FAILED: patch "[PATCH] hwmon: (tmp108) Fix initial conversion delay and wait until ready" failed to apply to 6.18-stable tree

FAILED: patch "[PATCH] hwmon: (tmp108) Fix initial conversion delay and wait until ready" failed to apply to 6.18-stable tree

[Sasha Levin]

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 7cd60538073e465310c94b2a2f0ea8d2f03768ef
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261109200336-failed-6.18-7cd60538073e@kernel.org' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 7cd60538073e465310c94b2a2f0ea8d2f03768ef Mon Sep 17 00:00:00 2001
From: Guenter Roeck <linux@roeck-us.net>
Date: Fri, 30 Oct 2026 20:02:08 -0700
Subject: [PATCH] hwmon: (tmp108) Fix initial conversion delay and wait until
 ready
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In tmp108_common_probe(), the driver only adds the 30 ms conversion delay
(TMP108_CONVERSION_TIME_MS) to ready_time if the sensor was previously in
TMP108_MODE_SHUTDOWN. However, the TMP108 hardware defaults to continuous
conversion mode (TMP108_MODE_CONTINUOUS) upon power-on reset, including
immediately after enabling the vcc supply regulator during probe, while
the temperature register retains its power-on reset value of 0x0000 (0°C)
until the first conversion completes. Because the initial mode is not
shutdown, the delay is bypassed and early reads via thermal zone
registration or sysfs before the first conversion finishes return an
uninitialized 0°C reading.

In addition, returning -EAGAIN from tmp108_read() while waiting for a
conversion to complete after probe or resume can trigger an unnecessary
tight retry loop in callers or fail initial reads.

Unconditionally set ready_time to TMP108_CONVERSION_TIME_MS ahead in
tmp108_common_probe(), track ready_time as ktime_t, and wait for the
remaining conversion time in tmp108_read() using usleep_range() instead
of returning -EAGAIN.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: 66e1c9171339 ("hwmon: Add Texas Instruments TMP108 temperature sensor driver.")
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/tmp108.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/hwmon/tmp108.c b/drivers/hwmon/tmp108.c
index 91d20a1ce1120..862b944d3e609 100644
--- a/drivers/hwmon/tmp108.c
+++ b/drivers/hwmon/tmp108.c
@@ -13,7 +13,7 @@
 #include <linux/i2c.h>
 #include <linux/i3c/device.h>
 #include <linux/init.h>
-#include <linux/jiffies.h>
+#include <linux/ktime.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
@@ -78,7 +78,7 @@
 struct tmp108 {
 	struct regmap *regmap;
 	u16 orig_config;
-	u64 ready_time;
+	ktime_t ready_time;
 	const struct tmp108_params *params;
 };
 
@@ -121,6 +121,7 @@ static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
 	struct tmp108 *tmp108 = dev_get_drvdata(dev);
 	unsigned int regval;
 	int err, hyst;
+	s64 delay;
 
 	if (type == hwmon_chip) {
 		if (attr == hwmon_chip_update_interval) {
@@ -137,12 +138,10 @@ static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
 
 	switch (attr) {
 	case hwmon_temp_input:
-		/* Is it too early to return a conversion ? */
-		if (time_before64(get_jiffies_64(), tmp108->ready_time)) {
-			dev_dbg(dev, "%s: Conversion not ready yet..\n",
-				__func__);
-			return -EAGAIN;
-		}
+		/* Wait if it is too early to return a conversion */
+		delay = ktime_us_delta(tmp108->ready_time, ktime_get());
+		if (delay > 0)
+			usleep_range(delay, delay + 1000);
 		err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, &regval);
 		if (err < 0)
 			return err;
@@ -477,11 +476,8 @@ static int tmp108_common_probe(struct device *dev, struct regmap *regmap, char *
 		return err;
 	}
 
