summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/acpi/fan_performance_states.rst62
-rw-r--r--Documentation/admin-guide/acpi/index.rst1
-rw-r--r--Documentation/firmware-guide/acpi/enumeration.rst16
3 files changed, 71 insertions, 8 deletions
diff --git a/Documentation/admin-guide/acpi/fan_performance_states.rst b/Documentation/admin-guide/acpi/fan_performance_states.rst
new file mode 100644
index 000000000000..21d233ca50d8
--- /dev/null
+++ b/Documentation/admin-guide/acpi/fan_performance_states.rst
@@ -0,0 +1,62 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================
+ACPI Fan Performance States
+===========================
+
+When the optional _FPS object is present under an ACPI device representing a
+fan (for example, PNP0C0B or INT3404), the ACPI fan driver creates additional
+"state*" attributes in the sysfs directory of the ACPI device in question.
+These attributes list properties of fan performance states.
+
+For more information on _FPS refer to the ACPI specification at:
+
+http://uefi.org/specifications
+
+For instance, the contents of the INT3404 ACPI device sysfs directory
+may look as follows::
+
+ $ ls -l /sys/bus/acpi/devices/INT3404:00/
+ total 0
+...
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state0
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state1
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state10
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state11
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state2
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state3
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state4
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state5
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state6
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state7
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state8
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state9
+ -r--r--r-- 1 root root 4096 Dec 13 01:00 status
+ ...
+
+where each of the "state*" files represents one performance state of the fan
+and contains a colon-separated list of 5 integer numbers (fields) with the
+following interpretation::
+
+control_percent:trip_point_index:speed_rpm:noise_level_mdb:power_mw
+
+* ``control_percent``: The percent value to be used to set the fan speed to a
+ specific level using the _FSL object (0-100).
+
+* ``trip_point_index``: The active cooling trip point number that corresponds
+ to this performance state (0-9).
+
+* ``speed_rpm``: Speed of the fan in rotations per minute.
+
+* ``noise_level_mdb``: Audible noise emitted by the fan in this state in
+ millidecibels.
+
+* ``power_mw``: Power draw of the fan in this state in milliwatts.
+
+For example::
+
+ $cat /sys/bus/acpi/devices/INT3404:00/state1
+ 25:0:3200:12500:1250
+
+When a given field is not populated or its value provided by the platform
+firmware is invalid, the "not-defined" string is shown instead of the value.
diff --git a/Documentation/admin-guide/acpi/index.rst b/Documentation/admin-guide/acpi/index.rst
index 4d13eeea1eca..71277689ad97 100644
--- a/Documentation/admin-guide/acpi/index.rst
+++ b/Documentation/admin-guide/acpi/index.rst
@@ -12,3 +12,4 @@ the Linux ACPI support.
dsdt-override
ssdt-overlays
cppc_sysfs
+ fan_performance_states
diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst
index 0a72b6321f5f..c13fee8b02ba 100644
--- a/Documentation/firmware-guide/acpi/enumeration.rst
+++ b/Documentation/firmware-guide/acpi/enumeration.rst
@@ -71,8 +71,8 @@ DMA support
DMA controllers enumerated via ACPI should be registered in the system to
provide generic access to their resources. For example, a driver that would
like to be accessible to slave devices via generic API call
-dma_request_slave_channel() must register itself at the end of the probe
-function like this::
+dma_request_chan() must register itself at the end of the probe function like
+this::
err = devm_acpi_dma_controller_register(dev, xlate_func, dw);
/* Handle the error if it's not a case of !CONFIG_ACPI */
@@ -112,15 +112,15 @@ could look like::
}
#endif
-dma_request_slave_channel() will call xlate_func() for each registered DMA
-controller. In the xlate function the proper channel must be chosen based on
+dma_request_chan() will call xlate_func() for each registered DMA controller.
+In the xlate function the proper channel must be chosen based on
information in struct acpi_dma_spec and the properties of the controller
provided by struct acpi_dma.
-Clients must call dma_request_slave_channel() with the string parameter that
-corresponds to a specific FixedDMA resource. By default "tx" means the first
-entry of the FixedDMA resource array, "rx" means the second entry. The table
-below shows a layout::
+Clients must call dma_request_chan() with the string parameter that corresponds
+to a specific FixedDMA resource. By default "tx" means the first entry of the
+FixedDMA resource array, "rx" means the second entry. The table below shows a
+layout::
Device (I2C0)
{