@@ -1124,6 +1124,13 @@ Contact: linux-iio@vger.kernel.org
Description:
Number of scans contained by the buffer.
+What: /sys/bus/iio/devices/iio:deviceX/bufferY/direction
+KernelVersion: 5.11
+Contact: linux-iio@vger.kernel.org
+Description:
+ Returns the direction of the data stream of the buffer.
+ The output is "in" or "out".
+
What: /sys/bus/iio/devices/iio:deviceX/buffer/enable
KernelVersion: 2.6.35
What: /sys/bus/iio/devices/iio:deviceX/bufferY/enable
@@ -162,6 +162,69 @@ static ssize_t iio_buffer_read(struct file *filp, char __user *buf,
return ret;
}
+static size_t iio_buffer_space_available(struct iio_buffer *buf)
+{
+ if (buf->access->space_available)
+ return buf->access->space_available(buf);
+
+ return SIZE_MAX;
+}
+
+static ssize_t iio_buffer_write(struct file *filp, const char __user *buf,
+ size_t n, loff_t *f_ps)
+{
+ struct iio_dev_buffer_pair *ib = filp->private_data;
+ struct iio_buffer *rb = ib->buffer;
+ struct iio_dev *indio_dev = ib->indio_dev;
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ size_t datum_size;
+ size_t to_wait;
+ int ret;
+
+ if (!rb || !rb->access->write)
+ return -EINVAL;
+
+ datum_size = rb->bytes_per_datum;
+
+ /*
+ * If datum_size is 0 there will never be anything to read from the
+ * buffer, so signal end of file now.
+ */
+ if (!datum_size)
+ return 0;
+
+ if (filp->f_flags & O_NONBLOCK)
+ to_wait = 0;
+ else
+ to_wait = min_t(size_t, n / datum_size, rb->watermark);
+
+ add_wait_queue(&rb->pollq, &wait);
+ do {
+ if (!indio_dev->info) {
+ ret = -ENODEV;
+ break;
+ }
+
+ if (iio_buffer_space_available(rb) < to_wait) {
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ wait_woken(&wait, TASK_INTERRUPTIBLE,
+ MAX_SCHEDULE_TIMEOUT);
+ continue;
+ }
+
+ ret = rb->access->write(rb, n, buf);
+ if (ret == 0 && (filp->f_flags & O_NONBLOCK))
+ ret = -EAGAIN;
+ } while (ret == 0);
+ remove_wait_queue(&rb->pollq, &wait);
+
+ return ret;
+}
+
/**
* iio_buffer_poll() - poll the buffer to find out if it has data
* @filp: File structure pointer for device access
@@ -182,8 +245,19 @@ static __poll_t iio_buffer_poll(struct file *filp,
return 0;
poll_wait(filp, &rb->pollq, wait);
- if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
- return EPOLLIN | EPOLLRDNORM;
+
+ switch (rb->direction) {
+ case IIO_BUFFER_DIRECTION_IN:
+ if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
+ return EPOLLIN | EPOLLRDNORM;
+ break;
+ case IIO_BUFFER_DIRECTION_OUT:
+ if (iio_buffer_space_available(rb) >= rb->watermark)
+ return EPOLLOUT | EPOLLWRNORM;
+ break;
+ }
+
+ /* need a way of knowing if there may be enough data... */
return 0;
}
@@ -232,6 +306,16 @@ void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
}
}
+int iio_buffer_remove_sample(struct iio_buffer *buffer, u8 *data)
+{
+ if (!buffer || !buffer->access)
+ return -EINVAL;
+ if (!buffer->access->write)
+ return -ENOSYS;
+ return buffer->access->remove_from(buffer, data);
+}
+EXPORT_SYMBOL_GPL(iio_buffer_remove_sample);
+
void iio_buffer_init(struct iio_buffer *buffer)
{
INIT_LIST_HEAD(&buffer->demux_list);
@@ -803,6 +887,8 @@ static int iio_verify_update(struct iio_dev *indio_dev,
}
if (insert_buffer) {
+ if (insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT)
+ strict_scanmask = true;
bitmap_or(compound_mask, compound_mask,
insert_buffer->scan_mask, indio_dev->masklength);
scan_timestamp |= insert_buffer->scan_timestamp;
@@ -945,6 +1031,8 @@ static int iio_update_demux(struct iio_dev *indio_dev)
int ret;
list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
+ if (buffer->direction == IIO_BUFFER_DIRECTION_OUT)
+ continue;
ret = iio_buffer_update_demux(indio_dev, buffer);
if (ret < 0)
goto error_clear_mux_table;
@@ -1155,6 +1243,11 @@ int iio_update_buffers(struct iio_dev *indio_dev,
mutex_lock(&indio_dev->info_exist_lock);
