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 */ 33 struct 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 */ 50 struct 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 */ 62 struct 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