LXR linux/include/linux/atmel-isc-media.h

   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
  39enum 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