linux-kernel - [PATCH 1/3] hwmon/adt7470: allow 'fan*

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Message-ID: <20250105195521.3263193-2-radian.dc@gmail.com>
Date: Sun,  5 Jan 2025 20:55:14 +0100
From: Adrian DC <radian.dc@...il.com>
To: Jean Delvare <jdelvare@...e.com>,
	Guenter Roeck <linux@...ck-us.net>,
	linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Adrian DC <radian.dc@...il.com>
Subject: [PATCH 1/3] hwmon/adt7470: allow 'fan*_{min,max}' to be reset to '0'

Tested with the following script and values
---

{
  # Access hwmon
  cd /sys/class/hwmon/hwmon1/

  # Set to 1 => 82
  echo -n ' [TEST] Set to 1 : '
  echo '1' >./fan1_max
  cat ./fan1_max

  # Set to 1234 => 1234
  echo -n ' [TEST] Set to 1234 : '
  echo '1234' >./fan1_max
  cat ./fan1_max

  # Reset to 0 => 0
  echo -n ' [TEST] Set to 0 : '
  echo '0' >./fan1_max
  cat ./fan1_max
}
---

Signed-off-by: Adrian DC <radian.dc@...il.com>
---
 drivers/hwmon/adt7470.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
index dbee6926fa05..712bc41b4a0d 100644
--- a/drivers/hwmon/adt7470.c
+++ b/drivers/hwmon/adt7470.c
@@ -662,11 +662,15 @@ static int adt7470_fan_write(struct device *dev, u32 attr, int channel, long val
 	struct adt7470_data *data = dev_get_drvdata(dev);
 	int err;
 
-	if (val <= 0)
+	if (val < 0)
 		return -EINVAL;
 
-	val = FAN_RPM_TO_PERIOD(val);
-	val = clamp_val(val, 1, 65534);
+	if (val) {
+		val = FAN_RPM_TO_PERIOD(val);
+		val = clamp_val(val, 1, 65534);
+	} else {
+		val = FAN_PERIOD_INVALID;
+	}
 
 	switch (attr) {
 	case hwmon_fan_min:
-- 
2.43.0