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Gigabeat S: Improve headphone thread implementation.

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Implement scanning as binary tree in array.

Make the ADC calls fewer without compromising read quality.

Declare the thread function as 'noreturn' to save some stack. Reduce
stack size (regardless, % use is now a bit lower).

Change-Id: I239792fd2a0a2c019d1ec4af1d6d4b466cdf0ef5
This commit is contained in:
Michael Sevakis 2013-08-31 22:18:19 -04:00
parent c64b59fc5e
commit 669fa9a130
1 changed files with 51 additions and 78 deletions
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131
firmware/target/arm/imx31/gigabeat-s/headphone-gigabeat-s.c
View file

@ -31,87 +31,65 @@
static struct semaphore headphone_wakeup;
static unsigned int headphone_thread_id;
static int headphone_stack[200/sizeof(int)]; /* Not much stack needed */
static unsigned int headphone_stack[176/sizeof(int)]; /* Little stack needed */
static const char * const headphone_thread_name = "headphone";
static bool headphones_detect = false;
/* Convert ADC reading into a button value. */
static int adc_data_to_button(unsigned int data)
{
int btn = BUTTON_NONE;
/* _______370_______
* ___149___ ___675___
* ___64__ __252__ __505__ __870__
* x PLAY DSP REW FF VOL+ VOL- x
*
* Child nodes are at 2*n and 2*n+1 per usual bintree array representation
*/
static const unsigned int button_tree[16] =
{
[ 0] = 0,
[ 1] = 370,
[ 2] = 149,
[ 3] = 675,
[ 4] = 64,
[ 5] = 252,
[ 6] = 505,
[ 7] = 870,
[ 8] = BUTTON_NONE,
[ 9] = BUTTON_RC_PLAY,
[10] = BUTTON_RC_DSP,
[11] = BUTTON_RC_REW,
[12] = BUTTON_RC_FF,
[13] = BUTTON_RC_VOL_UP,
[14] = BUTTON_RC_VOL_DOWN,
[15] = BUTTON_NONE,
};
if (data < 505)
{
if (data < 252)
{
if (data < 149)
{
if (data >= 64)
{
/* Play/Pause */
btn = BUTTON_RC_PLAY;
}
/* else headphone direct */
}
else
{
/* DSP */
btn = BUTTON_RC_DSP;
}
}
else
{
if (data < 370)
{
/* RW */
btn = BUTTON_RC_REW;
}
else
{
/* FF */
btn = BUTTON_RC_FF;
}
}
}
else
{
if (data < 870)
{
if (data < 675)
{
/* Vol + */
btn = BUTTON_RC_VOL_UP;
}
else
{
/* Vol - */
btn = BUTTON_RC_VOL_DOWN;
}
}
#if 0
else
{
int i, button;
if (data < 951)
{
/* No buttons */
}
else
{
/* Not inserted */
asm volatile (
"ldr %0, [%2, #1*4] \n" /* button = button_tree[1] */
"mov %1, #1 \n" /* i = 1 */
"cmp %3, %0 \n" /* C=1 if data > button */
"adc %1, %1, %1 \n" /* i = 2*n + C */
"ldr %0, [%2, %1, lsl #2] \n" /* button = button_tree[i] */
"cmp %3, %0 \n" /* C=1 if data > button */
"adc %1, %1, %1 \n" /* i = 2*n + C */
"ldr %0, [%2, %1, lsl #2] \n" /* button = button_tree[i] */
"cmp %3, %0 \n" /* C=1 if data > button */
"adc %1, %1, %1 \n" /* i = 2*n + C */
"ldr %0, [%2, %1, lsl #2] \n" /* button = button_tree[i] */
: "=&r"(button), "=&r"(i)
: "r"(button_tree), "r"(data));
}
}
#endif
return button;
}
return btn;
}
static void headphone_thread(void)
static void NORETURN_ATTR headphone_thread(void)
{
int headphone_sleep_countdown = 0;
int headphone_wait_timeout = TIMEOUT_BLOCK;
int last_btn = BUTTON_NONE;
while (1)
{
@ -123,15 +101,10 @@ static void headphone_thread(void)
if (headphone_sleep_countdown <= 0)
{
/* Polling ADC */
int btn, btn2;
btn = adc_data_to_button(data);
sleep(HZ/50);
data = adc_read(ADC_HPREMOTE);
btn2 = adc_data_to_button(data);
if (btn != btn2)
int btn = adc_data_to_button(data);
if (btn != last_btn)
{
last_btn = btn;
/* If the buttons dont agree twice in a row, then it's
* none (from meg-fx remote reader). */
btn = BUTTON_NONE;
@ -154,11 +127,12 @@ static void headphone_thread(void)
/* Cancel any buttons if jack readings are unstable. */
button_headphone_set(BUTTON_NONE);
last_btn = BUTTON_NONE;
if (data >= 64 && data <= 951)
{
/* Should be a remote control - accelerate */
headphone_wait_timeout = HZ/20-HZ/50;
headphone_wait_timeout = HZ/25;
headphone_sleep_countdown = 0;
}
else if (rc == OBJ_WAIT_SUCCEEDED)
@ -187,7 +161,7 @@ bool headphones_inserted(void)
void INIT_ATTR headphone_init(void)
{
/* A thread is required to monitor the remote ADC and jack state. */
semaphore_init(&headphone_wakeup, 1, 0);
semaphore_init(&headphone_wakeup, 1, 1);
headphone_thread_id = create_thread(headphone_thread,
headphone_stack,
sizeof(headphone_stack),
@ -195,7 +169,6 @@ void INIT_ATTR headphone_init(void)
IF_PRIO(, PRIORITY_REALTIME)
IF_COP(, CPU));
/* Initially poll and then enable PMIC event */
headphone_detect_event();
/* Enable PMIC event */
mc13783_enable_event(MC13783_ONOFD2_EVENT, true);
}