From: Alexandru Ardelean <alexandru.ardelean@analog.com>
To: <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: <lars@metafoo.de>, <jic23@kernel.org>, <pmeerw@pmeerw.net>,
Alexandru Ardelean <alexandru.ardelean@analog.com>
Subject: [PATCH v5 3/6] iio: core: register chardev only if needed
Date: Sun, 26 Apr 2020 10:38:14 +0300 [thread overview]
Message-ID: <20200426073817.33307-4-alexandru.ardelean@analog.com> (raw)
In-Reply-To: <20200426073817.33307-1-alexandru.ardelean@analog.com>
The final intent is to localize all buffer ops into the
industrialio-buffer.c file, to be able to add support for multiple buffers
per IIO device.
We only need a chardev if we need to support buffers and/or events.
With this change, a chardev will be created only if an IIO buffer is
attached OR an event_interface is configured.
Otherwise, no chardev will be created, and the IIO device will get
registered with the 'device_add()' call.
Quite a lot of IIO devices don't really need a chardev, so this is a minor
improvement to the IIO core, as the IIO device will take up (slightly)
fewer resources.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/industrialio-core.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 32c489139cd2..a65022396329 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1682,6 +1682,15 @@ static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
static const struct iio_buffer_setup_ops noop_ring_setup_ops;
+static const struct file_operations iio_event_fileops = {
+ .release = iio_chrdev_release,
+ .open = iio_chrdev_open,
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = iio_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+};
+
int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
{
int ret;
@@ -1732,11 +1741,18 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
indio_dev->setup_ops == NULL)
indio_dev->setup_ops = &noop_ring_setup_ops;
- cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
+ if (indio_dev->buffer)
+ cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
+ else if (indio_dev->event_interface)
+ cdev_init(&indio_dev->chrdev, &iio_event_fileops);
indio_dev->chrdev.owner = this_mod;
- ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
+ if (indio_dev->buffer || indio_dev->event_interface)
+ ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
+ else
+ ret = device_add(&indio_dev->dev);
+
if (ret < 0)
goto error_unreg_eventset;
@@ -1760,7 +1776,10 @@ EXPORT_SYMBOL(__iio_device_register);
**/
void iio_device_unregister(struct iio_dev *indio_dev)
{
- cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
+ if (indio_dev->buffer || indio_dev->event_interface)
+ cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
+ else
+ device_del(&indio_dev->dev);
mutex_lock(&indio_dev->info_exist_lock);
--
2.17.1
next prev parent reply other threads:[~2020-04-26 7:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-26 7:38 [PATCH v5 0/6] iio: core,buffer: re-organize chardev creation Alexandru Ardelean
2020-04-26 7:38 ` [PATCH v5 1/6] iio: buffer: add back-ref from iio_buffer to iio_dev Alexandru Ardelean
2020-04-26 7:38 ` [PATCH v5 2/6] iio: core,buffer: wrap iio_buffer_put() call into iio_buffers_put() Alexandru Ardelean
2020-04-26 7:38 ` Alexandru Ardelean [this message]
2020-04-26 7:38 ` [PATCH v5 4/6] iio: buffer,event: duplicate chardev creation for buffers & events Alexandru Ardelean
2020-04-26 10:00 ` Jonathan Cameron
2020-04-27 6:38 ` Ardelean, Alexandru
2020-04-26 7:38 ` [PATCH v5 5/6] iio: core: add simple centralized mechanism for ioctl() handlers Alexandru Ardelean
2020-04-26 10:10 ` Jonathan Cameron
2020-04-26 10:21 ` Jonathan Cameron
2020-04-27 6:43 ` Ardelean, Alexandru
2020-04-27 10:04 ` Ardelean, Alexandru
2020-04-26 7:38 ` [PATCH v5 6/6] iio: core: use new common ioctl() mechanism Alexandru Ardelean
2020-04-26 10:13 ` Jonathan Cameron
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