V4L/DVB (8348): gspca: Add auto gain/exposure to sonixb and tas5110 / ov6650 sensors.
sonixb: Do auto gain for tas5110 / ov6650 sensors.
pac207: Move the auto_gain function to gspca.
gspca: New function gspca_auto_gain_n_exposure().
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@infradead.org>
diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c
index 09f190c..2ffb00a 100644
--- a/drivers/media/video/gspca/gspca.c
+++ b/drivers/media/video/gspca/gspca.c
@@ -1790,6 +1790,94 @@
}
EXPORT_SYMBOL(gspca_disconnect);
+/* -- cam driver utility functions -- */
+
+/* auto gain and exposure algorithm based on the knee algorithm described here:
+ http://ytse.tricolour.net/docs/LowLightOptimization.html
+
+ Returns 0 if no changes were made, 1 if the gain and or exposure settings
+ where changed. */
+int gspca_auto_gain_n_exposure(struct gspca_dev *gspca_dev, int avg_lum,
+ int desired_avg_lum, int deadzone, int gain_knee, int exposure_knee)
+{
+ int i, steps, gain, orig_gain, exposure, orig_exposure, autogain;
+ const struct ctrl *gain_ctrl = NULL;
+ const struct ctrl *exposure_ctrl = NULL;
+ const struct ctrl *autogain_ctrl = NULL;
+ int retval = 0;
+
+ for (i = 0; i < gspca_dev->sd_desc->nctrls; i++) {
+ if (gspca_dev->sd_desc->ctrls[i].qctrl.id == V4L2_CID_GAIN)
+ gain_ctrl = &gspca_dev->sd_desc->ctrls[i];
+ if (gspca_dev->sd_desc->ctrls[i].qctrl.id == V4L2_CID_EXPOSURE)
+ exposure_ctrl = &gspca_dev->sd_desc->ctrls[i];
+ if (gspca_dev->sd_desc->ctrls[i].qctrl.id == V4L2_CID_AUTOGAIN)
+ autogain_ctrl = &gspca_dev->sd_desc->ctrls[i];
+ }
+ if (!gain_ctrl || !exposure_ctrl || !autogain_ctrl) {
+ PDEBUG(D_ERR, "Error: gspca_auto_gain_n_exposure called "
+ "on cam without (auto)gain/exposure");
+ return 0;
+ }
+
+ if (gain_ctrl->get(gspca_dev, &gain) ||
+ exposure_ctrl->get(gspca_dev, &exposure) ||
+ autogain_ctrl->get(gspca_dev, &autogain) || !autogain)
+ return 0;
+
+ orig_gain = gain;
+ orig_exposure = exposure;
+
+ /* If we are of a multiple of deadzone, do multiple steps to reach the
+ desired lumination fast (with the risc of a slight overshoot) */
+ steps = abs(desired_avg_lum - avg_lum) / deadzone;
+
+ PDEBUG(D_FRAM, "autogain: lum: %d, desired: %d, steps: %d\n",
+ avg_lum, desired_avg_lum, steps);
+
+ for (i = 0; i < steps; i++) {
+ if (avg_lum > desired_avg_lum) {
+ if (gain > gain_knee)
+ gain--;
+ else if (exposure > exposure_knee)
+ exposure--;
+ else if (gain > gain_ctrl->qctrl.default_value)
+ gain--;
+ else if (exposure > exposure_ctrl->qctrl.minimum)
+ exposure--;
+ else if (gain > gain_ctrl->qctrl.minimum)
+ gain--;
+ else
+ break;
+ } else {
+ if (gain < gain_ctrl->qctrl.default_value)
+ gain++;
+ else if (exposure < exposure_knee)
+ exposure++;
+ else if (gain < gain_knee)
+ gain++;
+ else if (exposure < exposure_ctrl->qctrl.maximum)
+ exposure++;
+ else if (gain < gain_ctrl->qctrl.maximum)
+ gain++;
+ else
+ break;
+ }
+ }
+
+ if (gain != orig_gain) {
+ gain_ctrl->set(gspca_dev, gain);
+ retval = 1;
+ }
+ if (exposure != orig_exposure) {
+ exposure_ctrl->set(gspca_dev, exposure);
+ retval = 1;
+ }
+
+ return retval;
+}
+EXPORT_SYMBOL(gspca_auto_gain_n_exposure);
+
/* -- module insert / remove -- */
static int __init gspca_init(void)
{