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

[Michael Hennerich <michael.hennerich@analog.com>]

On 05/11/2012 09:45 AM, Jonathan Cameron wrote:
> On 5/11/2012 8:43 AM, Jonathan Cameron wrote:
>> 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.
> That an consistency with the others.  There it makes sense because of
> breaking round the decimal point.
Hi Jonathan,

Ideally I leave the driver as is.

If we really want the keep consistency, I would need to make integer
type s64, that will add a lot of unnecessary overhead.


>>> Thoughts?
>>>
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-- 
Greetings,
Michael

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