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Input: tsc2007 - make get_pendown_state platform callback optional

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In cases when get_pendown_state callback is not available have
the driver to fallback on pressure calculation to determine if
the pen is up.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Dmitry Torokhov 2009-08-04 22:07:26 -07:00
parent 9e3b25837a
commit d570e9ef84
1 changed files with 93 additions and 79 deletions
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172
drivers/input/touchscreen/tsc2007.c
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@ -70,7 +70,6 @@ struct tsc2007 {
struct input_dev *input;
char phys[32];
struct delayed_work work;
struct ts_event tc;
struct i2c_client *client;
@ -106,51 +105,96 @@ static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
return val;
}
static void tsc2007_send_event(void *tsc)
static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
{
struct tsc2007 *ts = tsc;
u32 rt;
u16 x, y, z1, z2;
/* y- still on; turn on only y+ (and ADC) */
tc->y = tsc2007_xfer(tsc, READ_Y);
x = ts->tc.x;
y = ts->tc.y;
z1 = ts->tc.z1;
z2 = ts->tc.z2;
/* turn y- off, x+ on, then leave in lowpower */
tc->x = tsc2007_xfer(tsc, READ_X);
/* turn y+ off, x- on; we'll use formula #1 */
tc->z1 = tsc2007_xfer(tsc, READ_Z1);
tc->z2 = tsc2007_xfer(tsc, READ_Z2);
/* Prepare for next touch reading - power down ADC, enable PENIRQ */
tsc2007_xfer(tsc, PWRDOWN);
}
static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
{
u32 rt = 0;
/* range filtering */
if (x == MAX_12BIT)
x = 0;
if (tc->x == MAX_12BIT)
tc->x = 0;
if (likely(x && z1)) {
if (likely(tc->x && tc->z1)) {
/* compute touch pressure resistance using equation #1 */
rt = z2;
rt -= z1;
rt *= x;
rt *= ts->x_plate_ohms;
rt /= z1;
rt = tc->z2 - tc->z1;
rt *= tc->x;
rt *= tsc->x_plate_ohms;
rt /= tc->z1;
rt = (rt + 2047) >> 12;
} else
rt = 0;
/*
* Sample found inconsistent by debouncing or pressure is beyond
* the maximum. Don't report it to user space, repeat at least
* once more the measurement
*/
if (rt > MAX_12BIT) {
dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
return;
}
return rt;
}
static void tsc2007_send_up_event(struct tsc2007 *tsc)
{
struct input_dev *input = tsc->input;
dev_dbg(&tsc->client->dev, "UP\n");
input_report_key(input, BTN_TOUCH, 0);
input_report_abs(input, ABS_PRESSURE, 0);
input_sync(input);
}
static void tsc2007_work(struct work_struct *work)
{
struct tsc2007 *ts =
container_of(to_delayed_work(work), struct tsc2007, work);
struct ts_event tc;
u32 rt;
/*
* NOTE: We can't rely on the pressure to determine the pen down
* state, even this controller has a pressure sensor. The pressure
* value can fluctuate for quite a while after lifting the pen and
* in some cases may not even settle at the expected value.
* state, even though this controller has a pressure sensor.
* The pressure value can fluctuate for quite a while after
* lifting the pen and in some cases may not even settle at the
* expected value.
*
* The only safe way to check for the pen up condition is in the
* work function by reading the pen signal state (it's a GPIO and IRQ).
* work function by reading the pen signal state (it's a GPIO
* and IRQ). Unfortunately such callback is not always available,
* in that case we have rely on the pressure anyway.
*/
if (ts->get_pendown_state) {
if (unlikely(!ts->get_pendown_state())) {
tsc2007_send_up_event(ts);
ts->pendown = false;
goto out;
}
dev_dbg(&ts->client->dev, "pen is still down\n");
}
tsc2007_read_values(ts, &tc);
rt = tsc2007_calculate_pressure(ts, &tc);
if (rt > MAX_12BIT) {
/*
* Sample found inconsistent by debouncing or pressure is
* beyond the maximum. Don't report it to user space,
* repeat at least once more the measurement.
*/
dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
goto out;
}
if (rt) {
struct input_dev *input = ts->input;
@ -161,68 +205,38 @@ static void tsc2007_send_event(void *tsc)
ts->pendown = true;
}
input_report_abs(input, ABS_X, x);
input_report_abs(input, ABS_Y, y);
input_report_abs(input, ABS_X, tc.x);
input_report_abs(input, ABS_Y, tc.y);
input_report_abs(input, ABS_PRESSURE, rt);
input_sync(input);
dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
x, y, rt);
}
}
static int tsc2007_read_values(struct tsc2007 *tsc)
{
/* y- still on; turn on only y+ (and ADC) */
tsc->tc.y = tsc2007_xfer(tsc, READ_Y);
/* turn y- off, x+ on, then leave in lowpower */
tsc->tc.x = tsc2007_xfer(tsc, READ_X);
/* turn y+ off, x- on; we'll use formula #1 */
tsc->tc.z1 = tsc2007_xfer(tsc, READ_Z1);
tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2);
/* Prepare for next touch reading - power down ADC, enable PENIRQ */
tsc2007_xfer(tsc, PWRDOWN);
return 0;
}
static void tsc2007_work(struct work_struct *work)
{
struct tsc2007 *ts =
container_of(to_delayed_work(work), struct tsc2007, work);
if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
struct input_dev *input = ts->input;
dev_dbg(&ts->client->dev, "UP\n");
input_report_key(input, BTN_TOUCH, 0);
input_report_abs(input, ABS_PRESSURE, 0);
input_sync(input);
tc.x, tc.y, rt);
} else if (!ts->get_pendown_state && ts->pendown) {
/*
* We don't have callback to check pendown state, so we
* have to assume that since pressure reported is 0 the
* pen was lifted up.
*/
tsc2007_send_up_event(ts);
ts->pendown = false;
enable_irq(ts->irq);
} else {
/* pen is still down, continue with the measurement */
dev_dbg(&ts->client->dev, "pen is still down\n");
tsc2007_read_values(ts);
tsc2007_send_event(ts);
}
out:
if (ts->pendown)
schedule_delayed_work(&ts->work,
msecs_to_jiffies(TS_POLL_PERIOD));
}
else
enable_irq(ts->irq);
}
static irqreturn_t tsc2007_irq(int irq, void *handle)
{
struct tsc2007 *ts = handle;
if (likely(ts->get_pendown_state())) {
if (!ts->get_pendown_state || likely(ts->get_pendown_state())) {
disable_irq_nosync(ts->irq);
schedule_delayed_work(&ts->work,
msecs_to_jiffies(TS_POLL_DELAY));
@ -255,7 +269,7 @@ static int __devinit tsc2007_probe(struct i2c_client *client,
struct input_dev *input_dev;
int err;
if (!pdata || !pdata->get_pendown_state) {
if (!pdata) {
dev_err(&client->dev, "platform data is required!\n");
return -EINVAL;
}