summaryrefslogtreecommitdiff
path: root/Documentation/acpi
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/acpi')
-rw-r--r--Documentation/acpi/enumeration.txt11
-rw-r--r--Documentation/acpi/i2c-muxes.txt58
2 files changed, 66 insertions, 3 deletions
diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index b731b292e..a91ec5af5 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -347,13 +347,18 @@ For the first case, the MFD drivers do not need to do anything. The
resulting child platform device will have its ACPI_COMPANION() set to point
to the parent device.
-If the ACPI namespace has a device that we can match using an ACPI id,
-the id should be set like:
+If the ACPI namespace has a device that we can match using an ACPI id or ACPI
+adr, the cell should be set like:
+
+ static struct mfd_cell_acpi_match my_subdevice_cell_acpi_match = {
+ .pnpid = "XYZ0001",
+ .adr = 0,
+ };
static struct mfd_cell my_subdevice_cell = {
.name = "my_subdevice",
/* set the resources relative to the parent */
- .acpi_pnpid = "XYZ0001",
+ .acpi_match = &my_subdevice_cell_acpi_match,
};
The ACPI id "XYZ0001" is then used to lookup an ACPI device directly under
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,,)
+ }
+ }
+ }
+ }
+}