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thermal/drivers/mediatek: Add temperature constraints to validate read

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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>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230419061146.22246-3-angelogioacchino.delregno@collabora.com
This commit is contained in:
AngeloGioacchino Del Regno 2023-04-19 08:11:46 +02:00 committed by Daniel Lezcano
parent 0a677eea71
commit 47cbb0467b
1 changed files with 18 additions and 6 deletions
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24
drivers/thermal/mediatek/auxadc_thermal.c
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@ -116,6 +116,10 @@
/* The calibration coefficient of sensor */ /* The calibration coefficient of sensor */
#define MT8173_CALIBRATION 165 #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 * Layout of the fuses providing the calibration data
* These macros could be used for MT8183, MT8173, MT2701, and MT2712. * 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, .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 * raw_to_mcelsius_v1 - convert a raw ADC value to mcelsius
* @mt: The thermal controller * @mt: The thermal controller
@ -815,14 +824,17 @@ static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
temp = mt->raw_to_mcelsius( temp = mt->raw_to_mcelsius(
mt, conf->bank_data[bank->id].sensors[i], raw); mt, conf->bank_data[bank->id].sensors[i], raw);
/* /*
* The first read of a sensor often contains very high bogus * Depending on the filt/sen intervals and ADC polling time,
* temperature value. Filter these out so that the system does * we may need up to 60 milliseconds after initialization: this
* not immediately shut down. * 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) if (!mtk_thermal_temp_is_valid(temp))
temp = 0; temp = THERMAL_TEMP_INVALID;
if (temp > max) if (temp > max)
max = temp; max = temp;