[PATCH] i8k: Add support for temperature sensor labels

["Pali Rohár" <pali.rohar@gmail.com>]

This patch adds labels for temperature sensors if SMM function with EAX register
0x11a3 reports it. These informations was taken from DOS binary NBSVC.MDM.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
---
 drivers/char/i8k.c |  110 +++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 88 insertions(+), 22 deletions(-)

diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index e34a019..77af46b 100644
--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -42,6 +42,7 @@
 #define I8K_SMM_GET_FAN		0x00a3
 #define I8K_SMM_GET_SPEED	0x02a3
 #define I8K_SMM_GET_TEMP	0x10a3
+#define I8K_SMM_GET_TEMP_TYPE	0x11a3
 #define I8K_SMM_GET_DELL_SIG1	0xfea3
 #define I8K_SMM_GET_DELL_SIG2	0xffa3
 
@@ -288,6 +289,14 @@ static int i8k_set_fan(int fan, int speed)
 	return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
 }
 
+static int i8k_get_temp_type(int sensor)
+{
+	struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, };
+
+	regs.ebx = sensor & 0xff;
+	return i8k_smm(&regs) ? : regs.eax & 0xff;
+}
+
 /*
  * Read the cpu temperature.
  */
@@ -493,6 +502,29 @@ static int i8k_open_fs(struct inode *inode, struct file *file)
  * Hwmon interface
  */
 
+static ssize_t i8k_hwmon_show_temp_label(struct device *dev,
+				   struct device_attribute *devattr,
+				   char *buf)
+{
+	static const char * const labels[] = {
+		"CPU",
+		"GPU",
+		"SODIMM",
+		"Other",
+		"Ambient",
+		"Other",
+	};
+	int index = to_sensor_dev_attr(devattr)->index;
+	int type;
+
+	type = i8k_get_temp_type(index);
+	if (type < 0)
+		return type;
+	if (type >= ARRAY_SIZE(labels))
+		type = ARRAY_SIZE(labels) - 1;
+	return sprintf(buf, "%s\n", labels[type]);
+}
+
 static ssize_t i8k_hwmon_show_temp(struct device *dev,
 				   struct device_attribute *devattr,
 				   char *buf)
@@ -555,9 +587,13 @@ static ssize_t i8k_hwmon_set_pwm(struct device *dev,
 }
 
 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL, 0);
 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL, 1);
 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL, 2);
 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL, 3);
 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
 			  I8K_FAN_LEFT);
 static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
@@ -569,31 +605,35 @@ static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
 
 static struct attribute *i8k_attrs[] = {
 	&sensor_dev_attr_temp1_input.dev_attr.attr,	/* 0 */
-	&sensor_dev_attr_temp2_input.dev_attr.attr,	/* 1 */
-	&sensor_dev_attr_temp3_input.dev_attr.attr,	/* 2 */
-	&sensor_dev_attr_temp4_input.dev_attr.attr,	/* 3 */
-	&sensor_dev_attr_fan1_input.dev_attr.attr,	/* 4 */
-	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 5 */
-	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 6 */
-	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 7 */
+	&sensor_dev_attr_temp1_label.dev_attr.attr,	/* 1 */
+	&sensor_dev_attr_temp2_input.dev_attr.attr,	/* 2 */
+	&sensor_dev_attr_temp2_label.dev_attr.attr,	/* 3 */
+	&sensor_dev_attr_temp3_input.dev_attr.attr,	/* 4 */
+	&sensor_dev_attr_temp3_label.dev_attr.attr,	/* 5 */
+	&sensor_dev_attr_temp4_input.dev_attr.attr,	/* 6 */
+	&sensor_dev_attr_temp4_label.dev_attr.attr,	/* 7 */
+	&sensor_dev_attr_fan1_input.dev_attr.attr,	/* 8 */
+	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 9 */
+	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 10 */
+	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 11 */
 	NULL
 };
 
 static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
 			      int index)
 {
-	if (index == 0 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
+	if (index >= 0 && index <= 1 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
 		return 0;
-	if (index == 1 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP2))
+	if (index >= 2 && index <= 3 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP2))
 		return 0;
-	if (index == 2 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP3))
+	if (index >= 4 && index <= 5 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP3))
 		return 0;
-	if (index == 3 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
+	if (index >= 6 && index <= 7 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
 		return 0;
-	if (index >= 4 && index <= 5 &&
+	if (index >= 8 && index <= 9 &&
 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
 		return 0;
-	if (index >= 6 && index <= 7 &&
+	if (index >= 10 && index <= 11 &&
 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
 		return 0;
 
@@ -606,6 +646,37 @@ static const struct attribute_group i8k_group = {
 };
 __ATTRIBUTE_GROUPS(i8k);
 
+static bool __init i8k_check_temp(int sensor)
+{
+	int err;
+
+	/*
+	 * Check if temperature sensor type is valid.
+	 *
+	 * If it is valid then sensor should work. But some sensors are not
+	 * available at any time. E.g GPU sensor on Optimus/PowerExpress/Enduro
+	 * card does not work (or return bogus value) when card is turned off.
+	 * So this function should not fail in this case.
+	 */
+	err = i8k_get_temp_type(sensor);
+	if (err >= 0)
+		return true;
+
+	/*
+	 * Check if temperatrue reading does not fail.
+	 *
+	 * Sometimes detection of temperature sensor type does not work but
+	 * reading temperature working fine. Sometimes temperature value is too
+	 * high and i8k_get_temp() returns -ERANGE. But there is no reason to
+	 * ignore these temperature sensors.
+	 */
+	err = i8k_get_temp(sensor);
+	if (err >= 0 || err == -ERANGE)
+		return true;
+
+	return false;
+}
+
 static int __init i8k_init_hwmon(void)
 {
 	int err;
@@ -613,18 +684,13 @@ static int __init i8k_init_hwmon(void)
 	i8k_hwmon_flags = 0;
 
 	/* CPU temperature attributes, if temperature reading is OK */
-	err = i8k_get_temp(0);
-	if (err >= 0 || err == -ERANGE)
+	if (i8k_check_temp(0))
 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP1;
-	/* check for additional temperature sensors */
-	err = i8k_get_temp(1);
-	if (err >= 0 || err == -ERANGE)
+	if (i8k_check_temp(1))
 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP2;
-	err = i8k_get_temp(2);
-	if (err >= 0 || err == -ERANGE)
+	if (i8k_check_temp(2))
 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP3;
-	err = i8k_get_temp(3);
-	if (err >= 0 || err == -ERANGE)
+	if (i8k_check_temp(3))
 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
 
 	/* Left fan attributes, if left fan is present */
-- 
1.7.9.5