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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>, <rafael@kernel.org>,
	<gregkh@linuxfoundation.org>,
	Alexandru Ardelean <alexandru.ardelean@analog.com>
Subject: [PATCH v5 04/17] iio: core: rework iio device group creation
Date: Thu, 11 Feb 2021 14:24:39 +0200	[thread overview]
Message-ID: <20210211122452.78106-5-alexandru.ardelean@analog.com> (raw)
In-Reply-To: <20210211122452.78106-1-alexandru.ardelean@analog.com>

Up until now, the device groups that an IIO device had were limited to 6.
Two of these groups would account for buffer attributes (the buffer/ and
scan_elements/ directories).

Since we want to add multiple buffers per IIO device, this number may not
be enough, when adding a second buffer. So, this change reallocates the
groups array whenever an IIO device group is added, via a
iio_device_register_sysfs_group() helper.

This also means that the groups array should be assigned to
'indio_dev.dev.groups' really late, right before {cdev_}device_add() is
called to do the entire setup.
And we also must take care to free this array when the sysfs resources are
being cleaned up.

With this change we can also move the 'groups' & 'groupcounter' fields to
the iio_dev_opaque object. Up until now, this didn't make a whole lot of
sense (especially since we weren't sure how multibuffer support would look
like in the end).
But doing it now kills one birds with one stone.

An alternative, would be to add a configurable Kconfig symbol
CONFIG_IIO_MAX_BUFFERS_PER_DEVICE (or something like that) and compute a
static maximum of the groups we can support per IIO device. But that would
probably annoy a few people since that would make the system less
configurable.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/iio/iio_core.h             |  3 +++
 drivers/iio/industrialio-buffer.c  | 12 ++++++++++--
 drivers/iio/industrialio-core.c    | 30 +++++++++++++++++++++++++++---
 drivers/iio/industrialio-event.c   |  5 ++++-
 drivers/iio/industrialio-trigger.c |  6 ++----
 include/linux/iio/iio-opaque.h     |  4 ++++
 include/linux/iio/iio.h            |  5 -----
 7 files changed, 50 insertions(+), 15 deletions(-)

diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
index fced02cadcc3..7d5b179c1fe7 100644
--- a/drivers/iio/iio_core.h
+++ b/drivers/iio/iio_core.h
@@ -46,6 +46,9 @@ int __iio_add_chan_devattr(const char *postfix,
 			   struct list_head *attr_list);
 void iio_free_chan_devattr_list(struct list_head *attr_list);
 
+int iio_device_register_sysfs_group(struct iio_dev *indio_dev,
+				    const struct attribute_group *group);
+
 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals);
 
 /* Event interface flags */
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 2f7426a2f47c..cc846988fdb9 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1287,7 +1287,9 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 	buffer->buffer_group.name = "buffer";
 	buffer->buffer_group.attrs = attr;
 
-	indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
+	ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group);
+	if (ret)
+		goto error_free_buffer_attrs;
 
 	attrcount = 0;
 	INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
@@ -1330,14 +1332,20 @@ 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;
+
+	ret = iio_device_register_sysfs_group(indio_dev, &buffer->scan_el_group);
+	if (ret)
+		goto error_free_scan_el_attrs;
 
 	return 0;
 
+error_free_scan_el_attrs:
+	kfree(buffer->scan_el_group.attrs);
 error_free_scan_mask:
 	bitmap_free(buffer->scan_mask);
 error_cleanup_dynamic:
 	iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
+error_free_buffer_attrs:
 	kfree(buffer->buffer_group.attrs);
 
 	return ret;
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 0a6fd299a978..2db460ac30b2 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1452,6 +1452,25 @@ static ssize_t iio_store_timestamp_clock(struct device *dev,
 	return len;
 }
 
