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Message-Id: <20250715012023.2050178-3-sean.anderson@linux.dev>
Date: Mon, 14 Jul 2025 21:20:18 -0400
From: Sean Anderson <sean.anderson@...ux.dev>
To: Jonathan Cameron <jic23@...nel.org>,
Jean Delvare <jdelvare@...e.com>,
Guenter Roeck <linux@...ck-us.net>,
linux-iio@...r.kernel.org,
linux-hwmon@...r.kernel.org
Cc: Andy Shevchenko <andy@...nel.org>,
Nuno Sá <nuno.sa@...log.com>,
linux-kernel@...r.kernel.org,
David Lechner <dlechner@...libre.com>,
Sean Anderson <sean.anderson@...ux.dev>
Subject: [PATCH 2/7] iio: inkern: Add API for reading/writing events
Add an in-kernel API for reading/writing event properties. Like the
raw-to-processed conversion, with processed-to-raw we only convert the
integer part, introducing some round-off error.
A common case is for other drivers to re-expose IIO events as sysfs
properties with a different API. To help out with this, iio_event_mode
returns the appropriate mode. It can also be used to test for existence
if the consumer doesn't care about read/write capability.
Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
---
drivers/iio/inkern.c | 198 +++++++++++++++++++++++++++++++++++
include/linux/iio/consumer.h | 56 ++++++++++
2 files changed, 254 insertions(+)
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index c174ebb7d5e6..d3bbd2444fb5 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -1028,3 +1028,201 @@ ssize_t iio_read_channel_label(struct iio_channel *chan, char *buf)
return do_iio_read_channel_label(chan->indio_dev, chan->channel, buf);
}
EXPORT_SYMBOL_GPL(iio_read_channel_label);
+
+static bool iio_event_exists(struct iio_channel *channel,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info)
+{
+ struct iio_chan_spec const *chan = channel->channel;
+ int i;
+
+ if (!channel->indio_dev->info)
+ return false;
+
+ for (i = 0; i < chan->num_event_specs; i++) {
+ if (chan->event_spec[i].type != type)
+ continue;
+ if (chan->event_spec[i].dir != dir)
+ continue;
+ if (chan->event_spec[i].mask_separate & BIT(info))
+ return true;
+ }
+
+ return false;
+}
+
+umode_t iio_event_mode(struct iio_channel *chan, enum iio_event_type type,
+ enum iio_event_direction dir, enum iio_event_info info)
+{
+ struct iio_dev *indio_dev = chan->indio_dev;
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ umode_t mode = 0;
+
+ guard(mutex)(&iio_dev_opaque->info_exist_lock);
+ if (!iio_event_exists(chan, type, dir, info))
+ return 0;
+
+ if (info == IIO_EV_INFO_ENABLE) {
+ if (indio_dev->info->read_event_config)
+ mode |= 0444;
+
+ if (indio_dev->info->write_event_config)
+ mode |= 0200;
+ } else {
+ if (indio_dev->info->read_event_value)
+ mode |= 0444;
+
+ if (indio_dev->info->write_event_value)
+ mode |= 0200;
+ }
+
+ return mode;
+}
+EXPORT_SYMBOL_GPL(iio_event_mode);
+
+int iio_read_event_processed_scale(struct iio_channel *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info, int *val,
+ unsigned int scale)
+{
+ struct iio_dev *indio_dev = chan->indio_dev;
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ int ret, raw;
+
+ guard(mutex)(&iio_dev_opaque->info_exist_lock);
+ if (!iio_event_exists(chan, type, dir, info))
+ return -ENODEV;
+
+ if (info == IIO_EV_INFO_ENABLE) {
+ if (!indio_dev->info->read_event_config)
+ return -EINVAL;
+
+ raw = indio_dev->info->read_event_config(indio_dev,
+ chan->channel, type,
+ dir);
+ if (raw < 0)
+ return raw;
+
+ *val = raw;
+ return 0;
+ }
+
+ if (!indio_dev->info->read_event_value)
+ return -EINVAL;
+
+ ret = indio_dev->info->read_event_value(indio_dev, chan->channel, type,
+ dir, info, &raw, NULL);
+ if (ret < 0)
+ return ret;
+
+ return iio_convert_raw_to_processed_unlocked(chan, raw, val, scale);
+}
+EXPORT_SYMBOL_GPL(iio_read_event_processed_scale);
+
+static int iio_convert_processed_to_raw_unlocked(struct iio_channel *chan,
+ int processed, int *raw,
+ unsigned int scale)
+{
+ int scale_type, scale_val, scale_val2;
+ int offset_type, offset_val, offset_val2;
+ s64 r, scale64, raw64;
+
+ scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
+ IIO_CHAN_INFO_SCALE);
+ if (scale_type < 0) {
+ raw64 = processed / scale;
+ } else {
+ switch (scale_type) {
+ case IIO_VAL_INT:
+ scale64 = (s64)scale_val * scale;
+ if (scale64 <= INT_MAX && scale64 >= INT_MIN)
+ raw64 = processed / (int)scale64;
+ else
+ raw64 = 0;
+ break;
+ case IIO_VAL_INT_PLUS_MICRO:
