From d6c85afca764dc32c3d7981867471fc820e07388 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Thu, 11 Jun 2020 18:19:13 +0100
Subject: [PATCH] media: i2c: imx290: Add exposure control to the
 driver.

Adds support for V4L2_CID_EXPOSURE so that userspace can control
the sensor exposure time.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/media/i2c/imx290.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

--- a/drivers/media/i2c/imx290.c
+++ b/drivers/media/i2c/imx290.c
@@ -45,6 +45,10 @@ enum imx290_clk_index {
 #define IMX290_HMAX_MIN_2LANE 4400 /* Min of 4400 pixels = 30fps */
 #define IMX290_HMAX_MIN_4LANE 2200 /* Min of 2200 pixels = 60fps */
 #define IMX290_HMAX_MAX 0xffff
+
+#define IMX290_EXPOSURE_MIN 2
+#define IMX290_EXPOSURE_STEP 1
+#define IMX290_EXPOSURE_LOW 0x3020
 #define IMX290_PGCTRL 0x308c
 #define IMX290_PHY_LANE_NUM 0x3407
 #define IMX290_CSI_LANE_MODE 0x3443
@@ -103,6 +107,7 @@ struct imx290 {
 	struct v4l2_ctrl *pixel_rate;
 	struct v4l2_ctrl *hblank;
 	struct v4l2_ctrl *vblank;
+	struct v4l2_ctrl *exposure;
 
 	struct mutex lock;
 };
@@ -529,6 +534,20 @@ static int imx290_set_gain(struct imx290
 	return ret;
 }
 
+static int imx290_set_exposure(struct imx290 *imx290, u32 value)
+{
+	u32 exposure = (imx290->current_mode->height + imx290->vblank->val) -
+						value;
+	int ret;
+
+	ret = imx290_write_buffered_reg(imx290, IMX290_EXPOSURE_LOW, 3,
+					exposure);
+	if (ret)
+		dev_err(imx290->dev, "Unable to write exposure\n");
+
+	return ret;
+}
+
 static int imx290_set_hmax(struct imx290 *imx290, u32 val)
 {
 	u32 hmax = val + imx290->current_mode->width;
@@ -590,6 +609,9 @@ static int imx290_set_ctrl(struct v4l2_c
 	case V4L2_CID_GAIN:
 		ret = imx290_set_gain(imx290, ctrl->val);
 		break;
+	case V4L2_CID_EXPOSURE:
+		ret = imx290_set_exposure(imx290, ctrl->val);
+		break;
 	case V4L2_CID_HBLANK:
 		ret = imx290_set_hmax(imx290, ctrl->val);
 		break;
@@ -764,6 +786,12 @@ static int imx290_set_fmt(struct v4l2_su
 						 IMX290_VMAX_MAX - mode->height,
 						 1,
 						 mode->vmax - mode->height);
+		if (imx290->exposure)
+			__v4l2_ctrl_modify_range(imx290->exposure,
+						 mode->vmax - mode->height,
+						 mode->vmax - 4,
+						 IMX290_EXPOSURE_STEP,
+						 mode->vmax - 4);
 	}
 
 	*format = fmt->format;
@@ -1182,6 +1210,13 @@ static int imx290_probe(struct i2c_clien
 					   IMX290_VMAX_MAX - mode->height, 1,
 					   mode->vmax - mode->height);
 
+	imx290->exposure = v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops,
+					     V4L2_CID_EXPOSURE,
+					     IMX290_EXPOSURE_MIN,
+					     mode->vmax - 4,
+					     IMX290_EXPOSURE_STEP,
+					     mode->vmax - 4);
+
 	imx290->link_freq =
 		v4l2_ctrl_new_int_menu(&imx290->ctrls, &imx290_ctrl_ops,
 				       V4L2_CID_LINK_FREQ,
