thermal: intel Quark SoC X1000 DTS thermal driver

In Intel Quark SoC X1000, there is one on-die digital temperature sensor(DTS).
The DTS offers both hot & critical trip points.

However, in current distribution of UEFI BIOS for Quark platform, only
critical trip point is configured to be 105 degree Celsius (based on Quark
SW ver1.0.1 and hot trip point is not used due to lack of IRQ.

There is no active cooling device for Quark SoC, so Quark SoC thermal
management logic expects Linux distro to orderly power-off when temperature
of the DTS exceeds the configured critical trip point.

Kernel param "polling_delay" in milliseconds is used to control the frequency
the DTS temperature is read by thermal framework. It defaults to 2-second.
To change it, use kernel boot param "intel_quark_dts_thermal.polling_delay=X".

User interacts with Quark SoC DTS thermal driver through sysfs via:
/sys/class/thermal/thermal_zone0/

For example:
 - to read DTS temperature
   $ cat temp
 - to read critical trip point
   $ cat trip_point_0_temp
 - to read trip point type
   $ cat trip_point_0_type
 - to emulate temperature raise to test orderly shutdown by Linux distro
   $ echo 105 > emul_temp

Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Reviewed-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Reviewed-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

drivers/thermal/Kconfig

@@ -272,6 +272,16 @@ config INTEL_SOC_DTS_THERMAL
 	  notification methods.The other trip is a critical trip point, which
 	  was set by the driver based on the TJ MAX temperature.
 
+config INTEL_QUARK_DTS_THERMAL
+	tristate "Intel Quark DTS thermal driver"
+	depends on X86_INTEL_QUARK
+	help
+	  Enable this to register Intel Quark SoC (e.g. X1000) platform digital
+	  temperature sensor (DTS). For X1000 SoC, it has one on-die DTS.
+	  The DTS will be registered as a thermal zone. There are two trip points:
+	  hot & critical. The critical trip point default value is set by
+	  underlying BIOS/Firmware.
+
 config INT340X_THERMAL
 	tristate "ACPI INT340X thermal drivers"
 	depends on X86 && ACPI

drivers/thermal/Makefile

@@ -36,6 +36,7 @@ obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
 obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o
 obj-$(CONFIG_INTEL_SOC_DTS_IOSF_CORE)	+= intel_soc_dts_iosf.o
 obj-$(CONFIG_INTEL_SOC_DTS_THERMAL)	+= intel_soc_dts_thermal.o
+obj-$(CONFIG_INTEL_QUARK_DTS_THERMAL)	+= intel_quark_dts_thermal.o
 obj-$(CONFIG_TI_SOC_THERMAL)	+= ti-soc-thermal/
 obj-$(CONFIG_INT340X_THERMAL)  += int340x_thermal/
 obj-$(CONFIG_ST_THERMAL)	+= st/