[PATCH 2/5] iio: kfifo: add devm_iio_kfifo_buffer_setup() helper

From: Alexandru Ardelean
Date: Sun Feb 14 2021 - 09:35:42 EST


This change adds the devm_iio_kfifo_buffer_setup() helper/short-hand,
which groups the simple routine of allocating a kfifo buffers via
devm_iio_kfifo_allocate() and calling iio_device_attach_buffer().

The mode_flags parameter is required, as the IIO kfifo supports 2 modes:
INDIO_BUFFER_SOFTWARE & INDIO_BUFFER_TRIGGERED.
The setup_ops parameter is optional.

This function will be a bit more useful when needing to define multiple
buffers per IIO device.

The naming for this function has been inspired from
iio_triggered_buffer_setup() since that one does a kfifo alloc + a pollfunc
alloc. So, this should have a more familiar ring to what it is.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
.../driver-api/driver-model/devres.rst | 1 +
drivers/iio/buffer/kfifo_buf.c | 39 +++++++++++++++++++
include/linux/iio/kfifo_buf.h | 7 ++++
3 files changed, 47 insertions(+)

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index cd8b6e657b94..562f5722281e 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -286,6 +286,7 @@ IIO
devm_iio_device_alloc()
devm_iio_device_register()
devm_iio_kfifo_allocate()
+ devm_iio_kfifo_buffer_setup()
devm_iio_triggered_buffer_setup()
devm_iio_trigger_alloc()
devm_iio_trigger_register()
diff --git a/drivers/iio/buffer/kfifo_buf.c b/drivers/iio/buffer/kfifo_buf.c
index 1359abed3b31..6472c9fa1937 100644
--- a/drivers/iio/buffer/kfifo_buf.c
+++ b/drivers/iio/buffer/kfifo_buf.c
@@ -206,4 +206,43 @@ struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
}
EXPORT_SYMBOL(devm_iio_kfifo_allocate);

+/**
+ * devm_iio_kfifo_buffer_setup - Allocate a kfifo buffer & attach it to an IIO device
+ * @dev: Device object to which to attach the life-time of this kfifo buffer
+ * @indio_dev: The device the buffer should be attached to
+ * @mode_flags: The mode flags for this buffer (INDIO_BUFFER_SOFTWARE and/or
+ * INDIO_BUFFER_TRIGGERED).
+ * @setup_ops: The setup_ops required to configure the HW part of the buffer (optional)
+ *
+ * This function allocates a kfifo buffer via devm_iio_kfifo_allocate() and
+ * attaches it to the IIO device via iio_device_attach_buffer().
+ * This is meant to be a bit of a short-hand/helper function as there are a few
+ * drivers that seem to do this.
+ */
+int devm_iio_kfifo_buffer_setup(struct device *dev,
+ struct iio_dev *indio_dev,
+ int mode_flags,
+ const struct iio_buffer_setup_ops *setup_ops)
+{
+ struct iio_buffer *buffer;
+
+ if (mode_flags)
+ mode_flags &= kfifo_access_funcs.modes;
+
+ if (!mode_flags)
+ return -EINVAL;
+
+ buffer = devm_iio_kfifo_allocate(dev);
+ if (!buffer)
+ return -ENOMEM;
+
+ iio_device_attach_buffer(indio_dev, buffer);
+
+ indio_dev->modes |= mode_flags;
+ indio_dev->setup_ops = setup_ops;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup);
+
MODULE_LICENSE("GPL");
diff --git a/include/linux/iio/kfifo_buf.h b/include/linux/iio/kfifo_buf.h
index 1fc1efa7799d..92c411b9ac26 100644
--- a/include/linux/iio/kfifo_buf.h
+++ b/include/linux/iio/kfifo_buf.h
@@ -3,6 +3,8 @@
#define __LINUX_IIO_KFIFO_BUF_H__

struct iio_buffer;
+struct iio_buffer_setup_ops;
+struct iio_dev;
struct device;

struct iio_buffer *iio_kfifo_allocate(void);
@@ -10,4 +12,9 @@ void iio_kfifo_free(struct iio_buffer *r);

struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev);

+int devm_iio_kfifo_buffer_setup(struct device *dev,
+ struct iio_dev *indio_dev,
+ int mode_flags,
+ const struct iio_buffer_setup_ops *setup_ops);
+
#endif
--
2.17.1