On 6/13/24 02:51, Naresh Solanki wrote:
...
+ switch (attr) {
+ case hwmon_fan_pulses:
+ if (val <= 0 || val > 5)
+ return -EINVAL;
+
+ /* Set Fan pulse per revolution */
+ err = max6639_set_ppr(data, channel, val);
+ if (err < 0)
+ return err;
+
+ data->ppr[channel] = val;
Needs mutex protection to avoid inconsistencies due to concurrent writes.
This is single i2c access. Still we need mutex protection here ?
In this case, the mutex doesn't protect the i2c access, it protects the
consistency between the chip configuration and the information stored
in data->ppr[].
CPU1 CPU2
[val==1] [val!=1]
max6639_set_ppr();
max6639_set_ppr();
data->ppr[channel] = val;
data->ppr[channel] = val;
The alternative would be to not cache ppr and read it from the regmap cache
when needed.
Guenter
