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.
> + *val2 = cmsr_get_time_unlocked(cm);
> + *val = 1000000;
> + return IIO_VAL_FRACTIONAL;
> +
> + default:
> + return -EINVAL;
> + }
> +}
> +
