thermal/drivers/mediatek/lvts: Support MSR offset for 16-bit calibration data

On MT8196/MT6991, per-sensor calibration data read from eFuses is
16-bit. When the LVTS controller operates in 16-bit mode, a fixed offset
must be added to MSR values during post-processing to obtain correct
temperature readings. Introduce a new msr_offset field in lvts_data,
program the respective register and apply the offset to the calibration
data read from eFuses.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Frank Wunderlich <frank-w@public-files.de>
Signed-off-by: Laura Nao <laura.nao@collabora.com>
Link: https://patch.msgid.link/20251125-mt8196-lvts-v4-v5-6-6db7eb903fb7@collabora.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Author: laura-nao

drivers/thermal/mediatek/lvts_thermal.c

@@ -44,6 +44,7 @@
 #define LVTS_EDATA01(__base)	(__base + 0x0058)
 #define LVTS_EDATA02(__base)	(__base + 0x005C)
 #define LVTS_EDATA03(__base)	(__base + 0x0060)
+#define LVTS_MSROFT(__base)		(__base + 0x006C)
 #define LVTS_ATP0(__base)		(__base + 0x0070)
 #define LVTS_ATP1(__base)		(__base + 0x0074)
 #define LVTS_ATP2(__base)		(__base + 0x0078)
@@ -151,6 +152,7 @@ struct lvts_data {
 	int temp_offset;
 	int gt_calib_bit_offset;
 	unsigned int def_calibration;
+	u16 msr_offset;
 };
 
 struct lvts_sensor {
@@ -219,6 +221,7 @@ static const struct debugfs_reg32 lvts_regs[] = {
 	LVTS_DEBUG_FS_REGS(LVTS_EDATA01),
 	LVTS_DEBUG_FS_REGS(LVTS_EDATA02),
 	LVTS_DEBUG_FS_REGS(LVTS_EDATA03),
+	LVTS_DEBUG_FS_REGS(LVTS_MSROFT),
 	LVTS_DEBUG_FS_REGS(LVTS_ATP0),
 	LVTS_DEBUG_FS_REGS(LVTS_ATP1),
 	LVTS_DEBUG_FS_REGS(LVTS_ATP2),
@@ -811,6 +814,8 @@ static int lvts_calibration_init(struct device *dev, struct lvts_ctrl *lvts_ctrl
 
 		if (gt) {
 			lvts_ctrl->calibration[i] = calib;
+			if (lvts_ctrl->lvts_data->msr_offset)
+				lvts_ctrl->calibration[i] += lvts_ctrl->lvts_data->msr_offset;
 		} else if (lvts_ctrl->lvts_data->def_calibration) {
 			lvts_ctrl->calibration[i] = lvts_ctrl->lvts_data->def_calibration;
 		} else {
@@ -1118,6 +1123,17 @@ static int lvts_ctrl_calibrate(struct device *dev, struct lvts_ctrl *lvts_ctrl)
 	for (i = 0; i < LVTS_SENSOR_MAX; i++)
 		writel(lvts_ctrl->calibration[i], lvts_edata[i]);
 
+	/* LVTS_MSROFT : Constant offset applied to MSR values
+	 * for post-processing
+	 *
+	 * Bits:
+	 *
+	 * 20-0 : Constant data added to MSR values
+	 */
+	if (lvts_ctrl->lvts_data->msr_offset)
+		writel(lvts_ctrl->lvts_data->msr_offset,
+		       LVTS_MSROFT(lvts_ctrl->base));
+
 	return 0;
 }