diff mbox series

[v3,2/2] hwmon: (jc42) Restore the min/max/critical temperatures on resume

Message ID 20221021165000.1865615-3-martin.blumenstingl@googlemail.com
State New
Headers
Series hwmon: (jc42) regmap conversion and resume fix |

Commit Message

Martin Blumenstingl Oct. 21, 2022, 4:50 p.m. UTC 
  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")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 drivers/hwmon/jc42.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Comments

Guenter Roeck Oct. 21, 2022, 5:25 p.m. UTC | #1 
On Fri, Oct 21, 2022 at 06:50:00PM +0200, Martin Blumenstingl wrote:
> 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")
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

Nice use of regmap.

For my reference:

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

Thanks,
Guenter

> ---
>  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 8d70960d5444..52a60eb0791b 100644
> --- a/drivers/hwmon/jc42.c
> +++ b/drivers/hwmon/jc42.c
> @@ -565,6 +565,10 @@ 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;
>  }
>  
> @@ -572,9 +576,13 @@ 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 = {
> -- 
> 2.38.1
>
diff mbox series

Patch

diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
index 8d70960d5444..52a60eb0791b 100644
--- a/drivers/hwmon/jc42.c
+++ b/drivers/hwmon/jc42.c
@@ -565,6 +565,10 @@  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;
 }
 
@@ -572,9 +576,13 @@  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 = {