2 files changed, 130 insertions, 2 deletions

diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index f2ff638cce8d..0d5e91379ae8 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -1269,7 +1269,7 @@ Fan control and monitoring: fan speed, fan enable/disable
 
 procfs: /proc/acpi/ibm/fan
 sysfs device attributes: (hwmon "thinkpad") fan1_input, pwm1,
-                          pwm1_enable
+                          pwm1_enable, fan2_input
 sysfs hwmon driver attributes: fan_watchdog
 
 NOTE NOTE NOTE: fan control operations are disabled by default for
@@ -1282,6 +1282,9 @@ from the hardware registers of the embedded controller.  This is known
 to work on later R, T, X and Z series ThinkPads but may show a bogus
 value on other models.
 
+Some Lenovo ThinkPads support a secondary fan.  This fan cannot be
+controlled separately, it shares the main fan control.
+
 Fan levels:
 
 Most ThinkPad fans work in "levels" at the firmware interface.  Level 0
@@ -1412,6 +1415,11 @@ hwmon device attribute fan1_input:
         which can take up to two minutes.  May return rubbish on older
         ThinkPads.
 
+hwmon device attribute fan2_input:
+        Fan tachometer reading, in RPM, for the secondary fan.
+        Available only on some ThinkPads.  If the secondary fan is
+        not installed, will always read 0.
+
 hwmon driver attribute fan_watchdog:
         Fan safety watchdog timer interval, in seconds.  Minimum is
         1 second, maximum is 120 seconds.  0 disables the watchdog.
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index c8d74dbacbbd..27ca676a7092 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -264,6 +264,7 @@ static struct {
         u32 wan:1;
         u32 uwb:1;
         u32 fan_ctrl_status_undef:1;
+        u32 second_fan:1;
         u32 beep_needs_two_args:1;
         u32 input_device_registered:1;
         u32 platform_drv_registered:1;
@@ -6298,6 +6299,21 @@ static struct ibm_struct volume_driver_data = {
  *      For firmware bugs, refer to:
  *      http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Firmware_Issues
  *
+ *      ----
+ *
+ *      ThinkPad EC register 0x31 bit 0 (only on select models)
+ *
+ *      When bit 0 of EC register 0x31 is zero, the tachometer registers
+ *      show the speed of the main fan.  When bit 0 of EC register 0x31
+ *      is one, the tachometer registers show the speed of the auxiliary
+ *      fan.
+ *
+ *      Fan control seems to affect both fans, regardless of the state
+ *      of this bit.
+ *
+ *      So far, only the firmware for the X60/X61 non-tablet versions
+ *      seem to support this (firmware TP-7M).
+ *
  * TPACPI_FAN_WR_ACPI_FANS:
  *      ThinkPad X31, X40, X41.  Not available in the X60.
  *
@@ -6324,6 +6340,8 @@ enum {					/* Fan control constants */
         fan_status_offset = 0x2f,       /* EC register 0x2f */
         fan_rpm_offset = 0x84,          /* EC register 0x84: LSB, 0x85 MSB (RPM)
                                          * 0x84 must be read before 0x85 */
+        fan_select_offset = 0x31,       /* EC register 0x31 (Firmware 7M)
+                                           bit 0 selects which fan is active */
 
         TP_EC_FAN_FULLSPEED = 0x40,     /* EC fan mode: full speed */
         TP_EC_FAN_AUTO      = 0x80,     /* EC fan mode: auto fan control */
@@ -6417,6 +6435,38 @@ static void fan_quirk1_handle(u8 *fan_status)
         }
 }
 
+/* Select main fan on X60/X61, NOOP on others */
+static bool fan_select_fan1(void)
+{
+        if (tp_features.second_fan) {
+                u8 val;
+
+                if (ec_read(fan_select_offset, &val) < 0)
+                        return false;
+                val &= 0xFEU;
+                if (ec_write(fan_select_offset, val) < 0)
+                        return false;
+        }
+        return true;
+}
+
+/* Select secondary fan on X60/X61 */
+static bool fan_select_fan2(void)
+{
+        u8 val;
+
+        if (!tp_features.second_fan)
+                return false;
+
+        if (ec_read(fan_select_offset, &val) < 0)
+                return false;
+        val |= 0x01U;
+        if (ec_write(fan_select_offset, val) < 0)
+                return false;
+
+        return true;
+}
+
 /*
  * Call with fan_mutex held
  */
@@ -6494,6 +6544,8 @@ static int fan_get_speed(unsigned int *speed)
         switch (fan_status_access_mode) {
         case TPACPI_FAN_RD_TPEC:
                 /* all except 570, 600e/x, 770e, 770x */
+                if (unlikely(!fan_select_fan1()))
+                        return -EIO;
                 if (unlikely(!acpi_ec_read(fan_rpm_offset, &lo) ||
                              !acpi_ec_read(fan_rpm_offset + 1, &hi)))
                         return -EIO;
@@ -6510,6 +6562,34 @@ static int fan_get_speed(unsigned int *speed)
         return 0;
 }
 
