LXR linux/drivers/media/test-drivers/vidtv/vidtv

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * The Virtual DTV test driver serves as a reference DVB driver and helps
   4 * validate the existing APIs in the media subsystem. It can also aid
   5 * developers working on userspace applications.
   6 *
   7 * Copyright (C) 2020 Daniel W. S. Almeida
   8 * Based on the example driver written by Emard <emard@softhome.net>
   9 */
  10
  11#ifndef VIDTV_DEMOD_H
  12#define VIDTV_DEMOD_H
  13
  14#include <linux/dvb/frontend.h>
  15
  16#include <media/dvb_frontend.h>
  17
  18/**
  19 * struct vidtv_demod_cnr_to_qual_s - Map CNR values to a given combination of
  20 * modulation and fec_inner
  21 * @modulation: see enum fe_modulation
  22 * @fec: see enum fe_fec_rate
  23 * @cnr_ok: S/N threshold to consider the signal as OK. Below that, there's
  24 *          a chance of losing sync.
  25 * @cnr_good: S/N threshold to consider the signal strong.
  26 *
  27 * This struct matches values for 'good' and 'ok' CNRs given the combination
  28 * of modulation and fec_inner in use. We might simulate some noise if the
  29 * signal quality is not too good.
  30 *
  31 * The values were taken from libdvbv5.
  32 */
  33struct vidtv_demod_cnr_to_qual_s {
  34        u32 modulation;
  35        u32 fec;
  36        u32 cnr_ok;
  37        u32 cnr_good;
  38};
  39
  40/**
  41 * struct vidtv_demod_config - Configuration used to init the demod
  42 * @drop_tslock_prob_on_low_snr: probability of losing the lock due to low snr
  43 * @recover_tslock_prob_on_good_snr: probability of recovering when the signal
  44 * improves
  45 *
  46 * The configuration used to init the demodulator module, usually filled
  47 * by a bridge driver. For vidtv, this is filled by vidtv_bridge before the
  48 * demodulator module is probed.
  49 */
  50struct vidtv_demod_config {
  51        u8 drop_tslock_prob_on_low_snr;
  52        u8 recover_tslock_prob_on_good_snr;
  53};
  54
  55/**
  56 * struct vidtv_demod_state - The demodulator state
  57 * @frontend: The frontend structure allocated by the demod.
  58 * @config: The config used to init the demod.
  59 * @status: the demod status.
  60 * @tuner_cnr: current S/N ratio for the signal carrier
  61 */
  62struct vidtv_demod_state {
  63        struct dvb_frontend frontend;
  64        struct vidtv_demod_config config;
  65        enum fe_status status;
  66        u16 tuner_cnr;
  67};
  68#endif // VIDTV_DEMOD_H
  69