The sensors analogue gain is stored within two "LONG GAIN" registers
(0x3508 and 0x3509) where the first one holds the upper 5 bits of the
value. The second register (0x3509) holds the lower 4 bits of the gain
value in its upper 4 bits. The lower 4 register bits are fraction bits.
This patch changes the gain control to adhere to the datasheet and
make the "upper gain register" (0x3508) accessible via the gain control,
resulting in a new maximum of 0x1fff instead of 0xff.
As the "upper gain register" is now written during exposure/gain update
remove the hard-coded 0x00 write to it from common_regs.
We cover only the "real gain format" use-case. The "sensor gain
format" one is ignored as based on the hard-coded "AEC MANUAL" register
configuration it is disabled.
All values are based on the OV9281 datasheet v1.01 (09.18.2015).
Signed-off-by: Richard Leitner <richard.leitner@xxxxxxxxx>
---
drivers/media/i2c/ov9282.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
index c882a021cf18852237bf9b9524d3de0c5b48cbcb..e6effb2b42d4d5d0ca3d924df59c60512f9ce65d 100644
--- a/drivers/media/i2c/ov9282.c
+++ b/drivers/media/i2c/ov9282.c
@@ -54,11 +54,11 @@
#define OV9282_AEC_MANUAL_DEFAULT 0x00
/* Analog gain control */
-#define OV9282_REG_AGAIN 0x3509
-#define OV9282_AGAIN_MIN 0x10
-#define OV9282_AGAIN_MAX 0xff
-#define OV9282_AGAIN_STEP 1
-#define OV9282_AGAIN_DEFAULT 0x10
+#define OV9282_REG_AGAIN 0x3508
+#define OV9282_AGAIN_MIN 0x0010
+#define OV9282_AGAIN_MAX 0x1fff
+#define OV9282_AGAIN_STEP 0x0001
+#define OV9282_AGAIN_DEFAULT 0x0010
/* Group hold register */
#define OV9282_REG_HOLD 0x3308
@@ -226,7 +226,6 @@ static const struct ov9282_reg common_regs[] = {
{OV9282_REG_AEC_MANUAL, OV9282_GAIN_PREC16_EN},
{0x3505, 0x8c},
{0x3507, 0x03},
- {0x3508, 0x00},
{0x3610, 0x80},
{0x3611, 0xa0},
{0x3620, 0x6e},
@@ -605,7 +604,11 @@ static int ov9282_update_exp_gain(struct ov9282 *ov9282, u32 exposure, u32 gain)
if (ret)
goto error_release_group_hold;
- ret = ov9282_write_reg(ov9282, OV9282_REG_AGAIN, 1, gain);
+ ret = ov9282_write_reg(ov9282, OV9282_REG_AGAIN, 1, (gain >> 8) & 0x1f);
+ if (ret)
+ goto error_release_group_hold;
+
+ ret = ov9282_write_reg(ov9282, OV9282_REG_AGAIN + 1, 1, gain & 0xff);
error_release_group_hold:
ov9282_write_reg(ov9282, OV9282_REG_HOLD, 1, 0);
--
2.47.2