+ scale64 = scale_val * scale * 1000000LL + scale_val2;
+ raw64 = div64_s64_rem(processed, scale64, &r);
+ raw64 = raw64 * 1000000 +
+ div64_s64(r * 1000000, scale64);
+ break;
+ case IIO_VAL_INT_PLUS_NANO:
+ scale64 = scale_val * scale * 1000000000LL + scale_val2;
+ raw64 = div64_s64_rem(processed, scale64, &r);
+ raw64 = raw64 * 1000000000 +
+ div64_s64(r * 1000000000, scale64);
+ break;
+ case IIO_VAL_FRACTIONAL:
+ raw64 = div64_s64((s64)processed * scale_val2,
+ (s64)scale_val * scale);
+ break;
+ case IIO_VAL_FRACTIONAL_LOG2:
+ raw64 = div64_s64((s64)processed << scale_val2,
+ (s64)scale_val * scale);
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ offset_type = iio_channel_read(chan, &offset_val, &offset_val2,
+ IIO_CHAN_INFO_OFFSET);
+ if (offset_type >= 0) {
+ switch (offset_type) {
+ case IIO_VAL_INT:
+ case IIO_VAL_INT_PLUS_MICRO:
+ case IIO_VAL_INT_PLUS_NANO:
+ raw64 -= offset_val;
+ break;
+ case IIO_VAL_FRACTIONAL:
+ raw64 -= offset_val / offset_val2;
+ break;
+ case IIO_VAL_FRACTIONAL_LOG2:
+ raw64 -= offset_val >> offset_val2;
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ *raw = clamp(raw64, (s64)INT_MIN, (s64)INT_MAX);
+ return 0;
+}
+
+int iio_write_event_processed_scale(struct iio_channel *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info, int processed,
+ unsigned int scale)
+{
+ struct iio_dev *indio_dev = chan->indio_dev;
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(chan->indio_dev);
+ int ret, raw;
+
+ guard(mutex)(&iio_dev_opaque->info_exist_lock);
+ if (!iio_event_exists(chan, type, dir, info))
+ return -ENODEV;
+
+ if (info == IIO_EV_INFO_ENABLE) {
+ if (!indio_dev->info->write_event_config)
+ return -EINVAL;
+
+ return indio_dev->info->write_event_config(indio_dev,
+ chan->channel, type,
+ dir, processed);
+ }
+
+ if (!indio_dev->info->write_event_value)
+ return -EINVAL;
+
+ ret = iio_convert_processed_to_raw_unlocked(chan, processed, &raw,
+ scale);
+ if (ret < 0)
+ return ret;
+
+ return indio_dev->info->write_event_value(indio_dev, chan->channel,
+ type, dir, info, raw, 0);
+}
+EXPORT_SYMBOL_GPL(iio_write_event_processed_scale);
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 6a4479616479..16e7682474f3 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -451,4 +451,60 @@ ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
*/
ssize_t iio_read_channel_label(struct iio_channel *chan, char *buf);
+/**
+ * iio_event_mode() - get file mode for an event property
+ * @chan: Channel being queried
+ * @type: Event type (theshold, rate-of-change, etc.)
+ * @dir: Event direction (rising, falling, etc.)
+ * @info: Event property (enable, value, etc.)
+ *
+ * Determine an appropriate mode for sysfs files derived from this event.
+ *
+ * Return:
+ * - `0000` if the event is unsupported or otherwise unavailable
+ * - `0444` if the event is read-only
+ * - `0200` if the event is write-only
+ * - `0644` if the event is read-write
+ */
+umode_t iio_event_mode(struct iio_channel *chan, enum iio_event_type type,
+ enum iio_event_direction dir, enum iio_event_info info);
+
+/**
+ * iio_read_event_processed_scale() - Read an event property
+ * @chan: Channel being queried
+ * @type: Event type (theshold, rate-of-change, etc.)
+ * @dir: Event direction (rising, falling, etc.)
+ * @info: Event property (enable, value, etc.)
+ * @val: Processed property value
+ * @scale: Factor to scale @val by
+ *
+ * Read a processed (scaled and offset) event property of a given channel.
+ *
+ * Return: 0 on success, or negative error on failure
+ */
+int iio_read_event_processed_scale(struct iio_channel *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info, int *val,
+ unsigned int scale);
+
+/**
+ * iio_write_event_processed_scale() - Read an event property
+ * @chan: Channel being queried
+ * @type: Event type (theshold, rate-of-change, etc.)
+ * @dir: Event direction (rising, falling, etc.)
+ * @info: Event property (enable, value, etc.)
+ * @processed: Processed property value
+ * @scale: Factor to scale @processed by
+ *
+ * Write a processed (scaled and offset) event property of a given channel.
+ *
+ * Return: 0 on success, or negative error on failure
+ */
+int iio_write_event_processed_scale(struct iio_channel *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info, int processed,
+ unsigned int scale);
+
#endif
--
2.35.1.1320.gc452695387.dirty
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