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w1: w1_therm: fix locking behavior in convert_t

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[ Upstream commit dca5480ab7 ]

The commit 67b392f7b8 ("w1_therm: optimizing temperature read timings")
accidentially inverted the logic for lock handling of the bus mutex.

Before:
  pullup -> release lock before sleep
  no pullup -> release lock after sleep

After:
  pullup -> release lock after sleep
  no pullup -> release lock before sleep

This cause spurious measurements of 85 degree (powerup value) on the
Tarragon board with connected 1-w temperature sensor
(w1_therm.w1_strong_pull=0).

In the meantime a new feature for polling the conversion
completion has been integrated in these branches with
commit 021da53e65 ("w1: w1_therm: Add sysfs entries to control
conversion time and driver features"). But this feature isn't
available for parasite power mode, so handle this separately.

Link: https://lore.kernel.org/regressions/2023042645-attentive-amends-7b0b@gregkh/T/
Fixes: 67b392f7b8 ("w1_therm: optimizing temperature read timings")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/20230427112152.12313-1-stefan.wahren@i2se.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Stefan Wahren 2023-04-27 13:21:52 +02:00 committed by Greg Kroah-Hartman
parent ef04741188
commit eab6485377
1 changed files with 14 additions and 17 deletions
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19
drivers/w1/slaves/w1_therm.c
View File

@ -1159,14 +1159,6 @@ static int convert_t(struct w1_slave *sl, struct therm_info *info)
w1_write_8(dev_master, W1_CONVERT_TEMP);
if (strong_pullup) { /*some device need pullup */
sleep_rem = msleep_interruptible(t_conv);
if (sleep_rem != 0) {
ret = -EINTR;
goto mt_unlock;
}
mutex_unlock(&dev_master->bus_mutex);
} else { /*no device need pullup */
if (SLAVE_FEATURES(sl) & W1_THERM_POLL_COMPLETION) {
ret = w1_poll_completion(dev_master, W1_POLL_CONVERT_TEMP);
if (ret) {
@ -1174,8 +1166,14 @@ static int convert_t(struct w1_slave *sl, struct therm_info *info)
goto mt_unlock;
}
mutex_unlock(&dev_master->bus_mutex);
} else {
/* Fixed delay */
} else if (!strong_pullup) { /*no device need pullup */
sleep_rem = msleep_interruptible(t_conv);
if (sleep_rem != 0) {
ret = -EINTR;
goto mt_unlock;
}
mutex_unlock(&dev_master->bus_mutex);
} else { /*some device need pullup */
mutex_unlock(&dev_master->bus_mutex);
sleep_rem = msleep_interruptible(t_conv);
if (sleep_rem != 0) {
@ -1183,7 +1181,6 @@ static int convert_t(struct w1_slave *sl, struct therm_info *info)
goto dec_refcnt;
}
}
}
ret = read_scratchpad(sl, info);
/* If enabled, check for conversion success */