commit ddad0320a8905019a9221df6b2c1ea556bf566de
author Simon Glass <sjg@chromium.org> Thu Nov 15 19:56:13 2018 -0700
committer Simon Glass <sjg@chromium.org> Thu Nov 29 09:30:05 2018 -0700
tree 4afa25f53b27bf4f76cac7e0a80ef8bb1de36242
parent ffefc8d93b3369da7170998d0e934384982f0967

sound: Add sample rate as a parameter for square wave

At present this value is hard-coded in the function that generates a
square wave. Since sample rates vary between different hardware, it makes
more sense to have this as a parameter.

Update the function and its users.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/cpu/sdl.c

diff --git a/arch/sandbox/cpu/sdl.c b/arch/sandbox/cpu/sdl.c
index adcb738..36f1bf0 100644
--- a/arch/sandbox/cpu/sdl.c
+++ b/arch/sandbox/cpu/sdl.c
@@ -322,7 +322,7 @@
 	if (!sdl.audio_active)
 		return -1;
 	sdl.frequency = frequency;
-	sound_create_square_wave((unsigned short *)sdl.audio_data,
+	sound_create_square_wave(22050, (unsigned short *)sdl.audio_data,
 				 sdl.audio_size, frequency);
 	sdl.audio_pos = 0;
 	SDL_PauseAudio(0);

drivers/sound/sound-i2s.c

diff --git a/drivers/sound/sound-i2s.c b/drivers/sound/sound-i2s.c
index 9f09e3b..f0f0b79 100644
--- a/drivers/sound/sound-i2s.c
+++ b/drivers/sound/sound-i2s.c
@@ -185,7 +185,8 @@
 		return -1;
 	}
 
-	sound_create_square_wave((unsigned short *)data,
+	sound_create_square_wave(g_i2stx_pri.samplingrate,
+				 (unsigned short *)data,
 				 data_size / sizeof(unsigned short),
 				 frequency);
 

drivers/sound/sound.c

diff --git a/drivers/sound/sound.c b/drivers/sound/sound.c
index 6c1eb4c..4f0ad0d 100644
--- a/drivers/sound/sound.c
+++ b/drivers/sound/sound.c
@@ -7,11 +7,11 @@
 #include <common.h>
 #include <sound.h>
 
-void sound_create_square_wave(unsigned short *data, int size, uint32_t freq)
+void sound_create_square_wave(uint sample_rate, unsigned short *data, int size,
+			      uint freq)
 {
-	const int sample = 48000;
 	const unsigned short amplitude = 16000; /* between 1 and 32767 */
-	const int period = freq ? sample / freq : 0;
+	const int period = freq ? sample_rate / freq : 0;
 	const int half = period / 2;
 
 	assert(freq);

include/sound.h

diff --git a/include/sound.h b/include/sound.h
index 3269f23..77bfe6a 100644
--- a/include/sound.h
+++ b/include/sound.h
@@ -31,11 +31,13 @@
 /*
  * Generates square wave sound data for 1 second
  *
+ * @param sample_rate   Sample rate in Hz
  * @param data          data buffer pointer
  * @param size          size of the buffer
  * @param freq          frequency of the wave
  */
-void sound_create_square_wave(unsigned short *data, int size, uint32_t freq);
+void sound_create_square_wave(uint sample_rate, unsigned short *data, int size,
+			      uint freq);
 
 /*
  * Initialises audio sub system