Re: [PATCH v2 5/5] iio: adc: ad7793: use read_avail iio hook for scale available

[Ardelean, Alexandru]

On Sat, 2020-03-21 at 16:57 +0000, Jonathan Cameron wrote:
> [External]
> 
> On Sat, 21 Mar 2020 11:08:02 +0200
> Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote:
> 
> > This change uses the read_avail and '.info_mask_shared_by_type_available'
> > modifier to set the available scale.
> > Essentially, nothing changes to the driver's ABI.
> > 
> > The main idea for this patch is to remove the AD7793 driver from
> > checkpatch's radar. There have been about ~3 attempts to fix/break the
> > 'in_voltage-voltage_scale_available' attribute, because checkpatch assumed
> > it to be an arithmetic operation and people were trying to change that.
> > 
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
> At some point it might be nice to move the sampling_frequency over as well
> but clearly not remotely urgent!

I also thought about that now.
But I decided to defer it; the patchset to do just this seemed big enough.
I mostly want to avoid checkpatch fixes for this.
It looks bad on our part if we get hit periodically on this, and don't do
anything about it.

> 
> Applied to the togreg branch of iio.git and pushed out as testing
> for the autobuilders to poke at it.
> 
> Thanks,
> 
> Jonathan
>  
> > ---
> >  drivers/iio/adc/ad7793.c | 53 +++++++++++++++++++++++++++-------------
> >  1 file changed, 36 insertions(+), 17 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
> > index 5592ae573e6b..fad98f1801db 100644
> > --- a/drivers/iio/adc/ad7793.c
> > +++ b/drivers/iio/adc/ad7793.c
> > @@ -354,29 +354,28 @@ static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
> >  static IIO_CONST_ATTR_NAMED(sampling_frequency_available_ad7797,
> >  	sampling_frequency_available, "123 62 50 33 17 16 12 10 8 6 4");
> >  
> > -static ssize_t ad7793_show_scale_available(struct device *dev,
> > -			struct device_attribute *attr, char *buf)
> > +static int ad7793_read_avail(struct iio_dev *indio_dev,
> > +			     struct iio_chan_spec const *chan,
> > +			     const int **vals, int *type, int *length,
> > +			     long mask)
> >  {
> > -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> >  	struct ad7793_state *st = iio_priv(indio_dev);
> > -	int i, len = 0;
> >  
> > -	for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
> > -		len += sprintf(buf + len, "%d.%09u ", st->scale_avail[i][0],
> > -			       st->scale_avail[i][1]);
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_SCALE:
> > +		*vals = (int *)st->scale_avail;
> > +		*type = IIO_VAL_INT_PLUS_NANO;
> > +		/* Values are stored in a 2D matrix  */
> > +		*length = ARRAY_SIZE(st->scale_avail) * 2;
> >  
> > -	len += sprintf(buf + len, "\n");
> > +		return IIO_AVAIL_LIST;
> > +	}
> >  
> > -	return len;
> > +	return -EINVAL;
> >  }
> >  
> > -static IIO_DEVICE_ATTR_NAMED(in_m_in_scale_available,
> > -		in_voltage-voltage_scale_available, S_IRUGO,
> > -		ad7793_show_scale_available, NULL, 0);
> > -
> >  static struct attribute *ad7793_attributes[] = {
> >  	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
> > -	&iio_dev_attr_in_m_in_scale_available.dev_attr.attr,
> >  	NULL
> >  };
> >  
> > @@ -534,6 +533,7 @@ static const struct iio_info ad7793_info = {
> >  	.read_raw = &ad7793_read_raw,
> >  	.write_raw = &ad7793_write_raw,
