thermal/drivers/mediatek/lvts_thermal: Return error in case of invalid efuse data

[ Upstream commit 72cacd06e47d86d89b0e7179fbc9eb3a0f39cd93 ]

This patch prevents from registering thermal entries and letting the
driver misbehave if efuse data is invalid. A device is not properly
calibrated if the golden temperature is zero.

Fixes: f5f633b18234 ("thermal/drivers/mediatek: Add the Low Voltage Thermal Sensor driver")
Signed-off-by: Julien Panis <jpanis@baylibre.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240604-mtk-thermal-calib-check-v2-1-8f258254051d@baylibre.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/thermal/mediatek/lvts_thermal.c b/drivers/thermal/mediatek/lvts_thermal.c
index a4e56017dda3f96e12fd4acdd78260e32edb0f90..666f440b66631fd17ac2b89eef71aa000d89ea24 100644 (file)
--- a/drivers/thermal/mediatek/lvts_thermal.c
+++ b/drivers/thermal/mediatek/lvts_thermal.c
@@ -700,7 +700,11 @@ static int lvts_golden_temp_init(struct device *dev, u32 *value)
 
        gt = (*value) >> 24;
 
-       if (gt && gt < LVTS_GOLDEN_TEMP_MAX)
+       /* A zero value for gt means that device has invalid efuse data */
+       if (!gt)
+               return -ENODATA;
+
+       if (gt < LVTS_GOLDEN_TEMP_MAX)
                golden_temp = gt;
 
        coeff_b = golden_temp * 500 + LVTS_COEFF_B;