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Date:      Fri, 2 May 2014 10:24:34 -0400
From:      Winston Smith <smith.winston.101@gmail.com>
To:        "Sulev-Madis Silber (ketas)" <madis555@hot.ee>
Cc:        FreeBSD ARM <freebsd-arm@freebsd.org>
Subject:   Re: BBB/I2C: Read PMIC data
Message-ID:  <CADH-AwHKKXDTotrk_tQMsZ0WToyk55JgZEmLk0AkHJzGLiGKvA@mail.gmail.com>
In-Reply-To: <53633440.3070702@hot.ee>
References:  <CADH-AwGbnqzGqbzpV9YMgdOciLpoy3fqxF1RtCmMPZtgc%2BAcXg@mail.gmail.com> <53633440.3070702@hot.ee>

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On Fri, May 2, 2014 at 1:59 AM, Sulev-Madis Silber (ketas)
<madis555@hot.ee> wrote:
> Could you look into reading data from PMIC? I tried... there is all the
> code that shows power status on boot... there are PMIC I2C specs...
> there is your code... however I clearly can't write C enough to get that
> one byte out of PMIC and displayed in human-readable form.

Hmmm ... I'm reading reg 0x0 (CHIPID) and 0xA (STATUS) from the PMIC @
address 0x24 on I2C0, but I get strange values:

root@beaglebone:~ # ./bbb_pmic
TPS65217 PMIC @ address 24:
ChipID: 3D (Unknown) rev 1.13
Status: 00


0x3D isn't a valid CHIPID according to the TPS65217 datasheet; and
0x00 doesn't look like a valid value for the status register (there
should be some 1's in there to indicate the ACPWR or USBPWR).

I wonder if the device has been "claimed" by the kernel and is inaccessible?



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