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Date: Fri, 22 Jan 2021 18:25:28 +0200
From: Alexandru Ardelean <alexandru.ardelean@...log.com>
To: <linux-kernel@...r.kernel.org>, <linux-iio@...r.kernel.org>
CC: <lars@...afoo.de>, <Michael.Hennerich@...log.com>,
<jic23@...nel.org>, <nuno.sa@...log.com>,
<dragos.bogdan@...log.com>,
Alexandru Ardelean <alexandru.ardelean@...log.com>
Subject: [PATCH v2 11/12][RESEND] iio: buffer: introduce support for attaching more IIO buffers
With this change, calling iio_device_attach_buffer() will actually attach
more buffers.
Right now this doesn't do any validation of whether a buffer is attached
twice; maybe that can be added later (if needed). Attaching a buffer more
than once should yield noticeably bad results.
The first buffer is the legacy buffer, so a reference is kept to it.
At this point, accessing the data for the extra buffers (that are added
after the first one) isn't possible yet.
The iio_device_attach_buffer() is also changed to return an error code,
which for now is -ENOMEM if the array could not be realloc-ed for more
buffers.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
---
drivers/iio/industrialio-buffer.c | 67 ++++++++++++++++++++++++-------
include/linux/iio/buffer.h | 4 +-
include/linux/iio/buffer_impl.h | 3 ++
include/linux/iio/iio-opaque.h | 4 ++
4 files changed, 62 insertions(+), 16 deletions(-)
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 62cb90385246..2f429616e998 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1561,9 +1561,10 @@ static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
*/
int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer = indio_dev->buffer;
const struct iio_chan_spec *channels;
- int i, ret;
+ int i, cnt, ret;
channels = indio_dev->channels;
if (channels) {
@@ -1577,15 +1578,18 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
if (!buffer)
return 0;
- ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, 0);
- if (ret)
- return ret;
+ for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
+ buffer = iio_dev_opaque->attached_buffers[i];
+ ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, i);
+ if (ret)
+ goto error_unwind_sysfs_and_mask;
+ }
ret = sysfs_create_link(&indio_dev->dev.kobj,
&indio_dev->buffer->buffer_dir,
"buffer");
if (ret)
- goto error_free_sysfs_and_mask;
+ goto error_unwind_sysfs_and_mask;
ret = sysfs_create_link(&indio_dev->dev.kobj,
&indio_dev->buffer->scan_el_dir,
@@ -1597,8 +1601,14 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
error_remove_buffer_dir_link:
sysfs_remove_link(&indio_dev->dev.kobj, "buffer");
-error_free_sysfs_and_mask:
- __iio_buffer_free_sysfs_and_mask(buffer);
+ cnt = iio_dev_opaque->attached_buffers_cnt - 1;
+error_unwind_sysfs_and_mask:
+ for (; cnt >= 0; cnt--) {
+ buffer = iio_dev_opaque->attached_buffers[cnt];
+ __iio_buffer_free_sysfs_and_mask(buffer);
+ }
+ kfree(iio_dev_opaque->attached_buffers);
+ iio_dev_opaque->attached_buffers = NULL;
return ret;
}
@@ -1610,7 +1620,9 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
*/
void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer = indio_dev->buffer;
+ int i;
if (!buffer)
return;
@@ -1618,7 +1630,13 @@ void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
sysfs_remove_link(&indio_dev->dev.kobj, "scan_elements");
sysfs_remove_link(&indio_dev->dev.kobj, "buffer");
- __iio_buffer_free_sysfs_and_mask(buffer);
+ for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) {
+ buffer = iio_dev_opaque->attached_buffers[i];
+ __iio_buffer_free_sysfs_and_mask(buffer);
+ }
+
+ kfree(iio_dev_opaque->attached_buffers);
+ iio_dev_opaque->attached_buffers = NULL;
}
/**
@@ -1750,15 +1768,36 @@ EXPORT_SYMBOL_GPL(iio_buffer_get_iio_dev);
* @indio_dev: The device the buffer should be attached to
* @buffer: The buffer to attach to the device
*
+ * Return 0 if buffer attached, or negative if error occured.
+ *
* This function attaches a buffer to a IIO device. The buffer stays attached to
- * the device until the device is freed. The function should only be called at
- * most once per device.
+ * the device until the device is freed. For legacy reasons, the first attached
+ * buffer will also be assigned to 'indio_dev->buffer'.
*/
-void iio_device_attach_buffer(struct iio_dev *indio_dev,
- struct iio_buffer *buffer)
+int iio_device_attach_buffer(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
{
- indio_dev->buffer = iio_buffer_get(buffer);
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer **new, **old = iio_dev_opaque->attached_buffers;
+ unsigned int cnt = iio_dev_opaque->attached_buffers_cnt;
+
+ cnt++;
+
+ new = krealloc(old, sizeof(*new) * cnt, GFP_KERNEL);
+ if (!new)
+ return -ENOMEM;
- indio_dev->buffer->indio_dev = indio_dev;
+ iio_dev_opaque->attached_buffers = new;
+
+ /* first buffer is legacy; attach it to the IIO device directly */
+ if (!indio_dev->buffer)
+ indio_dev->buffer = iio_buffer_get(buffer);
+
+ buffer->indio_dev = indio_dev;
+
+ iio_dev_opaque->attached_buffers[cnt - 1] = buffer;
+ iio_dev_opaque->attached_buffers_cnt = cnt;
+
+ return 0;
}
EXPORT_SYMBOL_GPL(iio_device_attach_buffer);
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index b27d8c81f32c..5532eddb7808 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -43,7 +43,7 @@ static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev,
bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
const unsigned long *mask);
-void iio_device_attach_buffer(struct iio_dev *indio_dev,
- struct iio_buffer *buffer);
+int iio_device_attach_buffer(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer);
#endif /* _IIO_BUFFER_GENERIC_H_ */
diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h
index 77e169e51434..e25d26a7f601 100644
--- a/include/linux/iio/buffer_impl.h
+++ b/include/linux/iio/buffer_impl.h
@@ -124,6 +124,9 @@ struct iio_buffer {
/* @demux_bounce: Buffer for doing gather from incoming scan. */
void *demux_bounce;
+ /* @attached_entry: Entry in the devices list of buffers attached by the driver. */
+ struct list_head attached_entry;
+
/* @buffer_list: Entry in the devices list of current buffers. */
struct list_head buffer_list;
diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h
index 07c5a8e52ca8..1db0ea09520e 100644
--- a/include/linux/iio/iio-opaque.h
+++ b/include/linux/iio/iio-opaque.h
@@ -7,6 +7,8 @@
* struct iio_dev_opaque - industrial I/O device opaque information
* @indio_dev: public industrial I/O device information
* @event_interface: event chrdevs associated with interrupt lines
+ * @attached_buffers: array of buffers statically attached by the driver
+ * @attached_buffers_cnt: number of buffers in the array of statically attached buffers
* @buffer_list: list of all buffers currently attached
* @channel_attr_list: keep track of automatically created channel
* attributes
@@ -20,6 +22,8 @@
struct iio_dev_opaque {
struct iio_dev indio_dev;
struct iio_event_interface *event_interface;
+ struct iio_buffer **attached_buffers;
+ unsigned int attached_buffers_cnt;
struct list_head buffer_list;
struct list_head channel_attr_list;
struct attribute_group chan_attr_group;
--
2.17.1
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