linux-kernel - [PATCH RFC 4/9] iio: consumer: Add new API iio_poll_func

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Message-ID: <20250519-timestamp-v1-4-fcb4f6c2721c@gmail.com>
Date: Mon, 19 May 2025 23:25:56 +0900
From: Gyeyoung Baek <gye976@...il.com>
To: Jonathan Cameron <jic23@...nel.org>,
	David Lechner <dlechner@...libre.com>,
	Nuno Sá <nuno.sa@...log.com>,
	Andy Shevchenko <andy@...nel.org>
Cc: Gyeyoung Baek <gye976@...il.com>,
	linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH RFC 4/9] iio: consumer: Add new API iio_poll_func_register()

This API wraps either the tophalf or bottomhalf handler to grab a timestamp,
based on the consumer's `timestamp_enabled` and the trigger's `trig_type` and `early_timestamp`.

Signed-off-by: Gyeyoung Baek <gye976@...il.com>
---
 drivers/iio/industrialio-trigger.c | 58 +++++++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index 527c3cf84be0..1a7bab2741af 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -65,6 +65,24 @@ ATTRIBUTE_GROUPS(iio_trig_dev);
 
 static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
 
+/* Only be invoked in consumer top-half */
+static irqreturn_t iio_pollfunc_top_half_wrapper(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+
+	pf->timestamp = iio_get_time_ns(pf->indio_dev);
+	return IRQ_WAKE_THREAD;
+}
+
+/* Only be invoked in consumer botom-half */
+static irqreturn_t iio_pollfunc_bottom_half_wrapper(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+
+	pf->timestamp = iio_get_time_ns(pf->indio_dev);
+	return pf->thread(irq, p);
+}
+
 int iio_trigger_register(struct iio_trigger *trig_info)
 {
 	int ret;
@@ -270,6 +288,36 @@ static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
 	clear_bit(irq - trig->subirq_base, trig->pool);
 }
 
+static int iio_poll_func_register(struct iio_poll_func *pf,
+				  struct iio_trigger *trig)
+{
+	irq_handler_t tophalf = NULL;
+	irq_handler_t bottomhalf = pf->thread;
+	int ret;
+
+	/*
+	 * The consumer does not need timestamp.
+	 * Just request raw irq handler.
+	 */
+	if (!pf->timestamp_enabled)
+		goto out_request_irq;
+
+	if (trig->trig_type & IIO_TRIG_TYPE_POLL_NESTED) {
+		bottomhalf = iio_pollfunc_bottom_half_wrapper;
+		pf->timestamp_type = IIO_TIMESTAMP_TYPE_CONSUMER_BOTTOM_HALF;
+	} else if (trig->trig_type & IIO_TRIG_TYPE_POLL) {
+		tophalf = iio_pollfunc_top_half_wrapper;
+		pf->timestamp_type = IIO_TIMESTAMP_TYPE_CONSUMER_TOP_HALF;
+	} else {
+		pr_err("Trigger does not set valid trig_type.");
+		return -EINVAL;
+	}
+
+out_request_irq:
+	return request_threaded_irq(pf->irq, tophalf, bottomhalf,
+				    pf->type, pf->name, pf);
+}
+
 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
  * may be needed if the pollfuncs do not include the data read for the
  * triggering device.
@@ -296,10 +344,8 @@ int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 		goto out_put_module;
 	}
 
-	/* Request irq */
-	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
-				   pf->type, pf->name,
-				   pf);
+	/* Register consumer handlers */
+	ret = iio_poll_func_register(pf, trig);
 	if (ret < 0)
 		goto out_put_irq;
 
@@ -352,6 +398,10 @@ int iio_trigger_detach_poll_func(struct iio_trigger *trig,
 	return ret;
 }
 
+/*
+ * Will be deprecated.
+ * We do not need to set this as a top half manually to grab a timestamp.
+ */
 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;

-- 
2.43.0