mutex_lock(&indio_dev->mlock);
+ if (insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
if (insert_buffer && iio_buffer_is_active(insert_buffer))
insert_buffer = NULL;
@@ -1273,6 +1366,22 @@ static ssize_t iio_dma_show_data_available(struct device *dev,
return sprintf(buf, "%zu\n", iio_buffer_data_available(buffer));
}
+static ssize_t direction_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ switch (buffer->direction) {
+ case IIO_BUFFER_DIRECTION_IN:
+ return sprintf(buf, "in\n");
+ case IIO_BUFFER_DIRECTION_OUT:
+ return sprintf(buf, "out\n");
+ default:
+ return -EINVAL;
+ }
+}
+
static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
iio_buffer_write_length);
static struct device_attribute dev_attr_length_ro = __ATTR(length,
@@ -1285,9 +1394,11 @@ static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
S_IRUGO, iio_buffer_show_watermark, NULL);
static DEVICE_ATTR(data_available, S_IRUGO,
iio_dma_show_data_available, NULL);
+static DEVICE_ATTR_RO(direction);
static struct attribute *iio_buffer_attrs[] = {
&dev_attr_length.attr,
+ &dev_attr_direction.attr,
&dev_attr_enable.attr,
&dev_attr_watermark.attr,
&dev_attr_data_available.attr,
@@ -1401,6 +1512,7 @@ static const struct file_operations iio_buffer_chrdev_fileops = {
.owner = THIS_MODULE,
.llseek = noop_llseek,
.read = iio_buffer_read,
+ .write = iio_buffer_write,
.poll = iio_buffer_poll,
.unlocked_ioctl = iio_buffer_ioctl,
.compat_ioctl = compat_ptr_ioctl,
@@ -1920,8 +2032,16 @@ static int iio_buffer_mmap(struct file *filep, struct vm_area_struct *vma)
if (!(vma->vm_flags & VM_SHARED))
return -EINVAL;
- if (!(vma->vm_flags & VM_READ))
- return -EINVAL;
+ switch (buffer->direction) {
+ case IIO_BUFFER_DIRECTION_IN:
+ if (!(vma->vm_flags & VM_READ))
+ return -EINVAL;
+ break;
+ case IIO_BUFFER_DIRECTION_OUT:
+ if (!(vma->vm_flags & VM_WRITE))
+ return -EINVAL;
+ break;
+ }
return buffer->access->mmap(buffer, vma);
}
@@ -11,8 +11,15 @@
struct iio_buffer;
+enum iio_buffer_direction {
+ IIO_BUFFER_DIRECTION_IN,
+ IIO_BUFFER_DIRECTION_OUT,
+};
+
int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data);
+int iio_buffer_remove_sample(struct iio_buffer *buffer, u8 *data);
+
/**
* iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers
* @indio_dev: iio_dev structure for device.
@@ -7,6 +7,7 @@
#ifdef CONFIG_IIO_BUFFER
#include <uapi/linux/iio/buffer.h>
+#include <linux/iio/buffer.h>
struct iio_dev;
struct iio_buffer;
@@ -23,6 +24,10 @@ struct iio_buffer;
* @read: try to get a specified number of bytes (must exist)
* @data_available: indicates how much data is available for reading from
* the buffer.
+ * @remove_from: remove sample from buffer. Drivers should calls this to
+ * remove a sample from a buffer.
+ * @write: try to write a number of bytes
+ * @space_available: returns the amount of bytes available in a buffer
* @request_update: if a parameter change has been marked, update underlying
* storage.
* @set_bytes_per_datum:set number of bytes per datum
@@ -61,6 +66,9 @@ struct iio_buffer_access_funcs {
int (*store_to)(struct iio_buffer *buffer, const void *data);
int (*read)(struct iio_buffer *buffer, size_t n, char __user *buf);
size_t (*data_available)(struct iio_buffer *buffer);
+ int (*remove_from)(struct iio_buffer *buffer, void *data);
+ int (*write)(struct iio_buffer *buffer, size_t n, const char __user *buf);
+ size_t (*space_available)(struct iio_buffer *buffer);
int (*request_update)(struct iio_buffer *buffer);
@@ -103,6 +111,9 @@ struct iio_buffer {
/** @bytes_per_datum: Size of individual datum including timestamp. */
size_t bytes_per_datum;
+ /* @direction: Direction of the data stream (in/out). */
+ enum iio_buffer_direction direction;
+
/**
* @access: Buffer access functions associated with the
* implementation.