Messages in this thread | | | Subject | Re: [PATCH 2/2] iio: chemical: Add driver support for sgp40 | From | Guenter Roeck <> | Date | Sat, 31 Jul 2021 11:06:25 -0700 |
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On 7/31/21 9:39 AM, Jonathan Cameron wrote: > On Tue, 27 Jul 2021 18:35:19 +0200 > Andreas Klinger <ak@it-klinger.de> wrote: > >> sgp40 is a gas sensor used for measuring the air quality. >> >> This driver is reading the raw resistance value which can be passed to >> a userspace algorithm for further calculation. >> >> The raw value is also used to calculate an estimated absolute voc index >> in the range from 0 to 500. For this purpose the raw_mean value of the >> resistance for which the index value is 250 might be set up as a >> calibration step. >> >> Compensation of relative humidity and temperature is supported and can >> be used by writing to device attributes of the driver. >> >> There is a predecesor sensor type (sgp30) already existing. This driver >> module was not extended because the new sensor is quite different in its >> i2c telegrams. >> >> Signed-off-by: Andreas Klinger <ak@it-klinger.de> > > Hi Andreas, > > Non standard ABI in here, so we are missing documentation in Documentation/ABI/testing/sysfs-bus-iio-* > > Otherwise a few suggestions inline. > > Thanks, > > Jonathan > > >> --- [ ... ]
>> +static int sgp40_read_raw(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, int *val, >> + int *val2, long mask) >> +{ >> + struct sgp40_data *data = iio_priv(indio_dev); >> + int ret; >> + u16 raw; >> + int voc; >> + >> + switch (mask) { >> + case IIO_CHAN_INFO_RAW: >> + mutex_lock(&data->lock); >> + ret = sgp40_measure_raw(data, &raw); >> + if (ret) { >> + mutex_unlock(&data->lock); >> + return ret; >> + } >> + *val = raw; >> + ret = IIO_VAL_INT; >> + mutex_unlock(&data->lock); >> + break; >> + case IIO_CHAN_INFO_PROCESSED: >> + mutex_lock(&data->lock); >> + ret = sgp40_measure_raw(data, &raw); >> + if (ret) { >> + mutex_unlock(&data->lock); >> + return ret; >> + } >> + ret = sgp40_calc_voc(data, raw, &voc); >> + if (ret) { >> + mutex_unlock(&data->lock); >> + return ret; >> + } >> + *val = voc; >> + ret = IIO_VAL_INT; >> + mutex_unlock(&data->lock); > > You are holding the lock longer than needed - it would be good > to reduce this, hopefully removing the need for unlocking separately > in each of the error paths. > >> + break; >> + default: >> + return -EINVAL; >> + } >> + >> + return ret; > > Drop this as you can't get here. >
Are you sure ? I see several "break;" above.
Guenter
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