[RFC PATCH 11/14] iio: buffer: add underlying device object and convert buffers to devices

Alexandru Ardelean
2020-05-08T13:54:32Z

WIP

Currently, IIO is broken here.
Each buffer is now an object.
The part where this is broken is backwards compatibility.
We need to:
- convert all external buffer attributes to unpack to IIO buffers and not
IIO devices
- symlink the 'scan_elements' folder of the (first) IIO buffer device to
the IIO device
- symlink the chardev of the first IIO buffer device to the IIO device

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/iio_core.h | 11 ++--
drivers/iio/industrialio-buffer.c | 98 ++++++++++++++++++++++++-------
drivers/iio/industrialio-core.c | 39 +++++++-----
include/linux/iio/buffer_impl.h | 6 ++
include/linux/iio/iio.h | 2 +-
5 files changed, 116 insertions(+), 40 deletions(-)

diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
index f68de4af2738..890577766f9b 100644
--- a/drivers/iio/iio_core.h
+++ b/drivers/iio/iio_core.h
@@ -54,10 +54,13 @@ ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals);
#ifdef CONFIG_IIO_BUFFER
struct poll_table_struct;

+int iio_device_alloc_chrdev_id(struct device *dev);
+void iio_device_free_chrdev_id(struct device *dev);
+
void iio_device_buffer_attach_chrdev(struct iio_dev *indio_dev);

-int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev);
-void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev);
+int iio_device_buffers_init(struct iio_dev *indio_dev);
+void iio_device_buffers_cleanup(struct iio_dev *indio_dev);

void iio_device_buffers_put(struct iio_dev *indio_dev);

@@ -68,12 +71,12 @@ void iio_buffer_wakeup_poll(struct iio_dev *indio_dev);

static inline void iio_device_buffer_attach_chrdev(struct iio_dev *indio_dev) {}

-static inline int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
+static inline int iio_device_buffers_init(struct iio_dev *indio_dev)
{
return 0;
}

-static inline void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev) {}
+static inline void iio_device_buffers_cleanup(struct iio_dev *indio_dev) {}

static inline void iio_device_buffers_put(struct iio_dev *indio_dev) {}

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index efebf74a05af..6c35de7ebd9e 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1235,8 +1235,6 @@ static ssize_t iio_buffer_store_enable(struct device *dev,
return (ret < 0) ? ret : len;
}

-static const char * const iio_scan_elements_group_name = "scan_elements";
-
static ssize_t iio_buffer_show_watermark(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -1312,7 +1310,7 @@ static struct attribute *iio_buffer_attrs[] = {
&dev_attr_data_available.attr,
};

-static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer)
+static int iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer)
{
struct iio_dev *indio_dev = buffer->indio_dev;
struct iio_dev_attr *p;
@@ -1344,10 +1342,9 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer)

attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;

- buffer->buffer_group.name = "buffer";
buffer->buffer_group.attrs = attr;

- indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
+ buffer->groups[0] = &buffer->buffer_group;

attrcount = 0;
INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
@@ -1373,7 +1370,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer)
goto error_cleanup_dynamic;
}

- buffer->scan_el_group.name = iio_scan_elements_group_name;
+ buffer->scan_el_group.name = "scan_elements";

buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
sizeof(buffer->scan_el_group.attrs[0]),
@@ -1386,7 +1383,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer)

list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
- indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
+ buffer->groups[1] = &buffer->scan_el_group;

return 0;

@@ -1399,11 +1396,66 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer)
return ret;
}

-int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
+static void iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
+{
+ iio_buffer_free_scanmask(buffer);
+ kfree(buffer->buffer_group.attrs);
+ kfree(buffer->scan_el_group.attrs);
+ iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
+}
+
+static int iio_device_buffer_init(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer,
+ int index)
+{
+ int ret;
+
+ ret = iio_buffer_alloc_sysfs_and_mask(buffer);
+ if (ret)
+ return ret;
+
+ ret = iio_device_alloc_chrdev_id(&buffer->dev);
+ if (ret)
+ goto error_free_sysfs_and_mask;
+
+ buffer->dev.parent = &indio_dev->dev;
+ buffer->dev.groups = buffer->groups;
+ buffer->dev.bus = &iio_bus_type;
+ device_initialize(&buffer->dev);
+
+ dev_set_name(&buffer->dev, "iio:buffer%d:%d",
+ indio_dev->id, index);
+
+ ret = cdev_device_add(&buffer->chrdev, &buffer->dev);
+ if (ret)
+ goto error_free_chrdev_id;
+
+ return 0;
+
+error_free_chrdev_id:
+ iio_device_free_chrdev_id(&buffer->dev);
+error_free_sysfs_and_mask:
+ iio_buffer_free_sysfs_and_mask(buffer);
+ return ret;
+}
+
+void iio_device_buffer_cleanup(struct iio_buffer *buffer)
+{
+ if (!buffer)
+ return;
+
+ iio_buffer_free_sysfs_and_mask(buffer);
+
+ cdev_device_del(&buffer->chrdev, &buffer->dev);
+
+ iio_device_free_chrdev_id(&buffer->dev);
+}
+
+int iio_device_buffers_init(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer = indio_dev->buffer;
const struct iio_chan_spec *channels;
- int i;
+ int i, ret;

channels = indio_dev->channels;
if (channels) {
@@ -1417,25 +1469,29 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
if (!buffer)
return 0;

