IIO: Move the core files to drivers/iio

Take the core support + the kfifo buffer implentation out of
staging.  Whilst we are far from done in improving this subsystem
it is now at a stage where the userspae interfaces (provided by
the core) can be considered stable.

Drivers will follow over a longer time scale.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
new file mode 100644
index 000000000000..6bf9d05f4841
--- /dev/null
+++ b/drivers/iio/kfifo_buf.c
@@ -0,0 +1,150 @@
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/workqueue.h>
+#include <linux/kfifo.h>
+#include <linux/mutex.h>
+#include <linux/iio/kfifo_buf.h>
+
+struct iio_kfifo {
+        struct iio_buffer buffer;
+        struct kfifo kf;
+        int update_needed;
+};
+
+#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
+
+static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
+                                int bytes_per_datum, int length)
+{
+        if ((length == 0) || (bytes_per_datum == 0))
+                return -EINVAL;
+
+        __iio_update_buffer(&buf->buffer, bytes_per_datum, length);
+        return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL);
+}
+
+static int iio_request_update_kfifo(struct iio_buffer *r)
+{
+        int ret = 0;
+        struct iio_kfifo *buf = iio_to_kfifo(r);
+
+        if (!buf->update_needed)
+                goto error_ret;
+        kfifo_free(&buf->kf);
+        ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
+                                   buf->buffer.length);
+error_ret:
+        return ret;
+}
+
+static int iio_get_length_kfifo(struct iio_buffer *r)
+{
+        return r->length;
+}
+
+static IIO_BUFFER_ENABLE_ATTR;
+static IIO_BUFFER_LENGTH_ATTR;
+
+static struct attribute *iio_kfifo_attributes[] = {
+        &dev_attr_length.attr,
+        &dev_attr_enable.attr,
+        NULL,
+};
+
+static struct attribute_group iio_kfifo_attribute_group = {
+        .attrs = iio_kfifo_attributes,
+        .name = "buffer",
+};
+
+static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
+{
+        return r->bytes_per_datum;
+}
+
+static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
+{
+        struct iio_kfifo *kf = iio_to_kfifo(r);
+        kf->update_needed = true;
+        return 0;
+}
+
+static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
+{
+        if (r->bytes_per_datum != bpd) {
+                r->bytes_per_datum = bpd;
+                iio_mark_update_needed_kfifo(r);
+        }
+        return 0;
+}
+
+static int iio_set_length_kfifo(struct iio_buffer *r, int length)
+{
+        if (r->length != length) {
+                r->length = length;
+                iio_mark_update_needed_kfifo(r);
+        }
+        return 0;
+}
+
+static int iio_store_to_kfifo(struct iio_buffer *r,
+                              u8 *data,
+                              s64 timestamp)
+{
+        int ret;
+        struct iio_kfifo *kf = iio_to_kfifo(r);
+        ret = kfifo_in(&kf->kf, data, r->bytes_per_datum);
+        if (ret != r->bytes_per_datum)
+                return -EBUSY;
+        return 0;
+}
+
+static int iio_read_first_n_kfifo(struct iio_buffer *r,
+                           size_t n, char __user *buf)
+{
+        int ret, copied;
+        struct iio_kfifo *kf = iio_to_kfifo(r);
+
+        if (n < r->bytes_per_datum)
+                return -EINVAL;
+
+        n = rounddown(n, r->bytes_per_datum);
+        ret = kfifo_to_user(&kf->kf, buf, n, &copied);
+
+        return copied;
+}
+
+static const struct iio_buffer_access_funcs kfifo_access_funcs = {
+        .store_to = &iio_store_to_kfifo,
+        .read_first_n = &iio_read_first_n_kfifo,
+        .request_update = &iio_request_update_kfifo,
+        .get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
+        .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
+        .get_length = &iio_get_length_kfifo,
+        .set_length = &iio_set_length_kfifo,
+};
+
+struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
+{
+        struct iio_kfifo *kf;
+
+        kf = kzalloc(sizeof *kf, GFP_KERNEL);
+        if (!kf)
+                return NULL;
+        kf->update_needed = true;
+        iio_buffer_init(&kf->buffer);
+        kf->buffer.attrs = &iio_kfifo_attribute_group;
+        kf->buffer.access = &kfifo_access_funcs;
+
+        return &kf->buffer;
+}
+EXPORT_SYMBOL(iio_kfifo_allocate);
+
+void iio_kfifo_free(struct iio_buffer *r)
+{
+        kfree(iio_to_kfifo(r));
+}
+EXPORT_SYMBOL(iio_kfifo_free);
+
+MODULE_LICENSE("GPL");