[PATCH 6/6] iio: filter: admv8818: Support frequencies >= 2^32

Sam Winchenbach
2025-03-06T19:15:00Z

From: Brian Pellegrino <bpellegrino@arka.org>

This patch allows writing u64 values to the ADMV8818's high and low-pass
filter frequencies. It includes the following changes:

- Rejects negative frequencies in admv8818_write_raw.
- Adds a write_raw_get_fmt function to admv8818's iio_info, returning
IIO_VAL_INT_64 for the high and low-pass filter 3dB frequency channels.

Fixes: f34fe888ad05 ("iio:filter:admv8818: add support for ADMV8818")
Signed-off-by: Brian Pellegrino <bpellegrino@arka.org>
Signed-off-by: Sam Winchenbach <sam.winchenbach@framepointer.org>
---
drivers/iio/filter/admv8818.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/drivers/iio/filter/admv8818.c b/drivers/iio/filter/admv8818.c
index 8cdfae56199b..1228dd5ddb36 100644
--- a/drivers/iio/filter/admv8818.c
+++ b/drivers/iio/filter/admv8818.c
@@ -402,6 +402,19 @@ static int admv8818_read_lpf_freq(struct admv8818_state *st, u64 *lpf_freq)
return ret;
}

+static int admv8818_write_raw_get_fmt(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
+ case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+ return IIO_VAL_INT_64;
+ default:
+ return -EINVAL;
+ }
+}
+
static int admv8818_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long info)
@@ -410,6 +423,9 @@ static int admv8818_write_raw(struct iio_dev *indio_dev,

u64 freq = ((u64)val2 << 32 | (u32)val);

+ if ((s64)freq < 0)
+ return -EINVAL;
+
switch (info) {
case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
return admv8818_lpf_select(st, freq);
@@ -571,6 +587,7 @@ static int admv8818_set_mode(struct iio_dev *indio_dev,

static const struct iio_info admv8818_info = {
.write_raw = admv8818_write_raw,
+ .write_raw_get_fmt = admv8818_write_raw_get_fmt,
.read_raw = admv8818_read_raw,
.debugfs_reg_access = &admv8818_reg_access,
};
--
2.48.1