u-boot/drivers/sound/sound.c
Simon Glass f987177db9 dm: sound: Use the correct number of channels for sound
At present the 'beep' sound generates a waveform for only one channel even
if two are being used. This means that the beep is twice the frequency it
should be. Correct this by making it a parameter.

The fix in a previous commit was correct for sandbox but not for other
boards.

Fixes: 03f11e87a8 ("sound: Correct data output in sound_create_square_wave()")
Signed-off-by: Simon Glass <sjg@chromium.org>
2018-12-13 16:37:10 -07:00

37 lines
798 B
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2012 Samsung Electronics
* R. Chandrasekar <rcsekar@samsung.com>
*/
#include <common.h>
#include <sound.h>
void sound_create_square_wave(uint sample_rate, unsigned short *data, int size,
uint freq, uint channels)
{
const unsigned short amplitude = 16000; /* between 1 and 32767 */
const int period = freq ? sample_rate / 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, j;
for (i = 0; size && i < half; i++) {
size -= 2;
for (j = 0; j < channels; j++)
*data++ = amplitude;
}
for (i = 0; size && i < period - half; i++) {
size -= 2;
for (j = 0; j < channels; j++)
*data++ = -amplitude;
}
}
}