hwmon: (dell-smm) Cache fan_type() calls and change fan detection

[firefly-linux-kernel-4.4.55.git] / drivers / hwmon / dell-smm-hwmon.c

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 497efa03d98979a0dd3644e37ff8ee7f005b0845..a9356a3dea926e96b54fae6ed253f1b69aeb0311 100644 (file)
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -237,7 +237,7 @@ static int i8k_get_fan_speed(int fan)
 /*
  * Read the fan type.
  */
-static int i8k_get_fan_type(int fan)
+static int _i8k_get_fan_type(int fan)
 {
        struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
 
@@ -248,6 +248,17 @@ static int i8k_get_fan_type(int fan)
        return i8k_smm(&regs) ? : regs.eax & 0xff;
 }
 
+static int i8k_get_fan_type(int fan)
+{
+       /* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
+       static int types[2] = { INT_MIN, INT_MIN };
+
+       if (types[fan] == INT_MIN)
+               types[fan] = _i8k_get_fan_type(fan);
+
+       return types[fan];
+}
+
 /*
  * Read the fan nominal rpm for specific fan speed.
  */
@@ -777,13 +788,17 @@ static int __init i8k_init_hwmon(void)
        if (err >= 0)
                i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
 
-       /* First fan attributes, if fan type is OK */
-       err = i8k_get_fan_type(0);
+       /* First fan attributes, if fan status or type is OK */
+       err = i8k_get_fan_status(0);
+       if (err < 0)
+               err = i8k_get_fan_type(0);
        if (err >= 0)
                i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;
 
-       /* Second fan attributes, if fan type is OK */
-       err = i8k_get_fan_type(1);
+       /* Second fan attributes, if fan status or type is OK */
+       err = i8k_get_fan_status(1);
+       if (err < 0)
+               err = i8k_get_fan_type(1);
        if (err >= 0)
                i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;