Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/Documentation/acpi/i2c-muxes.txt b/Documentation/acpi/i2c-muxes.txt
new file mode 100644
index 000000000..9fcc4f0b8
--- /dev/null
+++ b/Documentation/acpi/i2c-muxes.txt
@@ -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,,)
+                }
+            }
+        }
+    }
+}