From 3f83dae88422992140b6125ab866cdec9fd7b3b6 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Sat, 28 Sep 2013 10:31:00 +0100 Subject: [PATCH] iio:ad5764: Report scale as fractional value Move the complexity of calculating the fixed point scale to the core. Also fix a off by one error in the comment describing the transfer function. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/dac/ad5764.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/iio/dac/ad5764.c b/drivers/iio/dac/ad5764.c index df7e028d9db5..a8ff5b2ed13e 100644 --- a/drivers/iio/dac/ad5764.c +++ b/drivers/iio/dac/ad5764.c @@ -217,7 +217,6 @@ static int ad5764_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long info) { struct ad5764_state *st = iio_priv(indio_dev); - unsigned long scale_uv; unsigned int reg; int vref; int ret; @@ -245,15 +244,14 @@ static int ad5764_read_raw(struct iio_dev *indio_dev, *val = sign_extend32(*val, 5); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: - /* vout = 4 * vref + ((dac_code / 65535) - 0.5) */ + /* vout = 4 * vref + ((dac_code / 65536) - 0.5) */ vref = ad5764_get_channel_vref(st, chan->channel); if (vref < 0) return vref; - scale_uv = (vref * 4 * 100) >> chan->scan_type.realbits; - *val = scale_uv / 100000; - *val2 = (scale_uv % 100000) * 10; - return IIO_VAL_INT_PLUS_MICRO; + *val = vref * 4 / 1000; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; case IIO_CHAN_INFO_OFFSET: *val = -(1 << chan->scan_type.realbits) / 2; return IIO_VAL_INT;