[PATCH v3 5/5] iio: adc: ltc2378: Enable triggered buffer data capture

[Marcelo Schmitt]

Enable users to run triggered data captures with LTC2378 and similar ADCs.

Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
---
Change log v2 -> v3:
- Extracted from main driver file into a separate buffer-specific containment.

 drivers/iio/adc/ltc2378-lib-core.c         | 17 +++++++-
 drivers/iio/adc/ltc2378-triggered-buffer.c | 49 ++++++++++++++++++++++
 drivers/iio/adc/ltc2378.h                  | 15 +++++++
 3 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iio/adc/ltc2378-triggered-buffer.c

diff --git a/drivers/iio/adc/ltc2378-lib-core.c b/drivers/iio/adc/ltc2378-lib-core.c
index 1160f4324d01..ec83e9f2ae81 100644
--- a/drivers/iio/adc/ltc2378-lib-core.c
+++ b/drivers/iio/adc/ltc2378-lib-core.c
@@ -18,7 +18,7 @@ int ltc2378_lib_buffer_setup(struct iio_dev *indio_dev, struct ltc2378_state *st
 
 	ret = __ltc2378_set_offload_ops(st);
 	if (ret == -EOPNOTSUPP)
-		return 0; /* Let device setup complete without buffer support */
+		goto trigger_buf_setup;
 
 	if (!ret)
 		ret = st->ops->buffer_setup(indio_dev, st);
@@ -27,6 +27,21 @@ int ltc2378_lib_buffer_setup(struct iio_dev *indio_dev, struct ltc2378_state *st
 		return dev_err_probe(dev, ret, "error on SPI offload setup\n");
 
 	return 0;
+
+trigger_buf_setup:
+	ret = __ltc2378_set_triggered_buf_ops(st);
+	if (ret == -EOPNOTSUPP)
+		return 0; /* Let device setup complete without buffer support */
+
+	if (!ret)
+		ret = st->ops->buffer_setup(indio_dev, st);
+
+	if (ret)
+		return dev_err_probe(dev, ret, "error on buffer setup\n");
+
+	st->chans[st->num_iio_chans++] = IIO_CHAN_SOFT_TIMESTAMP(1);
+
+	return 0;
 }
 EXPORT_SYMBOL_NS_GPL(ltc2378_lib_buffer_setup, "IIO_LTC2378");
 
diff --git a/drivers/iio/adc/ltc2378-triggered-buffer.c b/drivers/iio/adc/ltc2378-triggered-buffer.c
new file mode 100644
index 000000000000..d1d788fb5cb4
--- /dev/null
+++ b/drivers/iio/adc/ltc2378-triggered-buffer.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2026 Analog Devices, Inc.
+ * Author: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
+ */
+
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#include <ltc2378.h>
+
+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_triggered_buffer_setup(struct iio_dev *indio_dev, struct ltc2378_state *st)
+{
+	return devm_iio_triggered_buffer_setup(&st->spi->dev, indio_dev,
+					       &iio_pollfunc_store_time,
+					       &ltc2378_trigger_handler,
+					       NULL);
+}
+
+static const struct ltc2378_ops ltc2378_triggered_buf_ops = {
+	.buffer_setup = ltc2378_triggered_buffer_setup,
+};
+
+int ltc2378_set_triggered_buf_ops(struct ltc2378_state *st)
+{
+	st->ops = &ltc2378_triggered_buf_ops;
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(ltc2378_set_triggered_buf_ops, "IIO_LTC2378");
diff --git a/drivers/iio/adc/ltc2378.h b/drivers/iio/adc/ltc2378.h
index f6e10f9a83e0..4241b1e79ac0 100644
--- a/drivers/iio/adc/ltc2378.h
+++ b/drivers/iio/adc/ltc2378.h
@@ -89,6 +89,8 @@ int ltc2378_lib_buffer_setup(struct iio_dev *indio_dev, struct ltc2378_state *st
 
 #define __ltc2378_set_offload_ops(st) ltc2378_set_offload_ops((st))
 
+#define __ltc2378_set_triggered_buf_ops(st) ltc2378_set_triggered_buf_ops((st))
+
 #ifdef CONFIG_LTC2378_LIB_OFFLOAD_BUFFER
 
 int ltc2378_set_offload_ops(struct ltc2378_state *st);
@@ -102,4 +104,17 @@ static inline int ltc2378_set_offload_ops(struct ltc2378_state *st)
 
 #endif /* CONFIG_LTC2378_LIB_OFFLOAD_BUFFER */
 
+#ifdef CONFIG_LTC2378_LIB_TRIGGERED_BUFFER
+
+int ltc2378_set_triggered_buf_ops(struct ltc2378_state *st);
+
+#else
+
+static inline int ltc2378_set_triggered_buf_ops(struct ltc2378_state *st)
+{
+	return -EOPNOTSUPP;
+}
+
+#endif /* CONFIG_LTC2378_LIB_TRIGGERED_BUFFER */
+
 #endif /* __DRIVERS_IIO_ADC_LTC2378_H__ */
-- 
2.53.0