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| author | Lars-Peter Clausen <lars@metafoo.de> | 2019-03-19 13:37:55 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 06:46:24 -0700 |
| commit | d7c773412f4bc05e2a68cbf7b93447dd0e9b1453 (patch) | |
| tree | 09128300ad95405c8fc1b63b663c92c463c2cfcc /include/linux | |
| parent | ce59174d4e69b3a8d788e7c7875d1e492bccbb84 (diff) | |
| download | linux-rpi3-d7c773412f4bc05e2a68cbf7b93447dd0e9b1453.tar.gz linux-rpi3-d7c773412f4bc05e2a68cbf7b93447dd0e9b1453.tar.bz2 linux-rpi3-d7c773412f4bc05e2a68cbf7b93447dd0e9b1453.zip | |
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/linux')
| -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 730ead1a46df..57c122ae5452 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; |