iio/scmi: Adding support for IIO SCMI Based Sensors

This change provides ARM SCMI Protocol based IIO device.
This driver provides support for Accelerometer and Gyroscope using
SCMI Sensor Protocol extensions added in the SCMIv3.0 ARM specification
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jyoti Bhayana <jbhayana@google.com>
Link: https://lore.kernel.org/r/20210212172235.507028-2-jbhayana@google.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20210309231259.78050-2-jbhayana@google.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -8692,6 +8692,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/multiplexer/io-channel-mux.txt
 F:	drivers/iio/multiplexer/iio-mux.c
 
+IIO SCMI BASED DRIVER
+M:	Jyoti Bhayana <jbhayana@google.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	drivers/iio/common/scmi_sensors/scmi_iio.c
+
 IIO SUBSYSTEM AND DRIVERS
 M:	Jonathan Cameron <jic23@kernel.org>
 R:	Lars-Peter Clausen <lars@metafoo.de>

drivers/firmware/arm_scmi/driver.c

@@ -741,7 +741,7 @@ static struct scmi_prot_devnames devnames[] = {
 	{ SCMI_PROTOCOL_SYSTEM, { "syspower" },},
 	{ SCMI_PROTOCOL_PERF,   { "cpufreq" },},
 	{ SCMI_PROTOCOL_CLOCK,  { "clocks" },},
-	{ SCMI_PROTOCOL_SENSOR, { "hwmon" },},
+	{ SCMI_PROTOCOL_SENSOR, { "hwmon", "iiodev" },},
 	{ SCMI_PROTOCOL_RESET,  { "reset" },},
 	{ SCMI_PROTOCOL_VOLTAGE,  { "regulator" },},
 };

drivers/iio/common/Kconfig

@@ -6,5 +6,6 @@
 source "drivers/iio/common/cros_ec_sensors/Kconfig"
 source "drivers/iio/common/hid-sensors/Kconfig"
 source "drivers/iio/common/ms_sensors/Kconfig"
+source "drivers/iio/common/scmi_sensors/Kconfig"
 source "drivers/iio/common/ssp_sensors/Kconfig"
 source "drivers/iio/common/st_sensors/Kconfig"

drivers/iio/common/Makefile

@@ -11,5 +11,6 @@
 obj-y += cros_ec_sensors/
 obj-y += hid-sensors/
 obj-y += ms_sensors/
+obj-y += scmi_sensors/
 obj-y += ssp_sensors/
 obj-y += st_sensors/

drivers/iio/common/scmi_sensors/Kconfig

+#
+# IIO over SCMI
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "IIO SCMI Sensors"
+
+config IIO_SCMI
+	tristate "IIO SCMI"
+        depends on ARM_SCMI_PROTOCOL
+        select IIO_BUFFER
+        select IIO_KFIFO_BUF
+	help
+          Say yes here to build support for IIO SCMI Driver.
+          This provides ARM SCMI Protocol based IIO device.
+          This driver provides support for accelerometer and gyroscope
+          sensors available on SCMI based platforms.
+endmenu

drivers/iio/common/scmi_sensors/Makefile

+# SPDX - License - Identifier : GPL - 2.0 - only
+#
+# Makefile for the IIO over SCMI
+#
+obj-$(CONFIG_IIO_SCMI) += scmi_iio.o