hwmon: (coretemp) Add maximum cooling temperature readout

Following patch will add reporting of maximum temperature, at which all fans
should spin full speed. It may be non-physical temperature on Desktop/Server CPUs.

Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>

2 files changed, 32 insertions, 5 deletions

diff --git a/Documentation/hwmon/coretemp b/Documentation/hwmon/coretemp
index 170bf862437b..7fb74419590f 100644
--- a/Documentation/hwmon/coretemp
+++ b/Documentation/hwmon/coretemp
@@ -25,7 +25,8 @@ may be raised, if the temperature grows enough (more than TjMax) to trigger
 the Out-Of-Spec bit. Following table summarizes the exported sysfs files:
 
 temp1_input      - Core temperature (in millidegrees Celsius).
-temp1_crit       - Maximum junction temperature  (in millidegrees Celsius).
+temp1_max        - All cooling devices should be turned on (on Core2).
+temp1_crit       - Maximum junction temperature (in millidegrees Celsius).
 temp1_crit_alarm - Set when Out-of-spec bit is set, never clears.
                    Correct CPU operation is no longer guaranteed.
 temp1_label      - Contains string "Core X", where X is processor
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 3ee60d26e3a2..52914e95e9dc 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -38,7 +38,8 @@
 
 #define DRVNAME "coretemp"
 
-typedef enum { SHOW_TEMP, SHOW_TJMAX, SHOW_LABEL, SHOW_NAME } SHOW;
+typedef enum { SHOW_TEMP, SHOW_TJMAX, SHOW_TTARGET, SHOW_LABEL,
+                SHOW_NAME } SHOW;
 
 /*
  * Functions declaration
@@ -55,6 +56,7 @@ struct coretemp_data {
         unsigned long last_updated;     /* in jiffies */
         int temp;
         int tjmax;
+        int ttarget;
         u8 alarm;
 };
 
@@ -93,9 +95,10 @@ static ssize_t show_temp(struct device *dev,
 
         if (attr->index == SHOW_TEMP)
                 err = data->valid ? sprintf(buf, "%d\n", data->temp) : -EAGAIN;
-        else
+        else if (attr->index == SHOW_TJMAX)
                 err = sprintf(buf, "%d\n", data->tjmax);
-
+        else
+                err = sprintf(buf, "%d\n", data->ttarget);
         return err;
 }
 
@@ -103,6 +106,8 @@ static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL,
                           SHOW_TEMP);
 static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_temp, NULL,
                           SHOW_TJMAX);
+static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL,
+                          SHOW_TTARGET);
 static DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL);
 static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_name, NULL, SHOW_LABEL);
 static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, SHOW_NAME);
@@ -223,8 +228,26 @@ static int __devinit coretemp_probe(struct platform_device *pdev)
 
         platform_set_drvdata(pdev, data);
 
+        /* read the still undocumented IA32_TEMPERATURE_TARGET it exists
+           on older CPUs but not in this register */
+
+        if (c->x86_model > 0xe) {
+                err = rdmsr_safe_on_cpu(data->id, 0x1a2, &eax, &edx);
+                if (err) {
+                        dev_warn(&pdev->dev, "Unable to read"
+                                        " IA32_TEMPERATURE_TARGET MSR\n");
+                } else {
+                        data->ttarget = data->tjmax -
+                                        (((eax >> 8) & 0xff) * 1000);
+                        err = device_create_file(&pdev->dev,
+                                        &sensor_dev_attr_temp1_max.dev_attr);
+                        if (err)
+                                goto exit_free;
+                }
+        }
+
         if ((err = sysfs_create_group(&pdev->dev.kobj, &coretemp_group)))
-                goto exit_free;
+                goto exit_dev;
 
         data->hwmon_dev = hwmon_device_register(&pdev->dev);
         if (IS_ERR(data->hwmon_dev)) {
@@ -238,6 +261,8 @@ static int __devinit coretemp_probe(struct platform_device *pdev)
 
 exit_class:
         sysfs_remove_group(&pdev->dev.kobj, &coretemp_group);
+exit_dev:
+        device_remove_file(&pdev->dev, &sensor_dev_attr_temp1_max.dev_attr);
 exit_free:
         kfree(data);
 exit:
@@ -250,6 +275,7 @@ static int __devexit coretemp_remove(struct platform_device *pdev)
 
         hwmon_device_unregister(data->hwmon_dev);
         sysfs_remove_group(&pdev->dev.kobj, &coretemp_group);
+        device_remove_file(&pdev->dev, &sensor_dev_attr_temp1_max.dev_attr);
         platform_set_drvdata(pdev, NULL);
         kfree(data);
         return 0;