The current implementation is based on an algorithm published in the
docs. Instead of reading the temperature thrice w/o any explanation,
improve the algorithm.
This will become the basis for a common get_temp routine in the future.
Signed-off-by: Amit Kucheria <amit.kucheria@xxxxxxxxxx>
---
drivers/thermal/qcom/tsens-v2.c | 55 ++++++++++-----------------------
1 file changed, 17 insertions(+), 38 deletions(-)
diff --git a/drivers/thermal/qcom/tsens-v2.c b/drivers/thermal/qcom/tsens-v2.c
index f3eb8661cf7a..716d7f827459 100644
--- a/drivers/thermal/qcom/tsens-v2.c
+++ b/drivers/thermal/qcom/tsens-v2.c
@@ -25,58 +25,37 @@
#define TM_Sn_STATUS_OFF 0x00a0
#define TM_TRDY_OFF 0x00e4
-#define LAST_TEMP_MASK 0xfff
-
-static int get_temp_tsens_v2(struct tsens_priv *priv, int id, int *temp)
+static int get_temp_tsens_v2(struct tsens_priv *priv, int i, int *temp)
{
- struct tsens_sensor *s = &priv->sensor[id];
+ struct tsens_sensor *s = &priv->sensor[i];
u32 temp_idx = LAST_TEMP_0 + s->hw_id;
u32 valid_idx = VALID_0 + s->hw_id;
- u32 last_temp = 0, last_temp2 = 0, last_temp3 = 0, valid;
+ u32 last_temp = 0, valid, mask;
int ret;
- ret = regmap_field_read(priv->rf[temp_idx], &last_temp);
- if (ret)
- return ret;
-
ret = regmap_field_read(priv->rf[valid_idx], &valid);
if (ret)
return ret;
-
- if (valid)
- goto done;
-
- /* Try a second time */
- ret = regmap_field_read(priv->rf[valid_idx], &valid);
- if (ret)
- return ret;
- ret = regmap_field_read(priv->rf[temp_idx], &last_temp2);
- if (ret)
- return ret;
- if (valid) {
- last_temp = last_temp2;
- goto done;
+ while (!valid) {
+ /* Valid bit is 0 for 6 AHB clock cycles.
+ * At 19.2MHz, 1 AHB clock is ~60ns.
+ * We should enter this loop very, very rarely.
+ */
+ ndelay(400);
+ ret = regmap_field_read(priv->rf[valid_idx], &valid);
+ if (ret)
+ return ret;
}
- /* Try a third/last time */
- ret = regmap_field_read(priv->rf[valid_idx], &valid);
- if (ret)
- return ret;
- ret = regmap_field_read(priv->rf[temp_idx], &last_temp3);
+ /* Valid bit is set, OK to read the temperature */
+ ret = regmap_field_read(priv->rf[temp_idx], &last_temp);
if (ret)
return ret;
- if (valid) {
- last_temp = last_temp3;
- goto done;
- }
- if (last_temp == last_temp2)
- last_temp = last_temp2;
- else if (last_temp2 == last_temp3)
- last_temp = last_temp3;
-done:
+ 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(LAST_TEMP_MASK) - 1) * 100;
+ *temp = sign_extend32(last_temp, fls(mask) - 1) * 100;
return 0;
}
--
2.17.1
