[PATCH v3] touchscreen: tps6507x-ts: only poll while touch event is occurring

[jon@ringle.org]

From: Jon Ringle <jringle@gridpoint.com>

(Resending without corporate dislaimer in email footer)

We only need to poll for touch events after an interrupt occurs due to the
user touching the screen. We continue to poll until the user stops touching
the screen

Signed-off-by: Jon Ringle <jringle@gridpoint.com>
---
 drivers/input/touchscreen/tps6507x-ts.c | 189 +++++++++++++++++++++++++-------
 include/linux/input/tps6507x-ts.h       |   1 +
 include/linux/mfd/tps6507x.h            |   1 +
 3 files changed, 151 insertions(+), 40 deletions(-)

diff --git a/drivers/input/touchscreen/tps6507x-ts.c b/drivers/input/touchscreen/tps6507x-ts.c
index 94cde2c..c051419 100644
--- a/drivers/input/touchscreen/tps6507x-ts.c
+++ b/drivers/input/touchscreen/tps6507x-ts.c
@@ -17,11 +17,14 @@
 #include <linux/workqueue.h>
 #include <linux/slab.h>
 #include <linux/input.h>
-#include <linux/input-polldev.h>
 #include <linux/platform_device.h>
 #include <linux/mfd/tps6507x.h>
 #include <linux/input/tps6507x-ts.h>
 #include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
 
 #define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
 #define TPS_DEFAULT_MIN_PRESSURE 0x30
@@ -39,13 +42,17 @@ struct ts_event {
 };
 
 struct tps6507x_ts {
+	struct input_dev	*input_dev;
 	struct device		*dev;
-	struct input_polled_dev	*poll_dev;
 	struct tps6507x_dev	*mfd;
 	char			phys[32];
+	struct delayed_work	work;
 	struct ts_event		tc;
+	int			irq;
+	unsigned long		poll_period;	/* ms */
 	u16			min_pressure;
 	bool			pendown;
+	int			open_count;
 };
 
 static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
@@ -155,13 +162,20 @@ static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
 	return ret;
 }
 
-static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
+static void tps6507x_ts_handler(struct work_struct *work)
 {
-	struct tps6507x_ts *tsc = poll_dev->private;
-	struct input_dev *input_dev = poll_dev->input;
+	struct tps6507x_ts *tsc =  container_of(work, struct tps6507x_ts, work.work);
+	struct input_dev *input_dev = tsc->input_dev;
 	bool pendown;
+	int schd;
+	int poll = 0;
 	s32 ret;
 
+	if (tsc->irq) {
+		// Disable the touch interrupt
+		tps6507x_write_u8(tsc, TPS6507X_REG_INT, 0);
+	}
+
 	ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
 				      &tsc->tc.pressure);
 	if (ret)
@@ -178,10 +192,11 @@ static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
 	}
 
 	if (pendown) {
+		int report_pendown = 0;
 
 		if (!tsc->pendown) {
 			dev_dbg(tsc->dev, "DOWN\n");
-			input_report_key(input_dev, BTN_TOUCH, 1);
+			report_pendown = 1;
 		} else
 			dev_dbg(tsc->dev, "still down\n");
 
@@ -195,15 +210,86 @@ static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
 		if (ret)
 			goto done;
 
-		input_report_abs(input_dev, ABS_X, tsc->tc.x);
-		input_report_abs(input_dev, ABS_Y, tsc->tc.y);
-		input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
-		input_sync(input_dev);
-		tsc->pendown = true;
+		if (tsc->tc.x && tsc->tc.y) {
+			if (report_pendown)
+				input_report_key(input_dev, BTN_TOUCH, 1);
+
+			input_report_abs(input_dev, ABS_X, tsc->tc.x);
+			input_report_abs(input_dev, ABS_Y, tsc->tc.y);
+			input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
+			input_sync(input_dev);
+			tsc->pendown = true;
+		} else {
+			dev_dbg(tsc->dev, "discarding bogus read x=%d, y=%d, pressure=%d\n", tsc->tc.x, tsc->tc.y, tsc->tc.pressure);
+		}
+		poll = 1;
 	}
 
