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Commit d570e9ef authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: tsc2007 - make get_pendown_state platform callback optional 



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: default avatarDmitry Torokhov <dtor@mail.ru>
parent 9e3b2583

drivers/input/touchscreen/tsc2007.c

+93 −79
Original line number Diff line number Diff line
@@ -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;

	}