sound: x86: Add beeping support in i8254
Adjust the code to allow beeping at different frequencies, using a
calculated value for timer 2.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/lib/i8254.c b/arch/x86/lib/i8254.c
index 1f10124..d022795 100644
--- a/arch/x86/lib/i8254.c
+++ b/arch/x86/lib/i8254.c
@@ -8,8 +8,20 @@
#include <asm/io.h>
#include <asm/i8254.h>
-#define TIMER1_VALUE 18 /* 15.6us */
-#define TIMER2_VALUE 0x0a8e /* 440Hz */
+#define TIMER1_VALUE 18 /* 15.6us */
+#define BEEP_FREQUENCY_HZ 440
+#define SYSCTL_PORTB 0x61
+#define PORTB_BEEP_ENABLE 0x3
+
+static void i8254_set_beep_freq(uint frequency_hz)
+{
+ uint countdown;
+
+ countdown = PIT_TICK_RATE / frequency_hz;
+
+ outb(countdown & 0xff, PIT_BASE + PIT_T2);
+ outb((countdown >> 8) & 0xff, PIT_BASE + PIT_T2);
+}
int i8254_init(void)
{
@@ -29,8 +41,23 @@
*/
outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
PIT_BASE + PIT_COMMAND);
- outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2);
- outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2);
+ i8254_set_beep_freq(BEEP_FREQUENCY_HZ);
return 0;
}
+
+int i8254_enable_beep(uint frequency_hz)
+{
+ if (!frequency_hz)
+ return -EINVAL;
+
+ i8254_set_beep_freq(frequency_hz);
+ setio_8(SYSCTL_PORTB, PORTB_BEEP_ENABLE);
+
+ return 0;
+}
+
+void i8254_disable_beep(void)
+{
+ clrio_8(SYSCTL_PORTB, PORTB_BEEP_ENABLE);
+}