Re: [PATCH] iio: lidar: return -EIO on invalid signal

[Jonathan Cameron <jic23@kernel.org>]

On 01/11/15 00:47, Matt Ranostay wrote:
> Actually the INVALID status happens even it isn't out of range
> sometimes roughly once every second or two. This can be from an
> invalid second signal return path and etc..
> 
> So there are spurious zero readings from the triggered buffer, and
> warning messages in the kernel log.
Thanks for the clarification.  I've added a version of this response
to the patch description and applied to the fixes-togreg-post-rc1
branch I'm running at the moment as we have a few outstanding fixes
for stuff going in during the merge window that is opening very soon.

> 
> Thanks,
> 
> Matt
> 
> On Sat, Oct 31, 2015 at 2:29 AM, Jonathan Cameron <jic23@kernel.org> wrote:
>> On 25/10/15 23:07, Matt Ranostay wrote:
>>> Returning zero from the measurment function has the side effect of
>>> corrupting the triggered buffer readings, better to use -EIO than a
>>> zero measurement reading.
>> When you say 'corrupting' what do you mean?  As far as I can quickly see
>> it will give a spurious 0 distance when it really means a long distance.
>> Is that what you are referring to?
>>
>> Jonathan
>>>
>>> Signed-off-by: Matt Ranostay <mranostay@gmail.com>
>>> ---
>>>  drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
>>> index 961f9f99..359beac 100644
>>> --- a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
>>> +++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
>>> @@ -130,10 +130,10 @@ static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
>>>               if (ret < 0)
>>>                       break;
>>>
>>> -             /* return 0 since laser is likely pointed out of range */
>>> +             /* return -EIO since laser is likely pointed out of range */
>>>               if (ret & LIDAR_REG_STATUS_INVALID) {
>>>                       *reg = 0;
>>> -                     ret = 0;
>>> +                     ret = -EIO;
>>>                       break;
>>>               }
>>>
>>>
>>
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