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Subject[PATCH 05/21] staging:iio: Add polling of events on the ring access chrdev.
Date
Staging one of combining the ring chrdevs.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
---
drivers/staging/iio/industrialio-ring.c | 29 ++++++++++++++++++++++++-----
drivers/staging/iio/ring_generic.h | 3 +++
drivers/staging/iio/ring_sw.c | 8 ++++++++
3 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/iio/industrialio-ring.c b/drivers/staging/iio/industrialio-ring.c
index 466b9fa..464fec2 100644
--- a/drivers/staging/iio/industrialio-ring.c
+++ b/drivers/staging/iio/industrialio-ring.c
@@ -18,6 +18,7 @@
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/slab.h>
+#include <linux/poll.h>

#include "iio.h"
#include "ring_generic.h"
@@ -90,10 +91,27 @@ static ssize_t iio_ring_read_first_n_outer(struct file *filp, char __user *buf,
return ret;
}

+/**
+ * iio_ring_poll() - poll the ring to find out if it has data
+ */
+static unsigned int iio_ring_poll(struct file *filp,
+ struct poll_table_struct *wait)
+{
+ struct iio_ring_buffer *rb = filp->private_data;
+ int ret = 0;
+
+ poll_wait(filp, &rb->pollq, wait);
+ if (rb->stufftoread)
+ return POLLIN | POLLRDNORM;
+ /* need a way of knowing if there may be enough data... */
+ return ret;
+}
+
static const struct file_operations iio_ring_fileops = {
.read = iio_ring_read_first_n_outer,
.release = iio_ring_release,
.open = iio_ring_open,
+ .poll = iio_ring_poll,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
@@ -211,6 +229,7 @@ void iio_ring_buffer_init(struct iio_ring_buffer *ring,
ring->indio_dev = dev_info;
ring->ev_int.private = ring;
ring->access_handler.private = ring;
+ init_waitqueue_head(&ring->pollq);
}
EXPORT_SYMBOL(iio_ring_buffer_init);

@@ -392,7 +411,7 @@ int iio_ring_buffer_register_ex(struct iio_ring_buffer *ring, int id,
ring->owner);

if (ret)
- goto error_free_ring_buffer_event_chrdev;
+ goto error_ret;

if (ring->scan_el_attrs) {
ret = sysfs_create_group(&ring->dev.kobj,
@@ -400,13 +419,13 @@ int iio_ring_buffer_register_ex(struct iio_ring_buffer *ring, int id,
if (ret) {
dev_err(&ring->dev,
"Failed to add sysfs scan elements\n");
- goto error_free_ring_buffer_event_chrdev;
+ goto error_free_ring_buffer_access_chrdev;
}
} else if (channels) {
ret = sysfs_create_group(&ring->dev.kobj,
&iio_scan_el_dummy_group);
if (ret)
- goto error_free_ring_buffer_event_chrdev;
+ goto error_free_ring_buffer_access_chrdev;
}


@@ -424,8 +443,8 @@ int iio_ring_buffer_register_ex(struct iio_ring_buffer *ring, int id,
return 0;
error_cleanup_dynamic:
__iio_ring_attr_cleanup(ring);
-error_free_ring_buffer_event_chrdev:
- __iio_free_ring_buffer_event_chrdev(ring);
+error_free_ring_buffer_access_chrdev:
+ __iio_free_ring_buffer_access_chrdev(ring);
error_remove_device:
device_del(&ring->dev);
error_ret:
diff --git a/drivers/staging/iio/ring_generic.h b/drivers/staging/iio/ring_generic.h
index 320a11d..37b5eda 100644
--- a/drivers/staging/iio/ring_generic.h
+++ b/drivers/staging/iio/ring_generic.h
@@ -139,6 +139,9 @@ struct iio_ring_buffer {

struct list_head scan_el_dev_attr_list;
struct list_head scan_el_en_attr_list;
+
+ wait_queue_head_t pollq;
+ bool stufftoread;
};

/**
diff --git a/drivers/staging/iio/ring_sw.c b/drivers/staging/iio/ring_sw.c
index 0004814..53c6774 100644
--- a/drivers/staging/iio/ring_sw.c
+++ b/drivers/staging/iio/ring_sw.c
@@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/workqueue.h>
+#include <linux/sched.h>
#include <linux/poll.h>
#include "ring_sw.h"
#include "trigger.h"
@@ -136,6 +137,8 @@ static int iio_store_to_sw_ring(struct iio_sw_ring_buffer *ring,
ret = __iio_push_event(&ring->buf.ev_int,
code,
timestamp);
+ ring->buf.stufftoread = true;
+ wake_up_interruptible(&ring->buf.pollq);
}
return ret;
}
@@ -261,6 +264,10 @@ int iio_read_first_n_sw_rb(struct iio_ring_buffer *r,
ret = -EFAULT;
goto error_free_data_cpy;
}
+
+ if (bytes_to_rip >= ring->buf.length*ring->buf.bytes_per_datum/2)
+ ring->buf.stufftoread = 0;
+
error_free_data_cpy:
kfree(data);
error_ret:
@@ -310,6 +317,7 @@ int iio_request_update_sw_rb(struct iio_ring_buffer *r)
int ret = 0;
struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);

+ r->stufftoread = false;
spin_lock(&ring->use_lock);
if (!ring->update_needed)
goto error_ret;
--
1.7.3.4


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