From: Marcelo Schmitt <marcelo.schmitt@analog.com>
To: <linux-iio@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Cc: <jic23@kernel.org>, <nuno.sa@analog.com>,
<Michael.Hennerich@analog.com>, <dlechner@baylibre.com>,
<andy@kernel.org>, <robh@kernel.org>, <krzk+dt@kernel.org>,
<conor+dt@kernel.org>, <julianbraha@gmail.com>,
<marcelo.schmitt1@gmail.com>,
Andy Shevchenko <andriy.shevchenko@intel.com>
Subject: [PATCH v8 4/5] iio: adc: ltc2378: Enable triggered buffer data capture
Date: Thu, 23 Jul 2026 16:53:11 -0300 [thread overview]
Message-ID: <e4ed6dd82d52d0d6f8bf3eb5cd06142faf6f75e4.1784835663.git.marcelo.schmitt@analog.com> (raw)
In-Reply-To: <cover.1784835663.git.marcelo.schmitt@analog.com>
Enable users to run triggered data captures with LTC2378 and similar ADCs.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
---
No changes in v8.
drivers/iio/adc/Kconfig | 1 +
drivers/iio/adc/ltc2378.c | 75 +++++++++++++++++++++++++++------------
2 files changed, 53 insertions(+), 23 deletions(-)
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 96df8453b826..6cf67f7a6eed 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -952,6 +952,7 @@ config LTC2378
select IIO_BUFFER
select IIO_BUFFER_DMA
select IIO_BUFFER_DMAENGINE
+ select IIO_TRIGGERED_BUFFER
select SPI_OFFLOAD
select SPI_OFFLOAD_TRIGGER_PWM
help
diff --git a/drivers/iio/adc/ltc2378.c b/drivers/iio/adc/ltc2378.c
index 7baee02450d3..5128c2a23f75 100644
--- a/drivers/iio/adc/ltc2378.c
+++ b/drivers/iio/adc/ltc2378.c
@@ -6,6 +6,7 @@
* Author: Marcelo Schmitt <marcelo.schmitt@analog.com>
*/
+#include <linux/array_size.h>
#include <linux/bitops.h>
#include <linux/bits.h>
#include <linux/byteorder/generic.h>
@@ -32,6 +33,8 @@
#include <linux/iio/buffer.h>
#include <linux/iio/buffer-dmaengine.h>
#include <linux/iio/iio.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
#include <linux/iio/types.h>
#define LTC2378_TDSDOBUSYL_NS 5
@@ -105,7 +108,7 @@
struct ltc2378_chip_info {
const char *name;
unsigned int internal_ref_uV;
- struct iio_chan_spec chan;
+ struct iio_chan_spec chan[2]; /* 1 physical chan + 1 timestamp chan */
struct iio_chan_spec offload_chan;
unsigned int max_sample_rate_Hz;
unsigned int tconv_ns;
@@ -146,7 +149,7 @@ struct ltc2378_state {
static const struct ltc2378_chip_info ltc2338_18_chip_info = {
.name = "ltc2338-18",
.internal_ref_uV = 2048000,
- .chan = LTC2378_DIFF_CHANNEL(18),
+ .chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
.tconv_ns = 527,
@@ -154,7 +157,7 @@ static const struct ltc2378_chip_info ltc2338_18_chip_info = {
static const struct ltc2378_chip_info ltc2364_16_chip_info = {
.name = "ltc2364-16",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
.tconv_ns = 3000,
@@ -162,7 +165,7 @@ static const struct ltc2378_chip_info ltc2364_16_chip_info = {
static const struct ltc2378_chip_info ltc2364_18_chip_info = {
.name = "ltc2364-18",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
.tconv_ns = 3000,
@@ -170,7 +173,7 @@ static const struct ltc2378_chip_info ltc2364_18_chip_info = {
static const struct ltc2378_chip_info ltc2367_16_chip_info = {
.name = "ltc2367-16",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
.tconv_ns = 1500,
@@ -178,7 +181,7 @@ static const struct ltc2378_chip_info ltc2367_16_chip_info = {
