Re: [PATCH v3 7/8] iio: Add quaternion channel

[Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>]

Hi Jonathan,

On 11/05/2013 11:58 PM, Jonathan Cameron wrote:
>
> Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> wrote:
>> On 11/05/2013 03:10 PM, Jonathan Cameron wrote:
>>> On 10/30/13 22:48, Srinivas Pandruvada wrote:
>>>> A quaternion channel type is added. Here channel information is
>>>> composed of four components: a vector with x, y, z coordinates and
>>>> a w rotation. Reusing x, y, z channel modifiers, but added "w"
>>>> component in the modifier list.
>>>>
>>>> Signed-off-by: Srinivas Pandruvada
>> <srinivas.pandruvada@linux.intel.com>
>>> In brief I am against this for the same reason I didn't like this
>> before.
>>> A quaternion has no meaning if it isn't all present.  Hence we need
>> to
>>> ensure that it is always presented to userspace with all four
>> components
>>> present.
>>>
>>> I'll hopefully have a few mins at the weekend to to bash out some
>> example
>>> code for how I would suggest we handle this.
>>>
>>> If you could repost the patches before this one with everything that
>> should
>>> be in them then hopefully we can take those whilst still 'discussing'
>>> how to handle the last 2!
If you get chance, please send me some info on how you want to handle this.

Thanks,
Srinivas

>> Sorry about the issues with previous patches. I was trying to order new
>>
>> driver at the end and missed dependencies.
> Not to worry. We all make that mistake occasionally!
>> I have applied all patches which I am sending after this email safely
>> apply to fixes-togreg branch.
>> For the last two, I will wait for your suggestion.
>>
>> Thanks,
>> Srinivas
>>> Jonathan
>>>> ---
>>>>    drivers/iio/industrialio-core.c | 2 ++
>>>>    include/linux/iio/types.h       | 2 ++
>>>>    2 files changed, 4 insertions(+)
>>>>
>>>> diff --git a/drivers/iio/industrialio-core.c
>> b/drivers/iio/industrialio-core.c
>>>> index f95c697..b754f50 100644
>>>> --- a/drivers/iio/industrialio-core.c
>>>> +++ b/drivers/iio/industrialio-core.c
>>>> @@ -66,6 +66,7 @@ static const char * const
>> iio_chan_type_name_spec[] = {
>>>>    	[IIO_ALTVOLTAGE] = "altvoltage",
>>>>    	[IIO_CCT] = "cct",
>>>>    	[IIO_PRESSURE] = "pressure",
>>>> +	[IIO_QUAT_ROT] = "quat_rot",
>>>>    };
>>>>    
>>>>    static const char * const iio_modifier_names[] = {
>>>> @@ -80,6 +81,7 @@ static const char * const iio_modifier_names[] = {
>>>>    	[IIO_MOD_LIGHT_RED] = "red",
>>>>    	[IIO_MOD_LIGHT_GREEN] = "green",
>>>>    	[IIO_MOD_LIGHT_BLUE] = "blue",
>>>> +	[IIO_MOD_W] = "w",
>>>>    };
>>>>    
>>>>    /* relies on pairs of these shared then separate */
>>>> diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
>>>> index 88bf0f0..4565f5c 100644
>>>> --- a/include/linux/iio/types.h
>>>> +++ b/include/linux/iio/types.h
>>>> @@ -29,6 +29,7 @@ enum iio_chan_type {
>>>>    	IIO_ALTVOLTAGE,
>>>>    	IIO_CCT,
>>>>    	IIO_PRESSURE,
>>>> +	IIO_QUAT_ROT,
>>>>    };
>>>>    
>>>>    enum iio_modifier {
>>>> @@ -52,6 +53,7 @@ enum iio_modifier {
>>>>    	IIO_MOD_LIGHT_RED,
>>>>    	IIO_MOD_LIGHT_GREEN,
>>>>    	IIO_MOD_LIGHT_BLUE,
>>>> +	IIO_MOD_W,
>>>>    };
>>>>    
>>>>    #define IIO_VAL_INT 1
>>>>
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