linux-kernel - [PATCH v3 14/15] drivers: thermal: tsens: Create function to return sign-extended temperature

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Date:   Wed, 11 Sep 2019 12:46:31 +0530
From:   Amit Kucheria <amit.kucheria@...aro.org>
To:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        bjorn.andersson@...aro.org, edubezval@...il.com, agross@...nel.org,
        masneyb@...tation.org, swboyd@...omium.org,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>
Cc:     linux-pm@...r.kernel.org
Subject: [PATCH v3 14/15] drivers: thermal: tsens: Create function to return sign-extended temperature

Hide the details of how to convert values read from TSENS HW to mCelsius
behind a function. All versions of the IP can be supported as a result.

Signed-off-by: Amit Kucheria <amit.kucheria@...aro.org>
---
 drivers/thermal/qcom/tsens-common.c | 50 +++++++++++++++++++++--------
 1 file changed, 36 insertions(+), 14 deletions(-)

diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
index ea2c46cc6a66..6b6b3841c2d0 100644
--- a/drivers/thermal/qcom/tsens-common.c
+++ b/drivers/thermal/qcom/tsens-common.c
@@ -84,13 +84,46 @@ static inline int code_to_degc(u32 adc_code, const struct tsens_sensor *s)
 	return degc;
 }
 
+/**
+ * tsens_hw_to_mC - Return sign-extended temperature in mCelsius.
+ * @s:     Pointer to sensor struct
+ * @field: Index into regmap_field array pointing to temperature data
+ *
+ * This function handles temperature returned in ADC code or deciCelsius
+ * depending on IP version.
+ *
+ * Return: Temperature in milliCelsius on success, a negative errno will
+ * be returned in error cases
+ */
+static int tsens_hw_to_mC(struct tsens_sensor *s, int field)
+{
+	struct tsens_priv *priv = s->priv;
+	u32 resolution;
+	u32 temp = 0;
+	int ret;
+
+	resolution = priv->fields[LAST_TEMP_0].msb -
+		priv->fields[LAST_TEMP_0].lsb;
+
+	ret = regmap_field_read(priv->rf[field], &temp);
+	if (ret)
+		return ret;
+
+	/* Convert temperature from ADC code to milliCelsius */
+	if (priv->feat->adc)
+		return code_to_degc(temp, s) * 1000;
+
+	/* deciCelsius -> milliCelsius along with sign extension */
+	return sign_extend32(temp, resolution) * 100;
+}
+
 int get_temp_tsens_valid(struct tsens_sensor *s, int *temp)
 {
 	struct tsens_priv *priv = s->priv;
 	int hw_id = s->hw_id;
 	u32 temp_idx = LAST_TEMP_0 + hw_id;
 	u32 valid_idx = VALID_0 + hw_id;
-	u32 last_temp = 0, valid, mask;
+	u32 valid;
 	int ret;
 
 	ret = regmap_field_read(priv->rf[valid_idx], &valid);
@@ -108,19 +141,7 @@ int get_temp_tsens_valid(struct tsens_sensor *s, int *temp)
 	}
 
 	/* Valid bit is set, OK to read the temperature */
-	ret = regmap_field_read(priv->rf[temp_idx], &last_temp);
-	if (ret)
-		return ret;
-
-	if (priv->feat->adc) {
-		/* Convert temperature from ADC code to milliCelsius */
-		*temp = code_to_degc(last_temp, s) * 1000;
-	} else {
-		mask = GENMASK(priv->fields[LAST_TEMP_0].msb,
-			       priv->fields[LAST_TEMP_0].lsb);
-		/* Convert temperature from deciCelsius to milliCelsius */
-		*temp = sign_extend32(last_temp, fls(mask) - 1) * 100;
-	}
+	*temp = tsens_hw_to_mC(s, temp_idx);
 
 	return 0;
 }
@@ -310,6 +331,7 @@ int __init init_common(struct tsens_priv *priv)
 			goto err_put_device;
 		}
 	}
+
 	for (i = 0, j = VALID_0; i < priv->feat->max_sensors; i++, j++) {
 		priv->rf[j] = devm_regmap_field_alloc(dev, priv->tm_map,
 						      priv->fields[j]);
-- 
2.17.1