From 8cd058423f22072c1147d3e99161252e1e72333a Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Wed, 9 May 2012 09:58:33 -0300 Subject: [PATCH] [media] gspca: Add autogain functions for use with control framework drivers Signed-off-by: Hans de Goede Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/gspca/Makefile | 2 +- drivers/media/video/gspca/autogain_functions.c | 178 +++++++++++++++++++++++++ drivers/media/video/gspca/gspca.h | 15 +++ 3 files changed, 194 insertions(+), 1 deletion(-) create mode 100644 drivers/media/video/gspca/autogain_functions.c diff --git a/drivers/media/video/gspca/Makefile b/drivers/media/video/gspca/Makefile index 79ebe46..c901da0 100644 --- a/drivers/media/video/gspca/Makefile +++ b/drivers/media/video/gspca/Makefile @@ -43,7 +43,7 @@ obj-$(CONFIG_USB_GSPCA_VICAM) += gspca_vicam.o obj-$(CONFIG_USB_GSPCA_XIRLINK_CIT) += gspca_xirlink_cit.o obj-$(CONFIG_USB_GSPCA_ZC3XX) += gspca_zc3xx.o -gspca_main-objs := gspca.o +gspca_main-objs := gspca.o autogain_functions.o gspca_benq-objs := benq.o gspca_conex-objs := conex.o gspca_cpia1-objs := cpia1.o diff --git a/drivers/media/video/gspca/autogain_functions.c b/drivers/media/video/gspca/autogain_functions.c new file mode 100644 index 0000000..67db674 --- /dev/null +++ b/drivers/media/video/gspca/autogain_functions.c @@ -0,0 +1,178 @@ +/* + * Functions for auto gain. + * + * Copyright (C) 2010-2012 Hans de Goede + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include "gspca.h" + +/* 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_expo_autogain( + struct gspca_dev *gspca_dev, + int avg_lum, + int desired_avg_lum, + int deadzone, + int gain_knee, + int exposure_knee) +{ + s32 gain, orig_gain, exposure, orig_exposure; + int i, steps, retval = 0; + + if (v4l2_ctrl_g_ctrl(gspca_dev->autogain) == 0) + return 0; + + orig_gain = gain = v4l2_ctrl_g_ctrl(gspca_dev->gain); + orig_exposure = exposure = v4l2_ctrl_g_ctrl(gspca_dev->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", + 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 > gspca_dev->gain->default_value) + gain--; + else if (exposure > gspca_dev->exposure->minimum) + exposure--; + else if (gain > gspca_dev->gain->minimum) + gain--; + else + break; + } else { + if (gain < gspca_dev->gain->default_value) + gain++; + else if (exposure < exposure_knee) + exposure++; + else if (gain < gain_knee) + gain++; + else if (exposure < gspca_dev->exposure->maximum) + exposure++; + else if (gain < gspca_dev->gain->maximum) + gain++; + else + break; + } + } + + if (gain != orig_gain) { + v4l2_ctrl_s_ctrl(gspca_dev->gain, gain); + retval = 1; + } + if (exposure != orig_exposure) { + v4l2_ctrl_s_ctrl(gspca_dev->exposure, exposure); + retval = 1; + } + + if (retval) + PDEBUG(D_FRAM, "autogain: changed gain: %d, expo: %d", + gain, exposure); + return retval; +} +EXPORT_SYMBOL(gspca_expo_autogain); + +/* Autogain + exposure algorithm for cameras with a coarse exposure control + (usually this means we can only control the clockdiv to change exposure) + As changing the clockdiv so that the fps drops from 30 to 15 fps for + example, will lead to a huge exposure change (it effectively doubles), + this algorithm normally tries to only adjust the gain (between 40 and + 80 %) and if that does not help, only then changes exposure. This leads + to a much more stable image then using the knee algorithm which at + certain