Commit bfced6d1 authored by Chiranjeevi Rapolu's avatar Chiranjeevi Rapolu Committed by Mauro Carvalho Chehab
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media: ov13858: Increase digital gain granularity, range 



Previously, possible digital gains were just 1x, 2x and 4x. These
coarse gains were not sufficient in fine-tuning the image capture.

Now, digital gain range is [0, 16x] with each step 1/1024, default 1x.
This is achieved through OV13858 MWB R/G/B gain controls.

Signed-off-by: default avatarChiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>
Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 89d8b615

drivers/media/i2c/ov13858.c

+16 −16
Original line number Diff line number Diff line
@@ -77,13 +77,13 @@ 
#define OV13858_ANA_GAIN_DEFAULT	0x80



/* Digital gain control */

#define OV13858_REG_DIGITAL_GAIN	0x350a

#define OV13858_DGTL_GAIN_MASK		0xf3

#define OV13858_DGTL_GAIN_SHIFT		2

#define OV13858_DGTL_GAIN_MIN		1

#define OV13858_DGTL_GAIN_MAX		4

#define OV13858_DGTL_GAIN_STEP		1

#define OV13858_DGTL_GAIN_DEFAULT	1

#define OV13858_REG_B_MWB_GAIN		0x5100

#define OV13858_REG_G_MWB_GAIN		0x5102

#define OV13858_REG_R_MWB_GAIN		0x5104

#define OV13858_DGTL_GAIN_MIN		0

#define OV13858_DGTL_GAIN_MAX		16384	/* Max = 16 X */

#define OV13858_DGTL_GAIN_DEFAULT	1024	/* Default gain = 1 X */

#define OV13858_DGTL_GAIN_STEP		1	/* Each step = 1/1024 */



/* Test Pattern Control */

#define OV13858_REG_TEST_PATTERN	0x4503
@@ -1162,21 +1162,21 @@ static int ov13858_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh) 
static int ov13858_update_digital_gain(struct ov13858 *ov13858, u32 d_gain)

{

	int ret;

	u32 val;



	if (d_gain == 3)

		return -EINVAL;

	ret = ov13858_write_reg(ov13858, OV13858_REG_B_MWB_GAIN,

				OV13858_REG_VALUE_16BIT, d_gain);

	if (ret)

		return ret;



	ret = ov13858_read_reg(ov13858, OV13858_REG_DIGITAL_GAIN,

			       OV13858_REG_VALUE_08BIT, &val);

	ret = ov13858_write_reg(ov13858, OV13858_REG_G_MWB_GAIN,

				OV13858_REG_VALUE_16BIT, d_gain);

	if (ret)

		return ret;



	val &= OV13858_DGTL_GAIN_MASK;

	val |= (d_gain - 1) << OV13858_DGTL_GAIN_SHIFT;

	ret = ov13858_write_reg(ov13858, OV13858_REG_R_MWB_GAIN,

				OV13858_REG_VALUE_16BIT, d_gain);



	return ov13858_write_reg(ov13858, OV13858_REG_DIGITAL_GAIN,

				 OV13858_REG_VALUE_08BIT, val);

	return ret;

}



static int ov13858_enable_test_pattern(struct ov13858 *ov13858, u32 pattern)

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