b.g.
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Bill Gatliff
bg...@billgatliff.com
Which begs the question, how do the dual I2C links (power and control)
between the OMAP and TWL4030/TPS65950 work under Linux? Does the I2C driver
handle all the messages, especially when powering down individual domains on
the support chip (and where do the power management messages come from,
somewhere in the kernel)?
The programmers tell me all the power management magically happens in the
background, so their only task is turn the LCD backlight on and off. I am
not so sure the kernel has enough information to manage all those power
domains without some extensive knowledge of the application.
Jack Peacock
Sorry if this is a duplicate append, but my first try didn't seem to make it.
I have successfully connected from beagleboard userspace to a Gumstix robostix board over i2c. For hardware interconnect between the two boards, I had built a voltage level translation board, which used the NXP PCA9306. This was needed to level shift the 1.8 v beagleboard i2c to the 5.0 v i2c on the robostix. On the beagleboard I connected to the i2c-2 pins on the expansion connector (pin 1 for 1.8v, pin 23 for sdc, pin 24 for scl, pin 27 for ground). For the robostix board, I connected to the i2c on the UART header (pin 10 for ground, pin 14 for 5v, pin 12 for sda, pin 16 for scl). For software, on the begaleboard I used linux kernel 2.6.26-r64, with options CONFIG_I2C_OMAP and CONFIG_I2C2_OMAP_BEAGLE set to yes. For beagleboard userspace code, I used i2cdetect (from i2c-tools-3.0.1) and i2c-io (from gumstix-robostix utilities). The robostix board was running code that understood the api for the i2c-io program. Here is the output:
frank agius