The function can loop and lock the system if for whatever reason the bit
for the target sensor is NEVER valid. This is the case if a sensor is
disabled by the factory and the valid bit is never reported as actually
valid. Add a timeout check and exit if a timeout occurs. As this is
a very rare condition, handle the timeout only if the first read fails.
While at it also rework the function to improve readability.
Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx>
---
drivers/thermal/qcom/tsens.c | 40 +++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 14 deletions(-)
diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
index b1162e566a70..1ff244176beb 100644
--- a/drivers/thermal/qcom/tsens.c
+++ b/drivers/thermal/qcom/tsens.c
@@ -599,26 +599,38 @@ int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp)
int hw_id = s->hw_id;
u32 temp_idx = LAST_TEMP_0 + hw_id;
u32 valid_idx = VALID_0 + hw_id;
+ unsigned long timeout;
u32 valid;
int ret;
/* VER_0 doesn't have VALID bit */
- if (tsens_version(priv) >= VER_0_1) {
+ if (tsens_version(priv) == VER_0)
+ goto get_temp;
+
+ ret = regmap_field_read(priv->rf[valid_idx], &valid);
+ if (ret || valid)
+ goto check_valid;
+
+ timeout = jiffies + msecs_to_jiffies(20);
+ do {
+ /* 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;
- 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;
- }
- }
+ if (ret || valid)
+ goto check_valid;
+ } while (time_before(jiffies, timeout));
+
+ return -ETIMEDOUT;
+
+check_valid:
+ /* Check ret of valid bit read */
+ if (ret)
+ return ret;
+get_temp:
/* Valid bit is set, OK to read the temperature */
*temp = tsens_hw_to_mC(s, temp_idx);
--
2.32.0
