[MinnowBoard] i2c support

[John 'Warthog9' Hawley]

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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