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Commit 5fb2dde2 authored by Hans de Goede's avatar Hans de Goede Committed by Mauro Carvalho Chehab
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V4L/DVB: gspca_pac7302: much improved exposure control 



My experience with fixing up the controls for the PAS sensors in
sonixb, has lead me to re-investigate the exposure control for the
pac7302. I've now found a regular exposure register in register bank 3
(which seems to be the sensor registers bank), and with this added a proper
fine grained exposure control. This patch also updates the do_autogain
function to work properly with this new finer grained control.

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 0e4b91c3

drivers/media/video/gspca/pac7302.c

+50 −55
Original line number Diff line number Diff line
@@ -24,33 +24,26 @@ 
 */



/* Some documentation about various registers as determined by trial and error.

   When the register addresses differ between the 7202 and the 7311 the 2

   different addresses are written as 7302addr/7311addr, when one of the 2

   addresses is a - sign that register description is not valid for the

   matching IC.



   Register page 1:



   Address	Description

   -/0x08	Unknown compressor related, must always be 8 except when not

		in 640x480 resolution and page 4 reg 2 <= 3 then set it to 9 !

   -/0x1b	Auto white balance related, bit 0 is AWB enable (inverted)

		bits 345 seem to toggle per color gains on/off (inverted)

   0x78		Global control, bit 6 controls the LED (inverted)

   -/0x80	JPEG compression ratio ? Best not touched



   Register page 3/4:

   Register page 3:



   Address	Description

   0x02		Clock divider 2-63, fps =~ 60 / val. Must be a multiple of 3 on

   0x02		Clock divider 3-63, fps = 90 / val. Must be a multiple of 3 on

		the 7302, so one of 3, 6, 9, ..., except when between 6 and 12?

   -/0x0f	Master gain 1-245, low value = high gain

   0x10/-	Master gain 0-31

   -/0x10	Another gain 0-15, limited influence (1-2x gain I guess)

   0x03		Variable framerate ctrl reg2==3: 0 -> ~30 fps, 255 -> ~22fps

   0x04		Another var framerate ctrl reg2==3, reg3==0: 0 -> ~30 fps,

		63 -> ~27 fps, the 2 msb's must always be 1 !!

   0x05		Another var framerate ctrl reg2==3, reg3==0, reg4==0xc0:

		1 -> ~30 fps, 2 -> ~20 fps

   0x0e		Exposure bits 0-7, 0-448, 0 = use full frame time

   0x0f		Exposure bit 8, 0-448, 448 = no exposure at all

   0x10		Master gain 0-31

   0x21		Bitfield: 0-1 unused, 2-3 vflip/hflip, 4-5 unknown, 6-7 unused

   -/0x27	Seems to toggle various gains on / off, Setting bit 7 seems to

		completely disable the analog amplification block. Set to 0x68

		for max gain, 0x14 for minimal gain.



   The registers are accessed in the following functions:
@@ -89,8 +82,8 @@ struct sd { 
	unsigned char red_balance;

	unsigned char blue_balance;

	unsigned char gain;

	unsigned char exposure;

	unsigned char autogain;

	unsigned short exposure;

	__u8 hflip;

	__u8 vflip;

	u8 flags;
@@ -128,7 +121,6 @@ static int sd_setexposure(struct gspca_dev *gspca_dev, __s32 val); 
static int sd_getexposure(struct gspca_dev *gspca_dev, __s32 *val);



static const struct ctrl sd_ctrls[] = {

/* This control is pac7302 only */

	{

	    {

		.id      = V4L2_CID_BRIGHTNESS,
@@ -144,7 +136,6 @@ static const struct ctrl sd_ctrls[] = { 
	    .set = sd_setbrightness,

	    .get = sd_getbrightness,

	},

/* This control is for both the 7302 and the 7311 */

	{

	    {

		.id      = V4L2_CID_CONTRAST,
@@ -160,7 +151,6 @@ static const struct ctrl sd_ctrls[] = { 
	    .set = sd_setcontrast,

	    .get = sd_getcontrast,

	},

/* This control is pac7302 only */

	{

	    {

		.id      = V4L2_CID_SATURATION,
@@ -218,7 +208,6 @@ static const struct ctrl sd_ctrls[] = { 
	    .set = sd_setbluebalance,

	    .get = sd_getbluebalance,

	},

/* All controls below are for both the 7302 and the 7311 */

	{

	    {

		.id      = V4L2_CID_GAIN,
@@ -241,11 +230,10 @@ static const struct ctrl sd_ctrls[] = { 
		.type    = V4L2_CTRL_TYPE_INTEGER,

		.name    = "Exposure",

		.minimum = 0,

#define EXPOSURE_MAX 255

		.maximum = EXPOSURE_MAX,

		.maximum = 1023,

		.step    = 1,

#define EXPOSURE_DEF  16 /*  32 ms / 30 fps */

#define EXPOSURE_KNEE 50 /* 100 ms / 10 fps */

#define EXPOSURE_DEF  66  /*  33 ms / 30 fps */

#define EXPOSURE_KNEE 133 /*  66 ms / 15 fps */

		.default_value = EXPOSURE_DEF,

	    },

	    .set = sd_setexposure,
@@ -381,7 +369,7 @@ static const __u8 start_7302[] = { 
#define SKIP		0xaa

