iio: buffer-dmaengine: add devm_iio_dmaengine_buffer_setup_with_handle()

Add a new devm_iio_dmaengine_buffer_setup_with_handle() function to
handle cases where the DMA channel is managed by the caller rather than
being requested and released by the iio_dmaengine module.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250207-dlech-mainline-spi-engine-offload-2-v8-9-e48a489be48c@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
index 02847d3962fcbb43ec76167db6482ab951f20942..e9d9a7d39fe191c2b6e8c196a08cdd26cd3a8d4b 100644 (file)
--- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
+++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
@@ -380,6 +380,44 @@ int devm_iio_dmaengine_buffer_setup_ext(struct device *dev,
 }
 EXPORT_SYMBOL_NS_GPL(devm_iio_dmaengine_buffer_setup_ext, "IIO_DMAENGINE_BUFFER");
 
+static void devm_iio_dmaengine_buffer_free(void *buffer)
+{
+       iio_dmaengine_buffer_free(buffer);
+}
+
+/**
+ * devm_iio_dmaengine_buffer_setup_with_handle() - Setup a DMA buffer for an
+ *                                                IIO device
+ * @dev: Device for devm ownership
+ * @indio_dev: IIO device to which to attach this buffer.
+ * @chan: DMA channel
+ * @dir: Direction of buffer (in or out)
+ *
+ * This allocates a new IIO buffer with devm_iio_dmaengine_buffer_alloc()
+ * and attaches it to an IIO device with iio_device_attach_buffer().
+ * It also appends the INDIO_BUFFER_HARDWARE mode to the supported modes of the
+ * IIO device.
+ *
+ * This is the same as devm_iio_dmaengine_buffer_setup_ext() except that the
+ * caller manages requesting and releasing the DMA channel handle.
+ */
+int devm_iio_dmaengine_buffer_setup_with_handle(struct device *dev,
+                                               struct iio_dev *indio_dev,
+                                               struct dma_chan *chan,
+                                               enum iio_buffer_direction dir)
+{
+       struct iio_buffer *buffer;
+
+       buffer = __iio_dmaengine_buffer_setup_ext(indio_dev, chan, dir);
+       if (IS_ERR(buffer))
+               return PTR_ERR(buffer);
+
+       return devm_add_action_or_reset(dev, devm_iio_dmaengine_buffer_free,
+                                       buffer);
+}
+EXPORT_SYMBOL_NS_GPL(devm_iio_dmaengine_buffer_setup_with_handle,
+                    "IIO_DMAENGINE_BUFFER");
+
 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 MODULE_DESCRIPTION("DMA buffer for the IIO framework");
 MODULE_LICENSE("GPL");

diff --git a/include/linux/iio/buffer-dmaengine.h b/include/linux/iio/buffer-dmaengine.h
index 72a2e3fd8a5bf5e8f27ee226ddd92979d233754b..37f27545f69f761c3327c307cc6311b02a751096 100644 (file)
--- a/include/linux/iio/buffer-dmaengine.h
+++ b/include/linux/iio/buffer-dmaengine.h
@@ -11,6 +11,7 @@
 
 struct iio_dev;
 struct device;
+struct dma_chan;
 
 void iio_dmaengine_buffer_teardown(struct iio_buffer *buffer);
 struct iio_buffer *iio_dmaengine_buffer_setup_ext(struct device *dev,
@@ -26,6 +27,10 @@ int devm_iio_dmaengine_buffer_setup_ext(struct device *dev,
                                        struct iio_dev *indio_dev,
                                        const char *channel,
                                        enum iio_buffer_direction dir);
+int devm_iio_dmaengine_buffer_setup_with_handle(struct device *dev,
+                                               struct iio_dev *indio_dev,
+                                               struct dma_chan *chan,
+                                               enum iio_buffer_direction dir);
 
 #define devm_iio_dmaengine_buffer_setup(dev, indio_dev, channel)       \
        devm_iio_dmaengine_buffer_setup_ext(dev, indio_dev, channel,    \