staging:iio: Add polling of events on the ring access chrdev.

Staging one of combining the ring chrdevs.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/iio/industrialio-ring.c b/drivers/staging/iio/industrialio-ring.c
index 5d7cd0e..5c3f466 100644 (file)
--- 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 d51c21c..0640a8a 100644 (file)
--- 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 (file)
--- 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;