- return __iio_buffer_alloc_sysfs_and_mask(buffer);
-}
+ ret = iio_device_buffer_init(indio_dev, buffer, 0);
+ if (ret)
+ return ret;

-static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
-{
- iio_buffer_free_scanmask(buffer);
- kfree(buffer->buffer_group.attrs);
- kfree(buffer->scan_el_group.attrs);
- iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
+ ret = sysfs_create_link(&indio_dev->dev.kobj,
+ &buffer->dev.kobj, "buffer");
+ if (ret)
+ goto error_cleanup_buffers;
+
+ return 0;
+
+error_cleanup_buffers:
+ iio_device_buffer_cleanup(buffer);
+ return 0;
}

-void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
+void iio_device_buffers_cleanup(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer = indio_dev->buffer;

- if (!buffer)
- return;
+ sysfs_remove_link(&indio_dev->dev.kobj, "buffer");

- __iio_buffer_free_sysfs_and_mask(buffer);
+ iio_device_buffer_cleanup(buffer);
}

static const struct file_operations iio_buffer_fileops = {
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 5df3af5e7dcb..b27fabf13e9c 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1638,7 +1638,7 @@ static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
return 0;
}

-static int iio_device_alloc_chrdev_id(struct device *dev)
+int iio_device_alloc_chrdev_id(struct device *dev)
{
int id;

@@ -1654,7 +1654,7 @@ static int iio_device_alloc_chrdev_id(struct device *dev)
return 0;
}

-static void iio_device_free_chrdev_id(struct device *dev)
+void iio_device_free_chrdev_id(struct device *dev)
{
if (!dev->devt)
return;
@@ -1684,18 +1684,11 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)

iio_device_register_debugfs(indio_dev);

- ret = iio_buffer_alloc_sysfs_and_mask(indio_dev);
- if (ret) {
- dev_err(indio_dev->dev.parent,
- "Failed to create buffer sysfs interfaces\n");
- goto error_unreg_debugfs;
- }
-
ret = iio_device_register_sysfs(indio_dev);
if (ret) {
dev_err(indio_dev->dev.parent,
"Failed to register sysfs interfaces\n");
- goto error_buffer_free_sysfs;
+ goto error_unreg_debugfs;
}
ret = iio_device_register_eventset(indio_dev);
if (ret) {
@@ -1712,6 +1705,26 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)

iio_device_buffer_attach_chrdev(indio_dev);

+ if (indio_dev->chrdev) {
+ ret = device_add(&indio_dev->dev);
+
+ if (ret) {
+ put_device(&indio_dev->dev);
+ goto error_unreg_eventset;
+ }
+
+ ret = iio_device_buffers_init(indio_dev);
+ if (ret) {
+ device_del(&indio_dev->dev);
+
+ dev_err(indio_dev->dev.parent,
+ "Failed to create buffer sysfs interfaces\n");
+ goto error_unreg_eventset;
+ }
+
+ return 0;
+ }
+
/* No chrdev attached from buffer, we go with event-only chrdev */
if (!indio_dev->chrdev)
iio_device_event_attach_chrdev(indio_dev);
@@ -1736,8 +1749,6 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
iio_device_unregister_eventset(indio_dev);
error_free_sysfs:
iio_device_unregister_sysfs(indio_dev);
-error_buffer_free_sysfs:
- iio_buffer_free_sysfs_and_mask(indio_dev);
error_unreg_debugfs:
iio_device_unregister_debugfs(indio_dev);
return ret;
@@ -1752,6 +1763,8 @@ void iio_device_unregister(struct iio_dev *indio_dev)
{
struct iio_ioctl_handler *h, *t;

+ iio_device_buffers_cleanup(indio_dev);
+
cdev_device_del(indio_dev->chrdev, &indio_dev->dev);
iio_device_free_chrdev_id(&indio_dev->dev);

@@ -1770,8 +1783,6 @@ void iio_device_unregister(struct iio_dev *indio_dev)
iio_buffer_wakeup_poll(indio_dev);

mutex_unlock(&indio_dev->info_exist_lock);
-
- iio_buffer_free_sysfs_and_mask(indio_dev);
}
EXPORT_SYMBOL(iio_device_unregister);

diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h
index 46fc977deae3..eca3fe630230 100644
--- a/include/linux/iio/buffer_impl.h
+++ b/include/linux/iio/buffer_impl.h
@@ -104,6 +104,12 @@ struct iio_buffer {
unsigned int watermark;

/* private: */
+ /* @dev: underlying device object. */
+ struct device dev;
+
+#define IIO_BUFFER_MAX_GROUP 2
+ const struct attribute_group *groups[IIO_BUFFER_MAX_GROUP + 1];
+
/* @scan_timestamp: Does the scan mode include a timestamp. */
bool scan_timestamp;

diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index b6ca8d85629e..671f5818fa67 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -561,7 +561,7 @@ struct iio_dev {
struct mutex info_exist_lock;
const struct iio_buffer_setup_ops *setup_ops;
struct cdev *chrdev;
-#define IIO_MAX_GROUPS 6
+#define IIO_MAX_GROUPS 5
const struct attribute_group *groups[IIO_MAX_GROUPS + 1];
int groupcounter;

--
2.17.1