[MinnowBoard] i2c support

[Tony]

I am not sure, why read fails. It is Minnowboard MAX.


I tried running i2cdetect on bus 7 which fails with error

"Error: Can't use SMBus Quick Write command on this bus"

Reading from address also fails

"sudo i2cget -y 7 0x54 0x0c
Error: Read failed"

Can the problem with level shifters be fixed on MAX boards?

Many Thanks,
Tony


On 04/03/16 21:11, John Hawley wrote:
> 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
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