Input: tsc2005 - add open/close

Introduce open and close methods for the input device to keep the device
powered down when it is not in use. Also rework interaction between
interrupt thread and starting/shutting off/resetting the device: instead
of taking a mutex in the intterrupt thread and elsewhere disable interrupts
before transitioning the device in a new state.

The ESD handling is also separated from the IRQ thread; we poll regularly
at a given interval and simply skip reads if we see that valid interrupt
happened not so long ago. This allows us not cancel and reschedule ESD
work from interrupt context all the time.
Tested-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/touchscreen/tsc2005.c

@@ -133,13 +133,14 @@ struct tsc2005 {
 	struct timer_list	penup_timer;
 
 	unsigned int		esd_timeout;
-	struct timer_list	esd_timer;
-	struct work_struct	esd_work;
+	struct delayed_work	esd_work;
+	unsigned long		last_valid_interrupt;
 
 	unsigned int		x_plate_ohm;
 
 	bool			disabled;
-	unsigned int		disable_depth;
+	bool			opened;
+	bool			suspended;
 
 	bool			pen_down;
 
@@ -258,11 +259,6 @@ static irqreturn_t tsc2005_irq_thread(int irq, void *_ts)
 	u32 z1, z2;
 	int error;
 
-	mutex_lock(&ts->mutex);
-
-	if (unlikely(ts->disable_depth))
-		goto out;
-
 	/* read the coordinates */
 	error = spi_sync(ts->spi, &ts->spi_read_msg);
 	if (unlikely(error))
@@ -309,21 +305,13 @@ static irqreturn_t tsc2005_irq_thread(int irq, void *_ts)
 	spin_lock_irqsave(&ts->lock, flags);
 
 	tsc2005_update_pen_state(ts, x, y, pressure);
-
-	/* set the penup timer */
 	mod_timer(&ts->penup_timer,
 		  jiffies + msecs_to_jiffies(TSC2005_PENUP_TIME_MS));
 
-	if (ts->esd_timeout && ts->set_reset) {
-		/* update the watchdog timer */
-		mod_timer(&ts->esd_timer, round_jiffies(jiffies +
-					msecs_to_jiffies(ts->esd_timeout)));
-	}
-
 	spin_unlock_irqrestore(&ts->lock, flags);
 
+	ts->last_valid_interrupt = jiffies;
 out:
-	mutex_unlock(&ts->mutex);
 	return IRQ_HANDLED;
 }
 
@@ -350,29 +338,31 @@ static void tsc2005_stop_scan(struct tsc2005 *ts)
 	tsc2005_cmd(ts, TSC2005_CMD_STOP);
 }
 
-/* must be called with mutex held */
-static void tsc2005_disable(struct tsc2005 *ts)
+/* must be called with ts->mutex held */
+static void __tsc2005_disable(struct tsc2005 *ts)
 {
-	if (ts->disable_depth++ != 0)
-		return;
+	tsc2005_stop_scan(ts);
+
 	disable_irq(ts->spi->irq);
-	if (ts->esd_timeout)
-		del_timer_sync(&ts->esd_timer);
 	del_timer_sync(&ts->penup_timer);
-	tsc2005_stop_scan(ts);
+
+	cancel_delayed_work_sync(&ts->esd_work);
+
+	enable_irq(ts->spi->irq);
 }
 
-/* must be called with mutex held */
-static void tsc2005_enable(struct tsc2005 *ts)
+/* must be called with ts->mutex held */
+static void __tsc2005_enable(struct tsc2005 *ts)
 {
-	if (--ts->disable_depth != 0)
-		return;
 	tsc2005_start_scan(ts);
-	enable_irq(ts->spi->irq);
-	if (!ts->esd_timeout)
-		return;
-	mod_timer(&ts->esd_timer,
-		  round_jiffies(jiffies + msecs_to_jiffies(ts->esd_timeout)));
+
+	if (ts->esd_timeout && ts->set_reset) {
+		ts->last_valid_interrupt = jiffies;
+		schedule_delayed_work(&ts->esd_work,
+				round_jiffies(jiffies +
+					msecs_to_jiffies(ts->esd_timeout)));
+	}
+
 }
 
 static ssize_t tsc2005_disable_show(struct device *dev,
@@ -390,23 +380,29 @@ static ssize_t tsc2005_disable_store(struct device *dev,
 {
 	struct spi_device *spi = to_spi_device(dev);
 	struct tsc2005 *ts = spi_get_drvdata(spi);
-	unsigned long res;
-	int i;
+	unsigned long val;
+	int error;
 
