[MinnowBoard] i2c support

John Hawley warthog9 at eaglescrag.net
Fri Mar 4 21:11:36 UTC 2016


What's the problem with reading? Is this a MAX, or a Turbot? I2C on the MAX has a known issue with the level shifter on those pins not always working with some devices (I2C needs slightly different shifters), that's fixed on the Turbot right now.

- John

On March 4, 2016 10:46:20 AM PST, Tony <tony.makkiel at daqri.com> wrote:
>Hi John 'Warthog9' Hawley,
>	Thank you very much. It is bus 7. I can see the clock when I run
>i2cget.
>
>I guess something might be wrong with my led controller, which cause
>the 
>read to fail. But thanks to you I know Minnowboard is working :)
>
>Many Thanks,
>Tony
>
>On 04/03/16 16:38, John 'Warthog9' Hawley wrote:
>> The LSE and HSE's I2C is on physical interface #5 (which is the
>> DesignWare IP), but that doesn't mean it enumerates in the OS to #5. 
>In
>> your i2cdetect you'll note that the first DesignWare adapter is on
>bus
>> #7.  Re-running your tests on that bus should get you what you are
>> expecting.  I *HAVE* seen in a couple of cases where i2cdetect on the
>> bus won't report some devices, but if you attempt to read/write
>directly
>> to the address (I.E. just assume it's there) things work.  The issue
>> there is that some devices don't quite implement smbus / i2c quite
>right
>> and get confused on how to respond to the detection.
>>
>> Let me know if that works, and if it doesn't we'll try some
>additional
>> things.
>>
>> - John 'Warthog9' Hawley
>>
>> On 03/04/2016 07:58 AM, Tony wrote:
>>> Hi,
>>>      I am trying to talk to TI led controller using i2c#5, pin 13
>and 15.
>>> But for some reason I cant get the i2c pins working. I tried
>connecting
>>> i2c probe on the pins. But don't see any clock when I do i2cdetect.
>>>
>>> sudo i2cdetect -y 5
>>>
>>> I am using xubuntu kernel 4.4. The related kernel modules I could
>find are
>>>
>>> i2c_designware_platform and i2c_designware_core
>>>
>>> For some reason i2c-5 is getting used by display driver.
>>>
>>> i2cdetect -l
>>> i2c-0    unknown       i915 gmbus ssc                      N/A
>>> i2c-1    unknown       i915 gmbus vga                      N/A
>>> i2c-2    unknown       i915 gmbus panel                    N/A
>>> i2c-3    unknown       i915 gmbus dpc                      N/A
>>> i2c-4    unknown       i915 gmbus dpb                      N/A
>>> i2c-5    unknown       i915 gmbus dpd                      N/A
>>> i2c-6    unknown       DPDDC-B                             N/A
>>> i2c-7    unknown       Synopsys DesignWare I2C adapter     N/A
>>> i2c-8    unknown       Synopsys DesignWare I2C adapter     N/A
>>>
>>>
>>> Any suggestions on what I might be doing wrong?
>>>
>>> Many Thanks,
>>> Tony
>>> _______________________________________________
>>> elinux-MinnowBoard mailing list
>>> elinux-MinnowBoard at lists.elinux.org
>>> http://lists.elinux.org/mailman/listinfo/elinux-minnowboard
>>>
>>
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