+int iio_device_register_sysfs_group(struct iio_dev *indio_dev,
+				    const struct attribute_group *group)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	const struct attribute_group **new, **old = iio_dev_opaque->groups;
+	unsigned int cnt = iio_dev_opaque->groupcounter;
+
+	new = krealloc(old, sizeof(*new) * (cnt + 2), GFP_KERNEL);
+	if (!new)
+		return -ENOMEM;
+
+	new[iio_dev_opaque->groupcounter++] = group;
+	new[iio_dev_opaque->groupcounter] = NULL;
+
+	iio_dev_opaque->groups = new;
+
+	return 0;
+}
+
 static DEVICE_ATTR(current_timestamp_clock, S_IRUGO | S_IWUSR,
 		   iio_show_timestamp_clock, iio_store_timestamp_clock);
 
@@ -1525,8 +1544,10 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
 	if (clk)
 		iio_dev_opaque->chan_attr_group.attrs[attrn++] = clk;
 
-	indio_dev->groups[indio_dev->groupcounter++] =
-		&iio_dev_opaque->chan_attr_group;
+	ret = iio_device_register_sysfs_group(indio_dev,
+					      &iio_dev_opaque->chan_attr_group);
+	if (ret)
+		goto error_clear_attrs;
 
 	return 0;
 
@@ -1543,6 +1564,7 @@ static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
 	iio_free_chan_devattr_list(&iio_dev_opaque->channel_attr_list);
 	kfree(iio_dev_opaque->chan_attr_group.attrs);
 	iio_dev_opaque->chan_attr_group.attrs = NULL;
+	kfree(iio_dev_opaque->groups);
 }
 
 static void iio_dev_release(struct device *device)
@@ -1592,7 +1614,6 @@ struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv)
 		ALIGN(sizeof(struct iio_dev_opaque), IIO_ALIGN);
 
 	dev->dev.parent = parent;
-	dev->dev.groups = dev->groups;
 	dev->dev.type = &iio_device_type;
 	dev->dev.bus = &iio_bus_type;
 	device_initialize(&dev->dev);
@@ -1853,6 +1874,9 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
 		indio_dev->chrdev.owner = this_mod;
 	}
 
+	/* assign device groups now; they should be all registered now */
+	indio_dev->dev.groups = iio_dev_opaque->groups;
+
 	ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
 	if (ret < 0)
 		goto error_unreg_eventset;
diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
index 7e532117ac55..ea8947cc21e4 100644
--- a/drivers/iio/industrialio-event.c
+++ b/drivers/iio/industrialio-event.c
@@ -544,7 +544,10 @@ int iio_device_register_eventset(struct iio_dev *indio_dev)
 	/* Add all elements from the list. */
 	list_for_each_entry(p, &ev_int->dev_attr_list, l)
 		ev_int->group.attrs[attrn++] = &p->dev_attr.attr;
-	indio_dev->groups[indio_dev->groupcounter++] = &ev_int->group;
+
+	ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group);
+	if (ret)
+		goto error_free_setup_event_lines;
 
 	ev_int->ioctl_handler.ioctl = iio_event_ioctl;
 	iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev,
diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index 438d5012e8b8..a035d5c2a445 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -694,10 +694,8 @@ EXPORT_SYMBOL(iio_trigger_validate_own_device);
 
 int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
 {
-	indio_dev->groups[indio_dev->groupcounter++] =
-		&iio_trigger_consumer_attr_group;
-
-	return 0;
+	return iio_device_register_sysfs_group(indio_dev,
+					       &iio_trigger_consumer_attr_group);
 }
 
