soc: qcom: Add in-kernel sensors registry implementation.

Initial "Sensors Registry" daemon implementation of [1] as kernel
module.

Qualcomm Sensor Registry (SNS_REG) is a QMI service used by the
Snapdragon Sensor Core (SSC) on Qualcomm SoCs such as MSM8996 to
get platform-specific sensor data. It is served by the application
processor. This service provides SSC with the data it needs to
function, which is basically contents of binary sensor registry
file stored as firmware in qcom/sensors/sns.reg. On Android
devices this file is usually available on "persist" partition
on path: /persist/sensors/sns.reg.

This is yet another QMI service to provide firmware files for the
remote processors, like rmtfs, tqftpserv, pd_mapper and ath10k
WLAN firmware service. The structure of this driver, usage of
auxiliary device and reference counting is inspired by similar
in this regard qcom_pd_mapper driver.

[1] https://gitlab.com/msm8996-mainline/sns-reg

Signed-off-by: Alexey Minnekhanov <alexeymin@postmarketos.org>

Author: minlexx

drivers/soc/qcom/Kconfig

@@ -171,6 +171,25 @@ config QCOM_RPMH
 	  of hardware components aggregate requests for these resources and
 	  help apply the aggregated state on the resource.
 
+config QCOM_SNS_REG
+	tristate "Qualcomm Sensors Registry service"
+	select QCOM_QMI_HELPERS
+	select AUXILIARY_BUS
+	depends on NET && QRTR && (ARCH_QCOM || COMPILE_TEST)
+	default QCOM_RPROC_COMMON
+	help
+	  Qualcomm Sensor Registry is a QMI service used by the Snapdragon
+	  Sensor Core (SSC) on Qualcomm SoCs such as MSM8996 to get platform
+	  specific sensor data. It is served by the application processor, and
+	  SSC requests data from it in the form of groups of keys. This server
+	  emulates the proprietary sensor daemon used in Android and provides
+	  SSC with the data it needs to function.
+	  This sensor registry server reads a sensor registry firmware file from
+	  qcom/sensors/sns.reg to obtain data requested by SSC. On Android
+	  devices this file is usually available on "persist" partition on path:
+	  /persist/sensors/sns.reg. This service can be used to enable sensor
+	  readings on wide range of SoCs: from MSM8226 to SDM660.
+
 config QCOM_SMEM
 	tristate "Qualcomm Shared Memory Manager (SMEM)"
 	depends on ARCH_QCOM || COMPILE_TEST

drivers/soc/qcom/Makefile

@@ -23,6 +23,7 @@ obj-$(CONFIG_QCOM_RPMH)		+= qcom_rpmh.o
 qcom_rpmh-y			+= rpmh-rsc.o
 qcom_rpmh-y			+= rpmh.o
 obj-$(CONFIG_QCOM_SMD_RPM)	+= rpm-proc.o smd-rpm.o
+obj-$(CONFIG_QCOM_SNS_REG)	+= qcom_sns_reg.o
 obj-$(CONFIG_QCOM_SMEM) +=	smem.o
 obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
 CFLAGS_smp2p.o := -I$(src)