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staging: iio: resolver: ad2s1210: always use 16-bit value for raw read

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This removes the special handling for resolutions lower than 16 bits.
This will allow us to use a fixed scale independent of the resolution.

A new sample field is added to store the raw data instead of reusing
the config mode rx buffer so that we don't have to do a cast or worry
about unaligned access.

Also, for the record, according to the datasheet, the logic for the
special handling based on hysteresis that was removed was incorrect.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20230929-ad2s1210-mainline-v3-7-fa4364281745@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
David Lechner
2023-09-29 12:23:12 -05:00
committed by Jonathan Cameron
parent acbfaee170
commit 1b6eba71ca
1 changed files with 8 additions and 16 deletions
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drivers/staging/iio/resolver/ad2s1210.c
+8 -16
View File
@@ -95,7 +95,11 @@ struct ad2s1210_state {
bool hysteresis;
u8 resolution;
enum ad2s1210_mode mode;
u8 rx[2] __aligned(IIO_DMA_MINALIGN);
/** For reading raw sample value via SPI. */
__be16 sample __aligned(IIO_DMA_MINALIGN);
/** SPI transmit buffer. */
u8 rx[2];
/** SPI receive buffer. */
u8 tx[2];
};
@@ -464,10 +468,7 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
long m)
{
struct ad2s1210_state *st = iio_priv(indio_dev);
u16 negative;
int ret = 0;
u16 pos;
s16 vel;
mutex_lock(&st->lock);
gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
@@ -487,26 +488,17 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
}
if (ret < 0)
goto error_ret;
ret = spi_read(st->sdev, st->rx, 2);
ret = spi_read(st->sdev, &st->sample, 2);
if (ret < 0)
goto error_ret;
switch (chan->type) {
case IIO_ANGL:
pos = be16_to_cpup((__be16 *)st->rx);
if (st->hysteresis)
pos >>= 16 - st->resolution;
*val = pos;
*val = be16_to_cpu(st->sample);
ret = IIO_VAL_INT;
break;
case IIO_ANGL_VEL:
vel = be16_to_cpup((__be16 *)st->rx);
vel >>= 16 - st->resolution;
if (vel & 0x8000) {
negative = (0xffff >> st->resolution) << st->resolution;
vel |= negative;
}
*val = vel;
*val = (s16)be16_to_cpu(st->sample);
ret = IIO_VAL_INT;
break;
default: