[PATCH] iio: use boot time instead of realtime

[PATCH] iio: use boot time instead of realtime

[Keith Mok]

From: Keith Mok <ek9852@gmail.com>

Advanced sensor has fifo/ring buffer internally,
they can store data when the system is suspend,
we need a timestamp that is able to take into
account of the time when the system is suspend also.

Signed-off-by: Keith Mok <ek9852@gmail.com>
---
 include/linux/iio/iio.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index b589411..7092877 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -286,7 +286,7 @@ static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
  **/
 static inline s64 iio_get_time_ns(void)
 {
-	return ktime_get_real_ns();
+	return ktime_get_boot_ns();
 }
 
 /* Device operating modes */
-- 
2.5.1

Re: [PATCH] iio: use boot time instead of realtime

[Matt Ranostay]

Seems like doing a blanket change like this would break a lot of
drivers since it changes the core ABI

On Wed, Feb 3, 2016 at 11:29 AM, Keith Mok <ek9852@gmail.com> wrote:
> From: Keith Mok <ek9852@gmail.com>
>
> Advanced sensor has fifo/ring buffer internally,
> they can store data when the system is suspend,
> we need a timestamp that is able to take into
> account of the time when the system is suspend also.
>
> Signed-off-by: Keith Mok <ek9852@gmail.com>
> ---
>  include/linux/iio/iio.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index b589411..7092877 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -286,7 +286,7 @@ static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
>   **/
>  static inline s64 iio_get_time_ns(void)
>  {
> -       return ktime_get_real_ns();
> +       return ktime_get_boot_ns();
>  }
>
>  /* Device operating modes */
> --
> 2.5.1
>
> --
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Re: [PATCH] iio: use boot time instead of realtime

[Lars-Peter Clausen]

On 02/04/2016 01:36 AM, Matt Ranostay wrote:
> Seems like doing a blanket change like this would break a lot of
> drivers since it changes the core ABI

And I think the commit does not quite do what the description says.
ktime_get_real_ns() should account for the time when the system is in suspend.

Keith, please have a look at this discussion for a better approach to
solving this problem while keeping ABI compatibility:
http://marc.info/?l=linux-iio&m=145449725410306&w=2

Thanks for looking into this important issue.

- Lars

> 
> On Wed, Feb 3, 2016 at 11:29 AM, Keith Mok <ek9852@gmail.com> wrote:
>> From: Keith Mok <ek9852@gmail.com>
>>
>> Advanced sensor has fifo/ring buffer internally,
>> they can store data when the system is suspend,
>> we need a timestamp that is able to take into
>> account of the time when the system is suspend also.
>>
>> Signed-off-by: Keith Mok <ek9852@gmail.com>
>> ---
>>  include/linux/iio/iio.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
>> index b589411..7092877 100644
>> --- a/include/linux/iio/iio.h
>> +++ b/include/linux/iio/iio.h
>> @@ -286,7 +286,7 @@ static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
>>   **/
>>  static inline s64 iio_get_time_ns(void)
>>  {
>> -       return ktime_get_real_ns();
>> +       return ktime_get_boot_ns();
>>  }
>>
>>  /* Device operating modes */
>> --
>> 2.5.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
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>