[PATCH 03/13] iio: adc: mcp3564: Use __free(fwnode_handle) to replace fwnode_handle_put() calls

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

This use of the new cleanup.h scope based freeing infrastructure allows
us to exit directly from error conditions within the
device_for_each_child_node(dev, child) loop. On normal exit from that
loop no fwnode_handle reference will be held and the child pointer
will be NULL thus making the automatically run fwnode_handle_put() a
noop whereas it will release the reference held on early break or
return from the loop.

Return a little earlier in some error paths to avoid performing
pointless activity. Likely motivation for doing this previously was
to avoid repeating the fwnode_handle_put() calls.

Cc: Marius Cristea <marius.cristea@microchip.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/adc/mcp3564.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
index e3f1de5fcc5a..9a1029c93fb2 100644
--- a/drivers/iio/adc/mcp3564.c
+++ b/drivers/iio/adc/mcp3564.c
@@ -998,7 +998,7 @@ static int mcp3564_parse_fw_children(struct iio_dev *indio_dev)
 	struct mcp3564_state *adc = iio_priv(indio_dev);
 	struct device *dev = &adc->spi->dev;
 	struct iio_chan_spec *channels;
-	struct fwnode_handle *child;
+	struct fwnode_handle *child __free(fwnode_handle) = NULL;
 	struct iio_chan_spec chanspec = mcp3564_channel_template;
 	struct iio_chan_spec temp_chanspec = mcp3564_temp_channel_template;
 	struct iio_chan_spec burnout_chanspec = mcp3564_burnout_channel_template;
@@ -1033,26 +1033,25 @@ static int mcp3564_parse_fw_children(struct iio_dev *indio_dev)
 							     "diff-channels",
 							     inputs,
 							     ARRAY_SIZE(inputs));
+			if (ret)
+				return ret;
+
 			chanspec.differential = 1;
 		} else {
 			ret = fwnode_property_read_u32(child, "reg", &inputs[0]);
+			if (ret)
+				return ret;
 
 			chanspec.differential = 0;
 			inputs[1] = MCP3564_AGND;
 		}
-		if (ret) {
-			fwnode_handle_put(child);
-			return ret;
-		}
 
 		if (inputs[0] > MCP3564_INTERNAL_VCM ||
-		    inputs[1] > MCP3564_INTERNAL_VCM) {
-			fwnode_handle_put(child);
+		    inputs[1] > MCP3564_INTERNAL_VCM)
 			return dev_err_probe(&indio_dev->dev, -EINVAL,
 					     "Channel index > %d, for %s\n",
 					     MCP3564_INTERNAL_VCM + 1,
 					     node_name);
-		}
 
 		chanspec.address = (inputs[0] << 4) | inputs[1];
 		chanspec.channel = inputs[0];
-- 
2.43.0