[PATCH 08/11] media: i2c: ov5640: Document AWB control registers
From: Kieran Bingham
Date: Fri May 01 2026 - 11:45:30 EST
Identify and map the registers that are controlling the AWB and
document their current impact inline in the register set.
Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
---
drivers/media/i2c/ov5640.c | 61 +++++++++++++++++++++++++++++++++++-----------
1 file changed, 47 insertions(+), 14 deletions(-)
diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
index 4b6804fc47e1..34fe7f51e17b 100644
--- a/drivers/media/i2c/ov5640.c
+++ b/drivers/media/i2c/ov5640.c
@@ -112,6 +112,34 @@
#define OV5640_REG_PCLK_PERIOD 0x4837
#define OV5640_REG_ISP_FORMAT_MUX_CTRL 0x501f
#define OV5640_REG_PRE_ISP_TEST_SET1 0x503d
+
+#define OV5640_REG_AWB_CONTROL_00 0x5180 /* AWB B block */
+#define OV5640_REG_AWB_CONTROL_01 0x5181 /* AWB Step and Slope control */
+#define OV5640_REG_AWB_CONTROL_02 0x5182 /* 7:4 Max local counter 3:0 mas fast counter */
+#define OV5640_REG_AWB_CONTROL_03 0x5183 /* AWB Simple/Advanced control */
+#define OV5640_REG_AWB_CONTROL_04 0x5184 /* Count and G enable */
+#define OV5640_REG_AWB_CONTROL_05 0x5185 /* Stable Range Thresholds */
+
+#define OV5640_REG_AWB_CONTROL_17 0x5191 /* AWB Top limit */
+#define OV5640_REG_AWB_CONTROL_18 0x5192 /* AWB Bottom limit */
+#define OV5640_REG_AWB_CONTROL_19 0x5193 /* Red limit */
+#define OV5640_REG_AWB_CONTROL_20 0x5194 /* Green limit */
+#define OV5640_REG_AWB_CONTROL_21 0x5195 /* Blue limit */
+
+#define OV5640_REG_AWB_CONTROL_22 0x5196 /* AWB Freeze and Simple Selection */
+#define OV5640_AWB_FREEZE BIT(5) /* AWB freeze */
+#define OV5640_AWB_SIMPLE_SELECT_MASK GENMASK(3, 2)
+#define OV5640_AWB_SIMPLE_AFTER_AWB_0 0 /* AWB simple from after AWB gain */
+#define OV5640_AWB_SIMPLE_AFTER_GMA_0 1 /* AWB simple from after RAW GMA */
+#define OV5640_AWB_SIMPLE_AFTER_GMA_1 2 /* AWB simple from after RAW GMA */
+#define OV5640_AWB_SIMPLE_AFTER_AWB_1 3 /* AWB simple from after AWB gain */
+#define OV5640_AWB_FAST_ENABLE BIT(1) /* AWB fast enable */
+#define OV5640_AWB_BIAS_STAT BIT(0)
+
+#define OV5640_REG_AWB_CONTROL_23 0x5197 /* Local Limit */
+
+#define OV5640_REG_AWB_CONTROL_30 0x519e /* Local limit and Stable Select */
+
#define OV5640_REG_SDE_CTRL0 0x5580
#define OV5640_REG_SDE_CTRL1 0x5581
#define OV5640_REG_SDE_CTRL3 0x5583
@@ -576,12 +604,14 @@ static const struct reg_value ov5640_init_setting[] = {
{0x5000, 0xa7, 0, 0}, {0x5001, 0xa3, 0, 0},
/* AWB Control */
- {0x5180, 0xff, 0, 0},
- {0x5181, 0xf2, 0, 0},
- {0x5182, 0x00, 0, 0},
- {0x5183, 0x14, 0, 0},
- {0x5184, 0x25, 0, 0},
- {0x5185, 0x24, 0, 0},
+ {OV5640_REG_AWB_CONTROL_00, 0xff, 0, 0}, /* AWB B Block */
+ {OV5640_REG_AWB_CONTROL_01, 0xf2, 0, 0}, /* Step and Slope - one zone, 0 slope, step fast=step local = 3 */
+ {OV5640_REG_AWB_CONTROL_02, 0x00, 0, 0}, /* Local/Fast counters @ 0 */
+ {OV5640_REG_AWB_CONTROL_03, 0x14, 0, 0}, /* Advanced AWB: AWB SIMF, AWB Win = 1 */
+ {OV5640_REG_AWB_CONTROL_04, 0x25, 0, 0}, /* G-Enable, Count-limit=1, count threshold=1 */
+ {OV5640_REG_AWB_CONTROL_05, 0x24, 0, 0}, /* Stable Ranges: Threshold for [7:4] unstable to stable [3:0] stable to unstable */
+
+ /* AWB Advanced Control - Undocumented */
{0x5186, 0x09, 0, 0},
{0x5187, 0x09, 0, 0},
{0x5188, 0x09, 0, 0},
@@ -593,20 +623,23 @@ static const struct reg_value ov5640_init_setting[] = {
{0x518e, 0x34, 0, 0},
{0x518f, 0x6b, 0, 0},
{0x5190, 0x46, 0, 0},
- {0x5191, 0xf8, 0, 0},
- {0x5192, 0x04, 0, 0},
- {0x5193, 0x70, 0, 0},
- {0x5194, 0xf0, 0, 0},
- {0x5195, 0xf0, 0, 0},
- {0x5196, 0x03, 0, 0},
- {0x5197, 0x01, 0, 0},
+
+ {OV5640_REG_AWB_CONTROL_17, 0xf8, 0, 0}, /* AWB Top limit (Default 0xff)*/
+ {OV5640_REG_AWB_CONTROL_18, 0x04, 0, 0}, /* AWB Bottom limit (Default 0x00) */
+ {OV5640_REG_AWB_CONTROL_19, 0x70, 0, 0}, /* Red limit (Default 0xf0) */
+ {OV5640_REG_AWB_CONTROL_20, 0xf0, 0, 0}, /* Green Limit (Default 0xf0) */
+ {OV5640_REG_AWB_CONTROL_21, 0xf0, 0, 0}, /* Blue limit (Default 0xf0) */
+ {OV5640_REG_AWB_CONTROL_22, 0x03, 0, 0}, /* AWB after AWB gain; Fast enable; Bias stat; */
+ {OV5640_REG_AWB_CONTROL_23, 0x01, 0, 0}, /* Local limit (Default 0x02) */
+
+ /* Debug mode - Undocumented */
{0x5198, 0x04, 0, 0},
{0x5199, 0x6c, 0, 0},
{0x519a, 0x04, 0, 0},
{0x519b, 0x00, 0, 0},
{0x519c, 0x09, 0, 0},
{0x519d, 0x2b, 0, 0},
- {0x519e, 0x38, 0, 0},
+ {OV5640_REG_AWB_CONTROL_30, 0x38, 0, 0}, /* [7:4] Debug = 3; [3] Local Limit Select = 1; [2] Simple stable select=0; [1:0] Debug=0 */
{0x5381, 0x1e, 0, 0}, {0x5382, 0x5b, 0, 0}, {0x5383, 0x08, 0, 0},
{0x5384, 0x0a, 0, 0}, {0x5385, 0x7e, 0, 0}, {0x5386, 0x88, 0, 0},
--
2.52.0