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imx233: rework touchscreen driver

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The old driver didn't behave nicely because it waiting for
stability which could never arrive on some gestures. The new one
uses a fixed delay and averaging.

Change-Id: I8ff80f373b6792e6d5fc3cfe41b709642e61c38b
This commit is contained in:
Amaury Pouly 2013-06-18 15:34:54 +02:00
parent 0173f6edf5
commit 57bb7b2d27
1 changed files with 37 additions and 47 deletions
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84
firmware/target/arm/imx233/touchscreen-imx233.c
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@ -46,28 +46,53 @@ enum touch_state_t
TOUCH_STATE_VERIFY, /* verify touch */
};
#define DEBOUNCE_THRESHOLD 100
#define SAMPLES_THRESHOLD 4
#define NR_SAMPLES 10
#define DELAY 1
static enum touch_state_t touch_state;
static int touch_chan = -1;
static int touch_delay = -1;
static int touch_x, touch_y, nr_samples;
static int touch_x, touch_y;
/* once a touch is confirmed, the parameters are copied to these value for
* instant readout by button code. */
static bool old_touch_detect = false;
static int old_touch_x, old_touch_y;
static void kick_measure(bool pull_x, bool pull_y, bool detect, int lradc_phys)
static void process(void);
void INT_TOUCH_DETECT(void)
{
process();
}
static void touch_channel_irq(int chan)
{
imx233_icoll_enable_interrupt(INT_SRC_LRADC_CHx(chan), false);
imx233_lradc_enable_channel_irq(chan, false);
process();
}
static void kick_measure(bool pull_x, bool pull_y, bool detect, int src)
{
if(touch_chan >= 0)
imx233_lradc_release_channel(touch_chan);
touch_chan = imx233_lradc_acquire_channel(src, TIMEOUT_NOBLOCK);
if(touch_chan < 0)
panicf("touchscreen: cannot get adc channel");
/* enable interrupt */
imx233_lradc_set_channel_irq_callback(touch_chan, &touch_channel_irq);
imx233_icoll_enable_interrupt(INT_SRC_LRADC_CHx(touch_chan), true);
imx233_lradc_enable_channel_irq(touch_chan, true);
/* setup measurement: x- pull down and x+ pull up */
imx233_lradc_setup_touch(pull_x, pull_y, pull_x, pull_y, detect);
imx233_lradc_enable_touch_detect_irq(false);
imx233_lradc_enable_channel_irq(touch_chan, true);
/* measure channel, no accumulation */
imx233_lradc_setup_channel(touch_chan, false, false, 0, lradc_phys);
imx233_lradc_setup_channel(touch_chan, false, true, NR_SAMPLES - 1, src);
imx233_lradc_clear_channel(touch_chan);
/* use a delay */
imx233_lradc_setup_delay(touch_delay, 1 << touch_chan, 0, 0, 8);
imx233_lradc_setup_delay(touch_delay, 1 << touch_chan, 1 << touch_delay,
NR_SAMPLES -1, DELAY);
imx233_lradc_kick_delay(touch_delay);
}
@ -78,7 +103,6 @@ static void enter_state(enum touch_state_t state)
{
case TOUCH_STATE_WAIT:
imx233_lradc_setup_touch(false, false, false, false, true);
imx233_lradc_enable_channel_irq(touch_chan, false);
imx233_lradc_enable_touch_detect_irq(true);
break;
case TOUCH_STATE_MEASURE_X:
@ -95,7 +119,6 @@ static void enter_state(enum touch_state_t state)
static void process(void)
{
int val;
switch(touch_state)
{
case TOUCH_STATE_WAIT:
@ -110,32 +133,12 @@ static void process(void)
}
break;
case TOUCH_STATE_MEASURE_X:
/* read value */
val = imx233_lradc_read_channel(touch_chan);
/* if value is too far from average, restart */
if(nr_samples > 0 && abs(val - touch_x) > DEBOUNCE_THRESHOLD)
nr_samples = 0;
touch_x = (touch_x * nr_samples + val) / (nr_samples + 1);
nr_samples++;
/* if we have enough samples, measure Y */
if(nr_samples > SAMPLES_THRESHOLD)
enter_state(TOUCH_STATE_MEASURE_Y);
else
imx233_lradc_kick_delay(touch_delay);
touch_x = imx233_lradc_read_channel(touch_chan) / NR_SAMPLES;
enter_state(TOUCH_STATE_MEASURE_Y);
break;
case TOUCH_STATE_MEASURE_Y:
/* read value */
val = imx233_lradc_read_channel(touch_chan);
/* if value is too far from average, restart */
if(nr_samples > 0 && abs(val - touch_y) > DEBOUNCE_THRESHOLD)
nr_samples = 0;
touch_y = (touch_y * nr_samples + val) / (nr_samples + 1);
nr_samples++;
/* if we have enough samples, verify touch */
if(nr_samples > SAMPLES_THRESHOLD)
touch_y = imx233_lradc_read_channel(touch_chan) / NR_SAMPLES;
enter_state(TOUCH_STATE_VERIFY);
else
imx233_lradc_kick_delay(touch_delay);
break;
case TOUCH_STATE_VERIFY:
if(imx233_lradc_read_touch_detect())
@ -154,31 +157,18 @@ static void process(void)
}
}
void INT_TOUCH_DETECT(void)
{
process();
}
static void touch_channel_irq(int chan)
{
(void) chan;
process();
}
void imx233_touchscreen_init(void)
{
touch_chan = imx233_lradc_acquire_channel(LRADC_SRC_XPLUS, TIMEOUT_NOBLOCK);
touch_delay = imx233_lradc_acquire_delay(TIMEOUT_NOBLOCK);
if(touch_chan < 0 || touch_delay < 0)
if(touch_delay < 0)
panicf("Cannot acquire channel and delays for touchscreen measurement");
imx233_touchscreen_enable(false);
}
void imx233_touchscreen_enable(bool enable)
{
enter_state(TOUCH_STATE_WAIT);
imx233_lradc_set_channel_irq_callback(touch_chan, &touch_channel_irq);
imx233_icoll_enable_interrupt(INT_SRC_LRADC_CHx(touch_chan), enable);
if(enable)
enter_state(TOUCH_STATE_WAIT);
imx233_icoll_enable_interrupt(INT_SRC_TOUCH_DETECT, enable);
}