Add support for V4L2_CID_ANALOG_GAIN. The control programs the global
gain register which applies to all color channels.
As both the global digital and analog gains are controlled through a
single register, in order not to overwrite the configured digital gain
we need to read the current register value before modifying it.
Implement a function to read register values and use it before applying
the new analog gain.
Signed-off-by: Jacopo Mondi <jacopo@xxxxxxxxxx>
---
drivers/media/i2c/ar0521.c | 64 ++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/drivers/media/i2c/ar0521.c b/drivers/media/i2c/ar0521.c
index 89f3c01f18ce..581f5e42994d 100644
--- a/drivers/media/i2c/ar0521.c
+++ b/drivers/media/i2c/ar0521.c
@@ -5,6 +5,8 @@
* Written by Krzysztof Hałasa
*/
+#include <asm/unaligned.h>
+
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>
@@ -35,6 +37,11 @@
#define AR0521_HEIGHT_BLANKING_MIN 38u /* must be even */
#define AR0521_TOTAL_WIDTH_MIN 2968u
+#define AR0521_ANA_GAIN_MIN 0x00
+#define AR0521_ANA_GAIN_MAX 0x3f
+#define AR0521_ANA_GAIN_STEP 0x01
+#define AR0521_ANA_GAIN_DEFAULT 0x00
+
/* AR0521 registers */
#define AR0521_REG_VT_PIX_CLK_DIV 0x0300
#define AR0521_REG_FRAME_LENGTH_LINES 0x0340
@@ -55,6 +62,7 @@
#define AR0521_REG_RED_GAIN 0x305A
#define AR0521_REG_GREEN2_GAIN 0x305C
#define AR0521_REG_GLOBAL_GAIN 0x305E
+#define AR0521_REG_GLOBAL_GAIN_ANA_MASK 0x3f
#define AR0521_REG_HISPI_TEST_MODE 0x3066
#define AR0521_REG_HISPI_TEST_MODE_LP11 0x0004
@@ -77,6 +85,7 @@ static const char * const ar0521_supply_names[] = {
struct ar0521_ctrls {
struct v4l2_ctrl_handler handler;
+ struct v4l2_ctrl *ana_gain;
struct {
struct v4l2_ctrl *gain;
struct v4l2_ctrl *red_balance;
@@ -167,6 +176,36 @@ static int ar0521_write_reg(struct ar0521_dev *sensor, u16 reg, u16 val)
return ar0521_write_regs(sensor, buf, 2);
}
+static int ar0521_read_reg(struct ar0521_dev *sensor, u16 reg, u16 *val)
+{
+ struct i2c_client *client = sensor->i2c_client;
+ unsigned char buf[2];
+ struct i2c_msg msg;
+ int ret;
+
+ msg.addr = client->addr;
+ msg.flags = client->flags;
+ msg.len = sizeof(u16);
+ msg.buf = buf;
+ put_unaligned_be16(reg, buf);
+
+ ret = i2c_transfer(client->adapter, &msg, 1);
+ if (ret < 0)
+ return ret;
+
+ msg.len = sizeof(u16);
+ msg.flags = client->flags | I2C_M_RD;
+ msg.buf = buf;
+
+ ret = i2c_transfer(client->adapter, &msg, 1);
+ if (ret < 0)
+ return ret;
+
+ *val = get_unaligned_be16(buf);
+
+ return 0;
+}
+
static int ar0521_set_geometry(struct ar0521_dev *sensor)
{
/* All dimensions are unsigned 12-bit integers */
@@ -187,6 +226,21 @@ static int ar0521_set_geometry(struct ar0521_dev *sensor)
return ar0521_write_regs(sensor, regs, ARRAY_SIZE(regs));
}
+static int ar0521_set_analog_gain(struct ar0521_dev *sensor)
+{
+ u16 global_gain;
+ int ret;
+
+ ret = ar0521_read_reg(sensor, AR0521_REG_GLOBAL_GAIN, &global_gain);
+ if (ret)
+ return ret;
+
+ global_gain &= ~AR0521_REG_GLOBAL_GAIN_ANA_MASK;
+ global_gain |= sensor->ctrls.ana_gain->val & AR0521_REG_GLOBAL_GAIN_ANA_MASK;
+
+ return ar0521_write_reg(sensor, AR0521_REG_GLOBAL_GAIN, global_gain);
+}
+
static int ar0521_set_gains(struct ar0521_dev *sensor)
{
int green = sensor->ctrls.gain->val;
@@ -456,6 +510,9 @@ static int ar0521_s_ctrl(struct v4l2_ctrl *ctrl)
case V4L2_CID_VBLANK:
ret = ar0521_set_geometry(sensor);
break;
+ case V4L2_CID_ANALOGUE_GAIN:
+ ret = ar0521_set_analog_gain(sensor);
+ break;
case V4L2_CID_GAIN:
case V4L2_CID_RED_BALANCE:
case V4L2_CID_BLUE_BALANCE:
@@ -499,6 +556,13 @@ static int ar0521_init_controls(struct ar0521_dev *sensor)
/* We can use our own mutex for the ctrl lock */
hdl->lock = &sensor->lock;
+ /* Analog gain */
+ ctrls->ana_gain = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_ANALOGUE_GAIN,
+ AR0521_ANA_GAIN_MIN,
+ AR0521_ANA_GAIN_MAX,
+ AR0521_ANA_GAIN_STEP,
+ AR0521_ANA_GAIN_DEFAULT);
+
/* Manual gain */
ctrls->gain = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAIN, 0, 511, 1, 0);
ctrls->red_balance = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_RED_BALANCE,
--
2.37.3
