@Graham
Thank you very much for your response. I went back to the (BBB without
reserved I2C
addresses)[https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!searchin/beagleboard/BBB$20without$20reserved$20i2c$20addresses%7Csort:date/beagleboard/NG8cDWuv2Y0/XGzZ3SJIBQAJ]
and followed @RobertCNelson's post, switched to branch 4.4-ti, changed the
include at line 11 to "am335x-bone-common-no-capemgr.dtsi". make and then
make install and finally reboot. All compiled and got installed but when I
boot back into my BB i still am seeing the U under the addresses 0x54-0x57
for i2c-2.
debian@beaglebone:~$ i2cdetect -y -r 2
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- UU UU UU UU -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
when I check the dmesg I can see that cape manger is still enabled
(uboot_capemgr_enabled=1):
debian@beaglebone:~$ dmesg | grep cape
[ 0.000000] Kernel command line: console=ttyO0,115200n8
bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk1p1 ro rootfstype=ext4
rootwait coherent_pool=1M net.ifnames=0 quiet
[ 1.138635] gpio-of-helper ocp:cape-universal: Allocated GPIO id=0
[ 1.138782] gpio-of-helper ocp:cape-universal: Allocated GPIO id=1
[ 1.138793] gpio-of-helper ocp:cape-universal: ready
I know I'm missing something here to make it all work and be able to access
EEPROM @ 0x57 but do not know where else I need to disable it?
On Wednesday, October 31, 2018 at 12:14:23 PM UTC-4, Graham Haddock wrote:
>
> Detailed discussion on Apr 17 2017.
>
> --- Graham
>
> ==
>
> On Wed, Oct 31, 2018 at 10:15 AM Graham Haddock <[email protected]
> <javascript:>> wrote:
>
>> I think there is a detailed discussion as to what is supposed to be
>> inside the cape EEPROMs in the
>> "BeagleBone Black System Reference Manual"
>>
>> It looks like there is a live Wiki version at
>>
>> https://github.com/beagleboard/beaglebone-black/wiki/System-Reference-Manual
>>
>> But since that address has already been reserved by the kernel, for the
>> cape manager,
>> you will not be able to read/write it from user space.
>>
>> If you want to access that address from user space on a BBB, you need to
>> stop the cape manager.
>> Google "BBB without reserved I2C addresses" on this forum.
>> and look at "am335x-bone-common-no-capemgr.dtsi"
>>
>> --- Graham
>>
>> ==
>>
>>
>> On Wed, Oct 31, 2018 at 10:01 AM MG <[email protected] <javascript:>>
>> wrote:
>>
>>> @Graham I do have a cape with EEPROM at address 0x57 but the EEPROM is
>>> wiped with nothing on it so I guess that is why the board doesn't populate
>>> that address by default. How can I fix that?
>>>
>>> On Tuesday, October 30, 2018 at 11:14:50 PM UTC-4, [email protected]
>>> wrote:
>>>>
>>>> Those addresses at 0x54-0x57 are reserved by the kernel driver.
>>>>
>>>> Unless you have some capes with those EEPROMS populated, there is
>>>> nothing actually there.
