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Commit 2b34e9d1 authored by Frank Schäfer's avatar Frank Schäfer Committed by Mauro Carvalho Chehab
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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: default avatarFrank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 6f9b3312

drivers/media/usb/gspca/pac7302.c

+40 −11
Original line number Diff line number Diff line
@@ -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);