Hi guys:
> >static ssize_t set_fan_min(struct device *dev, const char *buf,
> > size_t count, int nr)
> >{
> > struct i2c_client *client = to_i2c_client(dev);
> > struct adm1026_data *data = i2c_get_clientdata(client);
> > int val;
> >
> > down(&data->update_lock);
> > val = simple_strtol(buf, NULL, 10);
> > data->fan_min[nr] = FAN_TO_REG(val, data->fan_div[nr]);
> > adm1026_write_value(client, ADM1026_REG_FAN_MIN(nr),
> > data->fan_min[nr]);
> > up(&data->update_lock);
> > return count;
> >}
* Jean Delvare <khali at linux-fr.org> [2004-10-19 12:09:43 +0200]:
> I see no reason to use the update_lock semaphore here. Other I2C client
> drivers don't.
This particular function does need the lock: it prevents a race condition
between data->fan_min[n] and data->fan_div[n]. I.e. the two lines starting
with the one containing FAN_TO_REG must occur atomically w.r.t. the client
data structure.
Other drivers may not need it, *iff* they do *not* adjust the fan min/max
during the set_fan_div function. This module does make that adjustment.
I think Phil P. was the first to add this code actually, and it was
something I copied into a couple other drivers (lm78 and asb100 I think).
Regards,
--
Mark M. Hoffman
mhoffman at lightlink.com
