On 6/24/24 5:51 PM, David Lechner wrote:
> On 6/24/24 12:31 PM, Jerome Brunet wrote:
>> Add support for the HW found in most Amlogic SoC dedicated to measure
>> system clocks.
>>
>
>
>
>> +static int cmsr_read_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan,
>> + int *val, int *val2, long mask)
>> +{
>> + struct amlogic_cmsr *cm = iio_priv(indio_dev);
>> +
>> + guard(mutex)(&cm->lock);
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_RAW:
>> + *val = cmsr_measure_unlocked(cm, chan->channel);
>
> Is this actually returning an alternating voltage magnitutde?
> Most frequency drivers don't have a raw value, only frequency.
>
>> + if (*val < 0)
>> + return *val;
>> + return IIO_VAL_INT;
>> +
>> + case IIO_CHAN_INFO_PROCESSED: /* Result in Hz */
>
> Shouldn't this be IIO_CHAN_INFO_FREQUENCY?
>
> Processed is just (raw + offset) * scale which would be a voltage
> in this case since the channel type is IIO_ALTVOLTAGE.
>
>> + *val = cmsr_measure_processed_unlocked(cm, chan->channel, val2);
>> + if (*val < 0)
>> + return *val;
>> + return IIO_VAL_INT_64;
>> +
>> + case IIO_CHAN_INFO_SCALE:
>
> What is this attribute being used for?
>
> (clearly not used to convert the raw value to millivolts :-) )
>
> Maybe IIO_CHAN_INFO_INT_TIME is the right one for this? Although
> so far, that has only been used with light sensors.
Probably not the right idea though since it applies to the frequency
measurement, not the voltage measurement.
>
>> + *val2 = cmsr_get_time_unlocked(cm);
>> + *val = 1000000;
>> + return IIO_VAL_FRACTIONAL;
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
