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

[Amit Kucheria]

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.kuche...@linaro.org>
Reviewed-by: Stephen Boyd <swb...@chromium.org>
---
 drivers/thermal/qcom/tsens-common.c | 49 ++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/drivers/thermal/qcom/tsens-common.c 
b/drivers/thermal/qcom/tsens-common.c
index ea2c46cc6a66..c34a1a26ce29 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;
 }
-- 
2.17.1