From bd1ccf9408e6155564530af5e09b53ae497fe332 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?N=C3=ADcolas=20F=2E=20R=2E=20A=2E=20Prado?=
 <nfraprado@collabora.com>
Date: Thu, 6 Jul 2023 11:37:36 -0400
Subject: [PATCH 29/42] thermal/drivers/mediatek/lvts_thermal: Don't leave
 threshold zeroed
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The thermal framework might leave the low threshold unset if there
aren't any lower trip points. This leaves the register zeroed, which
translates to a very high temperature for the low threshold. The
interrupt for this threshold is then immediately triggered, and the
state machine gets stuck, preventing any other temperature monitoring
interrupts to ever trigger.

(The same happens by not setting the Cold or Hot to Normal thresholds
when using those)

Set the unused threshold to a valid low value. This value was chosen so
that for any valid golden temperature read from the efuse, when the
value is converted to raw and back again to milliCelsius, the result
doesn't underflow.

Fixes: f5f633b18234 ("thermal/drivers/mediatek: Add the Low Voltage Thermal Sensor driver")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230706153823.201943-6-nfraprado@collabora.com
---
 drivers/thermal/mediatek/lvts_thermal.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/thermal/mediatek/lvts_thermal.c
+++ b/drivers/thermal/mediatek/lvts_thermal.c
@@ -83,6 +83,8 @@
 
 #define LVTS_HW_SHUTDOWN_MT8195		105000
 
+#define LVTS_MINIMUM_THRESHOLD		20000
+
 static int golden_temp = LVTS_GOLDEN_TEMP_DEFAULT;
 static int coeff_b = LVTS_COEFF_B;
 
@@ -294,7 +296,7 @@ static int lvts_set_trips(struct thermal
 {
 	struct lvts_sensor *lvts_sensor = thermal_zone_device_priv(tz);
 	void __iomem *base = lvts_sensor->base;
-	u32 raw_low = lvts_temp_to_raw(low);
+	u32 raw_low = lvts_temp_to_raw(low != -INT_MAX ? low : LVTS_MINIMUM_THRESHOLD);
 	u32 raw_high = lvts_temp_to_raw(high);
 
 	/*
@@ -306,11 +308,9 @@ static int lvts_set_trips(struct thermal
 	 *
 	 * 14-0 : Raw temperature for threshold
 	 */
-	if (low != -INT_MAX) {
-		pr_debug("%s: Setting low limit temperature interrupt: %d\n",
-			 thermal_zone_device_type(tz), low);
-		writel(raw_low, LVTS_OFFSETL(base));
-	}
+	pr_debug("%s: Setting low limit temperature interrupt: %d\n",
+		 thermal_zone_device_type(tz), low);
+	writel(raw_low, LVTS_OFFSETL(base));
 
 	/*
 	 * High offset temperature threshold