-	if (strict_strtoul(buf, 10, &res) < 0)
-		return -EINVAL;
-	i = res ? 1 : 0;
+	error = strict_strtoul(buf, 10, &val);
+	if (error)
+		return error;
 
 	mutex_lock(&ts->mutex);
-	if (i == ts->disabled)
-		goto out;
-	ts->disabled = i;
-	if (i)
-		tsc2005_disable(ts);
-	else
-		tsc2005_enable(ts);
-out:
+
+	if (!ts->suspended && ts->opened) {
+		if (val) {
+			if (!ts->disabled)
+				__tsc2005_disable(ts);
+		} else {
+			if (ts->disabled)
+				__tsc2005_enable(ts);
+		}
+	}
+
+	ts->disabled = !!val;
+
 	mutex_unlock(&ts->mutex);
+
 	return count;
 }
 static DEVICE_ATTR(disable, 0664, tsc2005_disable_show, tsc2005_disable_store);
@@ -428,7 +424,7 @@ static ssize_t tsc2005_selftest_show(struct device *dev,
 	/*
 	 * Test TSC2005 communications via temp high register.
 	 */
-	tsc2005_disable(ts);
+	__tsc2005_disable(ts);
 
 	error = tsc2005_read(ts, TSC2005_REG_TEMP_HIGH, &temp_high_orig);
 	if (error) {
@@ -484,7 +480,7 @@ static ssize_t tsc2005_selftest_show(struct device *dev,
 	}
 
 out:
-	tsc2005_enable(ts);
+	__tsc2005_enable(ts);
 	mutex_unlock(&ts->mutex);
 
 	return sprintf(buf, "%d\n", success);
@@ -519,44 +515,79 @@ static const struct attribute_group tsc2005_attr_group = {
 	.attrs		= tsc2005_attrs,
 };
 
-static void tsc2005_esd_timer(unsigned long data)
-{
-	struct tsc2005 *ts = (struct tsc2005 *)data;
-
-	schedule_work(&ts->esd_work);
-}
-
 static void tsc2005_esd_work(struct work_struct *work)
 {
-	struct tsc2005 *ts = container_of(work, struct tsc2005, esd_work);
+	struct tsc2005 *ts = container_of(work, struct tsc2005, esd_work.work);
 	int error;
 	u16 r;
 
 	mutex_lock(&ts->mutex);
 
-	if (ts->disable_depth)
+	if (time_is_after_jiffies(ts->last_valid_interrupt +
+				  msecs_to_jiffies(ts->esd_timeout)))
 		goto out;
 
-	/*
-	 * If we cannot read our known value from configuration register 0 then
-	 * reset the controller as if from power-up and start scanning again.
-	 */
+	/* We should be able to read register without disabling interrupts. */
 	error = tsc2005_read(ts, TSC2005_REG_CFR0, &r);
-	if (error ||
-	    ((r ^ TSC2005_CFR0_INITVALUE) & TSC2005_CFR0_RW_MASK)) {
-		dev_info(&ts->spi->dev, "TSC2005 not responding - resetting\n");
-		ts->set_reset(false);
-		tsc2005_update_pen_state(ts, 0, 0, 0);
-		usleep_range(100, 500); /* only 10us required */
-		ts->set_reset(true);
-		tsc2005_start_scan(ts);
+	if (!error &&
+	    !((r ^ TSC2005_CFR0_INITVALUE) & TSC2005_CFR0_RW_MASK)) {
+		goto out;
 	}
 
-	/* re-arm the watchdog */
-	mod_timer(&ts->esd_timer,
-		  round_jiffies(jiffies + msecs_to_jiffies(ts->esd_timeout)));
+	/*
+	 * If we could not read our known value from configuration register 0
+	 * then we should reset the controller as if from power-up and start
+	 * scanning again.
+	 */
+	dev_info(&ts->spi->dev, "TSC2005 not responding - resetting\n");
+
+	disable_irq(ts->spi->irq);
+	del_timer_sync(&ts->penup_timer);
+
+	tsc2005_update_pen_state(ts, 0, 0, 0);
+
+	ts->set_reset(false);
+	usleep_range(100, 500); /* only 10us required */
+	ts->set_reset(true);
+
+	enable_irq(ts->spi->irq);
+	tsc2005_start_scan(ts);
 