>>>>
>>>> --- Graham
>>>>
>>>> ==
>>>>
>>>> On Tuesday, October 30, 2018 at 7:01:27 PM UTC-5, MG wrote:
>>>>>
>>>>> The BeagleBoneBlack comes with an "internal" EEPROM connected to i2c-0
>>>>> line. I can see that clearly when I do i2cdetect:
>>>>>
>>>>> debian@beaglebone:~$ i2cdetect -y -r 0
>>>>> 0 1 2 3 4 5 6 7 8 9 a b c d e f
>>>>> 00: -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 20: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- --
>>>>> 30: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- --
>>>>> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 50: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 70: UU -- -- -- -- -- -- --
>>>>>
>>>>> It is showing under address 0x50. When I try to do ahexdump I get the
>>>>> following values with no issue:
>>>>>
>>>>> sudo hexdump -C /sys/class/i2c-dev/i2c-0/device/0-0050/eeprom |
>>>>> head -5
>>>>> 00000000 aa 55 33 ee 41 33 33 35 42 4e 4c 54 30 30 30 43
>>>>> |.U3.A335BNLT000C|
>>>>> 00000010 31 38 33 37 42 42 42 47 30 36 32 32 ff ff ff ff
>>>>> |1837BBBG0622....|
>>>>> 00000020 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>>>>> |................|
>>>>> *
>>>>> 00001000 aa 55 33 ee 41 33 33 35 42 4e 4c 54 30 30 30 43
>>>>> |.U3.A335BNLT000C|
>>>>>
>>>>> Now I want to add another EEPROM (with cape) on i2c-2 line which is
>>>>> supported according to [BBB SRM](
>>>>> https://cdn-shop.adafruit.com/datasheets/BBB_SRM.pdf) section 8.2. It
>>>>> is the CAT24C256 as mentioned in the SRM. The allowable address range for
>>>>> the expansion cards is 0x54-0x57. When I do i2cdetect I can see the
>>>>> following:
>>>>>
>>>>> debian@beaglebone:~$ i2cdetect -r -y 2
>>>>> 0 1 2 3 4 5 6 7 8 9 a b c d e f
>>>>> 00: -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 50: -- -- -- -- UU UU UU UU -- -- -- -- -- -- -- --
>>>>> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>>>> 70: -- -- -- -- -- -- -- --
>>>>>
>>>>> I can see the addresses 0x54-0x57 showing, but when I try hex dump I
>>>>> get an error:
>>>>>
>>>>> hexdump: /sys/class/i2c-dev/i2c-2/device/2-0054/eeprom:
>>>>> Connection timed out
>>>>>
>>>>> Questions:
>>>>>
>>>>> 1. Why are they showing as U's not actual address numbers? I know U
>>>>> stands for used resource?
>>>>> 2. Why am I failing to read from that EEPROM? I have tried all
>>>>> addreses from 0x54-0x57 with no luck. I can confirm that those addresses
>>>>> are showing in /sys/class/i2c-dev/i2c-2/device and the each dir has the
>>>>> following in it:
>>>>>
>>>>> debian@beaglebone:~$ ls
>>>>> /sys/class/i2c-dev/i2c-2/device/2-0054/ -la
>>>>> total 0
>>>>> drwxr-xr-x 4 root root 0 Oct 26 19:46 .
>>>>> drwxr-xr-x 8 root root 0 Oct 26 19:46 ..
>>>>> drwxr-xr-x 3 root root 0 Oct 26 19:47 2-00540
>>>>> lrwxrwxrwx 1 root root 0 Oct 26 19:47 driver ->
>>>>> ../../../../../../bus/i2c/drivers/at24
>>>>> -rw------- 1 root root 32768 Oct 26 19:47 eeprom
>>>>> -r--r--r-- 1 root root 4096 Oct 26 19:47 modalias
>>>>> -r--r--r-- 1 root root 4096 Oct 26 19:47 name
>>>>> lrwxrwxrwx 1 root root 0 Oct 26 19:47 of_node ->
>>>>> ../../../../../../firmware/devicetree/base/ocp/i2c@4819c000/cape_eeprom0@54
>>>>> drwxr-xr-x 2 root root 0 Oct 26 19:47 power
>>>>> lrwxrwxrwx 1 root root 0 Oct 26 19:47 subsystem ->
>>>>> ../../../../../../bus/i2c
>>>>> -rw-r--r-- 1 root root 4096 Oct 26 19:47 uevent
>>>>>
>>>>> I can see the addresses mapping into the kernel but when I try to
>>>>> hexdump eeprom it doesn't work at all. I though this was supposed to be
>>>>> setup by kernel since it is mentioned in BeagleBone SRM. Am I going to
>>>>> need
>>>>> an overlay to add to uboot for this? It doesn't make sense since i2c-2 is
>>>>> already set up by default i.e. when I connect another device at address
>>>>> aside from 0x54-0x57 it shows up fine and I'm able to interface to it?
>>>>>
>>>>> All I'm trying to do is read from the EEPROM like I did with the
>>>>> "internal" one to confirm it is working. What am I doing wrong?
>>>>>
>>>> --
>>> For more options, visit http://beagleboard.org/discuss
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