diff options
| author | Lars-Peter Clausen <lars@metafoo.de> | 2019-03-19 13:37:55 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 06:47:29 -0700 |
| commit | 50892cb2923a8a410bcf0edf56c52f21c87de903 (patch) | |
| tree | 5b55f243a3551da7b07f973eca979692058bf95d /include | |
| parent | 5163bc447add77cd7c321618b3012199480cd9b8 (diff) | |
iio: ad_sigma_delta: Properly handle SPI bus locking vs CS assertion
[ Upstream commit df1d80aee963480c5c2938c64ec0ac3e4a0df2e0 ]
For devices from the SigmaDelta family we need to keep CS low when doing a
conversion, since the device will use the MISO line as a interrupt to
indicate that the conversion is complete.
This is why the driver locks the SPI bus and when the SPI bus is locked
keeps as long as a conversion is going on. The current implementation gets
one small detail wrong though. CS is only de-asserted after the SPI bus is
unlocked. This means it is possible for a different SPI device on the same
bus to send a message which would be wrongfully be addressed to the
SigmaDelta device as well. Make sure that the last SPI transfer that is
done while holding the SPI bus lock de-asserts the CS signal.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <Alexandru.Ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/iio/adc/ad_sigma_delta.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h index 1fc7abd28b0b..7b7157c26d31 100644 --- a/include/linux/iio/adc/ad_sigma_delta.h +++ b/include/linux/iio/adc/ad_sigma_delta.h @@ -66,6 +66,7 @@ struct ad_sigma_delta { bool irq_dis; bool bus_locked; + bool keep_cs_asserted; uint8_t comm; |