From: Alexandru Ardelean <alexandru.ardelean@analog.com>
To: <linux-kernel@vger.kernel.org>, <linux-iio@vger.kernel.org>
Cc: <lars@metafoo.de>, <Michael.Hennerich@analog.com>,
<jic23@kernel.org>, <nuno.sa@analog.com>,
<dragos.bogdan@analog.com>,
Alexandru Ardelean <alexandru.ardelean@analog.com>
Subject: [PATCH v2 03/12] iio: buffer: rework buffer & scan_elements dir creation
Date: Fri, 22 Jan 2021 17:57:56 +0200 [thread overview]
Message-ID: <20210122155805.83012-4-alexandru.ardelean@analog.com> (raw)
In-Reply-To: <20210122155805.83012-1-alexandru.ardelean@analog.com>
When adding more than one IIO buffer per IIO device, we will need to create
a buffer & scan_elements directory for each buffer.
We also want to move the 'scan_elements' to be a sub-directory of the
'buffer' folder.
The format we want to reach is, for a iio:device0 folder, for 2 buffers
[for example], we have a 'buffer0' and a 'buffer1' subfolder, and each with
it's own 'scan_elements' subfolder.
So, for example:
iio:device0/buffer0
scan_elements/
iio:device0/buffer1
scan_elements/
The other attributes under 'bufferX' would remain unchanged.
However, we would also need to symlink back to the old 'buffer' &
'scan_elements' folders, to keep backwards compatibility.
Doing all these, require that we maintain the kobjects for each 'bufferX'
and 'scan_elements' so that we can symlink them back. We also need to
implement the sysfs_ops for these folders.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/industrialio-buffer.c | 195 +++++++++++++++++++++++++++---
drivers/iio/industrialio-core.c | 24 ++--
include/linux/iio/buffer_impl.h | 14 ++-
include/linux/iio/iio.h | 2 +-
4 files changed, 200 insertions(+), 35 deletions(-)
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 0412c4fda4c1..0f470d902790 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1175,8 +1175,6 @@ 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)
@@ -1252,6 +1250,124 @@ static struct attribute *iio_buffer_attrs[] = {
&dev_attr_data_available.attr,
};
+#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
+
+static ssize_t iio_buffer_dir_attr_show(struct kobject *kobj,
+ struct attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = container_of(kobj, struct iio_buffer, buffer_dir);
+ struct device_attribute *dattr;
+
+ dattr = to_dev_attr(attr);
+
+ return dattr->show(&buffer->indio_dev->dev, dattr, buf);
+}
+
+static ssize_t iio_buffer_dir_attr_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf,
+ size_t len)
+{
+ struct iio_buffer *buffer = container_of(kobj, struct iio_buffer, buffer_dir);
+ struct device_attribute *dattr;
+
+ dattr = to_dev_attr(attr);
+
+ return dattr->store(&buffer->indio_dev->dev, dattr, buf, len);
+}
+
+static const struct sysfs_ops iio_buffer_dir_sysfs_ops = {
+ .show = iio_buffer_dir_attr_show,
+ .store = iio_buffer_dir_attr_store,
+};
+
+static struct kobj_type iio_buffer_dir_ktype = {
+ .sysfs_ops = &iio_buffer_dir_sysfs_ops,
+};
+
+static ssize_t iio_scan_el_dir_attr_show(struct kobject *kobj,
+ struct attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = container_of(kobj, struct iio_buffer, scan_el_dir);
+ struct device_attribute *dattr = to_dev_attr(attr);
+
+ return dattr->show(&buffer->indio_dev->dev, dattr, buf);
+}
+
+static ssize_t iio_scan_el_dir_attr_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf,
+ size_t len)
+{
+ struct iio_buffer *buffer = container_of(kobj, struct iio_buffer, scan_el_dir);
+ struct device_attribute *dattr = to_dev_attr(attr);
+
+ return dattr->store(&buffer->indio_dev->dev, dattr, buf, len);
+}
+
+static const struct sysfs_ops iio_scan_el_dir_sysfs_ops = {
+ .show = iio_scan_el_dir_attr_show,
+ .store = iio_scan_el_dir_attr_store,
+};
+
+static struct kobj_type iio_scan_el_dir_ktype = {
+ .sysfs_ops = &iio_scan_el_dir_sysfs_ops,
+};
+
+/*
+ * These iio_sysfs_{add,del}_attrs() are essentially re-implementations of
+ * sysfs_create_files() & sysfs_remove_files(), but they are meant to get
+ * around the const-pointer mismatch situation with using them.
