iio: ti_am335x_adc: Fix prerequisite for stepid patch

Kernel series 3.11 and 3.12 does not initialize scan_index in the
iio_chan_spec structure as 3.13 and newer does. This is necessary
for the stepid patch to work, otherwise it even breaks the cases
that worked before the stepid patch.

Unfortunately the stepid patch seems to already be in 3.12.25,
must have missed that inclusion.

Signed-off-by: Jan Kardell <jan.kardell@telliq.com>
---
 drivers/iio/adc/ti_am335x_adc.c | 1 +
 1 file changed, 1 insertion(+)

On Fri, Jul 25, 2014 at 01:13:46PM +0200, Jan Kardell wrote:
> Kernel series 3.11 and 3.12 does not initialize scan_index in the
> iio_chan_spec structure as 3.13 and newer does. This is necessary
> for the stepid patch to work, otherwise it even breaks the cases
> that worked before the stepid patch.
> 
> Unfortunately the stepid patch seems to already be in 3.12.25,
> must have missed that inclusion.
> 
> Signed-off-by: Jan Kardell <jan.kardell@telliq.com>
> ---
>  drivers/iio/adc/ti_am335x_adc.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index 3ceac3e..6c56418 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -120,6 +120,7 @@ static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
>  		chan->channel = adc_dev->channel_line[i];
>  		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>  		chan->datasheet_name = chan_name_ain[chan->channel];
> +		chan->scan_index = i;
>  		chan->scan_type.sign = 'u';
>  		chan->scan_type.realbits = 12;
>  		chan->scan_type.storagebits = 32;
> -- 
> 1.8.4.5
> 

Ah, nice catch!

Ideally, I would pick commit ca9a563805f7ae821e3303b1bdbc65d3a3c783ff
("iio: ti_am335x_adc: Add continuous sampling support"), which adds
this scan_index initialisation.  However, this commit doesn't seem be
suitable for a stable kernel, so I'll add this patch to the 3.11.10.14
queue branch.  Thanks a lot, Jan.

Cheers,
--
Luís

On 28/07/14 11:05, Luis Henriques wrote:
> On Fri, Jul 25, 2014 at 01:13:46PM +0200, Jan Kardell wrote:
>> Kernel series 3.11 and 3.12 does not initialize scan_index in the
>> iio_chan_spec structure as 3.13 and newer does. This is necessary
>> for the stepid patch to work, otherwise it even breaks the cases
>> that worked before the stepid patch.
>>
>> Unfortunately the stepid patch seems to already be in 3.12.25,
>> must have missed that inclusion.
>>
>> Signed-off-by: Jan Kardell <jan.kardell@telliq.com>
>> ---
>>  drivers/iio/adc/ti_am335x_adc.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
>> index 3ceac3e..6c56418 100644
>> --- a/drivers/iio/adc/ti_am335x_adc.c
>> +++ b/drivers/iio/adc/ti_am335x_adc.c
>> @@ -120,6 +120,7 @@ static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
>>  		chan->channel = adc_dev->channel_line[i];
>>  		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>>  		chan->datasheet_name = chan_name_ain[chan->channel];
>> +		chan->scan_index = i;
>>  		chan->scan_type.sign = 'u';
>>  		chan->scan_type.realbits = 12;
>>  		chan->scan_type.storagebits = 32;
>> -- 
>> 1.8.4.5
>>
> Ah, nice catch!
>
> Ideally, I would pick commit ca9a563805f7ae821e3303b1bdbc65d3a3c783ff
> ("iio: ti_am335x_adc: Add continuous sampling support"), which adds
> this scan_index initialisation.  However, this commit doesn't seem be
> suitable for a stable kernel, so I'll add this patch to the 3.11.10.14
> queue branch.  Thanks a lot, Jan.
Indeed, thanks for picking this up.
Acked-by: Jonathan Cameron <jic23@kernel.org>
for any other stable trees where it is relevant (won't do any harm on any where
it isn't!)
>
> Cheers,
> --
> Luís