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[media] gspca: Add autogain functions for use with control framework …
…drivers Signed-off-by: Hans de Goede <[email protected]> Signed-off-by: Mauro Carvalho Chehab <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,178 @@ | ||
| /* | ||
| * Functions for auto gain. | ||
| * | ||
| * Copyright (C) 2010-2012 Hans de Goede <[email protected]> | ||
| * | ||
| * 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); |
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