[PATCH 02/10] hwmon: (amc6821) Make reading and writing fan speed limits consistent

Guenter Roeck
2024-06-28T15:13:56Z

The default value of the maximum fan speed limit register is 0,
essentially translating to an unlimited fan speed. When reading
the limit, a value of 0 is reported in this case. However, writing
a value of 0 results in writing a value of 0xffff into the register,
which is inconsistent.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/hwmon/amc6821.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 3c614a0bd192..e37257ae1a6b 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -601,7 +601,7 @@ static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
struct amc6821_data *data = amc6821_update_device(dev);
int ix = to_sensor_dev_attr(devattr)->index;
if (0 == data->fan[ix])
- return sprintf(buf, "0");
+ return sprintf(buf, "6000000");
return sprintf(buf, "%d\n", (int)(6000000 / data->fan[ix]));
}

@@ -625,10 +625,10 @@ static ssize_t fan_store(struct device *dev, struct device_attribute *attr,
int ret = kstrtol(buf, 10, &val);
if (ret)
return ret;
- val = 1 > val ? 0xFFFF : 6000000/val;
+ val = val < 1 ? 0xFFFF : 6000000 / val;

mutex_lock(&data->update_lock);
- data->fan[ix] = (u16) clamp_val(val, 1, 0xFFFF);
+ data->fan[ix] = (u16)clamp_val(val, 0, 0xFFFF);
if (i2c_smbus_write_byte_data(client, fan_reg_low[ix],
data->fan[ix] & 0xFF)) {
dev_err(&client->dev, "Register write error, aborting.\n");
--
2.39.2