[PATCH v3 3/9] thermal/drivers/mediatek/lvts: Guard against zero temp_factor in lvts_raw_to_temp

[Laura Nao <laura.nao@collabora.com>]

Add a guard against zero temp_factor in lvts_raw_to_temp() to prevent
division by zero and ensure safe conversion.

Fixes: 6725a29321e4 ("thermal/drivers/mediatek/lvts_thermal: Make coeff configurable")
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Fei Shao <fshao@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Laura Nao <laura.nao@collabora.com>
---
 drivers/thermal/mediatek/lvts_thermal.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/mediatek/lvts_thermal.c b/drivers/thermal/mediatek/lvts_thermal.c
index 05aa8895ccce..8398af657ba2 100644
--- a/drivers/thermal/mediatek/lvts_thermal.c
+++ b/drivers/thermal/mediatek/lvts_thermal.c
@@ -284,11 +284,14 @@ static int lvts_raw_to_temp(u32 raw_temp, int temp_factor)
 
 static u32 lvts_temp_to_raw(int temperature, int temp_factor)
 {
-	u32 raw_temp = ((s64)(golden_temp_offset - temperature)) << 14;
+	u32 raw_temp;
 
-	raw_temp = div_s64(raw_temp, -temp_factor);
+	if (temp_factor == 0)
+		return temperature;
 
-	return raw_temp;
+	raw_temp = ((s64)(golden_temp_offset - temperature)) << 14;
+
+	return div_s64(raw_temp, -temp_factor);
 }
 
 static int lvts_get_temp(struct thermal_zone_device *tz, int *temp)
@@ -1346,6 +1349,9 @@ static int lvts_probe(struct platform_device *pdev)
 	if (irq < 0)
 		return irq;
 
+	if (!lvts_data->temp_factor)
+		dev_warn(dev, "temp_factor should never be zero; check platform data.\n");
+
 	golden_temp_offset = lvts_data->temp_offset;
 
 	ret = lvts_domain_init(dev, lvts_td, lvts_data);
-- 
2.39.5