[PATCH] iio: pressure: bmp280: fix temp compensation

[PATCH] iio: pressure: bmp280: fix temp compensation

[Irina Tirdea]

Temperature reads on bmp280 device always return 0,
due to a missing step in the compensation formula
(data->tfine is never initialized).

Initialize data->tfine value so we get correct
temperature and pressure values.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/iio/pressure/bmp280.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c
index 7c623e2..a2602d8 100644
--- a/drivers/iio/pressure/bmp280.c
+++ b/drivers/iio/pressure/bmp280.c
@@ -172,6 +172,7 @@ static s32 bmp280_compensate_temp(struct bmp280_data *data,
 	var2 = (((((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1]))) *
 		  ((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1])))) >> 12) *
 		((s32)(s16)le16_to_cpu(buf[T3]))) >> 14;
+	data->t_fine = var1 + var2;
 
 	return (data->t_fine * 5 + 128) >> 8;
 }
-- 
1.9.1

Re: [PATCH] iio: pressure: bmp280: fix temp compensation

[Vlad Dogaru]

On Wed, Apr 08, 2015 at 06:26:12PM +0300, Irina Tirdea wrote:
> Temperature reads on bmp280 device always return 0,
> due to a missing step in the compensation formula
> (data->tfine is never initialized).
> 
> Initialize data->tfine value so we get correct
> temperature and pressure values.
> 
> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>

Reviewed-by: Vlad Dogaru <vlad.dogaru@intel.com>

Nice catch, this must have been lost during a refactoring.

Thanks,
Vlad

Re: [PATCH] iio: pressure: bmp280: fix temp compensation

[Jonathan Cameron]

On 08/04/15 16:30, Vlad Dogaru wrote:
> On Wed, Apr 08, 2015 at 06:26:12PM +0300, Irina Tirdea wrote:
>> Temperature reads on bmp280 device always return 0,
>> due to a missing step in the compensation formula
>> (data->tfine is never initialized).
>>
>> Initialize data->tfine value so we get correct
>> temperature and pressure values.
>>
>> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> 
> Reviewed-by: Vlad Dogaru <vlad.dogaru@intel.com>
> 
> Nice catch, this must have been lost during a refactoring.
> 
> Thanks,
> Vlad
> 
Thanks,

Applied to fixes-togreg which is now based on staging-next
which gives you an idea of when this will go to Greg now!