thermal/drivers/mediatek/lvts_thermal: Provide default calibration data

On some pre-production hardware, the SoCs do not contain calibration
data for the thermal sensors. The downstream drivers provide default
values that sort of work, instead of having the thermal sensors not
work at all.

Port the default values to the upstream driver. These values are from
the ChromeOS kernels, which sadly do not cover the MT7988.
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240620092306.2352606-1-wenst@chromium.orgSigned-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/thermal/mediatek/lvts_thermal.c

@@ -128,6 +128,7 @@ struct lvts_data {
 	int temp_factor;
 	int temp_offset;
 	int gt_calib_bit_offset;
+	unsigned int def_calibration;
 };
 
 struct lvts_sensor {
@@ -689,6 +690,10 @@ static int lvts_calibration_init(struct device *dev, struct lvts_ctrl *lvts_ctrl
 					size_t calib_len)
 {
 	int i;
+	u32 gt;
+
+	/* A zero value for gt means that device has invalid efuse data */
+	gt = (((u32 *)efuse_calibration)[0] >> lvts_ctrl->lvts_data->gt_calib_bit_offset) & 0xff;
 
 	lvts_for_each_valid_sensor(i, lvts_ctrl_data) {
 		const struct lvts_sensor_data *sensor =
@@ -699,10 +704,17 @@ static int lvts_calibration_init(struct device *dev, struct lvts_ctrl *lvts_ctrl
 		    sensor->cal_offsets[2] >= calib_len)
 			return -EINVAL;
 
-		lvts_ctrl->calibration[i] =
-			(efuse_calibration[sensor->cal_offsets[0]] << 0) +
-			(efuse_calibration[sensor->cal_offsets[1]] << 8) +
-			(efuse_calibration[sensor->cal_offsets[2]] << 16);
+		if (gt) {
+			lvts_ctrl->calibration[i] =
+				(efuse_calibration[sensor->cal_offsets[0]] << 0) +
+				(efuse_calibration[sensor->cal_offsets[1]] << 8) +
+				(efuse_calibration[sensor->cal_offsets[2]] << 16);
+		} else if (lvts_ctrl->lvts_data->def_calibration) {
+			lvts_ctrl->calibration[i] = lvts_ctrl->lvts_data->def_calibration;
+		} else {
+			dev_err(dev, "efuse contains invalid calibration data and no default given.\n");
+			return -ENODATA;
+		}
 	}
 
 	return 0;
@@ -770,14 +782,13 @@ static int lvts_golden_temp_init(struct device *dev, u8 *calib,
 	gt = (((u32 *)calib)[0] >> lvts_data->gt_calib_bit_offset) & 0xff;
 
 	/* A zero value for gt means that device has invalid efuse data */
-	if (!gt)
-		return -ENODATA;
-
-	if (gt < LVTS_GOLDEN_TEMP_MAX)
+	if (gt && gt < LVTS_GOLDEN_TEMP_MAX)
 		golden_temp = gt;
 
 	golden_temp_offset = golden_temp * 500 + lvts_data->temp_offset;
 
+	dev_info(dev, "%sgolden temp=%d\n", gt ? "" : "fake ", golden_temp);
+
 	return 0;
 }
 
@@ -1701,6 +1712,7 @@ static const struct lvts_data mt8186_lvts_data = {
 	.temp_factor	= LVTS_COEFF_A_MT7988,
 	.temp_offset	= LVTS_COEFF_B_MT7988,
 	.gt_calib_bit_offset = 24,
+	.def_calibration = 19000,
 };
 
 static const struct lvts_data mt8188_lvts_mcu_data = {
@@ -1709,6 +1721,7 @@ static const struct lvts_data mt8188_lvts_mcu_data = {
 	.temp_factor	= LVTS_COEFF_A_MT8195,
 	.temp_offset	= LVTS_COEFF_B_MT8195,
 	.gt_calib_bit_offset = 20,
+	.def_calibration = 35000,
 };
 
 static const struct lvts_data mt8188_lvts_ap_data = {
@@ -1717,6 +1730,7 @@ static const struct lvts_data mt8188_lvts_ap_data = {
 	.temp_factor	= LVTS_COEFF_A_MT8195,
 	.temp_offset	= LVTS_COEFF_B_MT8195,
 	.gt_calib_bit_offset = 20,
+	.def_calibration = 35000,
 };
 
 static const struct lvts_data mt8192_lvts_mcu_data = {
@@ -1725,6 +1739,7 @@ static const struct lvts_data mt8192_lvts_mcu_data = {
 	.temp_factor	= LVTS_COEFF_A_MT8195,
 	.temp_offset	= LVTS_COEFF_B_MT8195,
 	.gt_calib_bit_offset = 24,
+	.def_calibration = 35000,
 };
 
 static const struct lvts_data mt8192_lvts_ap_data = {
@@ -1733,6 +1748,7 @@ static const struct lvts_data mt8192_lvts_ap_data = {
 	.temp_factor	= LVTS_COEFF_A_MT8195,
 	.temp_offset	= LVTS_COEFF_B_MT8195,
 	.gt_calib_bit_offset = 24,
+	.def_calibration = 35000,
 };
 
 static const struct lvts_data mt8195_lvts_mcu_data = {
@@ -1741,6 +1757,7 @@ static const struct lvts_data mt8195_lvts_mcu_data = {
 	.temp_factor	= LVTS_COEFF_A_MT8195,
 	.temp_offset	= LVTS_COEFF_B_MT8195,
 	.gt_calib_bit_offset = 24,
+	.def_calibration = 35000,
 };
 
 static const struct lvts_data mt8195_lvts_ap_data = {
@@ -1749,6 +1766,7 @@ static const struct lvts_data mt8195_lvts_ap_data = {
 	.temp_factor	= LVTS_COEFF_A_MT8195,
 	.temp_offset	= LVTS_COEFF_B_MT8195,
 	.gt_calib_bit_offset = 24,
+	.def_calibration = 35000,
 };
 
 static const struct of_device_id lvts_of_match[] = {