linux-kernel - [PATCH 10/23] media: i2c: imx258: Follow normal V4L2 behaviours for clipping exposure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240327231710.53188-11-git@luigi311.com>
Date: Wed, 27 Mar 2024 17:16:56 -0600
From: git@...gi311.com
To: linux-media@...r.kernel.org
Cc: dave.stevenson@...pberrypi.com,
	jacopo.mondi@...asonboard.com,
	mchehab@...nel.org,
	robh@...nel.org,
	krzysztof.kozlowski+dt@...aro.org,
	conor+dt@...nel.org,
	shawnguo@...nel.org,
	s.hauer@...gutronix.de,
	kernel@...gutronix.de,
	festevam@...il.com,
	sakari.ailus@...ux.intel.com,
	devicetree@...r.kernel.org,
	imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 10/23] media: i2c: imx258: Follow normal V4L2 behaviours for clipping exposure

From: Dave Stevenson <dave.stevenson@...pberrypi.com>

V4L2 sensor drivers are expected are expected to clip the supported
exposure range based on the VBLANK configured.
IMX258 wasn't doing that as register 0x350 (FRM_LENGTH_CTL)
switches it to a mode where frame length tracks coarse exposure time.

Disable this mode and clip the range for V4L2_CID_EXPOSURE appropriately
based on V4L2_CID_VBLANK.

Signed-off-by: Dave Stevenson <dave.stevenson@...pberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@...asonboard.com>
---
 drivers/media/i2c/imx258.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
index c65b9aad3b0a..1f5fb980cfbe 100644
--- a/drivers/media/i2c/imx258.c
+++ b/drivers/media/i2c/imx258.c
@@ -37,10 +37,11 @@
 
 /* Exposure control */
 #define IMX258_REG_EXPOSURE		0x0202
+#define IMX258_EXPOSURE_OFFSET		10
 #define IMX258_EXPOSURE_MIN		4
 #define IMX258_EXPOSURE_STEP		1
 #define IMX258_EXPOSURE_DEFAULT		0x640
-#define IMX258_EXPOSURE_MAX		65535
+#define IMX258_EXPOSURE_MAX		(IMX258_VTS_MAX - IMX258_EXPOSURE_OFFSET)
 
 /* Analog gain control */
 #define IMX258_REG_ANALOG_GAIN		0x0204
@@ -371,7 +372,7 @@ static const struct imx258_reg mode_common_regs[] = {
 	{ 0x303A, 0x00 },
 	{ 0x303B, 0x10 },
 	{ 0x300D, 0x00 },
-	{ 0x0350, 0x01 },
+	{ 0x0350, 0x00 },
 	{ 0x0204, 0x00 },
 	{ 0x0205, 0x00 },
 	{ 0x020E, 0x01 },
@@ -741,6 +742,19 @@ static int imx258_update_digital_gain(struct imx258 *imx258, u32 len, u32 val)
 	return 0;
 }
 
+static void imx258_adjust_exposure_range(struct imx258 *imx258)
+{
+	int exposure_max, exposure_def;
+
+	/* Honour the VBLANK limits when setting exposure. */
+	exposure_max = imx258->cur_mode->height + imx258->vblank->val -
+		       IMX258_EXPOSURE_OFFSET;
+	exposure_def = min(exposure_max, imx258->exposure->val);
+	__v4l2_ctrl_modify_range(imx258->exposure, imx258->exposure->minimum,
+				 exposure_max, imx258->exposure->step,
+				 exposure_def);
+}
+
 static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
 {
 	struct imx258 *imx258 =
@@ -748,6 +762,13 @@ static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
 	struct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);
 	int ret = 0;
 
+	/*
+	 * The VBLANK control may change the limits of usable exposure, so check
+	 * and adjust if necessary.
+	 */
+	if (ctrl->id == V4L2_CID_VBLANK)
+		imx258_adjust_exposure_range(imx258);
+
 	/*
 	 * Applying V4L2 control value only happens
 	 * when power is up for streaming
-- 
2.42.0