[PATCH AUTOSEL 4.20 09/52] hwmon: (nct6775) Fix fan6 detection for NCT6793D

[Sasha Levin]

From: Guenter Roeck <linux@xxxxxxxxxxxx>

[ Upstream commit 2a2ec4aa0577ec0b7df2d1bde5c84ed39a8637cb ]

Commit 2d99925a15b6 ("hwmon: (nct6775) Separate fan/pwm configuration
detection for NCT6793D") accidentally removed part of the code detecting
if fan6 is enabled or not. As result, fan6 is no longer detected on Asus
PRIME Z370-A. Restore the missing detection code.

Fixes: 2d99925a15b6 ("hwmon: (nct6775) Separate fan/pwm configuration detection for NCT6793D")
Reported-by: Chris Siebenmann <cks@xxxxxxxxxxxxxx>
Cc: Chris Siebenmann <cks@xxxxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/hwmon/nct6775.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/nct6775.c b/drivers/hwmon/nct6775.c
index 4adec4ab7d06..59ee01f3d022 100644
--- a/drivers/hwmon/nct6775.c
+++ b/drivers/hwmon/nct6775.c
@@ -3594,7 +3594,8 @@ nct6775_check_fan_inputs(struct nct6775_data *data)
 			fan5pin |= cr1b & BIT(5);
 			fan5pin |= creb & BIT(5);
 
-			fan6pin = creb & BIT(3);
+			fan6pin = !dsw_en && (cr2d & BIT(1));
+			fan6pin |= creb & BIT(3);
 
 			pwm5pin |= cr2d & BIT(7);
 			pwm5pin |= (creb & BIT(4)) && !(cr2a & BIT(0));
-- 
2.19.1