Date: Fri, 2 May 2014 16:46:02 -0400 From: Winston Smith <smith.winston.101@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: FreeBSD ARM <freebsd-arm@freebsd.org> Subject: Re: BBB/I2C: Read PMIC data Message-ID: <CADH-AwER3hMhwY2i%2BJh4Fe04ZLYcRQ-e0gy==eotPgyZ0ZOnDA@mail.gmail.com> In-Reply-To: <C419C325-4354-4490-B7A8-29F4A606FD47@bsdimp.com> References: <CADH-AwGbnqzGqbzpV9YMgdOciLpoy3fqxF1RtCmMPZtgc%2BAcXg@mail.gmail.com> <53633440.3070702@hot.ee> <CADH-AwHKKXDTotrk_tQMsZ0WToyk55JgZEmLk0AkHJzGLiGKvA@mail.gmail.com> <C419C325-4354-4490-B7A8-29F4A606FD47@bsdimp.com>
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On Fri, May 2, 2014 at 11:30 AM, Warner Losh <imp@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@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
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