A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-30 11:41:38 -04:00
Code Issues Projects Releases Packages Wiki Activity

i2c: add ACPI support for I2C mux ports

Browse source 
Although I2C mux devices are easily enumerated using ACPI (_HID/_CID or
device property compatible string match), enumerating I2C client devices
connected through an I2C mux needs a little extra work.

This change implements a method for describing an I2C device hierarchy that
includes mux devices by using an ACPI Device() for each mux channel along
with an _ADR to set the channel number for the device.  See
Documentation/acpi/i2c-muxes.txt for a simple example.

To make this work the ismt, i801, and designware pci/platform devs now
share an ACPI companion with their I2C adapter dev similar to how it's done
in OF.  This is done on the assumption that power management functions will
not be called directly on the I2C dev that is sharing the ACPI node.

Acked-by: Mika Westerberg <[email protected]>
Tested-by: Mika Westerberg <[email protected]>
Signed-off-by: Dustin Byford <[email protected]>
Signed-off-by: Wolfram Sang <[email protected]>
This commit is contained in:
Dustin Byford 2015-10-23 12:27:07 -07:00 • committed by Wolfram Sang
commit 8eb5c87a92
7 changed files with 76 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

58
Documentation/acpi/i2c-muxes.txt Normal file
View file

@ -0,0 +1,58 @@
ACPI I2C Muxes
--------------
Describing an I2C device hierarchy that includes I2C muxes requires an ACPI
Device () scope per mux channel.
Consider this topology:
+------+ +------+
| SMB1 |-->| MUX0 |--CH00--> i2c client A (0x50)
| | | 0x70 |--CH01--> i2c client B (0x50)
+------+ +------+
which corresponds to the following ASL:
Device (SMB1)
{
Name (_HID, ...)
Device (MUX0)
{
Name (_HID, ...)
Name (_CRS, ResourceTemplate () {
I2cSerialBus (0x70, ControllerInitiated, I2C_SPEED,
AddressingMode7Bit, "^SMB1", 0x00,
ResourceConsumer,,)
}
Device (CH00)
{
Name (_ADR, 0)
Device (CLIA)
{
Name (_HID, ...)
Name (_CRS, ResourceTemplate () {
I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
AddressingMode7Bit, "^CH00", 0x00,
ResourceConsumer,,)
}
}
}
Device (CH01)
{
Name (_ADR, 1)
Device (CLIB)
{
Name (_HID, ...)
Name (_CRS, ResourceTemplate () {
I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
AddressingMode7Bit, "^CH01", 0x00,
ResourceConsumer,,)
}
}
}
}
}