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[media] gspca_pac7302: use registers 0x01 and 0x03 for red and blue balance controls 

Currently used registers 0xc5 and 0xc7 provide only a very coarse
adjustment possibility within a very small value range (0-3).
With registers 0x01 and 0x03, a fine grained adjustment with
255 steps is possible. This is also what the Windows driver does.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Frank Schäfer 2012-09-23 10:29:43 -03:00 committed by Mauro Carvalho Chehab
parent 6f9b33123c
commit 2b34e9d1be
1 changed files with 40 additions and 11 deletions
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41
drivers/media/usb/gspca/pac7302.c
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@ -77,12 +77,12 @@
*
* Page | Register | Function
* -----+------------+---------------------------------------------------
* 0 | 0x01 | setredbalance()
* 0 | 0x03 | setbluebalance()
* 0 | 0x0f..0x20 | setcolors()
* 0 | 0xa2..0xab | setbrightcont()
* 0 | 0xb6 | setsharpness()
* 0 | 0xc5 | setredbalance()
* 0 | 0xc6 | setwhitebalance()
* 0 | 0xc7 | setbluebalance()
* 0 | 0xdc | setbrightcont(), setcolors()
* 3 | 0x02 | setexposure()
* 3 | 0x10, 0x12 | setgain()
@ -98,6 +98,9 @@
/* Include pac common sof detection functions */
#include "pac_common.h"
#define PAC7302_RGB_BALANCE_MIN 0
#define PAC7302_RGB_BALANCE_MAX 200
#define PAC7302_RGB_BALANCE_DEFAULT 100
#define PAC7302_GAIN_DEFAULT 15
#define PAC7302_GAIN_KNEE 42
#define PAC7302_EXPOSURE_DEFAULT 66 /* 33 ms / 30 fps */
@ -438,12 +441,31 @@ static void setwhitebalance(struct gspca_dev *gspca_dev)
reg_w(gspca_dev, 0xdc, 0x01);
}
static u8 rgbbalance_ctrl_to_reg_value(s32 rgb_ctrl_val)
{
const unsigned int k = 1000; /* precision factor */
unsigned int norm;
/* Normed value [0...k] */
norm = k * (rgb_ctrl_val - PAC7302_RGB_BALANCE_MIN)
/ (PAC7302_RGB_BALANCE_MAX - PAC7302_RGB_BALANCE_MIN);
/* Qudratic apporach improves control at small (register) values: */
return 64 * norm * norm / (k*k) + 32 * norm / k + 32;
/* Y = 64*X*X + 32*X + 32
* => register values 0x20-0x80; Windows driver uses these limits */
/* NOTE: for full value range (0x00-0xff) use
* Y = 254*X*X + X
* => 254 * norm * norm / (k*k) + 1 * norm / k */
}
static void setredbalance(struct gspca_dev *gspca_dev)
{
struct sd *sd = (struct sd *) gspca_dev;
reg_w(gspca_dev, 0xff, 0x00); /* page 0 */
reg_w(gspca_dev, 0xc5, sd->red_balance->val);
reg_w(gspca_dev, 0x01,
rgbbalance_ctrl_to_reg_value(sd->red_balance->val));
reg_w(gspca_dev, 0xdc, 0x01);
}
@ -453,7 +475,8 @@ static void setbluebalance(struct gspca_dev *gspca_dev)
struct sd *sd = (struct sd *) gspca_dev;
reg_w(gspca_dev, 0xff, 0x00); /* page 0 */
reg_w(gspca_dev, 0xc7, sd->blue_balance->val);
reg_w(gspca_dev, 0x03,
rgbbalance_ctrl_to_reg_value(sd->blue_balance->val));
reg_w(gspca_dev, 0xdc, 0x01);
}
@ -642,9 +665,15 @@ static int sd_init_controls(struct gspca_dev *gspca_dev)
V4L2_CID_WHITE_BALANCE_TEMPERATURE,
0, 255, 1, 55);
sd->red_balance = v4l2_ctrl_new_std(hdl, &sd_ctrl_ops,
V4L2_CID_RED_BALANCE, 0, 3, 1, 1);
V4L2_CID_RED_BALANCE,
PAC7302_RGB_BALANCE_MIN,
PAC7302_RGB_BALANCE_MAX,
1, PAC7302_RGB_BALANCE_DEFAULT);
sd->blue_balance = v4l2_ctrl_new_std(hdl, &sd_ctrl_ops,
V4L2_CID_BLUE_BALANCE, 0, 3, 1, 1);
V4L2_CID_BLUE_BALANCE,
PAC7302_RGB_BALANCE_MIN,
PAC7302_RGB_BALANCE_MAX,
1, PAC7302_RGB_BALANCE_DEFAULT);
gspca_dev->autogain = v4l2_ctrl_new_std(hdl, &sd_ctrl_ops,
V4L2_CID_AUTOGAIN, 0, 1, 1, 1);