[PATCH v2 4/5] Input: mpr121: Add polling mode

[Michal Vokáč <michal.vokac@xxxxxxxxx>]

In case the interrupt line is not available, polling can be used
to read out the state of the keys. Period of the polling needs to
be configured by the poll-interval DT property.

Signed-off-by: Michal Vokáč <michal.vokac@xxxxxxxxx>
---
Changes since v1:
 - Use poll-interval property name instead of linux,poll-interval.

 drivers/input/keyboard/mpr121_touchkey.c | 69 +++++++++++++++++++++++---------
 1 file changed, 51 insertions(+), 18 deletions(-)

diff --git a/drivers/input/keyboard/mpr121_touchkey.c b/drivers/input/keyboard/mpr121_touchkey.c
index ee80de44ce3f..40d6e5087cde 100644
--- a/drivers/input/keyboard/mpr121_touchkey.c
+++ b/drivers/input/keyboard/mpr121_touchkey.c
@@ -54,6 +54,9 @@
 /* MPR121 has 12 keys */
 #define MPR121_MAX_KEY_COUNT		12
 
+#define MPR121_MIN_POLL_INTERVAL	10
+#define MPR121_MAX_POLL_INTERVAL	200
+
 struct mpr121_touchkey {
 	struct i2c_client	*client;
 	struct input_dev	*input_dev;
@@ -115,11 +118,11 @@ static struct regulator *mpr121_vdd_supply_init(struct device *dev)
 	return vdd_supply;
 }
 
-static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
+static void mpr_touchkey_report(struct input_dev *dev)
 {
-	struct mpr121_touchkey *mpr121 = dev_id;
-	struct i2c_client *client = mpr121->client;
+	struct mpr121_touchkey *mpr121 = input_get_drvdata(dev);
 	struct input_dev *input = mpr121->input_dev;
+	struct i2c_client *client = mpr121->client;
 	unsigned long bit_changed;
 	unsigned int key_num;
 	int reg;
@@ -127,14 +130,14 @@ static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
 	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
 	if (reg < 0) {
 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
-		goto out;
+		return;
 	}
 
 	reg <<= 8;
 	reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
 	if (reg < 0) {
 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
-		goto out;
+		return;
 	}
 
 	reg &= TOUCH_STATUS_MASK;
@@ -155,8 +158,14 @@ static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
 
 	}
 	input_sync(input);
+}
+
+static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
+{
+	struct mpr121_touchkey *mpr121 = dev_id;
+
+	mpr_touchkey_report(mpr121->input_dev);
 
-out:
 	return IRQ_HANDLED;
 }
 
@@ -229,14 +238,10 @@ static int mpr_touchkey_probe(struct i2c_client *client,
 	int vdd_uv;
 	struct mpr121_touchkey *mpr121;
 	struct input_dev *input_dev;
+	u32 poll_interval = 0;
 	int error;
 	int i;
 
-	if (!client->irq) {
-		dev_err(dev, "irq number should not be zero\n");
-		return -EINVAL;
-	}
-
 	vdd_supply = mpr121_vdd_supply_init(dev);
 	if (IS_ERR(vdd_supply))
 		return PTR_ERR(vdd_supply);
@@ -274,6 +279,7 @@ static int mpr_touchkey_probe(struct i2c_client *client,
 	if (device_property_read_bool(dev, "autorepeat"))
 		__set_bit(EV_REP, input_dev->evbit);
 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
+	input_set_drvdata(input_dev, mpr121);
 
 	input_dev->keycode = mpr121->keycodes;
 	input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
@@ -288,13 +294,40 @@ static int mpr_touchkey_probe(struct i2c_client *client,
 		return error;
 	}
 
-	error = devm_request_threaded_irq(dev, client->irq, NULL,
-					  mpr_touchkey_interrupt,
-					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
-					  dev->driver->name, mpr121);
-	if (error) {
-		dev_err(dev, "Failed to register interrupt\n");
-		return error;
+	device_property_read_u32(dev, "poll-interval", &poll_interval);
+
+	if (client->irq) {
+		error = devm_request_threaded_irq(dev, client->irq, NULL,
+						  mpr_touchkey_interrupt,
+						  IRQF_TRIGGER_FALLING |
+						  IRQF_ONESHOT,
+						  dev->driver->name, mpr121);
+		if (error) {
+			dev_err(dev, "Failed to register interrupt\n");
+			return error;
+		}
+	} else if (poll_interval) {
+		if (poll_interval < MPR121_MIN_POLL_INTERVAL)
+			return -EINVAL;
+
+		if (poll_interval > MPR121_MAX_POLL_INTERVAL)
+			return -EINVAL;
+
+		error = input_setup_polling(input_dev, mpr_touchkey_report);
+		if (error) {
+			dev_err(dev, "Failed to setup polling\n");
+			return error;
+		}
+
+		input_set_poll_interval(input_dev, poll_interval);
+		input_set_min_poll_interval(input_dev,
+					    MPR121_MIN_POLL_INTERVAL);
+		input_set_max_poll_interval(input_dev,
+					    MPR121_MAX_POLL_INTERVAL);
+	} else {
+		dev_err(dev,
+			"invalid IRQ number and polling not configured\n");
+		return -EINVAL;
 	}
 
 	error = input_register_device(input_dev);
-- 
2.1.4