[PATCH v2] iio: light: gp2ap020a00f: use iio_trigger_poll_nested()

The threaded IRQ handler queues an irq_work only so that
iio_trigger_poll() can run from a hardirq-like context. The driver's
own buffer consumer does not need that context: the only thing the
pollfunc top half, iio_pollfunc_store_time(), does is store a timestamp
in pf->timestamp, and deferring through the per-CPU irq_work queue
moves that timestamp further away from the actual event. Whilst in
theory there can be other consumers of this trigger relying on the
pollfunc top half running, given this is a light sensor those are
considered unlikely to exist in practice.

Switch from irq_work to direct call of iio_trigger_poll_nested().
Remove now unnecessary irq_work related infrastructure and ensure a
local time stamp is acquired.

Suggested-by: Jonathan Cameron <[email protected]>
Assisted-by: Codex:gpt-5.6
Signed-off-by: Fan Wu <[email protected]>
---
Applies on top of "iio: light: gp2ap020a00f: drain irq_work after
free_irq" in the fixes-togreg branch of iio.git; this drops the
irq_work_sync() drains that patch added.

v2:
  - commit message rework only, per maintainer review; code unchanged.
v1: https://lore.kernel.org/linux-iio/[email protected]/

---
 drivers/iio/light/gp2ap020a00f.c | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/drivers/iio/light/gp2ap020a00f.c b/drivers/iio/light/gp2ap020a00f.c
index 330d597..00164fd 100644
--- a/drivers/iio/light/gp2ap020a00f.c
+++ b/drivers/iio/light/gp2ap020a00f.c
@@ -37,7 +37,6 @@
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
-#include <linux/irq_work.h>
 #include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
@@ -245,7 +244,6 @@ struct gp2ap020a00f_data {
 	struct iio_trigger *trig;
 	struct regmap *regmap;
 	unsigned int thresh_val[4];
-	struct irq_work work;
 	wait_queue_head_t data_ready_queue;
 };
 
@@ -802,14 +800,6 @@ static void gp2ap020a00f_output_to_lux(struct gp2ap020a00f_data *data,
 		*output_val *= 16;
 }
 
-static void gp2ap020a00f_iio_trigger_work(struct irq_work *work)
-{
-	struct gp2ap020a00f_data *data =
-		container_of(work, struct gp2ap020a00f_data, work);
-
-	iio_trigger_poll(data->trig);
-}
-
 static irqreturn_t gp2ap020a00f_prox_sensing_handler(int irq, void *data)
 {
 	struct iio_dev *indio_dev = data;
@@ -932,8 +922,7 @@ static irqreturn_t gp2ap020a00f_thresh_event_handler(int irq, void *data)
 	if (test_bit(GP2AP020A00F_FLAG_ALS_CLEAR_TRIGGER, &priv->flags) ||
 	    test_bit(GP2AP020A00F_FLAG_ALS_IR_TRIGGER, &priv->flags) ||
 	    test_bit(GP2AP020A00F_FLAG_PROX_TRIGGER, &priv->flags))
-		/* This fires off the trigger. */
-		irq_work_queue(&priv->work);
+		iio_trigger_poll_nested(priv->trig);
 
 done:
 	return IRQ_HANDLED;
@@ -944,9 +933,12 @@ static irqreturn_t gp2ap020a00f_trigger_handler(int irq, void *data)
 	struct iio_poll_func *pf = data;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct gp2ap020a00f_data *priv = iio_priv(indio_dev);
+	s64 timestamp;
 	size_t d_size = 0;
 	int i, out_val, ret;
 
+	timestamp = iio_get_time_ns(indio_dev);
+
 	iio_for_each_active_channel(indio_dev, i) {
 		ret = regmap_bulk_read(priv->regmap, GP2AP020A00F_DATA_REG(i),
 				       &priv->buffer[d_size], 2);
@@ -964,7 +956,7 @@ static irqreturn_t gp2ap020a00f_trigger_handler(int irq, void *data)
 		}
 	}
 
-	iio_push_to_buffers_with_timestamp(indio_dev, priv->buffer, pf->timestamp);
+	iio_push_to_buffers_with_timestamp(indio_dev, priv->buffer, timestamp);
 done:
 	iio_trigger_notify_done(indio_dev->trig);
 
@@ -1455,8 +1447,9 @@ static int gp2ap020a00f_probe(struct i2c_client *client)
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
 	/* Allocate buffer */
-	err = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
-		&gp2ap020a00f_trigger_handler, &gp2ap020a00f_buffer_setup_ops);
+	err = iio_triggered_buffer_setup(indio_dev, NULL,
+					 &gp2ap020a00f_trigger_handler,
+					 &gp2ap020a00f_buffer_setup_ops);
 	if (err < 0)
 		goto error_regulator_disable;
 
@@ -1480,8 +1473,6 @@ static int gp2ap020a00f_probe(struct i2c_client *client)
 		goto error_uninit_buffer;
 	}
 
-	init_irq_work(&data->work, gp2ap020a00f_iio_trigger_work);
-
 	err = iio_trigger_register(data->trig);
 	if (err < 0) {
 		dev_err(dev, "Failed to register iio trigger.\n");
@@ -1498,7 +1489,6 @@ error_trigger_unregister:
 	iio_trigger_unregister(data->trig);
 error_free_irq:
 	free_irq(client->irq, indio_dev);
-	irq_work_sync(&data->work);
 error_uninit_buffer:
 	iio_triggered_buffer_cleanup(indio_dev);
 error_regulator_disable:
@@ -1521,7 +1511,6 @@ static void gp2ap020a00f_remove(struct i2c_client *client)
 	iio_device_unregister(indio_dev);
 	iio_trigger_unregister(data->trig);
 	free_irq(client->irq, indio_dev);
-	irq_work_sync(&data->work);
 	iio_triggered_buffer_cleanup(indio_dev);
 	regulator_disable(data->vled_reg);
 }