-	tmp108->ready_time = get_jiffies_64();
-	if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
-	    TMP108_MODE_SHUTDOWN)
-		tmp108->ready_time +=
-			msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
+	tmp108->ready_time = ktime_add_ms(ktime_get(),
+					  TMP108_CONVERSION_TIME_MS);
 
 	err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
 	if (err) {
@@ -528,8 +524,8 @@ static int tmp108_resume(struct device *dev)
 
 	err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 				 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
-	tmp108->ready_time = get_jiffies_64() +
-			     msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
+	tmp108->ready_time = ktime_add_ms(ktime_get(),
+					  TMP108_CONVERSION_TIME_MS);
 	return err;
 }
 
-- 
2.53.0

[PATCH 6.18.y 1/2] hwmon: (tmp108) Fix jiffies wraparound in conversion-ready check

[Sasha Levin]

From: Tom Verdonck <tom.verdonck@inspiral.be>

[ Upstream commit 6b8b1d1d7bc7e579b53fc7c3293b787d68de702a ]

tmp108 records a one-shot deadline in ->ready_time at probe (and resume)
and, on every temperature read, refuses the read with -EAGAIN while
time_before(jiffies, ready_time) is true, in order to skip the initial
conversion.

->ready_time is an unsigned long compared with time_before(), whose
signed difference is only meaningful while the two values are within
LONG_MAX jiffies of each other. Because ->ready_time is set once and
never refreshed, jiffies keeps advancing away from it, and after 2^31
jiffies the difference flips sign. On a 32-bit HZ=100 kernel that
happens ~248.5 days after boot: time_before() then permanently reports
"not ready" and the driver returns -EAGAIN on every read, without ever
touching the sensor, until the next reboot. The continuous-mode path,
which sets ->ready_time to jiffies with no added conversion delay, wraps
the same way.

Store the deadline as a 64-bit jiffies value and compare it with
get_jiffies_64()/time_before64(), which does not wrap in any practical
uptime.

Fixes: 66e1c9171339 ("hwmon: Add Texas Instruments TMP108 temperature sensor driver.")
Cc: stable@vger.kernel.org
Signed-off-by: Tom Verdonck <tom.verdonck@inspiral.be>
Link: https://patch.msgid.link/525fa49d8c50922344fa53e22be5e6133c9bbb62.1790358356.git.tom.verdonck@inspiral.be
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Keep the opaque per-device parameter pointer next to ready_time so the
subsequent conversion-delay fix applies cleanly. The pointer remains
unused; the unrelated device-support tables and register-access changes
are not needed.

Stable-dep-of: 7cd60538073e ("hwmon: (tmp108) Fix initial conversion delay and wait until ready")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/hwmon/tmp108.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/tmp108.c b/drivers/hwmon/tmp108.c
index a971ff628435b..f8b2d88d14665 100644
--- a/drivers/hwmon/tmp108.c
+++ b/drivers/hwmon/tmp108.c
@@ -74,7 +74,8 @@
 struct tmp108 {
 	struct regmap *regmap;
 	u16 orig_config;
-	unsigned long ready_time;
+	u64 ready_time;
+	const struct tmp108_params *params;
 };
 
 /* convert 12-bit TMP108 register value to milliCelsius */
@@ -125,7 +126,7 @@ static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
 	switch (attr) {
 	case hwmon_temp_input:
 		/* Is it too early to return a conversion ? */
-		if (time_before(jiffies, tmp108->ready_time)) {
+		if (time_before64(get_jiffies_64(), tmp108->ready_time)) {
 			dev_dbg(dev, "%s: Conversion not ready yet..\n",
 				__func__);
 			return -EAGAIN;
@@ -362,7 +363,7 @@ static int tmp108_common_probe(struct device *dev, struct regmap *regmap, char *
 		return err;
 	}
 
-	tmp108->ready_time = jiffies;
+	tmp108->ready_time = get_jiffies_64();
 	if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
 	    TMP108_MODE_SHUTDOWN)
 		tmp108->ready_time +=
@@ -413,7 +414,7 @@ static int tmp108_resume(struct device *dev)
 
 	err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 				 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
-	tmp108->ready_time = jiffies +
+	tmp108->ready_time = get_jiffies_64() +
 			     msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
 	return err;
 }
-- 
2.53.0

