linux-kernel - [PATCH 11/13] media: i2c: Switch exposure control unit to lines

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Date:   Thu, 22 Jul 2021 21:34:05 +0100
From:   Daniel Scally <djrscally@...il.com>
To:     Daniel Scally <djrscally@...il.com>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Paul Kocialkowski <paul.kocialkowski@...tlin.com>,
        Ezequiel Garcia <ezequiel@...labora.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Yang Li <yang.lee@...ux.alibaba.com>,
        linux-media@...r.kernel.org (open list:MEDIA INPUT INFRASTRUCTURE
        (V4L/DVB)), linux-kernel@...r.kernel.org (open list)
Cc:     Yong Zhi <yong.zhi@...el.com>, Bingbu Cao <bingbu.cao@...el.com>,
        Tianshu Qiu <tian.shu.qiu@...el.com>,
        Colin Ian King <colin.king@...onical.com>,
        laurent.pinchart@...asonboard.com, kieran.bingham@...asonboard.com
Subject: [PATCH 11/13] media: i2c: Switch exposure control unit to lines

The ov8865 driver currently has the unit of the V4L2_CID_EXPOSURE control
as 1/16th of a line. This is what the sensor expects, but isn't very
intuitive. Switch the control to be in units of a line and simply do the
16x multiplication before passing the value to the sensor.

The datasheet for this sensor gives minimum exposure as 2 lines, so take
the opportunity to correct the lower bounds of the control.

Signed-off-by: Daniel Scally <djrscally@...il.com>
---
 drivers/media/i2c/ov8865.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/ov8865.c b/drivers/media/i2c/ov8865.c
index 4954808f5416..dca4db3039bb 100644
--- a/drivers/media/i2c/ov8865.c
+++ b/drivers/media/i2c/ov8865.c
@@ -2126,6 +2126,9 @@ static int ov8865_exposure_configure(struct ov8865_sensor *sensor, u32 exposure)
 {
 	int ret;
 
+	/* The sensor stores exposure in units of 1/16th of a line */
+	exposure *= 16;
+
 	ret = ov8865_write(sensor, OV8865_EXPOSURE_CTRL_HH_REG,
 			   OV8865_EXPOSURE_CTRL_HH(exposure));
 	if (ret)
@@ -2525,8 +2528,8 @@ static int ov8865_ctrls_init(struct ov8865_sensor *sensor)
 
 	/* Exposure */
 
-	ctrls->exposure = v4l2_ctrl_new_std(handler, ops, V4L2_CID_EXPOSURE, 16,
-					    1048575, 16, 512);
+	ctrls->exposure = v4l2_ctrl_new_std(handler, ops, V4L2_CID_EXPOSURE, 2,
+					    65535, 1, 32);
 
 	/* Gain */
 
-- 
2.25.1