Re: [PATCH] iio: frequency: New driver for Analog Devices ADF4350/ADF4351 Wideband Synthesizers

[Jonathan Cameron <jic23@cam.ac.uk>]

On 5/11/2012 8:41 AM, Michael Hennerich wrote:
> On 05/10/2012 02:36 PM, Jonathan Cameron wrote:
>> On 5/8/2012 4:34 PM, Michael Hennerich wrote:
>>> On 05/08/2012 04:51 PM, Jonathan Cameron wrote:
>>>> On 5/7/2012 2:49 PM, michael.hennerich@analog.com wrote:
>>>>> From: Michael Hennerich<michael.hennerich@analog.com>
>>>>>
>>>>>
>>>>> +
>>>>> +static const struct iio_chan_spec_ext_info adf4350_ext_info[] = {
>>>>> + /* Ideally we use IIO_CHAN_INFO_FREQUENCY, but there are
>>>>> + * values> 2^32 in order to support the entire frequency range
>>>>> + * in Hz. Using scale is a bit ugly.
>>>>> + */
>>>> hmm.. Add IIO_VAL_MEGA_PLUS_INT.. We were always going to need a bigger
>>>> version at somepoint...
>>> Well - we then need an s64, however read|write_raw feature s32 for
>>> val and val2. So shall we pass low word in val and high word in val2?
>> I was thinking
>> val*1e6 + val2 would fit with what we have done elsewhere? Is that
>> enough room?
> Hi Jonathan,
>
> IIO_VAL_MEGA_PLUS_INT versus IIO_VAL_LONG_LONG
>
> It is enough room. But I wonder why we would do costly divide and
> modulus operations, when we can do sifts and ANDs? Splitting a s64 would
> give is the maximum available room with very little overhead.
human readability.  I'm anti breaking that if we can possibly avoid it.
>
> Thoughts?
>