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| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2021-07-09 12:11:10 +0200 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2021-07-17 18:36:53 +0100 |
| commit | 9898cb24e454602beb6e17bacf9f97b26c85c955 (patch) | |
| tree | 4c1353c6ffbd24bc325c25229f1e8f914cd75d33 /drivers | |
| parent | 4377d9ab1f162e58e0e5ae89c9a5fd7b4d8a6bdb (diff) | |
| download | linux-stable-9898cb24e454602beb6e17bacf9f97b26c85c955.tar.gz linux-stable-9898cb24e454602beb6e17bacf9f97b26c85c955.tar.bz2 linux-stable-9898cb24e454602beb6e17bacf9f97b26c85c955.zip | |
iio: adc: ti-ads7950: Ensure CS is deasserted after reading channels
The ADS7950 requires that CS is deasserted after each SPI word. Before
commit e2540da86ef8 ("iio: adc: ti-ads7950: use SPI_CS_WORD to reduce
CPU usage") the driver used a message with one spi transfer per channel
where each but the last one had .cs_change set to enforce a CS toggle.
This was wrongly translated into a message with a single transfer and
.cs_change set which results in a CS toggle after each word but the
last which corrupts the first adc conversion of all readouts after the
first readout.
Fixes: e2540da86ef8 ("iio: adc: ti-ads7950: use SPI_CS_WORD to reduce CPU usage")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210709101110.1814294-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/adc/ti-ads7950.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c index 2383eacada87..a2b83f0bd526 100644 --- a/drivers/iio/adc/ti-ads7950.c +++ b/drivers/iio/adc/ti-ads7950.c @@ -568,7 +568,6 @@ static int ti_ads7950_probe(struct spi_device *spi) st->ring_xfer.tx_buf = &st->tx_buf[0]; st->ring_xfer.rx_buf = &st->rx_buf[0]; /* len will be set later */ - st->ring_xfer.cs_change = true; spi_message_add_tail(&st->ring_xfer, &st->ring_msg); |