hwmon: (coretemp) Fix Atom CPUs support

Fix Atom CPUs support. Intel documents TjMax at 90 degrees C but
some Atoms may have 125 degrees C (this is undocumented speculation).

Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Cc: Huaxu Wan <huaxu.wan@linux.intel.com>
Cc: Kent Liu <kent.liu@linux.intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

3 files changed, 23 insertions, 14 deletions

diff --git a/Documentation/hwmon/coretemp b/Documentation/hwmon/coretemp
index dbbe6c7025b..d3d79e65871 100644
--- a/Documentation/hwmon/coretemp
+++ b/Documentation/hwmon/coretemp
@@ -4,7 +4,7 @@ Kernel driver coretemp
 Supported chips:
   * All Intel Core family
     Prefix: 'coretemp'
-    CPUID: family 0x6, models 0xe, 0xf, 0x16, 0x17
+    CPUID: family 0x6, models 0xe, 0xf, 0x16, 0x17, 0x1c (Atom)
     Datasheet: Intel 64 and IA-32 Architectures Software Developer's Manual
                Volume 3A: System Programming Guide
                http://softwarecommunity.intel.com/Wiki/Mobility/720.htm
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 9d881f70891..6857560144b 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -373,12 +373,12 @@ config SENSORS_GL520SM
 	  will be called gl520sm.
 
 config SENSORS_CORETEMP
-	tristate "Intel Core (2) Duo/Solo temperature sensor"
+	tristate "Intel Core/Core2/Atom temperature sensor"
 	depends on X86 && EXPERIMENTAL
 	help
 	  If you say yes here you get support for the temperature
-	  sensor inside your CPU. Supported all are all known variants
-	  of Intel Core family.
+	  sensor inside your CPU. Most of the family 6 CPUs
+	  are supported. Check documentation/driver for details.
 
 config SENSORS_IBMAEM
 	tristate "IBM Active Energy Manager temperature/power sensors and control"
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 972cf4ba963..4c15ed7eb78 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -157,17 +157,24 @@ static int __devinit adjust_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *
 	/* The 100C is default for both mobile and non mobile CPUs */
 
 	int tjmax = 100000;
-	int ismobile = 1;
+	int usemsr_ee = 1;
 	int err;
 	u32 eax, edx;
 
 	/* Early chips have no MSR for TjMax */
 
 	if ((c->x86_model == 0xf) && (c->x86_mask < 4)) {
-		ismobile = 0;
+		usemsr_ee = 0;
 	}
 
-	if ((c->x86_model > 0xe) && (ismobile)) {
+	/* Atoms seems to have TjMax at 90C */
+
+	if (c->x86_model == 0x1c) {
+		usemsr_ee = 0;
+		tjmax = 90000;
+	}
+
+	if ((c->x86_model > 0xe) && (usemsr_ee)) {
 
 		/* Now we can detect the mobile CPU using Intel provided table
 		   http://softwarecommunity.intel.com/Wiki/Mobility/720.htm
@@ -179,13 +186,13 @@ static int __devinit adjust_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *
 			dev_warn(dev,
 				 "Unable to access MSR 0x17, assuming desktop"
 				 " CPU\n");
-			ismobile = 0;
+			usemsr_ee = 0;
 		} else if (!(eax & 0x10000000)) {
-			ismobile = 0;
+			usemsr_ee = 0;
 		}
 	}
 
-	if (ismobile || c->x86_model == 0x1c) {
+	if (usemsr_ee) {
 
 		err = rdmsr_safe_on_cpu(id, 0xee, &eax, &edx);
 		if (err) {
@@ -195,7 +202,9 @@ static int __devinit adjust_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *
 		} else if (eax & 0x40000000) {
 			tjmax = 85000;
 		}
-	} else {
+	/* if we dont use msr EE it means we are desktop CPU (with exeception
+	   of Atom) */
+	} else if (tjmax == 100000) {
 		dev_warn(dev, "Using relative temperature scale!\n");
 	}
 
@@ -248,9 +257,9 @@ 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 */
+	   on older CPUs but not in this register, Atoms don't have it either */
 
-	if (c->x86_model > 0xe) {
+	if ((c->x86_model > 0xe) && (c->x86_model != 0x1c)) {
 		err = rdmsr_safe_on_cpu(data->id, 0x1a2, &eax, &edx);
 		if (err) {
 			dev_warn(&pdev->dev, "Unable to read"
@@ -413,7 +422,7 @@ static int __init coretemp_init(void)
 	for_each_online_cpu(i) {
 		struct cpuinfo_x86 *c = &cpu_data(i);
 
-		/* check if family 6, models 0xe, 0xf, 0x16, 0x17, 0x1A */
+		/* check if family 6, models 0xe, 0xf, 0x16, 0x17, 0x1A, 0x1c */
 		if ((c->cpuid_level < 0) || (c->x86 != 0x6) ||
 		    !((c->x86_model == 0xe) || (c->x86_model == 0xf) ||
 			(c->x86_model == 0x16) || (c->x86_model == 0x17) ||