thermal/drivers/tsens: Support using nvmem cells for msm8974 calibration

MSM8974 has two sets of calibration data: main one and backup. Add
support for parsing both sets of calibration data from nvmem cells.

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20230101194034.831222-11-dmitry.baryshkov@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/thermal/qcom/tsens-v0_1.c

@@ -3,6 +3,7 @@
  * Copyright (c) 2015, The Linux Foundation. All rights reserved.
  */
 
+#include <linux/nvmem-consumer.h>
 #include <linux/platform_device.h>
 #include "tsens.h"
 
@@ -354,13 +355,62 @@ static int calibrate_8939(struct tsens_priv *priv)
 	return 0;
 }
 
+static int calibrate_8974_nvmem(struct tsens_priv *priv)
+{
+	int i, ret, mode;
+	u32 p1[11], p2[11];
+	u32 backup;
+
+	ret = nvmem_cell_read_variable_le_u32(priv->dev, "use_backup", &backup);
+	if (ret == -ENOENT)
+		dev_warn(priv->dev, "Please migrate to separate nvmem cells for calibration data\n");
+	if (ret < 0)
+		return ret;
+
+	mode = tsens_read_calibration(priv, 2, p1, p2, backup == BKP_SEL);
+	if (mode < 0)
+		return mode;
+
+	if (mode == NO_PT_CALIB) {
+		p1[0] += 2;
+		p1[1] += 9;
+		p1[2] += 3;
+		p1[3] += 9;
+		p1[4] += 5;
+		p1[5] += 9;
+		p1[6] += 7;
+		p1[7] += 10;
+		p1[8] += 8;
+		p1[9] += 9;
+		p1[10] += 8;
+	} else {
+		for (i = 0; i < priv->num_sensors; i++) {
+			/*
+			 * ONE_PT_CALIB requires using addition here instead of
+			 * using OR operation.
+			 */
+			p1[i] += BIT_APPEND;
+			p2[i] += BIT_APPEND;
+		}
+	}
+
+	compute_intercept_slope(priv, p1, p2, mode);
+
+	return 0;
+}
+
 static int calibrate_8974(struct tsens_priv *priv)
 {
 	int base1 = 0, base2 = 0, i;
 	u32 p1[11], p2[11];
 	int mode = 0;
 	u32 *calib, *bkp;
 	u32 calib_redun_sel;
+	int ret;
+
+	ret = calibrate_8974_nvmem(priv);
+	if (ret == 0)
+		return 0;
 
 	calib = (u32 *)qfprom_read(priv->dev, "calib");
 	if (IS_ERR(calib))

drivers/thermal/qcom/tsens.c

@@ -70,43 +70,56 @@ char *qfprom_read(struct device *dev, const char *cname)
 	return ret;
 }
 
-int tsens_calibrate_nvmem(struct tsens_priv *priv, int shift)
+int tsens_read_calibration(struct tsens_priv *priv, int shift, u32 *p1, u32 *p2, bool backup)
 {
 	u32 mode;
 	u32 base1, base2;
-	u32 p1[MAX_SENSORS], p2[MAX_SENSORS];
-	char name[] = "sXX_pY"; /* s10_p1 */
+	char name[] = "sXX_pY_backup"; /* s10_p1_backup */
 	int i, ret;
 
 	if (priv->num_sensors > MAX_SENSORS)
 		return -EINVAL;
 
-	ret = nvmem_cell_read_variable_le_u32(priv->dev, "mode", &mode);
+	ret = snprintf(name, sizeof(name), "mode%s", backup ? "_backup" : "");
+	if (ret < 0)
+		return ret;
+
+	ret = nvmem_cell_read_variable_le_u32(priv->dev, name, &mode);
 	if (ret == -ENOENT)
 		dev_warn(priv->dev, "Please migrate to separate nvmem cells for calibration data\n");
 	if (ret < 0)
 		return ret;
 
 	dev_dbg(priv->dev, "calibration mode is %d\n", mode);
 
-	ret = nvmem_cell_read_variable_le_u32(priv->dev, "base1", &base1);
+	ret = snprintf(name, sizeof(name), "base1%s", backup ? "_backup" : "");
+	if (ret < 0)
+		return ret;
+
+	ret = nvmem_cell_read_variable_le_u32(priv->dev, name, &base1);
+	if (ret < 0)
+		return ret;
+
+	ret = snprintf(name, sizeof(name), "base2%s", backup ? "_backup" : "");
 	if (ret < 0)
 		return ret;
 
-	ret = nvmem_cell_read_variable_le_u32(priv->dev, "base2", &base2);
+	ret = nvmem_cell_read_variable_le_u32(priv->dev, name, &base2);
 	if (ret < 0)
 		return ret;
 
 	for (i = 0; i < priv->num_sensors; i++) {
-		ret = snprintf(name, sizeof(name), "s%d_p1", priv->sensor[i].hw_id);
+		ret = snprintf(name, sizeof(name), "s%d_p1%s", priv->sensor[i].hw_id,
+			       backup ? "_backup" : "");
 		if (ret < 0)
 			return ret;
 
 		ret = nvmem_cell_read_variable_le_u32(priv->dev, name, &p1[i]);
 		if (ret)
 			return ret;
 
-		ret = snprintf(name, sizeof(name), "s%d_p2", priv->sensor[i].hw_id);
+		ret = snprintf(name, sizeof(name), "s%d_p2%s", priv->sensor[i].hw_id,
+			       backup ? "_backup" : "");
 		if (ret < 0)
 			return ret;
 
@@ -136,6 +149,18 @@ int tsens_calibrate_nvmem(struct tsens_priv *priv, int shift)
 		}
 	}
 
+	return mode;
+}
+
+int tsens_calibrate_nvmem(struct tsens_priv *priv, int shift)
+{
+	u32 p1[MAX_SENSORS], p2[MAX_SENSORS];
+	int mode;
+
+	mode = tsens_read_calibration(priv, shift, p1, p2, false);
+	if (mode < 0)
+		return mode;
+
 	compute_intercept_slope(priv, p1, p2, mode);
 
 	return 0;

drivers/thermal/qcom/tsens.h

@@ -585,6 +585,7 @@ struct tsens_priv {
 };
 
 char *qfprom_read(struct device *dev, const char *cname);
+int tsens_read_calibration(struct tsens_priv *priv, int shift, u32 *p1, u32 *p2, bool backup);
 int tsens_calibrate_nvmem(struct tsens_priv *priv, int shift);
 int tsens_calibrate_common(struct tsens_priv *priv);
 void compute_intercept_slope(struct tsens_priv *priv, u32 *pt1, u32 *pt2, u32 mode);