1*4882a593Smuzhiyun /* 2*4882a593Smuzhiyun * Copyright (C) 2012 Samsung Electronics 3*4882a593Smuzhiyun * R. Chandrasekar <rcsekar@samsung.com> 4*4882a593Smuzhiyun * 5*4882a593Smuzhiyun * SPDX-License-Identifier: GPL-2.0+ 6*4882a593Smuzhiyun */ 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun #include <common.h> 9*4882a593Smuzhiyun #include <sound.h> 10*4882a593Smuzhiyun sound_create_square_wave(unsigned short * data,int size,uint32_t freq)11*4882a593Smuzhiyunvoid sound_create_square_wave(unsigned short *data, int size, uint32_t freq) 12*4882a593Smuzhiyun { 13*4882a593Smuzhiyun const int sample = 48000; 14*4882a593Smuzhiyun const unsigned short amplitude = 16000; /* between 1 and 32767 */ 15*4882a593Smuzhiyun const int period = freq ? sample / freq : 0; 16*4882a593Smuzhiyun const int half = period / 2; 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun assert(freq); 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun /* Make sure we don't overflow our buffer */ 21*4882a593Smuzhiyun if (size % 2) 22*4882a593Smuzhiyun size--; 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun while (size) { 25*4882a593Smuzhiyun int i; 26*4882a593Smuzhiyun for (i = 0; size && i < half; i++) { 27*4882a593Smuzhiyun size -= 2; 28*4882a593Smuzhiyun *data++ = amplitude; 29*4882a593Smuzhiyun *data++ = amplitude; 30*4882a593Smuzhiyun } 31*4882a593Smuzhiyun for (i = 0; size && i < period - half; i++) { 32*4882a593Smuzhiyun size -= 2; 33*4882a593Smuzhiyun *data++ = -amplitude; 34*4882a593Smuzhiyun *data++ = -amplitude; 35*4882a593Smuzhiyun } 36*4882a593Smuzhiyun } 37*4882a593Smuzhiyun } 38