217C rev 1.2
> Status: 08 ACPWR
> interrupt storm detected on "intr70:"; throttling interrupt source
> EEPROM @ address 50: signature=AA:55:33:EE
> Model:  A335BNLT0A6A
> Serial: 0214BBBK4321
> 
> 
> Let me know if there is any more data you want from the PMIC.
> 
> -W
> 


Oh, awesome! Now I think I know why I didn't get correct results...


I would also like to share something, it's a script I use to upgrade my
BBB: http://ketas.si.pri.ee/bbb-hotinstaller.sh


BTW, you could consider adding such small files as attachments, so they
will not disappear somewhere.