V4L/DVB (8873): gspca: Bad image offset with rev012a of spca561 and adjust exposure.

-Make raw bayer header size change from 20 to 16 affect rev072a only, my 2
 rev012a cams both have a header size of 20
-While testing this I also tested the new exposure setting (good work on
 finding the register JF), and after quite a bit of testing have found out the
 exact meaning of the register, this patch modifies setexposure to control
 the exposure over a much wider range.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 36 insertions, 19 deletions

diff --git a/drivers/media/video/gspca/spca561.c b/drivers/media/video/gspca/spca561.c
index d2f689e366af..1c29c279a982 100644
--- a/drivers/media/video/gspca/spca561.c
+++ b/drivers/media/video/gspca/spca561.c
@@ -38,9 +38,9 @@ struct sd {
 #define CONTRAST_MAX 0x3fff
 
         __u16 exposure;                 /* rev12a only */
-#define EXPOSURE_MIN 0
+#define EXPOSURE_MIN 1
 #define EXPOSURE_DEF 200
-#define EXPOSURE_MAX 762
+#define EXPOSURE_MAX (4095 - 900) /* see set_exposure */
 
         __u8 brightness;                /* rev72a only */
 #define BRIGHTNESS_MIN 0
@@ -648,9 +648,31 @@ static void setexposure(struct gspca_dev *gspca_dev)
 {
         struct sd *sd = (struct sd *) gspca_dev;
         int expo;
+        int clock_divider;
         __u8 data[2];
 
-        expo = sd->exposure + 0x20a8;   /* from test */
+        /* Register 0x8309 controls exposure for the spca561,
+           the basic exposure setting goes from 1-2047, where 1 is completely
+           dark and 2047 is very bright. It not only influences exposure but
+           also the framerate (to allow for longer exposure) from 1 - 300 it
+           only raises the exposure time then from 300 - 600 it halves the
+           framerate to be able to further raise the exposure time and for every
+           300 more it halves the framerate again. This allows for a maximum
+           exposure time of circa 0.2 - 0.25 seconds (30 / (2000/3000) fps).
+           Sometimes this is not enough, the 1-2047 uses bits 0-10, bits 11-12
+           configure a divider for the base framerate which us used at the
+           exposure setting of 1-300. These bits configure the base framerate
+           according to the following formula: fps = 60 / (value + 2) */
+        if (sd->exposure < 2048) {
+                expo = sd->exposure;
+                clock_divider = 0;
+        } else {
+                /* Add 900 to make the 0 setting of the second part of the
+                   exposure equal to the 2047 setting of the first part. */
+                expo = (sd->exposure - 2048) + 900;
+                clock_divider = 3;
+        }
+        expo |= clock_divider << 11;
         data[0] = expo;
         data[1] = expo >> 8;
         reg_w_buf(gspca_dev, 0x8309, data, 2);
@@ -680,23 +702,11 @@ static void setautogain(struct gspca_dev *gspca_dev)
 static void sd_start_12a(struct gspca_dev *gspca_dev)
 {
         struct usb_device *dev = gspca_dev->dev;
-        int Clck;
+        int Clck = 0x8a; /* lower 0x8X values lead to fps > 30 */
         __u8 Reg8307[] = { 0xaa, 0x00 };
         int mode;
 
         mode = gspca_dev->cam.cam_mode[(int) gspca_dev->curr_mode].priv;
-        switch (mode) {
-        case 0:
-        case 1:
-                Clck = 0x8a;
-                break;
-        case 2:
-                Clck = 0x85;
-                break;
-        default:
-                Clck = 0x83;
-                break;
-        }
         if (mode <= 1) {
                 /* Use compression on 320x240 and above */
                 reg_w_val(dev, 0x8500, 0x10 | mode);
@@ -714,6 +724,7 @@ static void sd_start_12a(struct gspca_dev *gspca_dev)
         setcontrast(gspca_dev);
         setwhite(gspca_dev);
         setautogain(gspca_dev);
+        setexposure(gspca_dev);
 }
 static void sd_start_72a(struct gspca_dev *gspca_dev)
 {
@@ -849,6 +860,8 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
                         __u8 *data,             /* isoc packet */
                         int len)                /* iso packet length */
 {
+        struct sd *sd = (struct sd *) gspca_dev;
+
         switch (data[0]) {
         case 0:         /* start of frame */
                 frame = gspca_frame_add(gspca_dev, LAST_PACKET, frame,
@@ -861,9 +874,13 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
                                         frame, data, len);
                 } else {
                         /* raw bayer (with a header, which we skip) */
-/*fixme: is this specific to the rev012a? */
-                        data += 16;
-                        len -= 16;
+                        if (sd->chip_revision == Rev012A) {
+                                data += 20;
+                                len -= 20;
+                        } else {
+                                data += 16;
+                                len -= 16;
+                        }
                         gspca_frame_add(gspca_dev, FIRST_PACKET,
                                                 frame, data, len);
                 }