staging: iio: ad5933: attach life-cycle of kfifo buffer to parent device and use managed calls throughout

This change makes the use of devm_iio_kfifo_allocate() to attach the
life-cycle of the kfifo buffer to the parent (client->dev) object.

This removes the need to explicitly free 'indio_dev->buffer' via
iio_kfifo_free(), which is the main intent.

Having done this, it is straight forward to move to devm_ calls throughout
and drop the remove function.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/impedance-analyzer/ad5933.c

@@ -602,11 +602,12 @@ static const struct iio_buffer_setup_ops ad5933_ring_setup_ops = {
 	.postdisable = ad5933_ring_postdisable,
 };
 
-static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
+static int ad5933_register_ring_funcs_and_init(struct device *dev,
+					       struct iio_dev *indio_dev)
 {
 	struct iio_buffer *buffer;
 
-	buffer = iio_kfifo_allocate();
+	buffer = devm_iio_kfifo_allocate(dev);
 	if (!buffer)
 		return -ENOMEM;
 
@@ -676,6 +677,20 @@ static void ad5933_work(struct work_struct *work)
 	}
 }
 
+static void ad5933_reg_disable(void *data)
+{
+	struct ad5933_state *st = data;
+
+	regulator_disable(st->reg);
+}
+
+static void ad5933_clk_disable(void *data)
+{
+	struct ad5933_state *st = data;
+
+	clk_disable_unprepare(st->mclk);
+}
+
 static int ad5933_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
@@ -703,23 +718,32 @@ static int ad5933_probe(struct i2c_client *client,
 		dev_err(&client->dev, "Failed to enable specified VDD supply\n");
 		return ret;
 	}
-	ret = regulator_get_voltage(st->reg);
 
+	ret = devm_add_action_or_reset(&client->dev, ad5933_reg_disable, st);
+	if (ret)
+		return ret;
+
+	ret = regulator_get_voltage(st->reg);
 	if (ret < 0)
-		goto error_disable_reg;
+		return ret;
 
 	st->vref_mv = ret / 1000;
 
 	st->mclk = devm_clk_get(&client->dev, "mclk");
-	if (IS_ERR(st->mclk) && PTR_ERR(st->mclk) != -ENOENT) {
+	if (IS_ERR(st->mclk) && PTR_ERR(st->mclk) != -ENOENT)
-		ret = PTR_ERR(st->mclk);
+		return PTR_ERR(st->mclk);
-		goto error_disable_reg;
-	}
 
 	if (!IS_ERR(st->mclk)) {
 		ret = clk_prepare_enable(st->mclk);
 		if (ret < 0)
-			goto error_disable_reg;
+			return ret;
+
+		ret = devm_add_action_or_reset(&client->dev,
+					       ad5933_clk_disable,
+					       st);
+		if (ret)
+			return ret;
+
 		ext_clk_hz = clk_get_rate(st->mclk);
 	}
 
@@ -742,41 +766,15 @@ static int ad5933_probe(struct i2c_client *client,
 	indio_dev->channels = ad5933_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ad5933_channels);
 
-	ret = ad5933_register_ring_funcs_and_init(indio_dev);
+	ret = ad5933_register_ring_funcs_and_init(&client->dev, indio_dev);
 	if (ret)
-		goto error_disable_mclk;
+		return ret;
 
 	ret = ad5933_setup(st);
 	if (ret)
-		goto error_unreg_ring;
+		return ret;
 
-	ret = iio_device_register(indio_dev);
+	return devm_iio_device_register(&client->dev, indio_dev);
-	if (ret)
-		goto error_unreg_ring;
-
-	return 0;
-
-error_unreg_ring:
-	iio_kfifo_free(indio_dev->buffer);
-error_disable_mclk:
-	clk_disable_unprepare(st->mclk);
-error_disable_reg:
-	regulator_disable(st->reg);
-
-	return ret;
-}
-
-static int ad5933_remove(struct i2c_client *client)
-{
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
-	struct ad5933_state *st = iio_priv(indio_dev);
-
-	iio_device_unregister(indio_dev);
-	iio_kfifo_free(indio_dev->buffer);
-	regulator_disable(st->reg);
-	clk_disable_unprepare(st->mclk);
-
-	return 0;
 }
 
 static const struct i2c_device_id ad5933_id[] = {
@@ -801,7 +799,6 @@ static struct i2c_driver ad5933_driver = {
 		.of_match_table = ad5933_of_match,
 	},
 	.probe = ad5933_probe,
-	.remove = ad5933_remove,
 	.id_table = ad5933_id,
 };
 module_i2c_driver(ad5933_driver);