thermal: armada: Allow to specify an 'inverted readout' sensor

In order to support inverted-formula thermal sensor readout, this commit
introduces an 'inverted' field in the SoC-specific structure which
allows to specify an inversion of the temperature formula.

Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/thermal/armada_thermal.c b/drivers/thermal/armada_thermal.c
index 6fd648337e63..f84d9f077fe2 100644
--- a/drivers/thermal/armada_thermal.c
+++ b/drivers/thermal/armada_thermal.c
@@ -56,6 +56,7 @@ struct armada_thermal_data {
         unsigned long coef_b;
         unsigned long coef_m;
         unsigned long coef_div;
+        bool inverted;
 
         /* Register shift and mask to access the sensor temperature */
         unsigned int temp_shift;
@@ -138,7 +139,10 @@ static int armada_get_temp(struct thermal_zone_device *thermal,
         m = priv->data->coef_m;
         div = priv->data->coef_div;
 
-        *temp = (b - (m * reg)) / div;
+        if (priv->data->inverted)
+                *temp = ((m * reg) - b) / div;
+        else
+                *temp = (b - (m * reg)) / div;
         return 0;
 }