Re: [PATCH 3/4] iio: mxs-lradc: add scale_available file to channels

[Hector Palacios <hector.palacios@digi.com>]

Dear Lars,

On 07/05/2013 12:40 PM, Lars-Peter Clausen wrote:
> On 07/05/2013 10:30 AM, Hector Palacios wrote:
> [...]
>> +#define SHOW_SCALE_AVAILABLE_FUNC(ch) 					\
>> +static ssize_t mxs_lradc_show_scale_available##ch(struct device *dev,	\
>> +		struct device_attribute *attr, 				\
>> +		char *buf)						\
>> +{ 									\
>> +	return c ch);	\
>> +}
>
> No need for a separate function for each channel. Use the address attribute
> of the iio_dev_attr. E.g.
>
> struct iio_dev_attr *iio_attr = to_iio_dev_attr(attr);
>
> return mxs_lradc_show_scale_available_ch(dev, attr, buf, iio_attr->address);
>
> The last parameter to IIO_DEVICE_ATTR initializes this field.

Nice, I knew there had to be a better way.

> But I think you can need less boilerplate code if you use the
> iio_chan_spec_ext_info feature. Take a look at IIO_ENUM_AVAILABLE and
> friends to see how it is done.

I just took a look but don't know how I can use this framework with scales, as a scale 
is an array composed of two numbers (integer and fractional parts), not simple strings 
which is what iio_enum.items expects.

Best regards,
--
Hector Palacios