iio: tcs3472: use devm for resource management

Convert the driver to use device-managed resource allocation:
- Add tcs3472_powerdown_action() and register it with
  devm_add_action_or_reset() to ensure the device is powered down on
  cleanup.
- Replace iio_triggered_buffer_setup() with
  devm_iio_triggered_buffer_setup().
- Replace request_threaded_irq() with devm_request_threaded_irq().
- Replace iio_device_register() with devm_iio_device_register().
- Replace mutex_init() with devm_mutex_init().
- Remove tcs3472_remove() as all cleanup is now handled by devm.

Use a local 'dev = &client->dev' in tcs3472_probe() to keep the devm
calls compact.

Signed-off-by: Aldo Conte <aldocontelk@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Author: aldocontelk

drivers/iio/light/tcs3472.c

@@ -17,6 +17,7 @@
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/pm.h>
 
 #include <linux/iio/buffer.h>
@@ -445,20 +446,28 @@ static int tcs3472_powerdown(struct tcs3472_data *data)
 	return 0;
 }
 
+static void tcs3472_powerdown_action(void *data)
+{
+	tcs3472_powerdown(data);
+}
+
 static int tcs3472_probe(struct i2c_client *client)
 {
+	struct device *dev = &client->dev;
 	struct tcs3472_data *data;
 	struct iio_dev *indio_dev;
 	int ret;
 
-	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
 
 	data = iio_priv(indio_dev);
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
-	mutex_init(&data->lock);
+	ret = devm_mutex_init(dev, &data->lock);
+	if (ret)
+		return ret;
 
 	indio_dev->info = &tcs3472_info;
 	indio_dev->name = TCS3472_DRV_NAME;
@@ -515,46 +524,27 @@ static int tcs3472_probe(struct i2c_client *client)
 	if (ret < 0)
 		return ret;
 
-	ret = iio_triggered_buffer_setup(indio_dev, NULL,
-		tcs3472_trigger_handler, NULL);
+	ret = devm_add_action_or_reset(dev, tcs3472_powerdown_action, data);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+					      tcs3472_trigger_handler, NULL);
 	if (ret < 0)
-		goto error_powerdown;
+		return ret;
 
 	if (client->irq) {
-		ret = request_threaded_irq(client->irq, NULL,
-					   tcs3472_event_handler,
-					   IRQF_TRIGGER_FALLING | IRQF_SHARED |
-					   IRQF_ONESHOT,
-					   client->name, indio_dev);
+		ret = devm_request_threaded_irq(dev, client->irq, NULL,
+						tcs3472_event_handler,
+						IRQF_TRIGGER_FALLING |
+						IRQF_SHARED |
+						IRQF_ONESHOT,
+						client->name, indio_dev);
 		if (ret)
-			goto buffer_cleanup;
+			return ret;
 	}
 
-	ret = iio_device_register(indio_dev);
-	if (ret < 0)
-		goto free_irq;
-
-	return 0;
-
-free_irq:
-	if (client->irq)
-		free_irq(client->irq, indio_dev);
-buffer_cleanup:
-	iio_triggered_buffer_cleanup(indio_dev);
-error_powerdown:
-	tcs3472_powerdown(data);
-	return ret;
-}
-
-static void tcs3472_remove(struct i2c_client *client)
-{
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
-
-	iio_device_unregister(indio_dev);
-	if (client->irq)
-		free_irq(client->irq, indio_dev);
-	iio_triggered_buffer_cleanup(indio_dev);
-	tcs3472_powerdown(iio_priv(indio_dev));
+	return devm_iio_device_register(dev, indio_dev);
 }
 
 static int tcs3472_suspend(struct device *dev)
@@ -598,7 +588,6 @@ static struct i2c_driver tcs3472_driver = {
 		.pm	= pm_sleep_ptr(&tcs3472_pm_ops),
 	},
 	.probe		= tcs3472_probe,
-	.remove		= tcs3472_remove,
 	.id_table	= tcs3472_id,
 };
 module_i2c_driver(tcs3472_driver);