linux/Documentation/ABI/testing/sysfs-driver-intc_sar
Shravan S dcfbd31ef4 platform/x86: BIOS SAR driver for Intel M.2 Modem
Dynamic BIOS SAR driver exposing dynamic SAR information from BIOS

The Dynamic SAR (Specific Absorption Rate) driver uses ACPI DSM
(Device Specific Method) to communicate with BIOS and retrieve
dynamic SAR information and change notifications. The driver uses
sysfs to expose this data to userspace via read and notify.

Sysfs interface is documented in detail under:
Documentation/ABI/testing/sysfs-driver-intc_sar

Signed-off-by: Shravan S <s.shravan@intel.com>
Link: https://lore.kernel.org/r/20210723211452.27995-2-s.shravan@intel.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2021-08-20 12:09:41 +02:00

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What: /sys/bus/platform/devices/INTC1092:00/intc_reg
Date: August 2021
KernelVersion: 5.15
Contact: Shravan S <s.shravan@intel.com>,
An Sudhakar <sudhakar.an@intel.com>
Description:
Specific Absorption Rate (SAR) regulatory mode is typically
derived based on information like mcc (Mobile Country Code) and
mnc (Mobile Network Code) that is available for the currently
attached LTE network. A userspace application is required to set
the current SAR regulatory mode on the Dynamic SAR driver using
this sysfs node. Such an application can also read back using
this sysfs node, the currently configured regulatory mode value
from the Dynamic SAR driver.
Acceptable regulatory modes are:
== ====
0 FCC
1 CE
2 ISED
== ====
- The regulatory mode value has one of the above values.
- The default regulatory mode used in the driver is 0.
What: /sys/bus/platform/devices/INTC1092:00/intc_data
Date: August 2021
KernelVersion: 5.15
Contact: Shravan S <s.shravan@intel.com>,
An Sudhakar <sudhakar.an@intel.com>
Description:
This sysfs entry is used to retrieve Dynamic SAR information
emitted/maintained by a BIOS that supports Dynamic SAR.
The retrieved information is in the order given below:
- device_mode
- bandtable_index
- antennatable_index
- sartable_index
The above information is sent as integer values separated
by a single space. This information can then be pushed to a
WWAN modem that uses this to control the transmit signal
level using the Band/Antenna/SAR table index information.
These parameters are derived/decided by aggregating
device-mode like laptop/tablet/clamshell etc. and the
proximity-sensor data available to the embedded controller on
given host. The regulatory mode configured on Dynamic SAR
driver also influences these values.
The userspace applications can poll for changes to this file
using POLLPRI event on file-descriptor (fd) obtained by opening
this sysfs entry. Application can then read this information from
the sysfs node and consume the given information.