[PATCH v3 01/11] hwmon: (amc6821) Stop accepting invalid pwm values

Guenter Roeck
2024-07-04T17:52:14Z

The pwm value range is well defined from 0..255. Don't accept any values
outside this range.

This changes the valid range of pwm1_auto_point2_pwm from 0..254 to 0..255,
meaning it can now be equivalent to not only pwm1_auto_point1_pwm (which is
always 0) but also to pwm1_auto_point3_pwm (which is always 255). While
that may not be practical, there seems to be no technical reason for
preventing a user from doing it.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Change valid range of pwm1_auto_point2_pwm from [0..254] to
[0, 255]
Add Quentin's Reviewed-by: tag

v2: Use kstrtou8() instead of kstrtol() where possible.
Limit range of pwm1_auto_point_pwm to 0..254 in patch 1
instead of limiting it later, and do not accept invalid
values for the attribute.

drivers/hwmon/amc6821.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 9b02b304c2f5..dc35e9b21f91 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -355,13 +355,13 @@ static ssize_t pwm1_store(struct device *dev,
{
struct amc6821_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
- long val;
- int ret = kstrtol(buf, 10, &val);
+ u8 val;
+ int ret = kstrtou8(buf, 10, &val);
if (ret)
return ret;

mutex_lock(&data->update_lock);
- data->pwm1 = clamp_val(val , 0, 255);
+ data->pwm1 = val;
i2c_smbus_write_byte_data(client, AMC6821_REG_DCY, data->pwm1);
mutex_unlock(&data->update_lock);
return count;
@@ -558,13 +558,15 @@ static ssize_t pwm1_auto_point_pwm_store(struct device *dev,
struct amc6821_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int dpwm;
- long val;
- int ret = kstrtol(buf, 10, &val);
+ u8 val;
+ int ret;
+
+ ret = kstrtou8(buf, 10, &val);
if (ret)
return ret;

mutex_lock(&data->update_lock);
- data->pwm1_auto_point_pwm[1] = clamp_val(val, 0, 254);
+ data->pwm1_auto_point_pwm[1] = val;
if (i2c_smbus_write_byte_data(client, AMC6821_REG_DCY_LOW_TEMP,
data->pwm1_auto_point_pwm[1])) {
dev_err(&client->dev, "Register write error, aborting.\n");
--
2.39.2