static const struct ltc2378_chip_info ltc2367_18_chip_info = {
.name = "ltc2367-18",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
.tconv_ns = 1500,
@@ -186,7 +189,7 @@ static const struct ltc2378_chip_info ltc2367_18_chip_info = {
static const struct ltc2378_chip_info ltc2368_16_chip_info = {
.name = "ltc2368-16",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
.tconv_ns = 527,
@@ -194,7 +197,7 @@ static const struct ltc2378_chip_info ltc2368_16_chip_info = {
static const struct ltc2378_chip_info ltc2368_18_chip_info = {
.name = "ltc2368-18",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
.tconv_ns = 527,
@@ -202,7 +205,7 @@ static const struct ltc2378_chip_info ltc2368_18_chip_info = {
static const struct ltc2378_chip_info ltc2369_18_chip_info = {
.name = "ltc2369-18",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 1600 * HZ_PER_KHZ,
.tconv_ns = 412,
@@ -210,7 +213,7 @@ static const struct ltc2378_chip_info ltc2369_18_chip_info = {
static const struct ltc2378_chip_info ltc2370_16_chip_info = {
.name = "ltc2370-16",
- .chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+ .chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 2 * HZ_PER_MHZ,
.tconv_ns = 322,
@@ -218,7 +221,7 @@ static const struct ltc2378_chip_info ltc2370_16_chip_info = {
static const struct ltc2378_chip_info ltc2376_16_chip_info = {
.name = "ltc2376-16",
- .chan = LTC2378_DIFF_CHANNEL(16),
+ .chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
.tconv_ns = 3000,
@@ -226,7 +229,7 @@ static const struct ltc2378_chip_info ltc2376_16_chip_info = {
static const struct ltc2378_chip_info ltc2376_18_chip_info = {
.name = "ltc2376-18",
- .chan = LTC2378_DIFF_CHANNEL(18),
+ .chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
.tconv_ns = 3000,
@@ -234,7 +237,7 @@ static const struct ltc2378_chip_info ltc2376_18_chip_info = {
static const struct ltc2378_chip_info ltc2376_20_chip_info = {
.name = "ltc2376-20",
- .chan = LTC2378_DIFF_CHANNEL(20),
+ .chan = { LTC2378_DIFF_CHANNEL(20), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(20),
.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
.tconv_ns = 3000,
@@ -242,7 +245,7 @@ static const struct ltc2378_chip_info ltc2376_20_chip_info = {
static const struct ltc2378_chip_info ltc2377_16_chip_info = {
.name = "ltc2377-16",
- .chan = LTC2378_DIFF_CHANNEL(16),
+ .chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
.tconv_ns = 1500,
@@ -250,7 +253,7 @@ static const struct ltc2378_chip_info ltc2377_16_chip_info = {
static const struct ltc2378_chip_info ltc2377_18_chip_info = {
.name = "ltc2377-18",
- .chan = LTC2378_DIFF_CHANNEL(18),
+ .chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
.tconv_ns = 1500,
@@ -258,7 +261,7 @@ static const struct ltc2378_chip_info ltc2377_18_chip_info = {
static const struct ltc2378_chip_info ltc2377_20_chip_info = {
.name = "ltc2377-20",
- .chan = LTC2378_DIFF_CHANNEL(20),
+ .chan = { LTC2378_DIFF_CHANNEL(20), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(20),
.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
.tconv_ns = 1500,
@@ -266,7 +269,7 @@ static const struct ltc2378_chip_info ltc2377_20_chip_info = {
static const struct ltc2378_chip_info ltc2378_16_chip_info = {
.name = "ltc2378-16",
- .chan = LTC2378_DIFF_CHANNEL(16),
