thermal: brcmstb_thermal: Prepare to support a different process

The driver is currently assuming that it is operating with a 28nm
process chip, which has a specific formula to convert temperature to a
code and vice versa. Update the code to support providing two key
values: offset and multiplier to derive the correct formulas.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200114190607.29339-3-f.fainelli@gmail.com

drivers/thermal/broadcom/brcmstb_thermal.c

@@ -102,18 +102,27 @@ static struct avs_tmon_trip avs_tmon_trips[] = {
 	},
 };
 
+struct brcmstb_thermal_params {
+	unsigned int offset;
+	unsigned int mult;
+};
+
 struct brcmstb_thermal_priv {
 	void __iomem *tmon_base;
 	struct device *dev;
 	struct thermal_zone_device *thermal;
+	/* Process specific thermal parameters used for calculations */
+	const struct brcmstb_thermal_params *temp_params;
 };
 
 /* Convert a HW code to a temperature reading (millidegree celsius) */
-static inline int avs_tmon_code_to_temp(struct thermal_zone_device *tz,
+static inline int avs_tmon_code_to_temp(struct brcmstb_thermal_priv *priv,
 					u32 code)
 {
-	return (AVS_TMON_TEMP_OFFSET -
-		(int)((code & AVS_TMON_TEMP_MAX) * AVS_TMON_TEMP_SLOPE));
+	int offset = priv->temp_params->offset;
+	int mult = priv->temp_params->mult;
+
+	return (offset - (int)((code & AVS_TMON_TEMP_MASK) * mult));
 }
 
 /*
@@ -122,21 +131,22 @@ static inline int avs_tmon_code_to_temp(struct thermal_zone_device *tz,
  * @temp: temperature to convert
  * @low: if true, round toward the low side
  */
-static inline u32 avs_tmon_temp_to_code(struct thermal_zone_device *tz,
+static inline u32 avs_tmon_temp_to_code(struct brcmstb_thermal_priv *priv,
 					int temp, bool low)
 {
+	int offset = priv->temp_params->offset;
+	int mult = priv->temp_params->mult;
+
 	if (temp < AVS_TMON_TEMP_MIN)
 		return AVS_TMON_TEMP_MAX;	/* Maximum code value */
 
-	if (temp >= AVS_TMON_TEMP_OFFSET)
+	if (temp >= offset)
 		return 0;	/* Minimum code value */
 
 	if (low)
-		return (u32)(DIV_ROUND_UP(AVS_TMON_TEMP_OFFSET - temp,
-					  AVS_TMON_TEMP_SLOPE));
+		return (u32)(DIV_ROUND_UP(offset - temp, mult));
 	else
-		return (u32)((AVS_TMON_TEMP_OFFSET - temp) /
-			      AVS_TMON_TEMP_SLOPE);
+		return (u32)((offset - temp) / mult);
 }
 
 static int brcmstb_get_temp(void *data, int *temp)
@@ -154,7 +164,7 @@ static int brcmstb_get_temp(void *data, int *temp)
 
 	val = (val & AVS_TMON_STATUS_data_msk) >> AVS_TMON_STATUS_data_shift;
 
-	t = avs_tmon_code_to_temp(priv->thermal, val);
+	t = avs_tmon_code_to_temp(priv, val);
 	if (t < 0)
 		*temp = 0;
 	else
@@ -188,7 +198,7 @@ static int avs_tmon_get_trip_temp(struct brcmstb_thermal_priv *priv,
 	val &= trip->reg_msk;
 	val >>= trip->reg_shift;
 
-	return avs_tmon_code_to_temp(priv->thermal, val);
+	return avs_tmon_code_to_temp(priv, val);
 }
 
 static void avs_tmon_set_trip_temp(struct brcmstb_thermal_priv *priv,
@@ -201,7 +211,7 @@ static void avs_tmon_set_trip_temp(struct brcmstb_thermal_priv *priv,
 	dev_dbg(priv->dev, "set temp %d to %d\n", type, temp);
 
 	/* round toward low temp for the low interrupt */
-	val = avs_tmon_temp_to_code(priv->thermal, temp,
+	val = avs_tmon_temp_to_code(priv, temp,
 				    type == TMON_TRIP_TYPE_LOW);
 
 	val <<= trip->reg_shift;
@@ -218,7 +228,7 @@ static int avs_tmon_get_intr_temp(struct brcmstb_thermal_priv *priv)
 	u32 val;
 
 	val = __raw_readl(priv->tmon_base + AVS_TMON_TEMP_INT_CODE);
-	return avs_tmon_code_to_temp(priv->thermal, val);
+	return avs_tmon_code_to_temp(priv, val);
 }
 
 static irqreturn_t brcmstb_tmon_irq_thread(int irq, void *data)
@@ -282,8 +292,13 @@ static const struct thermal_zone_of_device_ops of_ops = {
 	.set_trips	= brcmstb_set_trips,
 };
 
+static const struct brcmstb_thermal_params brcmstb_28nm_params = {
+	.offset	= 410040,
+	.mult	= 487,
+};
+
 static const struct of_device_id brcmstb_thermal_id_table[] = {
-	{ .compatible = "brcm,avs-tmon" },
+	{ .compatible = "brcm,avs-tmon", .data = &brcmstb_28nm_params },
 	{},
 };
 MODULE_DEVICE_TABLE(of, brcmstb_thermal_id_table);
@@ -299,6 +314,10 @@ static int brcmstb_thermal_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
+	priv->temp_params = of_device_get_match_data(&pdev->dev);
+	if (!priv->temp_params)
+		return -EINVAL;
+
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	priv->tmon_base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(priv->tmon_base))