summaryrefslogtreecommitdiff
path: root/Documentation/firmware-guide
diff options
context:
space:
mode:
authorChangbin Du <changbin.du@gmail.com>2019-04-25 01:52:54 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-04-25 23:07:20 +0200
commit572c9fa516f532d6cfd7123d7753fe52730f1c59 (patch)
tree905366cf7b7dfc5b643cb272f1aaf621de4e5fa4 /Documentation/firmware-guide
parent34bf473baef086ec0e277ffb0dbddb697da9f02e (diff)
Documentation: ACPI: move i2c-muxes.txt to firmware-guide/acpi and convert to reST
This converts the plain text documentation to reStructuredText format and adds it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/firmware-guide')
-rw-r--r--Documentation/firmware-guide/acpi/i2c-muxes.rst61
-rw-r--r--Documentation/firmware-guide/acpi/index.rst3
2 files changed, 63 insertions, 1 deletions
diff --git a/Documentation/firmware-guide/acpi/i2c-muxes.rst b/Documentation/firmware-guide/acpi/i2c-muxes.rst
new file mode 100644
index 000000000000..3a8997ccd7c4
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/i2c-muxes.rst
@@ -0,0 +1,61 @@
+.. 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,,)
+ }
+ }
+ }
+ }
+ }
diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst
index d1d069b26bbc..1c89888f6ee8 100644
--- a/Documentation/firmware-guide/acpi/index.rst
+++ b/Documentation/firmware-guide/acpi/index.rst
@@ -12,4 +12,5 @@ ACPI Support
osi
method-customizing
DSD-properties-rules
- gpio-properties \ No newline at end of file
+ gpio-properties
+ i2c-muxes