linux-kernel - [PATCH v2 3/5] hwmon: (max31790) Show 0 RPM/fault when input disabled

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Date:   Tue, 16 Mar 2021 18:55:00 +0100
From:   Václav Kubernát <kubernat@...net.cz>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Václav Kubernát <kubernat@...net.cz>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Jonathan Corbet <corbet@....net>, linux-hwmon@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/5] hwmon: (max31790) Show 0 RPM/fault when input disabled

When fan speed input is disabled, it makes no sense to show values in
fan*_input and fan*_fault.

Signed-off-by: Václav Kubernát <kubernat@...net.cz>
---
 drivers/hwmon/max31790.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
index d16b77472cc1..7b47797db471 100644
--- a/drivers/hwmon/max31790.c
+++ b/drivers/hwmon/max31790.c
@@ -168,6 +168,13 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel,
 
 	switch (attr) {
 	case hwmon_fan_input:
+		cfg = read_reg_byte(regmap, MAX31790_REG_FAN_CONFIG(channel));
+		if (cfg < 0)
+			return cfg;
+
+		if (!(cfg & MAX31790_FAN_CFG_TACH_INPUT_EN))
+			return -ENODATA;
+
 		dynamics = read_reg_byte(regmap, MAX31790_REG_FAN_DYNAMICS(channel));
 		if (dynamics < 0)
 			return dynamics;
@@ -192,6 +199,15 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel,
 		*val = rpm;
 		return 0;
 	case hwmon_fan_fault:
+		cfg = read_reg_byte(regmap, MAX31790_REG_FAN_CONFIG(channel));
+		if (cfg < 0)
+			return cfg;
+
+		if (!(cfg & MAX31790_FAN_CFG_TACH_INPUT_EN)) {
+			*val = 0;
+			return 0;
+		}
+
 		if (channel > 6)
 			fault = read_reg_byte(regmap, MAX31790_REG_FAN_FAULT_STATUS2);
 		else
-- 
2.30.2