// SPDX-License-Identifier: GPL-2.0-or-later /* * Stereo and SAP detection for cx88 * * Copyright (c) 2009 Marton Balint <[email protected]> */ #include "cx88.h" #include "cx88-reg.h" #include <linux/slab.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/jiffies.h> #include <asm/div64.h> #define INT_PI … #define compat_remainder(a, b) … #define baseband_freq(carrier, srate, tone) … /* * We calculate the baseband frequencies of the carrier and the pilot tones * based on the sampling rate of the audio rds fifo. */ #define FREQ_A2_CARRIER … #define FREQ_A2_DUAL … #define FREQ_A2_STEREO … /* * The frequencies below are from the reference driver. They probably need * further adjustments, because they are not tested at all. You may even need * to play a bit with the registers of the chip to select the proper signal * for the input of the audio rds fifo, and measure it's sampling rate to * calculate the proper baseband frequencies... */ #define FREQ_A2M_CARRIER … #define FREQ_A2M_DUAL … #define FREQ_A2M_STEREO … #define FREQ_EIAJ_CARRIER … #define FREQ_EIAJ_DUAL … #define FREQ_EIAJ_STEREO … #define FREQ_BTSC_DUAL … #define FREQ_BTSC_DUAL_REF … #define FREQ_BTSC_SAP … #define FREQ_BTSC_SAP_REF … /* The spectrum of the signal should be empty between these frequencies. */ #define FREQ_NOISE_START … #define FREQ_NOISE_END … static unsigned int dsp_debug; module_param(dsp_debug, int, 0644); MODULE_PARM_DESC(…) …; #define dprintk(level, fmt, arg...) … static s32 int_cos(u32 x) { … } static u32 int_goertzel(s16 x[], u32 N, u32 freq) { … } static u32 freq_magnitude(s16 x[], u32 N, u32 freq) { … } static u32 noise_magnitude(s16 x[], u32 N, u32 freq_start, u32 freq_end) { … } static s32 detect_a2_a2m_eiaj(struct cx88_core *core, s16 x[], u32 N) { … } static s32 detect_btsc(struct cx88_core *core, s16 x[], u32 N) { … } static s16 *read_rds_samples(struct cx88_core *core, u32 *N) { … } s32 cx88_dsp_detect_stereo_sap(struct cx88_core *core) { … } EXPORT_SYMBOL(…);
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