linux-kernel - [PATCH v3] media: v4l2-flash: Enter LED off state after file handle closed

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Message-ID: <1106c60cb96786ade1f60c692e566c408d7d8174.1768209230.git.cy_huang@richtek.com>
Date: Mon, 12 Jan 2026 17:20:04 +0800
From: <cy_huang@...htek.com>
To: Mauro Carvalho Chehab <mchehab@...nel.org>
CC: Bryan Wu <cooloney@...il.com>, Kyungmin Park <kyungmin.park@...sung.com>,
	Jacek Anaszewski <j.anaszewski@...sung.com>, ChiYuan Huang
	<cy_huang@...htek.com>, <roger-hy.wang@...iatek.com>,
	<linux-media@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<stable@...r.kernel.org>
Subject: [PATCH v3] media: v4l2-flash: Enter LED off state after file handle closed

From: ChiYuan Huang <cy_huang@...htek.com>

To make sure LED enter off state after file handle is closed, initiatively
configure LED_MODE to NONE. This can guarantee whatever the previous state
is torch or strobe mode, the final state will be off.

Cc: stable@...r.kernel.org
Fixes: 42bd6f59ae90 ("media: Add registration helpers for V4L2 flash sub-devices")
Signed-off-by: ChiYuan Huang <cy_huang@...htek.com>
---
Still cannot pass patch integration check, send v3 patch to fix all.

v3
- Remove 'Reported-by' tag
- Fix identation check for patch integration

v2
- Fix commit message redudant space cause patch robot parsing error

Hi,
  We encounter an issue. When the upper layer camera process is crashed,
if the new process did not reinit the LED,  it will keeps the previous
state whatever it's in torch or strobe mode

OS will handle the resource management. So when the process is crashed
or terminated, the 'close' API will be called to release resources.
That's why we add the initiative action to trigger LED off in file
handle close is called.
---
 drivers/media/v4l2-core/v4l2-flash-led-class.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-flash-led-class.c b/drivers/media/v4l2-core/v4l2-flash-led-class.c
index 355595a0fefa..46606f5cc192 100644
--- a/drivers/media/v4l2-core/v4l2-flash-led-class.c
+++ b/drivers/media/v4l2-core/v4l2-flash-led-class.c
@@ -623,6 +623,12 @@ static int v4l2_flash_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
 		return 0;
 
 	if (led_cdev) {
+		/* If file handle is released, make sure LED enter off state */
+		ret = v4l2_ctrl_s_ctrl(v4l2_flash->ctrls[LED_MODE],
+				       V4L2_FLASH_LED_MODE_NONE);
+		if (ret)
+			return ret;
+
 		mutex_lock(&led_cdev->led_access);
 
 		if (v4l2_flash->ctrls[STROBE_SOURCE])

base-commit: 8ac28a6642d1cc8bac0632222e66add800b027fa
-- 
2.34.1