ACPI: fan: Add additional attributes for fine grain control

Add additional attributes, which helps in implementing algorithm in
the user space to optimize fan control. These attributes are presented
in the same directory as the existing performance state attributes.

Additional attributes:

1. Support of fine grain control
Publish support of presence of fine grain control so that fan speed
can be tuned correctly. This attribute is called "fine_grain_control".

2. fan speed
Publish the actual fan rpm in sysfs. Knowing fan rpm is helpful to
reduce noise level and use passive control instead. Also fan performance
may not be same over time, so the same control value may not be enough
to run the fan at a speed. So a feedback value of speed is helpful. This
sysfs attribute is called "fan_speed_rpm".

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/acpi/fan_core.c b/drivers/acpi/fan_core.c
index 01616ec2e9ac..b9a9a59ddcc1 100644
--- a/drivers/acpi/fan_core.c
+++ b/drivers/acpi/fan_core.c
@@ -75,7 +75,7 @@ static int fan_get_max_state(struct thermal_cooling_device *cdev, unsigned long
 	return 0;
 }
 
-static int acpi_fan_get_fst(struct acpi_device *device, struct acpi_fan_fst *fst)
+int acpi_fan_get_fst(struct acpi_device *device, struct acpi_fan_fst *fst)
 {
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 	union acpi_object *obj;