+ .chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
.tconv_ns = 527,
@@ -274,7 +277,7 @@ static const struct ltc2378_chip_info ltc2378_16_chip_info = {
static const struct ltc2378_chip_info ltc2378_18_chip_info = {
.name = "ltc2378-18",
- .chan = LTC2378_DIFF_CHANNEL(18),
+ .chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
.tconv_ns = 527,
@@ -282,7 +285,7 @@ static const struct ltc2378_chip_info ltc2378_18_chip_info = {
static const struct ltc2378_chip_info ltc2378_20_chip_info = {
.name = "ltc2378-20",
- .chan = LTC2378_DIFF_CHANNEL(20),
+ .chan = { LTC2378_DIFF_CHANNEL(20), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(20),
.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
.tconv_ns = 675,
@@ -290,7 +293,7 @@ static const struct ltc2378_chip_info ltc2378_20_chip_info = {
static const struct ltc2378_chip_info ltc2379_18_chip_info = {
.name = "ltc2379-18",
- .chan = LTC2378_DIFF_CHANNEL(18),
+ .chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
.max_sample_rate_Hz = 1600 * HZ_PER_KHZ,
.tconv_ns = 412,
@@ -298,7 +301,7 @@ static const struct ltc2378_chip_info ltc2379_18_chip_info = {
static const struct ltc2378_chip_info ltc2380_16_chip_info = {
.name = "ltc2380-16",
- .chan = LTC2378_DIFF_CHANNEL(16),
+ .chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
.max_sample_rate_Hz = 2 * HZ_PER_MHZ,
.tconv_ns = 322,
@@ -317,6 +320,25 @@ static int ltc2378_convert_and_acquire(struct ltc2378_state *st)
return ret;
}
+static irqreturn_t ltc2378_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct ltc2378_state *st = iio_priv(indio_dev);
+ int ret;
+
+ ret = ltc2378_convert_and_acquire(st);
+ if (ret < 0)
+ goto err_out;
+
+ iio_push_to_buffers_with_ts(indio_dev, &st->scan, sizeof(st->scan),
+ pf->timestamp);
+
+err_out:
+ iio_trigger_notify_done(indio_dev->trig);
+ return IRQ_HANDLED;
+}
+
static int ltc2378_channel_single_read(const struct iio_chan_spec *chan,
struct ltc2378_state *st, int *val)
{
@@ -706,8 +728,15 @@ static int ltc2378_probe(struct spi_device *spi)
/* Fall back to low speed usage when no SPI offload is available. */
if (ret == -ENODEV) {
indio_dev->info = <c2378_iio_info;
- indio_dev->channels = &st->info->chan;
- indio_dev->num_channels = 1;
+ indio_dev->channels = st->info->chan;
+ indio_dev->num_channels = ARRAY_SIZE(st->info->chan);
+
+ ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+ iio_pollfunc_store_time,
+ ltc2378_trigger_handler,
+ NULL);
+ if (ret)
+ return ret;
} else if (ret) {
return dev_err_probe(dev, ret, "failed to get offload\n");
} else {
--
2.53.0
next prev parent reply other threads:[~2026-07-23 19:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-23 19:51 [PATCH v8 0/5] iio: adc: Add support for LTC2378 and similar ADCs Marcelo Schmitt
2026-07-23 19:52 ` [PATCH v8 1/5] dt-bindings: iio: adc: Add ltc2378 Marcelo Schmitt
2026-07-23 19:52 ` [PATCH v8 2/5] iio: adc: ltc2378: Add support for LTC2378-20 and similar ADCs Marcelo Schmitt
2026-07-23 19:52 ` [PATCH v8 3/5] iio: adc: ltc2378: Enable high-speed data capture Marcelo Schmitt
2026-07-23 19:53 ` Marcelo Schmitt [this message]
2026-07-23 19:53 ` [PATCH v8 5/5] iio: ABI: Encourage differential voltage ABI usage Marcelo Schmitt
2026-07-26 19:12 ` Jonathan Cameron
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