 out:
+	/* re-arm the watchdog */
+	schedule_delayed_work(&ts->esd_work,
+			      round_jiffies(jiffies +
+					msecs_to_jiffies(ts->esd_timeout)));
+	mutex_unlock(&ts->mutex);
+}
+
+static int tsc2005_open(struct input_dev *input)
+{
+	struct tsc2005 *ts = input_get_drvdata(input);
+
+	mutex_lock(&ts->mutex);
+
+	if (!ts->suspended && !ts->disabled)
+		__tsc2005_enable(ts);
+
+	ts->opened = true;
+
+	mutex_unlock(&ts->mutex);
+
+	return 0;
+}
+
+static void tsc2005_close(struct input_dev *input)
+{
+	struct tsc2005 *ts = input_get_drvdata(input);
+
+	mutex_lock(&ts->mutex);
+
+	if (!ts->suspended && !ts->disabled)
+		__tsc2005_disable(ts);
+
+	ts->opened = false;
+
 	mutex_unlock(&ts->mutex);
 }
 
@@ -628,8 +659,7 @@ static int __devinit tsc2005_probe(struct spi_device *spi)
 	spin_lock_init(&ts->lock);
 	setup_timer(&ts->penup_timer, tsc2005_penup_timer, (unsigned long)ts);
 
-	setup_timer(&ts->esd_timer, tsc2005_esd_timer, (unsigned long)ts);
-	INIT_WORK(&ts->esd_work, tsc2005_esd_work);
+	INIT_DELAYED_WORK(&ts->esd_work, tsc2005_esd_work);
 
 	tsc2005_setup_spi_xfer(ts);
 
@@ -647,6 +677,14 @@ static int __devinit tsc2005_probe(struct spi_device *spi)
 	input_set_abs_params(input_dev, ABS_Y, 0, max_y, fudge_y, 0);
 	input_set_abs_params(input_dev, ABS_PRESSURE, 0, max_p, fudge_p, 0);
 
+	input_dev->open = tsc2005_open;
+	input_dev->close = tsc2005_close;
+
+	input_set_drvdata(input_dev, ts);
+
+	/* Ensure the touchscreen is off */
+	tsc2005_stop_scan(ts);
+
 	error = request_threaded_irq(spi->irq, NULL, tsc2005_irq_thread,
 				     IRQF_TRIGGER_RISING, "tsc2005", ts);
 	if (error) {
@@ -669,14 +707,6 @@ static int __devinit tsc2005_probe(struct spi_device *spi)
 		goto err_remove_sysfs;
 	}
 
-	tsc2005_start_scan(ts);
-
-	if (ts->esd_timeout && ts->set_reset) {
-		/* start the optional ESD watchdog */
-		mod_timer(&ts->esd_timer, round_jiffies(jiffies +
-					msecs_to_jiffies(ts->esd_timeout)));
-	}
-
 	set_irq_wake(spi->irq, 1);
 	return 0;
 
@@ -697,16 +727,6 @@ static int __devexit tsc2005_remove(struct spi_device *spi)
 
 	sysfs_remove_group(&ts->spi->dev.kobj, &tsc2005_attr_group);
 
-	mutex_lock(&ts->mutex);
-	tsc2005_disable(ts);
-	mutex_unlock(&ts->mutex);
-
-	if (ts->esd_timeout)
-		del_timer_sync(&ts->esd_timer);
-	del_timer_sync(&ts->penup_timer);
-
-	flush_work(&ts->esd_work);
-
 	free_irq(ts->spi->irq, ts);
 	input_unregister_device(ts->idev);
 	kfree(ts);
@@ -722,7 +742,12 @@ static int tsc2005_suspend(struct device *dev)
 	struct tsc2005 *ts = spi_get_drvdata(spi);
 
 	mutex_lock(&ts->mutex);
-	tsc2005_disable(ts);
+
+	if (!ts->suspended && !ts->disabled && ts->opened)
+		__tsc2005_disable(ts);
+
+	ts->suspended = true;
+
 	mutex_unlock(&ts->mutex);
 
 	return 0;
@@ -734,7 +759,12 @@ static int tsc2005_resume(struct device *dev)
 	struct tsc2005 *ts = spi_get_drvdata(spi);
 
 	mutex_lock(&ts->mutex);
-	tsc2005_enable(ts);
+
+	if (ts->suspended && !ts->disabled && ts->opened)
+		__tsc2005_enable(ts);
+
+	ts->suspended = false;
+
 	mutex_unlock(&ts->mutex);
 
 	return 0;