> >  	.write_raw_get_fmt = &ad7793_write_raw_get_fmt,
> > +	.read_avail = ad7793_read_avail,
> >  	.attrs = &ad7793_attribute_group,
> >  	.validate_trigger = ad_sd_validate_trigger,
> >  };
> > @@ -547,7 +547,7 @@ static const struct iio_info ad7797_info = {
> >  };
> >  
> >  #define __AD7793_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
> > -	_storagebits, _shift, _extend_name, _type, _mask_all) \
> > +	_storagebits, _shift, _extend_name, _type, _mask_type_av, _mask_all) \
> >  	{ \
> >  		.type = (_type), \
> >  		.differential = (_channel2 == -1 ? 0 : 1), \
> > @@ -559,6 +559,7 @@ static const struct iio_info ad7797_info = {
> >  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> >  			BIT(IIO_CHAN_INFO_OFFSET), \
> >  		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> > +		.info_mask_shared_by_type_available = (_mask_type_av), \
> >  		.info_mask_shared_by_all = _mask_all, \
> >  		.scan_index = (_si), \
> >  		.scan_type = { \
> > @@ -574,23 +575,41 @@ static const struct iio_info ad7797_info = {
> >  	_storagebits, _shift) \
> >  	__AD7793_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
> >  		_storagebits, _shift, NULL, IIO_VOLTAGE, \
> > +		BIT(IIO_CHAN_INFO_SCALE), \
> >  		BIT(IIO_CHAN_INFO_SAMP_FREQ))
> >  
> >  #define AD7793_SHORTED_CHANNEL(_si, _channel, _address, _bits, \
> >  	_storagebits, _shift) \
> >  	__AD7793_CHANNEL(_si, _channel, _channel, _address, _bits, \
> >  		_storagebits, _shift, "shorted", IIO_VOLTAGE, \
> > +		BIT(IIO_CHAN_INFO_SCALE), \
> >  		BIT(IIO_CHAN_INFO_SAMP_FREQ))
> >  
> >  #define AD7793_TEMP_CHANNEL(_si, _address, _bits, _storagebits, _shift) \
> >  	__AD7793_CHANNEL(_si, 0, -1, _address, _bits, \
> >  		_storagebits, _shift, NULL, IIO_TEMP, \
> > +		0, \
> >  		BIT(IIO_CHAN_INFO_SAMP_FREQ))
> >  
> >  #define AD7793_SUPPLY_CHANNEL(_si, _channel, _address, _bits, _storagebits,
> > \
> >  	_shift) \
> >  	__AD7793_CHANNEL(_si, _channel, -1, _address, _bits, \
> >  		_storagebits, _shift, "supply", IIO_VOLTAGE, \
> > +		0, \
> > +		BIT(IIO_CHAN_INFO_SAMP_FREQ))
> > +
> > +#define AD7797_DIFF_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
> > +	_storagebits, _shift) \
> > +	__AD7793_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
> > +		_storagebits, _shift, NULL, IIO_VOLTAGE, \
> > +		0, \
> > +		BIT(IIO_CHAN_INFO_SAMP_FREQ))
> > +
> > +#define AD7797_SHORTED_CHANNEL(_si, _channel, _address, _bits, \
> > +	_storagebits, _shift) \
> > +	__AD7793_CHANNEL(_si, _channel, _channel, _address, _bits, \
> > +		_storagebits, _shift, "shorted", IIO_VOLTAGE, \
> > +		0, \
> >  		BIT(IIO_CHAN_INFO_SAMP_FREQ))
> >  
> >  #define DECLARE_AD7793_CHANNELS(_name, _b, _sb, _s) \
> > @@ -620,8 +639,8 @@ const struct iio_chan_spec _name##_channels[] = { \
> >  
> >  #define DECLARE_AD7797_CHANNELS(_name, _b, _sb) \
> >  const struct iio_chan_spec _name##_channels[] = { \
> > -	AD7793_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
> > -	AD7793_SHORTED_CHANNEL(1, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
> > +	AD7797_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
> > +	AD7797_SHORTED_CHANNEL(1, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
> >  	AD7793_TEMP_CHANNEL(2, AD7793_CH_TEMP, (_b), (_sb), 0), \
> >  	AD7793_SUPPLY_CHANNEL(3, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
> >  	IIO_CHAN_SOFT_TIMESTAMP(4), \