patch "iio: proximity: rfd77402: Fix completion race condition in IRQ mode" added to char-misc-linus

patch "iio: proximity: rfd77402: Fix completion race condition in IRQ mode" added to char-misc-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: proximity: rfd77402: Fix completion race condition in IRQ mode

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 9978d74031f25fde575bef3e4e3e35c5009091ce Mon Sep 17 00:00:00 2001
From: Felix Gu <ustc.gu@gmail.com>
Date: Wed, 4 Mar 2026 22:14:32 +0800
Subject: iio: proximity: rfd77402: Fix completion race condition in IRQ mode

In IRQ mode, the completion was being reinitialized after the
measurement command had already been sent to the hardware. This
created a race condition where the IRQ handler could call complete()
before reinit_completion() was executed. Consequently,
wait_for_completion_timeout() would fail to see the signal and wait
until it timed out.

Move reinit_completion() to occur before the measurement command is
triggered to ensure the synchronization primitive is ready to
capture the interrupt.

Fixes: dc81be96a73a ("iio: proximity: rfd77402: Add interrupt handling support")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Reviewed-by: Shrikant Raskar <raskar.shree97@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/proximity/rfd77402.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/proximity/rfd77402.c b/drivers/iio/proximity/rfd77402.c
index 6afdbfca3e5a..81b8daf17a54 100644
--- a/drivers/iio/proximity/rfd77402.c
+++ b/drivers/iio/proximity/rfd77402.c
@@ -173,10 +173,8 @@ static int rfd77402_wait_for_result(struct rfd77402_data *data)
 	struct i2c_client *client = data->client;
 	int val, ret;
 
-	if (data->irq_en) {
-		reinit_completion(&data->completion);
+	if (data->irq_en)
 		return rfd77402_wait_for_irq(data);
-	}
 
 	/*
 	 * As per RFD77402 datasheet section '3.1.1 Single Measure', the
@@ -204,6 +202,9 @@ static int rfd77402_measure(struct rfd77402_data *data)
 	if (ret < 0)
 		return ret;
 
+	if (data->irq_en)
+		reinit_completion(&data->completion);
+
 	ret = i2c_smbus_write_byte_data(client, RFD77402_CMD_R,
 					RFD77402_CMD_SINGLE |
 					RFD77402_CMD_VALID);
-- 
2.53.0