[PATCH 6.18.y 2/2] hwmon: (tmp108) Fix initial conversion delay and wait until ready

[Sasha Levin]

From: Guenter Roeck <linux@roeck-us.net>

[ Upstream commit 7cd60538073e465310c94b2a2f0ea8d2f03768ef ]

In tmp108_common_probe(), the driver only adds the 30 ms conversion delay
(TMP108_CONVERSION_TIME_MS) to ready_time if the sensor was previously in
TMP108_MODE_SHUTDOWN. However, the TMP108 hardware defaults to continuous
conversion mode (TMP108_MODE_CONTINUOUS) upon power-on reset, including
immediately after enabling the vcc supply regulator during probe, while
the temperature register retains its power-on reset value of 0x0000 (0°C)
until the first conversion completes. Because the initial mode is not
shutdown, the delay is bypassed and early reads via thermal zone
registration or sysfs before the first conversion finishes return an
uninitialized 0°C reading.

In addition, returning -EAGAIN from tmp108_read() while waiting for a
conversion to complete after probe or resume can trigger an unnecessary
tight retry loop in callers or fail initial reads.

Unconditionally set ready_time to TMP108_CONVERSION_TIME_MS ahead in
tmp108_common_probe(), track ready_time as ktime_t, and wait for the
remaining conversion time in tmp108_read() using usleep_range() instead
of returning -EAGAIN.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: 66e1c9171339 ("hwmon: Add Texas Instruments TMP108 temperature sensor driver.")
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/hwmon/tmp108.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/hwmon/tmp108.c b/drivers/hwmon/tmp108.c
index f8b2d88d14665..cb52b99eda4ab 100644
--- a/drivers/hwmon/tmp108.c
+++ b/drivers/hwmon/tmp108.c
@@ -14,7 +14,7 @@
 #include <linux/i2c.h>
 #include <linux/i3c/device.h>
 #include <linux/init.h>
-#include <linux/jiffies.h>
+#include <linux/ktime.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
@@ -74,7 +74,7 @@
 struct tmp108 {
 	struct regmap *regmap;
 	u16 orig_config;
-	u64 ready_time;
+	ktime_t ready_time;
 	const struct tmp108_params *params;
 };
 
@@ -96,6 +96,7 @@ static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
 	struct tmp108 *tmp108 = dev_get_drvdata(dev);
 	unsigned int regval;
 	int err, hyst;
+	s64 delay;
 
 	if (type == hwmon_chip) {
 		if (attr == hwmon_chip_update_interval) {
@@ -125,12 +126,10 @@ static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
 
 	switch (attr) {
 	case hwmon_temp_input:
-		/* Is it too early to return a conversion ? */
-		if (time_before64(get_jiffies_64(), tmp108->ready_time)) {
-			dev_dbg(dev, "%s: Conversion not ready yet..\n",
-				__func__);
-			return -EAGAIN;
-		}
+		/* Wait if it is too early to return a conversion */
+		delay = ktime_us_delta(tmp108->ready_time, ktime_get());
+		if (delay > 0)
+			usleep_range(delay, delay + 1000);
 		err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, &regval);
 		if (err < 0)
 			return err;
@@ -363,11 +362,8 @@ static int tmp108_common_probe(struct device *dev, struct regmap *regmap, char *
 		return err;
 	}
 
-	tmp108->ready_time = get_jiffies_64();
-	if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
-	    TMP108_MODE_SHUTDOWN)
-		tmp108->ready_time +=
-			msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
+	tmp108->ready_time = ktime_add_ms(ktime_get(),
+					  TMP108_CONVERSION_TIME_MS);
 
 	err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
 	if (err) {
@@ -414,8 +410,8 @@ static int tmp108_resume(struct device *dev)
 
 	err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 				 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
-	tmp108->ready_time = get_jiffies_64() +
-			     msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
+	tmp108->ready_time = ktime_add_ms(ktime_get(),
+					  TMP108_CONVERSION_TIME_MS);
 	return err;
 }
 
-- 
2.53.0