/* page 3 - the value SKIP says skip the index - see reg_w_page() */

static const __u8 page3_7302[] = {

	0x90, 0x40, 0x03, 0x50, 0xc2, 0x01, 0x14, 0x16,

	0x90, 0x40, 0x03, 0x00, 0xc0, 0x01, 0x14, 0x16,

	0x14, 0x12, 0x00, 0x00, 0x00, 0x02, 0x33, 0x00,

	0x0f, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

	0x00, 0x00, 0x00, 0x47, 0x01, 0xb3, 0x01, 0x00,
@@ -653,23 +641,39 @@ static void setgain(struct gspca_dev *gspca_dev) 
static void setexposure(struct gspca_dev *gspca_dev)

{

	struct sd *sd = (struct sd *) gspca_dev;

	__u8 reg;



	/* register 2 of frame 3/4 contains the clock divider configuring the

	   no fps according to the formula: 60 / reg. sd->exposure is the

	   desired exposure time in ms. */

	reg = 120 * sd->exposure / 1000;

	if (reg < 2)

		reg = 2;

	else if (reg > 63)

		reg = 63;



	/* On the pac7302 reg2 MUST be a multiple of 3, so round it to

	   the nearest multiple of 3, except when between 6 and 12? */

	if (reg < 6 || reg > 12)

		reg = ((reg + 1) / 3) * 3;

	__u8 clockdiv;

	__u16 exposure;



	/* register 2 of frame 3 contains the clock divider configuring the

	   no fps according to the formula: 90 / reg. sd->exposure is the

	   desired exposure time in 0.5 ms. */

	clockdiv = (90 * sd->exposure + 1999) / 2000;



	/* Note clockdiv = 3 also works, but when running at 30 fps, depending

	   on the scene being recorded, the camera switches to another

	   quantization table for certain JPEG blocks, and we don't know how

	   to decompress these blocks. So we cap the framerate at 15 fps */

	if (clockdiv < 6)

		clockdiv = 6;

	else if (clockdiv > 63)

		clockdiv = 63;



	/* reg2 MUST be a multiple of 3, except when between 6 and 12?

	   Always round up, otherwise we cannot get the desired frametime

	   using the partial frame time exposure control */

	if (clockdiv < 6 || clockdiv > 12)

		clockdiv = ((clockdiv + 2) / 3) * 3;



	/* frame exposure time in ms = 1000 * clockdiv / 90    ->

	exposure = (sd->exposure / 2) * 448 / (1000 * clockdiv / 90) */

	exposure = (sd->exposure * 45 * 448) / (1000 * clockdiv);

	/* 0 = use full frametime, 448 = no exposure, reverse it */

	exposure = 448 - exposure;



	reg_w(gspca_dev, 0xff, 0x03);			/* page 3 */

	reg_w(gspca_dev, 0x02, reg);

	reg_w(gspca_dev, 0x02, clockdiv);

	reg_w(gspca_dev, 0x0e, exposure & 0xff);

	reg_w(gspca_dev, 0x0f, exposure >> 8);



	/* load registers to sensor (Bit 0, auto clear) */

	reg_w(gspca_dev, 0x11, 0x01);
@@ -756,22 +760,13 @@ static void do_autogain(struct gspca_dev *gspca_dev) 
{

	struct sd *sd = (struct sd *) gspca_dev;

	int avg_lum = atomic_read(&sd->avg_lum);

	int desired_lum, deadzone;

	int desired_lum;

	const int deadzone = 30;



	if (avg_lum == -1)

		return;



	desired_lum = 270 + sd->brightness * 4;

	/* Hack hack, with the 7202 the first exposure step is

	   pretty large, so if we're about to make the first

	   exposure increase make the deadzone large to avoid

	   oscilating */

	if (desired_lum > avg_lum && sd->gain == GAIN_DEF &&

			sd->exposure > EXPOSURE_DEF &&

			sd->exposure < 42)

		deadzone = 90;

	else

		deadzone = 30;

	desired_lum = 270 + sd->brightness;



	if (sd->autogain_ignore_frames > 0)

		sd->autogain_ignore_frames--;

drivers/media/video/gspca/pac_common.h

+4 −5
Original line number Diff line number Diff line
@@ -24,11 +24,10 @@ 
 */



/* We calculate the autogain at the end of the transfer of a frame, at this

   moment a frame with the old settings is being transmitted, and a frame is

   being captured with the old settings. So if we adjust the autogain we must

   ignore atleast the 2 next frames for the new settings to come into effect

   before doing any other adjustments */

#define PAC_AUTOGAIN_IGNORE_FRAMES	3

   moment a frame with the old settings is being captured and transmitted. So

   if we adjust the gain or exposure we must ignore atleast the next frame for

   the new settings to come into effect before doing any other adjustments. */

#define PAC_AUTOGAIN_IGNORE_FRAMES	2



static const unsigned char pac_sof_marker[5] =

		{ 0xff, 0xff, 0x00, 0xff, 0x96 };