+static int fan2_get_speed(unsigned int *speed)
+{
+        u8 hi, lo;
+        bool rc;
+
+        switch (fan_status_access_mode) {
+        case TPACPI_FAN_RD_TPEC:
+                /* all except 570, 600e/x, 770e, 770x */
+                if (unlikely(!fan_select_fan2()))
+                        return -EIO;
+                rc = !acpi_ec_read(fan_rpm_offset, &lo) ||
+                             !acpi_ec_read(fan_rpm_offset + 1, &hi);
+                fan_select_fan1(); /* play it safe */
+                if (rc)
+                        return -EIO;
+
+                if (likely(speed))
+                        *speed = (hi << 8) | lo;
+
+                break;
+
+        default:
+                return -ENXIO;
+        }
+
+        return 0;
+}
+
 static int fan_set_level(int level)
 {
         if (!fan_control_allowed)
@@ -6915,6 +6995,25 @@ static struct device_attribute dev_attr_fan_fan1_input =
         __ATTR(fan1_input, S_IRUGO,
                 fan_fan1_input_show, NULL);
 
+/* sysfs fan fan2_input ------------------------------------------------ */
+static ssize_t fan_fan2_input_show(struct device *dev,
+                           struct device_attribute *attr,
+                           char *buf)
+{
+        int res;
+        unsigned int speed;
+
+        res = fan2_get_speed(&speed);
+        if (res < 0)
+                return res;
+
+        return snprintf(buf, PAGE_SIZE, "%u\n", speed);
+}
+
+static struct device_attribute dev_attr_fan_fan2_input =
+        __ATTR(fan2_input, S_IRUGO,
+                fan_fan2_input_show, NULL);
+
 /* sysfs fan fan_watchdog (hwmon driver) ------------------------------- */
 static ssize_t fan_fan_watchdog_show(struct device_driver *drv,
                                      char *buf)
@@ -6948,6 +7047,7 @@ static DRIVER_ATTR(fan_watchdog, S_IWUSR | S_IRUGO,
 static struct attribute *fan_attributes[] = {
         &dev_attr_fan_pwm1_enable.attr, &dev_attr_fan_pwm1.attr,
         &dev_attr_fan_fan1_input.attr,
+        NULL, /* for fan2_input */
         NULL
 };
 
@@ -6955,7 +7055,8 @@ static const struct attribute_group fan_attr_group = {
         .attrs = fan_attributes,
 };
 
-#define TPACPI_FAN_Q1   0x0001
+#define TPACPI_FAN_Q1   0x0001          /* Unitialized HFSP */
+#define TPACPI_FAN_2FAN 0x0002          /* EC 0x31 bit 0 selects fan2 */
 
 #define TPACPI_FAN_QI(__id1, __id2, __quirks)   \
         { .vendor = PCI_VENDOR_ID_IBM,          \
@@ -6963,13 +7064,21 @@ static const struct attribute_group fan_attr_group = {
           .ec = TPID(__id1, __id2),             \
           .quirks = __quirks }
 
+#define TPACPI_FAN_QL(__id1, __id2, __quirks)   \
+        { .vendor = PCI_VENDOR_ID_LENOVO,       \
+          .bios = TPACPI_MATCH_ANY,             \
+          .ec = TPID(__id1, __id2),             \
+          .quirks = __quirks }
+
 static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
         TPACPI_FAN_QI('1', 'Y', TPACPI_FAN_Q1),
         TPACPI_FAN_QI('7', '8', TPACPI_FAN_Q1),
         TPACPI_FAN_QI('7', '6', TPACPI_FAN_Q1),
         TPACPI_FAN_QI('7', '0', TPACPI_FAN_Q1),
+        TPACPI_FAN_QL('7', 'M', TPACPI_FAN_2FAN),
 };
 
+#undef TPACPI_FAN_QL
 #undef TPACPI_FAN_QI
 
 static int __init fan_init(struct ibm_init_struct *iibm)
@@ -6986,6 +7095,7 @@ static int __init fan_init(struct ibm_init_struct *iibm)
         fan_control_commands = 0;
         fan_watchdog_maxinterval = 0;
         tp_features.fan_ctrl_status_undef = 0;
+        tp_features.second_fan = 0;
         fan_control_desired_level = 7;
 
         TPACPI_ACPIHANDLE_INIT(fans);
@@ -7006,6 +7116,11 @@ static int __init fan_init(struct ibm_init_struct *iibm)
                         fan_status_access_mode = TPACPI_FAN_RD_TPEC;
                         if (quirks & TPACPI_FAN_Q1)
                                 fan_quirk1_setup();
+                        if (quirks & TPACPI_FAN_2FAN) {
+                                tp_features.second_fan = 1;
+                                dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_FAN,
+                                        "secondary fan support enabled\n");
+                        }
                 } else {
                         printk(TPACPI_ERR
                                "ThinkPad ACPI EC access misbehaving, "
@@ -7061,6 +7176,11 @@ static int __init fan_init(struct ibm_init_struct *iibm)
 
         if (fan_status_access_mode != TPACPI_FAN_NONE ||
             fan_control_access_mode != TPACPI_FAN_WR_NONE) {
+                if (tp_features.second_fan) {
+                        /* attach second fan tachometer */
+                        fan_attributes[ARRAY_SIZE(fan_attributes)-2] =
+                                        &dev_attr_fan_fan2_input.attr;
+                }
                 rc = sysfs_create_group(&tpacpi_sensors_pdev->dev.kobj,
                                          &fan_attr_group);
                 if (rc < 0)