[media] gspca: Add autogain functions for use with control framework drivers (8cd05842) · Commits · 戴 / test

drivers/media/video/gspca/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -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

drivers/media/video/gspca/autogain_functions.c

0 → 100644

+178 −0

Original line number	Diff line number	Diff line
		/*
		* Functions for auto gain.
		*
		* Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com>
		*
		* 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);

drivers/media/video/gspca/gspca.h

+15 −0

Original line number	Diff line number	Diff line
		@@ -6,6 +6,7 @@
		#include <linux/usb.h>
		#include <linux/videodev2.h>
		#include <media/v4l2-common.h>
		#include <media/v4l2-ctrls.h>
		#include <media/v4l2-device.h>
		#include <linux/mutex.h>

		@@ -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 */

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