staging: omap-thermal: document _omap_bandgap_read_threshold function

Add documentation of the function for reading alert thresholds
Signed-off-by: NEduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/omap-thermal/omap-bandgap.c

@@ -510,6 +510,18 @@ int _omap_bandgap_write_threshold(struct omap_bandgap *bg_ptr, int id, int val,
 	return ret;
 }
 
+/**
+ * _omap_bandgap_read_threshold() - helper to read TALERT t_cold or t_hot
+ * @bg_ptr: struct omap_bandgap pointer
+ * @id: bandgap sensor id
+ * @val: value (mCelsius) of a threshold
+ * @hot: desired threshold to be read. true if threshold hot, false if
+ *       threshold cold
+ *
+ * It will fetch the required thresholds (hot and cold) for TALERT signal.
+ * This function can be used to read t_hot or t_cold, depending on @hot value.
+ * Call this function only if bandgap features HAS(TALERT).
+ */
 int _omap_bandgap_read_threshold(struct omap_bandgap *bg_ptr, int id,
 				 int *val, bool hot)
 {