+ *
+ * sysfs_{create,remove}_files() uses 'const struct attribute * const *ptr',
+ * while these are happy with just 'struct attribute **ptr'
+ */
+static int iio_sysfs_add_attrs(struct kobject *kobj, struct attribute **ptr)
+{
+ int err = 0;
+ int i;
+
+ for (i = 0; ptr[i] && !err; i++)
+ err = sysfs_create_file(kobj, ptr[i]);
+ if (err)
+ while (--i >= 0)
+ sysfs_remove_file(kobj, ptr[i]);
+ return err;
+}
+
+static void iio_sysfs_del_attrs(struct kobject *kobj, struct attribute **ptr)
+{
+ int i;
+
+ for (i = 0; ptr[i]; i++)
+ sysfs_remove_file(kobj, ptr[i]);
+}
+
+/**
+ * __iio_buffer_alloc_sysfs_and_mask() - Allocate sysfs attributes to an attached buffer
+ * @buffer: the buffer object for which the sysfs attributes are created for
+ * @indio_dev: the iio device to which the iio buffer belongs to
+ *
+ * Return 0, or negative for error.
+ *
+ * This function must be called for each single buffer. The sysfs attributes for that
+ * buffer will be created, and the IIO device object will be the parent kobject of that
+ * the kobjects created here.
+ * Because we need to redirect sysfs attribute to it's IIO buffer object, we need to
+ * implement our own sysfs_ops, and each IIO buffer will keep a kobject for the
+ * 'bufferX' directory and one for the 'scan_elements' directory.
+ * And in order to do this, this function must be called after the IIO device object
+ * has been added via device_add(). This fundamentally changes how sysfs attributes
+ * were created before (with one single IIO buffer per IIO device), where the
+ * sysfs attributes for the buffer were mapped as attribute groups on the IIO device
+ * groups object list.
+ * Using kobjects directly for the 'bufferX' and 'scan_elements' directories allows
+ * us to symlink them back to keep backwards compatibility for the old sysfs interface
+ * for IIO buffers while also allowing us to support multiple IIO buffers per one
+ * IIO device.
+ */
static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
struct iio_dev *indio_dev)
{
@@ -1282,12 +1398,16 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
sizeof(struct attribute *) * attrcount);
- attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
+ buffer->buffer_attrs = attr;
- buffer->buffer_group.name = "buffer";
- buffer->buffer_group.attrs = attr;
+ ret = kobject_init_and_add(&buffer->buffer_dir, &iio_buffer_dir_ktype,
+ &indio_dev->dev.kobj, "buffer");
+ if (ret)
+ goto error_buffer_free_attrs;
- indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
+ ret = iio_sysfs_add_attrs(&buffer->buffer_dir, buffer->buffer_attrs);
+ if (ret)
+ goto error_buffer_kobject_put;
attrcount = 0;
INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
@@ -1317,32 +1437,57 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
}
}
- buffer->scan_el_group.name = iio_scan_elements_group_name;
-
- buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
- sizeof(buffer->scan_el_group.attrs[0]),
- GFP_KERNEL);
- if (buffer->scan_el_group.attrs == NULL) {
+ buffer->scan_el_attrs = kcalloc(attrcount + 1,
+ sizeof(buffer->scan_el_attrs[0]),
+ GFP_KERNEL);
+ if (buffer->scan_el_attrs == NULL) {
ret = -ENOMEM;
goto error_free_scan_mask;
}
- attrn = 0;
+ ret = kobject_init_and_add(&buffer->scan_el_dir, &iio_scan_el_dir_ktype,
+ &indio_dev->dev.kobj, "scan_elements");
+ if (ret)
+ goto error_free_scan_attrs;
+
+ attrn = 0;
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->scan_el_attrs[attrn++] = &p->dev_attr.attr;
+
+ ret = iio_sysfs_add_attrs(&buffer->scan_el_dir, buffer->scan_el_attrs);
+ if (ret)
+ goto error_scan_kobject_put;
return 0;
+error_scan_kobject_put:
+ kobject_put(&buffer->scan_el_dir);
+error_free_scan_attrs:
+ kfree(buffer->scan_el_attrs);
error_free_scan_mask:
bitmap_free(buffer->scan_mask);
error_cleanup_dynamic:
+ iio_sysfs_del_attrs(&buffer->buffer_dir, buffer->buffer_attrs);
iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
- kfree(buffer->buffer_group.attrs);
+error_buffer_kobject_put:
+ kobject_put(&buffer->buffer_dir);
+error_buffer_free_attrs:
+ kfree(buffer->buffer_attrs);
return ret;
}
+/**
+ * iio_buffer_alloc_sysfs_and_mask() - Allocate sysfs attributes to attached buffers
+ * @indio_dev: the iio device for which to create the buffer sysfs attributes
+ *
+ * Return 0, or negative for error.
+ *
+ * If the IIO device has no buffer attached, no sysfs attributes will be created.
+ * This function must be called after the IIO device object has been created and
+ * registered with device_add(). See __iio_buffer_alloc_sysfs_and_mask() for more
+ * details.