 done:
 	tps6507x_adc_standby(tsc);
+	if (tsc->irq && !poll) {
+		// Re-enable the interrupt
+		tps6507x_write_u8(tsc, TPS6507X_REG_INT, TPS6507X_REG_MASK_TSC);
+	} else {
+		/* always poll if not using interrupts */
+		schd = schedule_delayed_work(&tsc->work,
+					     msecs_to_jiffies(tsc->poll_period));
+	}
+}
+
+static irqreturn_t tps6507x_ts_irq(int irq, void * dev_id)
+{
+	struct tps6507x_ts * tsc = (struct tps6507x_ts *)dev_id;
+
+	schedule_delayed_work(&tsc->work, 0);
+
+	return IRQ_HANDLED;
+}
+
+static int tps6507x_ts_open(struct input_dev *input_dev)
+{
+	int ret;
+	struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
+
+	tsc->open_count++;
+
+	if (tsc->irq) {
+
+		tps6507x_write_u8(tsc, TPS6507X_REG_INT, 0);
+		tps6507x_adc_standby(tsc);
+
+		ret = request_irq(tsc->irq,tps6507x_ts_irq, 0, "TPS6507x",tsc);
+
+		if(ret < 0) {
+			tsc->open_count--;
+			dev_err(tsc->dev, "cannot register irq");
+			return ret;
+		}
+		// Enable the touch event interrupt
+		tps6507x_write_u8(tsc, TPS6507X_REG_INT, TPS6507X_REG_MASK_TSC);
+	} else {
+		ret = schedule_delayed_work(&tsc->work,
+					    msecs_to_jiffies(tsc->poll_period));
+
+		if (!ret) {
+			tsc->open_count--;
+			dev_err(tsc->dev, "schedule failed");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+static void tps6507x_ts_close(struct input_dev *input_dev)
+{
+	struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
+
+	tsc->open_count--;
+
+	if(tsc->irq) {
+		free_irq(tsc->irq,tsc);
+	}
 }
 
 static int tps6507x_ts_probe(struct platform_device *pdev)
@@ -212,8 +298,8 @@ static int tps6507x_ts_probe(struct platform_device *pdev)
 	const struct tps6507x_board *tps_board;
 	const struct touchscreen_init_data *init_data;
 	struct tps6507x_ts *tsc;
-	struct input_polled_dev *poll_dev;
 	struct input_dev *input_dev;
+	int schd;
 	int error;
 
 	/*
@@ -239,29 +325,18 @@ static int tps6507x_ts_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
+	tps6507x_dev->ts = tsc;
 	tsc->mfd = tps6507x_dev;
 	tsc->dev = tps6507x_dev->dev;
-	tsc->min_pressure = init_data ?
-			init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
-
-	snprintf(tsc->phys, sizeof(tsc->phys),
-		 "%s/input0", dev_name(tsc->dev));
-
-	poll_dev = input_allocate_polled_device();
-	if (!poll_dev) {
-		dev_err(tsc->dev, "Failed to allocate polled input device.\n");
+	input_dev = input_allocate_device();
+	if (!input_dev) {
+		dev_err(tsc->dev, "Failed to allocate input device.\n");
 		error = -ENOMEM;
 		goto err_free_mem;
 	}
 
-	tsc->poll_dev = poll_dev;
-
-	poll_dev->private = tsc;
-	poll_dev->poll = tps6507x_ts_poll;
-	poll_dev->poll_interval = init_data ?
-			init_data->poll_period : TSC_DEFAULT_POLL_PERIOD;
-
-	input_dev = poll_dev->input;
+	input_dev->open = tps6507x_ts_open;
+	input_dev->close = tps6507x_ts_close;
 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 
@@ -270,42 +345,76 @@ static int tps6507x_ts_probe(struct platform_device *pdev)
 	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
 