 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h
index 07c5a8e52ca8..8ba13a5c7af6 100644
--- a/include/linux/iio/iio-opaque.h
+++ b/include/linux/iio/iio-opaque.h
@@ -12,6 +12,8 @@
  *				attributes
  * @chan_attr_group:		group for all attrs in base directory
  * @ioctl_handlers:		ioctl handlers registered with the core handler
+ * @groups:			attribute groups
+ * @groupcounter:		index of next attribute group
  * @debugfs_dentry:		device specific debugfs dentry
  * @cached_reg_addr:		cached register address for debugfs reads
  * @read_buf:			read buffer to be used for the initial reg read
@@ -24,6 +26,8 @@ struct iio_dev_opaque {
 	struct list_head		channel_attr_list;
 	struct attribute_group		chan_attr_group;
 	struct list_head		ioctl_handlers;
+	const struct attribute_group	**groups;
+	int				groupcounter;
 #if defined(CONFIG_DEBUG_FS)
 	struct dentry			*debugfs_dentry;
 	unsigned			cached_reg_addr;
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index e4a9822e6495..f8585d01fc76 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -518,8 +518,6 @@ struct iio_buffer_setup_ops {
  * @setup_ops:		[DRIVER] callbacks to call before and after buffer
  *			enable/disable
  * @chrdev:		[INTERN] associated character device
- * @groups:		[INTERN] attribute groups
- * @groupcounter:	[INTERN] index of next attribute group
  * @flags:		[INTERN] file ops related flags including busy flag.
  * @priv:		[DRIVER] reference to driver's private information
  *			**MUST** be accessed **ONLY** via iio_priv() helper
@@ -556,9 +554,6 @@ struct iio_dev {
 	struct mutex			info_exist_lock;
 	const struct iio_buffer_setup_ops	*setup_ops;
 	struct cdev			chrdev;
-#define IIO_MAX_GROUPS 6
-	const struct attribute_group	*groups[IIO_MAX_GROUPS + 1];
-	int				groupcounter;
 
 	unsigned long			flags;
 	void				*priv;
-- 
2.17.1


  parent reply	other threads:[~2021-02-11 12:31 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-11 12:24 [PATCH v5 00/17] iio: core,buffer: add support for multiple IIO buffers per IIO device Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 01/17] docs: ioctl-number.rst: reserve IIO subsystem ioctl() space Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 02/17] iio: core: register chardev only if needed Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 03/17] iio: core-trigger: make iio_device_register_trigger_consumer() an int return Alexandru Ardelean
2021-02-11 12:24 ` Alexandru Ardelean [this message]
2021-02-11 12:24 ` [PATCH v5 05/17] iio: buffer: group attr count and attr alloc Alexandru Ardelean
2021-02-14 12:57   ` Jonathan Cameron
2021-02-11 12:24 ` [PATCH v5 06/17] iio: core: merge buffer/ & scan_elements/ attributes Alexandru Ardelean
2021-02-14 13:02   ` Jonathan Cameron
2021-02-11 12:24 ` [PATCH v5 07/17] iio: add reference to iio buffer on iio_dev_attr Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 08/17] iio: buffer: wrap all buffer attributes into iio_dev_attr Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 09/17] iio: buffer: dmaengine: obtain buffer object from attribute Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 10/17] iio: core: wrap iio device & buffer into struct for character devices Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 11/17] iio: buffer: move __iio_buffer_free_sysfs_and_mask() before alloc Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 12/17] iio: buffer: introduce support for attaching more IIO buffers Alexandru Ardelean
2021-02-14 13:19   ` Jonathan Cameron
2021-02-14 14:02     ` Alexandru Ardelean
2021-02-14 14:37       ` Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 13/17] iio: buffer: add ioctl() to support opening extra buffers for IIO device Alexandru Ardelean
2021-02-14 14:37   ` Jonathan Cameron
2021-02-15  9:35     ` Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 14/17] iio: core: rename 'dev' -> 'indio_dev' in iio_device_alloc() Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 15/17] tools: iio: make iioutils_get_type() private in iio_utils Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 16/17] tools: iio: privatize globals and functions in iio_generic_buffer.c file Alexandru Ardelean
2021-02-11 12:24 ` [PATCH v5 17/17] tools: iio: convert iio_generic_buffer to use new IIO buffer API Alexandru Ardelean
2021-02-14 14:49   ` Jonathan Cameron

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