[PATCH 2/3] media: mt9v032: Add control for row noise correction

[Primoz Fiser]

From: Jan Luebbe <jlu@xxxxxxxxxxxxxx>

The sensor's row noise correction algorithm was previously always
disabled by unconditionally writing 0 to MT9V032_ROW_NOISE_CORR_CONTROL,
with no way for userspace to enable it.

Add a V4L2_CID_ROW_NOISE_CORRECTION boolean control so userspace can
toggle the model-specific enable value (MT9V032_ROW_NOISE_CORR_ENABLE /
MT9V034_ROW_NOISE_CORR_ENABLE) at runtime. Default to disabled to
preserve existing behaviour.

Signed-off-by: Jan Luebbe <jlu@xxxxxxxxxxxxxx>
Signed-off-by: Primoz Fiser <primoz.fiser@xxxxxxxxx>
---
 drivers/media/i2c/mt9v032.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/media/i2c/mt9v032.c b/drivers/media/i2c/mt9v032.c
index 5da10fe42552..d8e34e128d77 100644
--- a/drivers/media/i2c/mt9v032.c
+++ b/drivers/media/i2c/mt9v032.c
@@ -167,6 +167,7 @@ struct mt9v032_model_data {
 	unsigned int pclk_reg;
 	unsigned int aec_max_shutter_reg;
 	const struct v4l2_ctrl_config * const aec_max_shutter_v4l2_ctrl;
+	unsigned int row_noise_enable;
 };
 
 struct mt9v032_model_info {
@@ -231,6 +232,7 @@ struct mt9v032 {
 	u32 sysclk;
 	u16 aec_agc;
 	u16 hblank;
+	bool row_noise_corr;
 	struct {
 		struct v4l2_ctrl *test_pattern;
 		struct v4l2_ctrl *test_pattern_color;
@@ -356,11 +358,6 @@ static int __mt9v032_set_power(struct mt9v032 *mt9v032, bool on)
 			return ret;
 	}
 
-	/* Disable the noise correction algorithm and restore the controls. */
-	ret = regmap_write(map, MT9V032_ROW_NOISE_CORR_CONTROL, 0);
-	if (ret < 0)
-		return ret;
-
 	return v4l2_ctrl_handler_setup(&mt9v032->ctrls);
 }
 
@@ -679,6 +676,10 @@ static int mt9v032_set_selection(struct v4l2_subdev *subdev,
  * Maximum shutter width used for AEC.
  */
 #define V4L2_CID_AEC_MAX_SHUTTER_WIDTH	(V4L2_CID_USER_BASE | 0x1007)
+/*
+ * Row Noise Correction enable.
+ */
+#define V4L2_CID_ROW_NOISE_CORRECTION	(V4L2_CID_USER_BASE | 0x1008)
 
 static int mt9v032_s_ctrl(struct v4l2_ctrl *ctrl)
 {
@@ -770,6 +771,11 @@ static int mt9v032_s_ctrl(struct v4l2_ctrl *ctrl)
 		return regmap_write(map,
 				    mt9v032->model->data->aec_max_shutter_reg,
 				    ctrl->val);
+	case V4L2_CID_ROW_NOISE_CORRECTION:
+		mt9v032->row_noise_corr = ctrl->val;
+		return regmap_write(map, MT9V032_ROW_NOISE_CORR_CONTROL,
+				    mt9v032->row_noise_corr ?
+				    mt9v032->model->data->row_noise_enable : 0);
 	}
 
 	return 0;
@@ -850,6 +856,16 @@ static const struct v4l2_ctrl_config mt9v032_aegc_controls[] = {
 		.step		= 1,
 		.def		= 2,
 		.flags		= 0,
+	}, {
+		.ops		= &mt9v032_ctrl_ops,
+		.id		= V4L2_CID_ROW_NOISE_CORRECTION,
+		.type		= V4L2_CTRL_TYPE_BOOLEAN,
+		.name		= "Row Noise Correction",
+		.min		= 0,
+		.max		= 1,
+		.step		= 1,
+		.def		= 0,
+		.flags		= 0,
 	}
 };
 
@@ -1246,6 +1262,7 @@ static const struct mt9v032_model_data mt9v032_model_data[] = {
 		.pclk_reg = MT9V032_PIXEL_CLOCK,
 		.aec_max_shutter_reg = MT9V032_AEC_MAX_SHUTTER_WIDTH,
 		.aec_max_shutter_v4l2_ctrl = &mt9v032_aec_max_shutter_width,
+		.row_noise_enable = MT9V032_ROW_NOISE_CORR_ENABLE,
 	}, {
 		/* MT9V024, MT9V034 */
 		.min_row_time = 690,
@@ -1257,6 +1274,7 @@ static const struct mt9v032_model_data mt9v032_model_data[] = {
 		.pclk_reg = MT9V034_PIXEL_CLOCK,
 		.aec_max_shutter_reg = MT9V034_AEC_MAX_SHUTTER_WIDTH,
 		.aec_max_shutter_v4l2_ctrl = &mt9v034_aec_max_shutter_width,
+		.row_noise_enable = MT9V034_ROW_NOISE_CORR_ENABLE,
 	},
 };
 
-- 
2.34.1