xref: /linux/include/linux/atmel-isc-media.h (revision 4e52889f)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (c) 2019 Microchip Technology Inc. and its subsidiaries
4  *
5  * Author: Eugen Hristev <eugen.hristev@microchip.com>
6  */
7 
8 #ifndef __LINUX_ATMEL_ISC_MEDIA_H__
9 #define __LINUX_ATMEL_ISC_MEDIA_H__
10 
11 /*
12  * There are 8 controls available:
13  * 4 gain controls, sliders, for each of the BAYER components: R, B, GR, GB.
14  * These gains are multipliers for each component, in format unsigned 0:4:9 with
15  * a default value of 512 (1.0 multiplier).
16  * 4 offset controls, sliders, for each of the BAYER components: R, B, GR, GB.
17  * These offsets are added/substracted from each component, in format signed
18  * 1:12:0 with a default value of 0 (+/- 0)
19  *
20  * To expose this to userspace, added 8 custom controls, in an auto cluster.
21  *
22  * To summarize the functionality:
23  * The auto cluster switch is the auto white balance control, and it works
24  * like this:
25  * AWB == 1: autowhitebalance is on, the do_white_balance button is inactive,
26  * the gains/offsets are inactive, but volatile and readable.
27  * Thus, the results of the whitebalance algorithm are available to userspace to
28  * read at any time.
29  * AWB == 0: autowhitebalance is off, cluster is in manual mode, user can
30  * configure the gain/offsets directly.
31  * More than that, if the do_white_balance button is
32  * pressed, the driver will perform one-time-adjustment, (preferably with color
33  * checker card) and the userspace can read again the new values.
34  *
35  * With this feature, the userspace can save the coefficients and reinstall them
36  * for example after reboot or reprobing the driver.
37  */
38 
39 enum atmel_isc_ctrl_id {
40 	/* Red component gain control */
41 	ISC_CID_R_GAIN = (V4L2_CID_USER_ATMEL_ISC_BASE + 0),
42 	/* Blue component gain control */
43 	ISC_CID_B_GAIN,
44 	/* Green Red component gain control */
45 	ISC_CID_GR_GAIN,
46 	/* Green Blue gain control */
47 	ISC_CID_GB_GAIN,
48 	/* Red component offset control */
49 	ISC_CID_R_OFFSET,
50 	/* Blue component offset control */
51 	ISC_CID_B_OFFSET,
52 	/* Green Red component offset control */
53 	ISC_CID_GR_OFFSET,
54 	/* Green Blue component offset control */
55 	ISC_CID_GB_OFFSET,
56 };
57 
58 #endif
59