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drivers: iio: adc: ltc2497: fix LSB shift

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commit 6327a930ab7bfa1ab33bcdffd5f5f4b1e7131504 upstream.

Correct the "sub_lsb" shift for the ltc2497 and drop the sub_lsb element
which is now constant.

An earlier version of the code shifted by 14 but this was a consequence
of reading three bytes into a __be32 buffer and using be32_to_cpu(), so
eight extra bits needed to be skipped.  Now we use get_unaligned_be24()
and thus the additional skip is wrong.

Fixes: 2187cfeb3626 ("drivers: iio: adc: ltc2497: LTC2499 support")
Signed-off-by: Ian Ray <ian.ray@ge.com>
Link: https://lore.kernel.org/r/20230127125714.44608-1-ian.ray@ge.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Ray 2023-01-27 14:57:14 +02:00 committed by Greg Kroah-Hartman
parent 2fc8660507
commit b3ea2426cc
1 changed files with 2 additions and 4 deletions
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6
drivers/iio/adc/ltc2497.c
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@ -28,7 +28,6 @@ struct ltc2497_driverdata {
struct ltc2497core_driverdata common_ddata;
struct i2c_client *client;
u32 recv_size;
u32 sub_lsb;
/*
* DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
@ -65,10 +64,10 @@ static int ltc2497_result_and_measure(struct ltc2497core_driverdata *ddata,
* equivalent to a sign extension.
*/
if (st->recv_size == 3) {
*val = (get_unaligned_be24(st->data.d8) >> st->sub_lsb)
*val = (get_unaligned_be24(st->data.d8) >> 6)
- BIT(ddata->chip_info->resolution + 1);
} else {
*val = (be32_to_cpu(st->data.d32) >> st->sub_lsb)
*val = (be32_to_cpu(st->data.d32) >> 6)
- BIT(ddata->chip_info->resolution + 1);
}
@ -122,7 +121,6 @@ static int ltc2497_probe(struct i2c_client *client,
st->common_ddata.chip_info = chip_info;
resolution = chip_info->resolution;
st->sub_lsb = 31 - (resolution + 1);
st->recv_size = BITS_TO_BYTES(resolution) + 1;
return ltc2497core_probe(dev, indio_dev);