iio: provide of_iio_channel_get_by_name() and devm_ version it

There might be cases when the IIO channel is attached to the device
subnode instead of being attached to the main device node. Allow drivers
to query IIO channels by using device tree nodes.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20201204025509.1075506-8-dmitry.baryshkov@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 26 insertions, 8 deletions

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index fe30bcb6a57b..db77a2d4a56b 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -191,8 +191,8 @@ err_free_channel:
 	return ERR_PTR(err);
 }
 
-static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
-						      const char *name)
+struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
+					       const char *name)
 {
 	struct iio_channel *chan = NULL;
 
@@ -230,6 +230,7 @@ static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
 
 	return chan;
 }
+EXPORT_SYMBOL_GPL(of_iio_channel_get_by_name);
 
 static struct iio_channel *of_iio_channel_get_all(struct device *dev)
 {
@@ -272,12 +273,6 @@ error_free_chans:
 
 #else /* CONFIG_OF */
 
-static inline struct iio_channel *
-of_iio_channel_get_by_name(struct device_node *np, const char *name)
-{
-	return NULL;
-}
-
 static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
 {
 	return NULL;
@@ -393,6 +388,29 @@ struct iio_channel *devm_iio_channel_get(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_iio_channel_get);
 
+struct iio_channel *devm_of_iio_channel_get_by_name(struct device *dev,
+						    struct device_node *np,
+						    const char *channel_name)
+{
+	struct iio_channel **ptr, *channel;
+
+	ptr = devres_alloc(devm_iio_channel_free, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	channel = of_iio_channel_get_by_name(np, channel_name);
+	if (IS_ERR(channel)) {
+		devres_free(ptr);
+		return channel;
+	}
+
+	*ptr = channel;
+	devres_add(dev, ptr);
+
+	return channel;
+}
+EXPORT_SYMBOL_GPL(devm_of_iio_channel_get_by_name);
+
 struct iio_channel *iio_channel_get_all(struct device *dev)
 {
 	const char *name;