 	input_dev->name = "TPS6507x Touchscreen";
-	input_dev->phys = tsc->phys;
-	input_dev->dev.parent = tsc->dev;
 	input_dev->id.bustype = BUS_I2C;
+	input_dev->dev.parent = tsc->dev;
+
+	snprintf(tsc->phys, sizeof(tsc->phys),
+		 "%s/input0", dev_name(tsc->dev));
+	input_dev->phys = tsc->phys;
+
+	dev_dbg(tsc->dev, "device: %s\n", input_dev->phys);
+
+	input_set_drvdata(input_dev, tsc);
+
+	tsc->input_dev = input_dev;
+
+	INIT_DELAYED_WORK(&tsc->work, tps6507x_ts_handler);
 	if (init_data) {
+		tsc->poll_period = init_data->poll_period;
+		tsc->irq = gpio_to_irq(init_data->irq_pin);
+		tsc->min_pressure = init_data->min_pressure;
 		input_dev->id.vendor = init_data->vendor;
 		input_dev->id.product = init_data->product;
 		input_dev->id.version = init_data->version;
+	} else {
+		tsc->poll_period = TSC_DEFAULT_POLL_PERIOD;
+		tsc->min_pressure = TPS_DEFAULT_MIN_PRESSURE;
 	}
 
 	error = tps6507x_adc_standby(tsc);
 	if (error)
-		goto err_free_polled_dev;
+		goto err_free_dev;
 
-	error = input_register_polled_device(poll_dev);
+	error = input_register_device(input_dev);
 	if (error)
-		goto err_free_polled_dev;
+		goto err_free_dev;
+
+	if (!tsc->irq) {
+		schd = schedule_delayed_work(&tsc->work,
+					     msecs_to_jiffies(tsc->poll_period));
+
+		if (!schd) {
+			dev_err(tsc->dev, "schedule failed");
+			goto err_cancel_work;
+		}
+	}
 
 	platform_set_drvdata(pdev, tsc);
 
 	return 0;
 
-err_free_polled_dev:
-	input_free_polled_device(poll_dev);
+err_cancel_work:
+	cancel_delayed_work_sync(&tsc->work);
+err_free_dev:
+	input_free_device(input_dev);
 err_free_mem:
 	kfree(tsc);
+	tps6507x_dev->ts = NULL;
+
 	return error;
 }
 
 static int tps6507x_ts_remove(struct platform_device *pdev)
 {
-	struct tps6507x_ts *tsc = platform_get_drvdata(pdev);
-	struct input_polled_dev *poll_dev = tsc->poll_dev;
+	struct tps6507x_dev *tps6507x_dev = platform_get_drvdata(pdev);
+	struct tps6507x_ts *tsc = tps6507x_dev->ts;
+	struct input_dev *input_dev = tsc->input_dev;
+
+	cancel_delayed_work_sync(&tsc->work);
 
-	input_unregister_polled_device(poll_dev);
-	input_free_polled_device(poll_dev);
+	input_unregister_device(input_dev);
 
+	tps6507x_dev->ts = NULL;
 	kfree(tsc);
 
 	return 0;
diff --git a/include/linux/input/tps6507x-ts.h b/include/linux/input/tps6507x-ts.h
index b433df8..3c5aa7b 100644
--- a/include/linux/input/tps6507x-ts.h
+++ b/include/linux/input/tps6507x-ts.h
@@ -14,6 +14,7 @@
 /* Board specific touch screen initial values */
 struct touchscreen_init_data {
 	int	poll_period;	/* ms */
+	int	irq_pin;
 	__u16	min_pressure;	/* min reading to be treated as a touch */
 	__u16	vendor;
 	__u16	product;
diff --git a/include/linux/mfd/tps6507x.h b/include/linux/mfd/tps6507x.h
index c2ae569..c923e486 100644
--- a/include/linux/mfd/tps6507x.h
+++ b/include/linux/mfd/tps6507x.h
@@ -163,6 +163,7 @@ struct tps6507x_dev {
 
 	/* Client devices */
 	struct tps6507x_pmic *pmic;
+	struct tps6507x_ts *ts;
 };
 
 #endif /*  __LINUX_MFD_TPS6507X_H */
-- 
1.8.5.4