[Gta04-owner] I2C3 on the GTA04

[Dr. H. Nikolaus Schaller]

Hi Paul,

Am 24.07.2014 um 19:07 schrieb Paul Kocialkowski:

> I'm currently working on an OMAP3630 phone (P970, LG Optimus Black),
> where I am attempting to port X-Loader to it. To make it easier for me,
> I'm using the GTA04 as a reference platforms, since its DM3730 is close
> enough to the OMAP3630.

Nice project!

Yes, they are almost the same chips. Maybe a beta-stage chip tapeout.

And they should be compatible to the OMAP3530 - so I would not
expect that there are significant differences in the programming model.

> On the P970, X-Loader starts, I have serial, RAM clocks and a few other
> things working nicely, but I need to use the I2C3 lines to activate the
> MMC1 (sd card) power supply, which is provided by an external PMIC (not
> TWL5030) connected to I2C3.
> 
> Despite all my attempts, I cannot get I2C3 to work on the P970, so I
> figured I would try on the GTA04 and work from there, but it doesn't
> seem to work either. From the U-Boot prompt:
> 
> GTA04 # i2c probe
> Valid chip addresses: 48 49 4A 4B
> 
> This is on I2C1 (default) and the chips that show up are the TWL4030
> modules.

Yes.

> 
> GTA04 # i2c dev 1
> Setting bus to 1
> GTA04 # i2c probe
> Valid chip addresses: 11 1E 33 41 45 48 50 54 68 77
> 
> This is on I2C2 and the chips are the various GTA04 ICs.

Yes.

You can also use our proprietary command "systest" [1]

> 
> When it comes to I2C3:
> GTA04 # i2c dev 2
> Setting bus to 2
> GTA04 # i2c probe
> Valid chip addresses:timed out in wait_for_bb: I2C_STAT=1000
> timed out in wait_for_bb: I2C_STAT=1000
> 
> Do you have any idea of why it doesn't work on either device? That could
> really help me sort out the situation for P970, where I2C3 is actually
> needed!
> 
> I2C3 does require external pullup resistors, which are present on P970
> but I'm not sure about GTA04, so that might be causing the issue on the
> GTA04, but not on P970.

The GTA04 has no pull-ups on I2C3, but you can enable the pullups
on pinmux. This should solve the "I2C_STAT" message.

Regarding I2C in x-loader or u-boot I think it must be configured to support
multiple I2C busses.

Hope this helps,
Nikolaus

http://projects.goldelico.com/p/gta04-uboot/page/NewCommands/