From: Martin Blumenstingl martin.blumenstingl@googlemail.com
[ 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@roeck-us.net Signed-off-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Link: https://lore.kernel.org/r/20221023213157.11078-3-martin.blumenstingl@googlem... Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hwmon/jc42.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
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 = {