[PATCH 08/11] platform/x86: asus-wmi: Enhance detection of thermal data

[Yurii Pavlovskyi]

The obviously wrong value 1 for temperature device ID in this driver is
returned by at least some devices, including TUF Gaming series laptops,
instead of 0 as expected previously. Observable effect is that a
temp1_input in hwmon reads temperature near absolute zero.

* Consider 0.1 K as erroneous value in addition to 0 K.
* Refactor detection of thermal input availability to a separate function.

Signed-off-by: Yurii Pavlovskyi <yurii.pavlovs...@gmail.com>
---
 drivers/platform/x86/asus-wmi.c | 46 ++++++++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 7 deletions(-)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index b9a6dc224e08..175ecd5b7c51 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -176,6 +176,7 @@ struct asus_wmi {
        struct asus_rfkill gps;
        struct asus_rfkill uwb;
 
+       bool asus_hwmon_thermal_available;
        bool asus_hwmon_fan_manual_mode;
        int asus_hwmon_num_fans;
        int asus_hwmon_pwm;
@@ -1373,6 +1374,32 @@ static struct attribute *hwmon_attributes[] = {
        NULL
 };
 
+static int asus_hwmon_check_thermal_available(struct asus_wmi *asus)
+{
+       u32 value = ASUS_WMI_UNSUPPORTED_METHOD;
+       int err;
+
+       asus->asus_hwmon_thermal_available = false;
+       err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_THERMAL_CTRL, &value);
+
+       if (err < 0) {
+               if (err == -ENODEV)
+                       return 0;
+
+               return err;
+       }
+
+       /*
+        * If the temperature value in deci-Kelvin is near the absolute
+        * zero temperature, something is clearly wrong.
+        */
+       if (!value || value == 1)
+               return 0;
+
+       asus->asus_hwmon_thermal_available = true;
+       return 0;
+}
+
 static umode_t asus_hwmon_sysfs_is_visible(struct kobject *kobj,
                                          struct attribute *attr, int idx)
 {
@@ -1386,8 +1413,6 @@ static umode_t asus_hwmon_sysfs_is_visible(struct kobject 
*kobj,
 
        if (attr == &dev_attr_pwm1.attr)
                dev_id = ASUS_WMI_DEVID_FAN_CTRL;
-       else if (attr == &dev_attr_temp1_input.attr)
-               dev_id = ASUS_WMI_DEVID_THERMAL_CTRL;
 
        if (attr == &dev_attr_fan1_input.attr
            || attr == &dev_attr_fan1_label.attr
@@ -1412,15 +1437,13 @@ static umode_t asus_hwmon_sysfs_is_visible(struct 
kobject *kobj,
                 * - reverved bits are non-zero
                 * - sfun and presence bit are not set
                 */
-               if (value == ASUS_WMI_UNSUPPORTED_METHOD || value & 0xFFF80000
+               if (value == ASUS_WMI_UNSUPPORTED_METHOD || (value & 0xFFF80000)
                    || (!asus->sfun && !(value & ASUS_WMI_DSTS_PRESENCE_BIT)))
                        ok = false;
                else
                        ok = fan_attr <= asus->asus_hwmon_num_fans;
-       } else if (dev_id == ASUS_WMI_DEVID_THERMAL_CTRL) {
-               /* If value is zero, something is clearly wrong */
-               if (!value)
-                       ok = false;
+       } else if (attr == &dev_attr_temp1_input.attr) {
+               ok = asus->asus_hwmon_thermal_available;
        } else if (fan_attr <= asus->asus_hwmon_num_fans && fan_attr != -1) {
                ok = true;
        } else {
@@ -1476,6 +1499,15 @@ static int asus_wmi_fan_init(struct asus_wmi *asus)
        }
 
        pr_info("Number of fans: %d\n", asus->asus_hwmon_num_fans);
+
+       status = asus_hwmon_check_thermal_available(asus);
+       if (status) {
+               pr_warn("Could not check if thermal available: %d\n", status);
+               return -ENXIO;
+       }
+
+       pr_info(PR "Thermal available: %d\n",
+                       asus->asus_hwmon_thermal_available);
        return 0;
 }
 
-- 
2.17.1