ASR_BASE
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+.. SPDX-License-Identifier: GPL-2.0
+
+==============
+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,,)
+ }
+ }
+ }
+ }
+ }