thermal/drivers/exynos: Stop using the threshold mechanism on Exynos 4210

Exynos 4210 supports setting a base threshold value, which is added to
all trip points. This might be useful, but is not really necessary in
our usecase, so we always set it to 0 to simplify the code a bit.

Additionally, this change makes it so that we convert the value to the
calibrated one in a slightly different place. This is more correct
morally, though it does not make any change when single-point
calibration is being used (which is the case currently).
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Mateusz Majewski <m.majewski2@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20231201095625.301884-7-m.majewski2@samsung.com

drivers/thermal/samsung/exynos_tmu.c

@@ -343,20 +343,7 @@ static void exynos_tmu_control(struct platform_device *pdev, bool on)
 static void exynos4210_tmu_set_trip_temp(struct exynos_tmu_data *data,
 					 int trip_id, u8 temp)
 {
-	struct thermal_trip trip;
-	u8 ref, th_code;
-
-	if (thermal_zone_get_trip(data->tzd, 0, &trip))
-		return;
-
-	ref = trip.temperature / MCELSIUS;
-
-	if (trip_id == 0) {
-		th_code = temp_to_code(data, ref);
-		writeb(th_code, data->base + EXYNOS4210_TMU_REG_THRESHOLD_TEMP);
-	}
-
-	temp -= ref;
+	temp = temp_to_code(data, temp);
 	writeb(temp, data->base + EXYNOS4210_TMU_REG_TRIG_LEVEL0 + trip_id * 4);
 }
 
@@ -371,6 +358,8 @@ static void exynos4210_tmu_initialize(struct platform_device *pdev)
 	struct exynos_tmu_data *data = platform_get_drvdata(pdev);
 
 	sanitize_temp_error(data, readl(data->base + EXYNOS_TMU_REG_TRIMINFO));
+
+	writeb(0, data->base + EXYNOS4210_TMU_REG_THRESHOLD_TEMP);
 }
 
 static void exynos4412_tmu_set_trip_temp(struct exynos_tmu_data *data,