points of the knee graph will only try to adjust exposure, + which leads to oscilating as one exposure step is huge. + + Returns 0 if no changes were made, 1 if the gain and or exposure settings + where changed. */ +int gspca_coarse_grained_expo_autogain( + struct gspca_dev *gspca_dev, + int avg_lum, + int desired_avg_lum, + int deadzone) +{ + s32 gain_low, gain_high, gain, orig_gain, exposure, orig_exposure; + int steps, retval = 0; + + if (v4l2_ctrl_g_ctrl(gspca_dev->autogain) == 0) + return 0; + + orig_gain = gain = v4l2_ctrl_g_ctrl(gspca_dev->gain); + orig_exposure = exposure = v4l2_ctrl_g_ctrl(gspca_dev->exposure); + + gain_low = (gspca_dev->gain->maximum - gspca_dev->gain->minimum) / + 5 * 2 + gspca_dev->gain->minimum; + gain_high = (gspca_dev->gain->maximum - gspca_dev->gain->minimum) / + 5 * 4 + gspca_dev->gain->minimum; + + /* 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 = (desired_avg_lum - avg_lum) / deadzone; + + PDEBUG(D_FRAM, "autogain: lum: %d, desired: %d, steps: %d", + avg_lum, desired_avg_lum, steps); + + if ((gain + steps) > gain_high && + exposure < gspca_dev->exposure->maximum) { + gain = gain_high; + gspca_dev->exp_too_low_cnt++; + gspca_dev->exp_too_high_cnt = 0; + } else if ((gain + steps) < gain_low && + exposure > gspca_dev->exposure->minimum) { + gain = gain_low; + gspca_dev->exp_too_high_cnt++; + gspca_dev->exp_too_low_cnt = 0; + } else { + gain += steps; + if (gain > gspca_dev->gain->maximum) + gain = gspca_dev->gain->maximum; + else if (gain < gspca_dev->gain->minimum) + gain = gspca_dev->gain->minimum; + gspca_dev->exp_too_high_cnt = 0; + gspca_dev->exp_too_low_cnt = 0; + } + + if (gspca_dev->exp_too_high_cnt > 3) { + exposure--; + gspca_dev->exp_too_high_cnt = 0; + } else if (gspca_dev->exp_too_low_cnt > 3) { + exposure++; + gspca_dev->exp_too_low_cnt = 0; + } + + if (gain != orig_gain) { + v4l2_ctrl_s_ctrl(gspca_dev->gain, gain); + retval = 1; + } + if (exposure != orig_exposure) { + v4l2_ctrl_s_ctrl(gspca_dev->exposure, exposure); + retval = 1; + } + + if (retval) + PDEBUG(D_FRAM, "autogain: changed gain: %d, expo: %d", + gain, exposure); + return retval; +} +EXPORT_SYMBOL(gspca_coarse_grained_expo_autogain); diff --git a/drivers/media/video/gspca/gspca.h b/drivers/media/video/gspca/gspca.h index 436d881..449ff8e 100644 --- a/drivers/media/video/gspca/gspca.h +++ b/drivers/media/video/gspca/gspca.h @@ -6,6 +6,7 @@ #include #include #include +#include #include #include @@ -174,6 +175,15 @@ struct gspca_dev { unsigned ctrl_dis; /* disabled controls (bit map) */ unsigned ctrl_inac; /* inactive controls (bit map) */ + /* autogain and exposure or gain control cluster, these are global as + the autogain/exposure functions in autogain_functions.c use them */ + struct { + struct v4l2_ctrl *autogain; + struct v4l2_ctrl *exposure; + struct v4l2_ctrl *gain; + int exp_too_low_cnt, exp_too_high_cnt; + }; + #define USB_BUF_SZ 64 __u8 *usb_buf; /* buffer for USB exchanges */ struct urb *urb[MAX_NURBS]; @@ -242,4 +252,9 @@ int gspca_resume(struct usb_interface *intf); #endif 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 gspca_expo_autogain(struct gspca_dev *gspca_dev, int avg_lum, + int desired_avg_lum, int deadzone, int gain_knee, int exposure_knee); +int gspca_coarse_grained_expo_autogain(struct gspca_dev *gspca_dev, + int avg_lum, int desired_avg_lum, int deadzone); + #endif /* GSPCAV2_H */ -- 2.7.4