rpi_temperature: New module to monitor RPi temperature (#3587)

Module to monitor RPi cpu temperature

Signed-off-by: Al Crate <aleph@al3ph.org>

docs/Command_Templates.md

@@ -256,6 +256,8 @@ The following are common printer attributes:
   from the sensor.
 - `printer["lm75 <sensor_name>"].temperature`: The last read
   temperature from the sensor.
+- `printer["rpi_temperature <sensor_name>"].temperature`: The last read
+  temperature from the sensor.
 - `printer["temperature_sensor <config_name>"].temperature`: The last read
   temperature from the sensor.
 - `printer["temperature_sensor <config_name>"].measured_min_temp`,

docs/Config_Reference.md

@@ -2058,6 +2058,27 @@ but this mode is not used here.
 #   0.5.
 ```
 
+## RPi temperature sensor
+
+CPU temperature from  Raspberry Pi.
+
+```
+#[temperature_sensor my_sensor]
+# See the "temperature_sensor" section for a description of its
+# parameters. The parameters below describe the Raspberry Pi sensor
+# parameters.
+#sensor_type:
+#   Must be "rpi_temperature".
+min_temp: -40
+max_temp: 85
+#   The maximum safe range of temperatures (in Celsius) that the
+#   RPi must remain within. This controls a safety feature
+#   implemented in the micro-controller code - should the measured
+#   temperature ever fall outside this range then the micro-controller
+#   will go into a shutdown state. Set this range just wide
+#   enough so that reasonable temperatures do not result in an error.
+```
+
 ## [heater_generic]
 
 Generic heaters (one may define any number of sections with a