Commit dcfbd31e authored by Shravan S's avatar Shravan S Committed by Hans de Goede
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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: default avatarShravan S <s.shravan@intel.com>
Link: https://lore.kernel.org/r/20210723211452.27995-2-s.shravan@intel.com


Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
parent ef195e8a

Documentation/ABI/testing/sysfs-driver-intc_sar

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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.

MAINTAINERS

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@@ -9220,6 +9220,13 @@ L: platform-driver-x86@vger.kernel.org 
S:	Maintained

F:	drivers/platform/x86/intel_atomisp2_led.c









INTEL BIOS SAR INT1092 DRIVER









M:	Shravan S <s.shravan@intel.com>









M:	Intel Corporation <linuxwwan@intel.com>









L:	platform-driver-x86@vger.kernel.org









S:	Maintained









F:	drivers/platform/x86/intel/int1092/

















INTEL BROXTON PMC DRIVER









M:	Mika Westerberg <mika.westerberg@linux.intel.com>









M:	Zha Qipeng <qipeng.zha@intel.com>
































drivers/platform/x86/intel/Kconfig



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@@ -16,6 +16,7 @@ menuconfig X86_PLATFORM_DRIVERS_INTEL

















if X86_PLATFORM_DRIVERS_INTEL



















source "drivers/platform/x86/intel/int1092/Kconfig"









source "drivers/platform/x86/intel/int33fe/Kconfig"









source "drivers/platform/x86/intel/int3472/Kconfig"









source "drivers/platform/x86/intel/pmt/Kconfig"
































drivers/platform/x86/intel/Makefile



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@@ -4,6 +4,7 @@







# Intel x86 Platform-Specific Drivers









#



















obj-$(CONFIG_INTEL_SAR_INT1092)		+= int1092/









obj-$(CONFIG_INTEL_CHT_INT33FE)		+= int33fe/









obj-$(CONFIG_INTEL_SKL_INT3472)		+= int3472/









obj-$(CONFIG_INTEL_PMT_CLASS)		+= pmt/
























drivers/platform/x86/intel/int1092/Kconfig
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config INTEL_SAR_INT1092









	tristate "Intel Specific Absorption Rate Driver"









	depends on ACPI









	help









	  This driver helps to limit the exposure of human body to RF frequency by









	  providing information to userspace application that will inform the Intel









	  M.2 modem to regulate the RF power based on SAR data obtained from the









	  sensors captured in the BIOS. ACPI interface exposes this data from the BIOS









	  to SAR driver. The front end application in userspace will interact with SAR









	  driver to obtain information like the device mode, Antenna index, baseband index,









	  SAR table index and use available communication like MBIM interface to enable









	  data communication to modem for RF power regulation. Enable this config when









	  given platform needs to support "Dynamic SAR" configuration for a modem available









	  on the platform.