Input: qt2160 - switch to using threaded interrupt handler

Instead of using combination of normal IRQ and work item which required
careful handling on device teardown, use standard threaded interrupt that
allows communication wityh the chip over slow (I2C) bus directly in the
interrupt handler.

To support polling mode switch to standard polling support implemented by
the input core.

Link: https://lore.kernel.org/r/20230724051345.335219-2-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: dtor

drivers/input/keyboard/qt2160.c

@@ -32,7 +32,7 @@
 
 #define QT2160_NUM_LEDS_X	8
 
-#define QT2160_CYCLE_INTERVAL	(2*HZ)
+#define QT2160_CYCLE_INTERVAL	2000 /* msec - 2 sec */
 
 static unsigned char qt2160_key2code[] = {
 	KEY_0, KEY_1, KEY_2, KEY_3,
@@ -54,7 +54,6 @@ struct qt2160_led {
 struct qt2160_data {
 	struct i2c_client *client;
 	struct input_dev *input;
-	struct delayed_work dwork;
 	unsigned short keycodes[ARRAY_SIZE(qt2160_key2code)];
 	u16 key_matrix;
 #ifdef CONFIG_LEDS_CLASS
@@ -155,10 +154,10 @@ static int qt2160_read_block(struct i2c_client *client,
 	return 0;
 }
 
-static int qt2160_get_key_matrix(struct qt2160_data *qt2160)
+static void qt2160_get_key_matrix(struct input_dev *input)
 {
+	struct qt2160_data *qt2160 = input_get_drvdata(input);
 	struct i2c_client *client = qt2160->client;
-	struct input_dev *input = qt2160->input;
 	u8 regs[6];
 	u16 old_matrix, new_matrix;
 	int ret, i, mask;
@@ -173,7 +172,7 @@ static int qt2160_get_key_matrix(struct qt2160_data *qt2160)
 	if (ret) {
 		dev_err(&client->dev,
 			"could not perform chip read.\n");
-		return ret;
+		return;
 	}
 
 	old_matrix = qt2160->key_matrix;
@@ -191,37 +190,17 @@ static int qt2160_get_key_matrix(struct qt2160_data *qt2160)
 	}
 
 	input_sync(input);
-
-	return 0;
 }
 
-static irqreturn_t qt2160_irq(int irq, void *_qt2160)
+static irqreturn_t qt2160_irq(int irq, void *data)
 {
-	struct qt2160_data *qt2160 = _qt2160;
+	struct input_dev *input = data;
 
-	mod_delayed_work(system_wq, &qt2160->dwork, 0);
+	qt2160_get_key_matrix(input);
 
 	return IRQ_HANDLED;
 }
 
-static void qt2160_schedule_read(struct qt2160_data *qt2160)
-{
-	schedule_delayed_work(&qt2160->dwork, QT2160_CYCLE_INTERVAL);
-}
-
-static void qt2160_worker(struct work_struct *work)
-{
-	struct qt2160_data *qt2160 =
-		container_of(work, struct qt2160_data, dwork.work);
-
-	dev_dbg(&qt2160->client->dev, "worker\n");
-
-	qt2160_get_key_matrix(qt2160);
-
-	/* Avoid device lock up by checking every so often */
-	qt2160_schedule_read(qt2160);
-}
-
 static int qt2160_read(struct i2c_client *client, u8 reg)
 {
 	int ret;
@@ -365,7 +344,6 @@ static int qt2160_probe(struct i2c_client *client)
 
 	qt2160->client = client;
 	qt2160->input = input;
-	INIT_DELAYED_WORK(&qt2160->dwork, qt2160_worker);
 
 	input->name = "AT42QT2160 Touch Sense Keyboard";
 	input->id.bustype = BUS_I2C;
@@ -382,6 +360,8 @@ static int qt2160_probe(struct i2c_client *client)
 	}
 	__clear_bit(KEY_RESERVED, input->keybit);
 
+	input_set_drvdata(input, qt2160);
+
 	/* Calibrate device */
 	error = qt2160_write(client, QT2160_CMD_CALIBRATE, 1);
 	if (error) {
@@ -390,13 +370,21 @@ static int qt2160_probe(struct i2c_client *client)
 	}
 
 	if (client->irq) {
-		error = request_irq(client->irq, qt2160_irq,
-				    IRQF_TRIGGER_FALLING, "qt2160", qt2160);
+		error = request_threaded_irq(client->irq, NULL, qt2160_irq,
+					     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					     "qt2160", input);
 		if (error) {
 			dev_err(&client->dev,
 				"failed to allocate irq %d\n", client->irq);
 			goto err_free_mem;
 		}
+	} else {
+		error = input_setup_polling(input, qt2160_get_key_matrix);
+		if (error) {
+			dev_err(&client->dev, "Failed to setup polling\n");
+			goto err_free_mem;
+		}
+		input_set_poll_interval(input, QT2160_CYCLE_INTERVAL);
 	}
 
 	error = qt2160_register_leds(qt2160);
@@ -413,7 +401,6 @@ static int qt2160_probe(struct i2c_client *client)
 	}
 
 	i2c_set_clientdata(client, qt2160);
-	qt2160_schedule_read(qt2160);
 
 	return 0;
 
@@ -438,8 +425,6 @@ static void qt2160_remove(struct i2c_client *client)
 	if (client->irq)
 		free_irq(client->irq, qt2160);
 
-	cancel_delayed_work_sync(&qt2160->dwork);
-
 	input_unregister_device(qt2160->input);
 	kfree(qt2160);
 }