thermal: add imx thermal driver support

This is based on the initial imx thermal work done by
Rob Lee <rob.lee@linaro.org> (Not sure if the email address is still
valid).  Since he is no longer interested in the work and I have
rewritten a significant amount of the code, I just took the authorship
over from him.

It adds the imx thermal support using Temperature Monitor (TEMPMON)
block found on some Freescale i.MX SoCs.  The driver uses syscon regmap
interface to access TEMPMON control registers and calibration data, and
supports cpufreq as the cooling device.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>

Documentation/devicetree/bindings/thermal/imx-thermal.txt

@@ -0,0 +1,17 @@
+* Temperature Monitor (TEMPMON) on Freescale i.MX SoCs
+
+Required properties:
+- compatible : "fsl,imx6q-thermal"
+- fsl,tempmon : phandle pointer to system controller that contains TEMPMON
+  control registers, e.g. ANATOP on imx6q.
+- fsl,tempmon-data : phandle pointer to fuse controller that contains TEMPMON
+  calibration data, e.g. OCOTP on imx6q.  The details about calibration data
+  can be found in SoC Reference Manual.
+
+Example:
+
+tempmon {
+	compatible = "fsl,imx6q-tempmon";
+	fsl,tempmon = <&anatop>;
+	fsl,tempmon-data = <&ocotp>;
+};

drivers/thermal/Kconfig

@@ -91,6 +91,17 @@ config THERMAL_EMULATION
 	  because userland can easily disable the thermal policy by simply
 	  flooding this sysfs node with low temperature values.
 
+config IMX_THERMAL
+	tristate "Temperature sensor driver for Freescale i.MX SoCs"
+	depends on CPU_THERMAL
+	depends on MFD_SYSCON
+	depends on OF
+	help
+	  Support for Temperature Monitor (TEMPMON) found on Freescale i.MX SoCs.
+	  It supports one critical trip point and one passive trip point.  The
+	  cpufreq is used as the cooling device to throttle CPUs when the
+	  passive trip is crossed.
+
 config SPEAR_THERMAL
 	bool "SPEAr thermal sensor driver"
 	depends on PLAT_SPEAR

drivers/thermal/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_EXYNOS_THERMAL)	+= exynos_thermal.o
 obj-$(CONFIG_DOVE_THERMAL)  	+= dove_thermal.o
 obj-$(CONFIG_DB8500_THERMAL)	+= db8500_thermal.o
 obj-$(CONFIG_ARMADA_THERMAL)	+= armada_thermal.o
+obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
 obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o
 obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
 obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o