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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[-- Attachment #1 --] 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. > > 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? 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 [-- Attachment #2 --] -----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-----help
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