+ */
int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer = indio_dev->buffer;
@@ -1364,14 +1509,28 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
return __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev);
}
+/**
+ * __iio_buffer_free_sysfs_and_mask() - Free sysfs objects for a single IIO buffer
+ * @buffer: the iio buffer for which to destroy the objects
+ */
static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
{
+ iio_sysfs_del_attrs(&buffer->scan_el_dir, buffer->scan_el_attrs);
+ kobject_put(&buffer->scan_el_dir);
+ kfree(buffer->scan_el_attrs);
bitmap_free(buffer->scan_mask);
- kfree(buffer->buffer_group.attrs);
- kfree(buffer->scan_el_group.attrs);
+ iio_sysfs_del_attrs(&buffer->buffer_dir, buffer->buffer_attrs);
iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
+ kobject_put(&buffer->buffer_dir);
+ kfree(buffer->buffer_attrs);
}
+/**
+ * iio_buffer_free_sysfs_and_mask() - Free sysfs objects for all IIO buffers
+ * @indio_dev: the iio device for which to destroy the objects
+ *
+ * If the IIO device has no buffer attached, nothing will be done.
+ */
void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer = indio_dev->buffer;
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 0a6fd299a978..95d66745f118 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1817,18 +1817,11 @@ 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) {
@@ -1857,14 +1850,21 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
if (ret < 0)
goto error_unreg_eventset;
+ 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_device_del;
+ }
+
return 0;
+error_device_del:
+ cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
error_unreg_eventset:
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;
@@ -1880,6 +1880,8 @@ void iio_device_unregister(struct iio_dev *indio_dev)
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_ioctl_handler *h, *t;
+ iio_buffer_free_sysfs_and_mask(indio_dev);
+
cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
mutex_lock(&indio_dev->info_exist_lock);
@@ -1897,8 +1899,6 @@ 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 67d73d465e02..77e169e51434 100644
--- a/include/linux/iio/buffer_impl.h
+++ b/include/linux/iio/buffer_impl.h
@@ -103,14 +103,20 @@ struct iio_buffer {
/* @scan_el_dev_attr_list: List of scan element related attributes. */
struct list_head scan_el_dev_attr_list;
- /* @buffer_group: Attributes of the buffer group. */
- struct attribute_group buffer_group;
+ /* @buffer_dir: kobject for the 'buffer' directory of this buffer */
+ struct kobject buffer_dir;
+
+ /* @buffer_attrs: Attributes of the buffer group. */
+ struct attribute **buffer_attrs;
+
+ /* @scan_el_dir: kobject for the 'scan_elements' directory of this buffer */
+ struct kobject scan_el_dir;
/*
- * @scan_el_group: Attribute group for those attributes not
+ * @scan_el_attrs: Array of attributes for those attributes not
* created from the iio_chan_info array.
*/
- struct attribute_group scan_el_group;
+ struct attribute **scan_el_attrs;
/* @attrs: Standard attributes of the buffer. */
const struct attribute **attrs;
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index e4a9822e6495..59b317dc45b8 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -556,7 +556,7 @@ 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 4
const struct attribute_group *groups[IIO_MAX_GROUPS + 1];
int groupcounter;
--
2.17.1
next prev parent reply other threads:[~2021-01-22 17:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 15:57 [PATCH v2 00/12] iio: core,buffer: add support for multiple IIO buffers per IIO device Alexandru Ardelean
2021-01-22 15:57 ` [PATCH v2 01/12] iio: core: register chardev only if needed Alexandru Ardelean
2021-01-22 15:57 ` [PATCH v2 02/12] iio: buffer: add back-ref from iio_buffer to iio_dev Alexandru Ardelean
2021-01-22 15:57 ` Alexandru Ardelean [this message]
2021-01-22 15:57 ` [PATCH v2 04/12] iio: buffer: add index to the first IIO buffer dir and symlink it back Alexandru Ardelean
2021-01-22 15:57 ` [PATCH v2 05/12] iio: core: split __iio_device_attr_init() to init only the attr object Alexandru Ardelean
2021-01-22 15:57 ` [PATCH v2 06/12] iio: buffer: re-route scan_elements via it's kobj_type Alexandru Ardelean
2021-01-22 16:12 ` Alexandru Ardelean
2021-01-22 15:58 ` [PATCH v2 07/12] iio: buffer: re-route core buffer attributes via it's new kobj_type Alexandru Ardelean
2021-01-22 15:58 ` [PATCH v2 08/12] iio: buffer: add helper to get the IIO device to which a buffer belongs Alexandru Ardelean
2021-01-22 15:58 ` [PATCH v2 09/12] iio: re-route all buffer attributes through new buffer kobj_type Alexandru Ardelean
2021-01-22 15:58 ` [PATCH v2 10/12] iio: core: wrap iio device & buffer into struct for character devices Alexandru Ardelean
2021-01-22 15:58 ` [PATCH v2 11/12] iio: buffer: introduce support for attaching more IIO buffers Alexandru Ardelean
2021-01-22 15:58 ` [PATCH v2 12/12] iio: buffer: add ioctl() to support opening extra buffers for IIO device Alexandru Ardelean
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