CC'ed Rebecca & Chia Ee for their response/attention. 

Short answer, we have both ACPI and PCI enumeration support for those low power 
IO like I2C, SPI, HS-UART. 
You can refer to 
http://git.yoctoproject.org/cgit/cgit.cgi/linux-yocto-3.8/tree/meta/cfg/kernel-cache/features/valleyisland-io?h=meta
 for v3.8.

For your knowledge, we are in the midst of making support for v3.10 too and we 
prefer that your long term goal is to converge into Linux LTS/LTSI. But, it is 
fine to try out v3.8 and eventually move to v3.10.   


From: linux-yocto-boun...@yoctoproject.org 
[mailto:linux-yocto-boun...@yoctoproject.org] On Behalf Of Sathish Kumar 
Balasubramaniam -ERS, HCL Tech
Sent: Tuesday, April 15, 2014 10:41 PM
To: linux-yo...@yoctoproject.org; Darren Hart (dvh...@linux.intel.com)
Subject: [linux-yocto] Regarding clarifications for adding support of I2C, SPI 
slave devices on x86 through ACPI
Importance: High

Hi,

For Intel, I can understand that the community is advising to implement the 
I2C, SPI slave devices info like base address, IRQs, etc through ACPI mechanism 
rather than using Board files and FDT

I read the following 
https://www.kernel.org/doc/Documentation/acpi/enumeration.txt
https://events.linuxfoundation.org/images/stories/slides/lfcs2013_wysocki.pdf

In Linux Kernel 3.8 we are trying to add support for (I2C, SPI) slave devices 
like video output decoder, video input decoder, etc which are behind the bus 
controllers

For ex, for adding support of ADV7180 through I2C

I have the following clarifications

1. Do we need any modification in the BIOS for adding support of I2C, SPI slave 
devices to Linux using ACPI ?
2. Do we need to add the CONFIG_ACPI code (described in "I2C serial bus 
support" section of acpi/enumeration.txt) to the drivers/media/i2c/adv7180.c 
file ?
3. Where we need to add the device info like I2C bus number, I2C slave address, 
IRQ ?
4. Do we need to add any additional code in the chip driver specifically for 
this ACPI support ?
5. We have an Intel reference board. The source code provided by Intel itself 
used certain board files to add support for SPI slave devices, Clock setup, 
Init, etc. Why it has been done without using ACPI ? Is it due to any 
restriction ?


Thanks,
B.Sathish Kumar


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