@@ -116,6 +116,10 @@
/* The calibration coefficient of sensor */
#define MT8173_CALIBRATION 165
+/* Valid temperatures range */
+#define MT8173_TEMP_MIN -20000
+#define MT8173_TEMP_MAX 150000
+
/*
* Layout of the fuses providing the calibration data
* These macros could be used for MT8183, MT8173, MT2701, and MT2712.
@@ -689,6 +693,11 @@ static const struct mtk_thermal_data mt7986_thermal_data = {
.version = MTK_THERMAL_V3,
};
+static bool mtk_thermal_temp_is_valid(int temp)
+{
+ return (temp >= MT8173_TEMP_MIN) && (temp <= MT8173_TEMP_MAX);
+}
+
/**
* raw_to_mcelsius_v1 - convert a raw ADC value to mcelsius
* @mt: The thermal controller
@@ -815,14 +824,17 @@ static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
temp = mt->raw_to_mcelsius(
mt, conf->bank_data[bank->id].sensors[i], raw);
-
/*
- * The first read of a sensor often contains very high bogus
- * temperature value. Filter these out so that the system does
- * not immediately shut down.
+ * Depending on the filt/sen intervals and ADC polling time,
+ * we may need up to 60 milliseconds after initialization: this
+ * will result in the first reading containing an out of range
+ * temperature value.
+ * Validate the reading to both address the aforementioned issue
+ * and to eventually avoid bogus readings during runtime in the
+ * event that the AUXADC gets unstable due to high EMI, etc.
*/
- if (temp > 200000)
- temp = 0;
+ if (!mtk_thermal_temp_is_valid(temp))
+ temp = THERMAL_TEMP_INVALID;
if (temp > max)
max = temp;
The AUXADC thermal v1 allows reading temperature range between -20°C to 150°C and any value out of this range is invalid. Add new definitions for MT8173_TEMP_{MIN_MAX} and a new small helper mtk_thermal_temp_is_valid() to check if new readings are in range: if not, we tell to the API that the reading is invalid by returning THERMAL_TEMP_INVALID. It was chosen to introduce the helper function because, even though this temperature range is realistically ok for all, it comes from a downstream kernel driver for version 1, but here we also support v2 and v3 which may may have wider constraints. Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> --- drivers/thermal/mediatek/auxadc_thermal.c | 24 +++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-)