Date: Fri, 2 May 2014 09:30:11 -0600 From: Warner Losh <imp@bsdimp.com> To: Winston Smith <smith.winston.101@gmail.com> Cc: FreeBSD ARM <freebsd-arm@freebsd.org> Subject: Re: BBB/I2C: Read PMIC data Message-ID: <C419C325-4354-4490-B7A8-29F4A606FD47@bsdimp.com> In-Reply-To: <CADH-AwHKKXDTotrk_tQMsZ0WToyk55JgZEmLk0AkHJzGLiGKvA@mail.gmail.com> References: <CADH-AwGbnqzGqbzpV9YMgdOciLpoy3fqxF1RtCmMPZtgc%2BAcXg@mail.gmail.com> <53633440.3070702@hot.ee> <CADH-AwHKKXDTotrk_tQMsZ0WToyk55JgZEmLk0AkHJzGLiGKvA@mail.gmail.com>
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--Apple-Mail=_64858297-1955-45FA-A052-B5977587DD8A Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On May 2, 2014, at 8:24 AM, Winston Smith <smith.winston.101@gmail.com> = wrote: > 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. >=20 > Hmmm ... I'm reading reg 0x0 (CHIPID) and 0xA (STATUS) from the PMIC @ > address 0x24 on I2C0, but I get strange values: >=20 > root@beaglebone:~ # ./bbb_pmic > TPS65217 PMIC @ address 24: > ChipID: 3D (Unknown) rev 1.13 > Status: 00 >=20 >=20 > 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). >=20 > I wonder if the device has been "claimed" by the kernel and is = inaccessible? 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. Warner --Apple-Mail=_64858297-1955-45FA-A052-B5977587DD8A Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJTY7oDAAoJEGwc0Sh9sBEAk1AP/imfctYnJ7yiDhqIHNLsMD5A 8ZP6EGSUIz4s2cAlaYH6jRGbL+dtmuXb3VPH8qJgQdmk83pkHK60Arnbiqhwq/ja pdaxAmWJZJnuh/18WFKdsv9VGREwXAXDWWtMjEFHejuH20sa/7VWaS7WAgB41MXj UhMU8Dpjoif9BKhIpO4O+T1nhk1ZVhmH/tq9LpLrr19ae6ezYBmweC0l8pdfq51h 0x2xnKvDCtOodDNBucU3sfJvCIgmBjpWmIP1uG4scnG+GOlx+XlkyPRQ21ZAw+bE DEGgNDlDraHIxjLp1AlLP7gnexZ4pvFcJSgjKqDCV4I/T0p3Hy/ZF9ywx8rthApd rL5yxOZtT6TrnUio5Lintpz0HO1jQjabr+N2RzC1wS+d0ERIGEAqcXtLwrfjJRqv v/8Av3Va69wT+wx7Lj5LRUmKkih64RS3ligc3ve5MSOmwLqMU14UKA/PP8Eg3T+Z bOAg4pzK9n6w5QBv7UCUoxt862C8KRYSGd9eR8sV+yMPbPTAixx/BESI2YygubqG ExOf/haK2A42Hu5WMIniwqWb8v7h+qUqtWY5eHnZ0ZkMsWN+EKYFJpbTbEutrvgt qt0brfqcfMATilTpgVWWv7O6p2UF0RbvcI3j3/ojSheAF7UD8xh8/ZOtdTIMBCA+ dFWRap4a993nuxL4oPyO =zmGe -----END PGP SIGNATURE----- --Apple-Mail=_64858297-1955-45FA-A052-B5977587DD8A--
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