This is a note to let you know that I've just added the patch titled
hwmon: (jc42) Restore the min/max/critical temperatures on resume
to the 5.15-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:
hwmon-jc42-restore-the-min-max-critical-temperatures.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b4e155244fabc183848ae2fb4e70d17daef47e3c
Author: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Date: Sun Oct 23 23:31:57 2022 +0200
hwmon: (jc42) Restore the min/max/critical temperatures on resume
[ Upstream commit 084ed144c448fd5bc8ed5a58247153fbbfd115c3 ]
The JC42 compatible thermal sensor on Kingston KSM32ES8/16ME DIMMs
(using Micron E-Die) is an ST Microelectronics STTS2004 (manufacturer
0x104a, device 0x2201). It does not keep the previously programmed
minimum, maximum and critical temperatures after system suspend and
resume (which is a shutdown / startup cycle for the JC42 temperature
sensor). This results in an alarm on system resume because the hardware
default for these values is 0°C (so any environment temperature greater
than 0°C will trigger the alarm).
Example before system suspend:
jc42-i2c-0-1a
Adapter: SMBus PIIX4 adapter port 0 at 0b00
temp1: +34.8°C (low = +0.0°C)
(high = +85.0°C, hyst = +85.0°C)
(crit = +95.0°C, hyst = +95.0°C)
Example after system resume (without this change):
jc42-i2c-0-1a
Adapter: SMBus PIIX4 adapter port 0 at 0b00
temp1: +34.8°C (low = +0.0°C) ALARM (HIGH, CRIT)
(high = +0.0°C, hyst = +0.0°C)
(crit = +0.0°C, hyst = +0.0°C)
Apply the cached values from the JC42_REG_TEMP_UPPER,
JC42_REG_TEMP_LOWER, JC42_REG_TEMP_CRITICAL and JC42_REG_SMBUS (where
the SMBUS register is not related to this issue but a side-effect of
using regcache_sync() during system resume with the previously
cached/programmed values. This fixes the alarm due to the hardware
defaults of 0°C because the previously applied limits (set by userspace)
are re-applied on system resume.
Fixes: 175c490c9e7f ("hwmon: (jc42) Add support for STTS2004 and AT30TSE004")
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221023213157.11078-3-martin.blumenstingl@xxxxxxxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
index 9a2a062eb7b8..5240bfdfcf2e 100644
--- a/drivers/hwmon/jc42.c
+++ b/drivers/hwmon/jc42.c
@@ -567,6 +567,10 @@ static int jc42_suspend(struct device *dev)
data->config |= JC42_CFG_SHUTDOWN;
regmap_write(data->regmap, JC42_REG_CONFIG, data->config);
+
+ regcache_cache_only(data->regmap, true);
+ regcache_mark_dirty(data->regmap);
+
return 0;
}
@@ -574,9 +578,13 @@ static int jc42_resume(struct device *dev)
{
struct jc42_data *data = dev_get_drvdata(dev);
+ regcache_cache_only(data->regmap, false);
+
data->config &= ~JC42_CFG_SHUTDOWN;
regmap_write(data->regmap, JC42_REG_CONFIG, data->config);
- return 0;
+
+ /* Restore cached register values to hardware */
+ return regcache_sync(data->regmap);
}
static const struct dev_pm_ops jc42_dev_pm_ops = {
