thermal: qcom: tsens: Add a skeletal TSENS drivers

TSENS is Qualcomms' thermal temperature sensor device. It
supports reading temperatures from multiple thermal sensors
present on various QCOM SoCs.
Calibration data is generally read from a non-volatile memory
(eeprom) device.

Add a skeleton driver with all the necessary abstractions so
a variety of qcom device families which support TSENS can
add driver extensions.

Also add the required device tree bindings which can be used
to describe the TSENS device in DT.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/thermal/qcom-tsens.txt b/Documentation/devicetree/bindings/thermal/qcom-tsens.txt
new file mode 100644
index 000000000000..8b1f26fa2552
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/qcom-tsens.txt
@@ -0,0 +1,33 @@
+* QCOM SoC Temperature Sensor (TSENS)
+
+Required properties:
+- compatible :
+ - "qcom,msm8916-tsens" : For 8916 Family of SoCs
+ - "qcom,msm8974-tsens" : For 8974 Family of SoCs
+
+- reg: Address range of the thermal registers
+- qcom,tsens-slopes : Must contain slope value for each of the sensors controlled
+			by this device
+- #thermal-sensor-cells : Should be 1. See ./thermal.txt for a description.
+- Refer to Documentation/devicetree/bindings/nvmem/nvmem.txt to know how to specify
+nvmem cells
+
+Optional properties:
+- qcom,sensor-id: List of sensor instances used in a given SoC. A TSENS IP can
+		  have a fixed number of sensors (like 11) but a given SoC can
+		  use only 5 of these and they might not always the first 5. They
+		  could be sensors 0, 1, 4, 8 and 9. This property is used to
+		  describe the subset of the sensors used. If this property is
+		  missing they are assumed to be the first 'n' sensors numbered
+		  sequentially in which case the number of sensors defaults to
+		  the number of slope values.
+
+Example:
+tsens: thermal-sensor@900000 {
+		compatible = "qcom,msm8916-tsens";
+		nvmem-cells = <&tsens_caldata>, <&tsens_calsel>;
+		nvmem-cell-names = "caldata", "calsel";
+		qcom,tsens-slopes = <3200 3200 3200 3200 3200>;
+		qcom,sensor-id = <0 1 2 4 5>;
+		#thermal-sensor-cells = <1>;
+	};