This is a note to let you know that I've just added the patch titled
thermal/drivers/tsens: Add timeout to get_temp_tsens_valid
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
thermal-drivers-tsens-add-timeout-to-get_temp_tsens_.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c2ed83e3eadef3c62b47f911ceb04dbfecb8d3d0
Author: Ansuel Smith <ansuelsmth@xxxxxxxxx>
Date: Thu Oct 7 19:28:59 2021 +0200
thermal/drivers/tsens: Add timeout to get_temp_tsens_valid
[ Upstream commit d012f9189fda0f3a1b303780ba0bbc7298d0d349 ]
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 and convert
to poll_timeout generic macro.
Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211007172859.583-1-ansuelsmth@xxxxxxxxx
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
index b1162e566a707..99a8d9f3e03ca 100644
--- a/drivers/thermal/qcom/tsens.c
+++ b/drivers/thermal/qcom/tsens.c
@@ -603,22 +603,21 @@ int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp)
int ret;
/* VER_0 doesn't have VALID bit */
- if (tsens_version(priv) >= VER_0_1) {
- 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 (tsens_version(priv) == VER_0)
+ goto get_temp;
+
+ /* 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.
+ * Wait 1 us since it's the min of poll_timeout macro.
+ * Old value was 400 ns.
+ */
+ ret = regmap_field_read_poll_timeout(priv->rf[valid_idx], valid,
+ valid, 1, 20 * USEC_PER_MSEC);
+ if (ret)
+ return ret;
+get_temp:
/* Valid bit is set, OK to read the temperature */
*temp = tsens_hw_to_mC(s, temp_idx);
