i8k: Add support for fan labels

This patch adds labels support for fans if SMM function with EAX register
0x03a3 reports it. This information was taken from DOS binary NBSVC.MDM.

Additionally this patch change detection of fan presece. Instead reading fan
status now detection is based on new label SMM function. Dell DOS binary
NBSVC.MDM is doing similar checks, so we should do that too.

This patch also remove I8K_FAN_LEFT and I8K_FAN_RIGHT usage from hwmon driver
part because that names does not make sense anymore. So numeric constants are
used instead. Original /proc/i8k ioctl part was not changed for compatibility
reasons.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/i8k.c

@@ -43,6 +43,7 @@
 #define I8K_SMM_SET_FAN		0x01a3
 #define I8K_SMM_GET_FAN		0x00a3
 #define I8K_SMM_GET_SPEED	0x02a3
+#define I8K_SMM_GET_FAN_TYPE	0x03a3
 #define I8K_SMM_GET_NOM_SPEED	0x04a3
 #define I8K_SMM_GET_TEMP	0x10a3
 #define I8K_SMM_GET_TEMP_TYPE	0x11a3
@@ -278,6 +279,17 @@ static int i8k_get_fan_speed(int fan)
 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
 }
 
+/*
+ * Read the fan type.
+ */
+static int i8k_get_fan_type(int fan)
+{
+	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
+
+	regs.ebx = fan & 0xff;
+	return i8k_smm(&regs) ? : regs.eax & 0xff;
+}
+
 /*
  * Read the fan nominal rpm for specific fan speed.
  */
@@ -553,6 +565,37 @@ static ssize_t i8k_hwmon_show_temp(struct device *dev,
 	return sprintf(buf, "%d\n", temp * 1000);
 }
 
+static ssize_t i8k_hwmon_show_fan_label(struct device *dev,
+					struct device_attribute *devattr,
+					char *buf)
+{
+	static const char * const labels[] = {
+		"Processor Fan",
+		"Motherboard Fan",
+		"Video Fan",
+		"Power Supply Fan",
+		"Chipset Fan",
+		"Other Fan",
+	};
+	int index = to_sensor_dev_attr(devattr)->index;
+	bool dock = false;
+	int type;
+
+	type = i8k_get_fan_type(index);
+	if (type < 0)
+		return type;
+
+	if (type & 0x10) {
+		dock = true;
+		type &= 0x0F;
+	}
+
+	if (type >= ARRAY_SIZE(labels))
+		type = (ARRAY_SIZE(labels) - 1);
+
+	return sprintf(buf, "%s%s\n", (dock ? "Docking " : ""), labels[type]);
+}
+
 static ssize_t i8k_hwmon_show_fan(struct device *dev,
 				  struct device_attribute *devattr,
 				  char *buf)
@@ -611,14 +654,17 @@ static SENSOR_DEVICE_ATTR(temp3_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
 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(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
+			  0);
 static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
-			  i8k_hwmon_set_pwm, I8K_FAN_LEFT);
+			  i8k_hwmon_set_pwm, 0);
 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
-			  I8K_FAN_RIGHT);
+			  1);
+static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
+			  1);
 static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
-			  i8k_hwmon_set_pwm, I8K_FAN_RIGHT);
+			  i8k_hwmon_set_pwm, 1);
 
 static struct attribute *i8k_attrs[] = {
 	&sensor_dev_attr_temp1_input.dev_attr.attr,	/* 0 */
@@ -630,9 +676,11 @@ static struct attribute *i8k_attrs[] = {
 	&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 */
+	&sensor_dev_attr_fan1_label.dev_attr.attr,	/* 9 */
+	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 10 */
+	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 11 */
+	&sensor_dev_attr_fan2_label.dev_attr.attr,	/* 12 */
+	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 13 */
 	NULL
 };
 
@@ -651,10 +699,10 @@ static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
 	if (index >= 6 && index <= 7 &&
 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
 		return 0;
-	if (index >= 8 && index <= 9 &&
+	if (index >= 8 && index <= 10 &&
 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
 		return 0;
-	if (index >= 10 && index <= 11 &&
+	if (index >= 11 && index <= 13 &&
 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
 		return 0;
 
@@ -688,13 +736,13 @@ static int __init i8k_init_hwmon(void)
 	if (err >= 0)
 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
 
-	/* Left fan attributes, if left fan is present */
-	err = i8k_get_fan_status(I8K_FAN_LEFT);
+	/* First fan attributes, if fan type is OK */
+	err = i8k_get_fan_type(0);
 	if (err >= 0)
 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;
 
-	/* Right fan attributes, if right fan is present */
-	err = i8k_get_fan_status(I8K_FAN_RIGHT);
+	/* Second fan attributes, if fan type is OK */
+	err = i8k_get_fan_type(1);
 	if (err >= 0)
 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;