/* * Copyright (C) 2012 Samsung Electronics * R. Chandrasekar <rcsekar@samsung.com> * * SPDX-License-Identifier: GPL-2.0+ */ #include <common.h> #include <sound.h> void sound_create_square_wave(unsigned short *data, int size, uint32_t freq) { const int sample = 48000; const unsigned short amplitude = 16000; /* between 1 and 32767 */ const int period = freq ? sample / freq : 0; const int half = period / 2; assert(freq); /* Make sure we don't overflow our buffer */ if (size % 2) size--; while (size) { int i; for (i = 0; size && i < half; i++) { size -= 2; *data++ = amplitude; *data++ = amplitude; } for (i = 0; size && i < period - half; i++) { size -= 2; *data++ = -amplitude; *data++ = -amplitude; } } }