V4L/DVB (7369): drivers/media/video/soc_camera.c: reads return size_t

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / media / video / soc_camera.c

/*
 * camera image capture (abstract) bus driver
 *
 * Copyright (C) 2008, Guennadi Liakhovetski <kernel@pengutronix.de>
 *
 * This driver provides an interface between platform-specific camera
 * busses and camera devices. It should be used if the camera is
 * connected not over a "proper" bus like PCI or USB, but over a
 * special bus, like, for example, the Quick Capture interface on PXA270
 * SoCs. Later it should also be used for i.MX31 SoCs from Freescale.
 * It can handle multiple cameras and / or multiple busses, which can
 * be used, e.g., in stereo-vision applications.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>

#include <media/v4l2-common.h>
#include <media/v4l2-dev.h>
#include <media/soc_camera.h>

static LIST_HEAD(hosts);
static LIST_HEAD(devices);
static DEFINE_MUTEX(list_lock);
static DEFINE_MUTEX(video_lock);

const static struct soc_camera_data_format*
format_by_fourcc(struct soc_camera_device *icd, unsigned int fourcc)
{
        unsigned int i;

        for (i = 0; i < icd->ops->num_formats; i++)
                if (icd->ops->formats[i].fourcc == fourcc)
                        return icd->ops->formats + i;
        return NULL;
}

static int soc_camera_try_fmt_cap(struct file *file, void *priv,
                                  struct v4l2_format *f)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici =
                to_soc_camera_host(icd->dev.parent);
        enum v4l2_field field;
        const struct soc_camera_data_format *fmt;
        int ret;

        WARN_ON(priv != file->private_data);

        fmt = format_by_fourcc(icd, f->fmt.pix.pixelformat);
        if (!fmt) {
                dev_dbg(&icd->dev, "invalid format 0x%08x\n",
                        f->fmt.pix.pixelformat);
                return -EINVAL;
        }

        dev_dbg(&icd->dev, "fmt: 0x%08x\n", fmt->fourcc);

        field = f->fmt.pix.field;

        if (field == V4L2_FIELD_ANY) {
                field = V4L2_FIELD_NONE;
        } else if (V4L2_FIELD_NONE != field) {
                dev_err(&icd->dev, "Field type invalid.\n");
                return -EINVAL;
        }

        /* test physical bus parameters */
        ret = ici->try_bus_param(icd, f->fmt.pix.pixelformat);
        if (ret)
                return ret;

        /* limit format to hardware capabilities */
        ret = ici->try_fmt_cap(icd, f);

        /* calculate missing fields */
        f->fmt.pix.field = field;
        f->fmt.pix.bytesperline =
                (f->fmt.pix.width * fmt->depth) >> 3;
        f->fmt.pix.sizeimage =
                f->fmt.pix.height * f->fmt.pix.bytesperline;

        return ret;
}

static int soc_camera_enum_input(struct file *file, void *priv,
                                 struct v4l2_input *inp)
{
        if (inp->index != 0)
                return -EINVAL;

        inp->type = V4L2_INPUT_TYPE_CAMERA;
        inp->std = V4L2_STD_UNKNOWN;
        strcpy(inp->name, "Camera");

        return 0;
}

static int soc_camera_g_input(struct file *file, void *priv, unsigned int *i)
{
        *i = 0;

        return 0;
}

static int soc_camera_s_input(struct file *file, void *priv, unsigned int i)
{
        if (i > 0)
                return -EINVAL;

        return 0;
}

static int soc_camera_s_std(struct file *file, void *priv, v4l2_std_id *a)
{
        return 0;
}

static int soc_camera_reqbufs(struct file *file, void *priv,
                              struct v4l2_requestbuffers *p)
{
        int ret;
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici =
                to_soc_camera_host(icd->dev.parent);

        WARN_ON(priv != file->private_data);

        dev_dbg(&icd->dev, "%s: %d\n", __FUNCTION__, p->memory);

        ret = videobuf_reqbufs(&icf->vb_vidq, p);
        if (ret < 0)
                return ret;

        return ici->reqbufs(icf, p);

        return ret;
}

static int soc_camera_querybuf(struct file *file, void *priv,
                               struct v4l2_buffer *p)
{
        struct soc_camera_file *icf = file->private_data;

        WARN_ON(priv != file->private_data);

        return videobuf_querybuf(&icf->vb_vidq, p);
}

static int soc_camera_qbuf(struct file *file, void *priv,
                           struct v4l2_buffer *p)
{
        struct soc_camera_file *icf = file->private_data;

        WARN_ON(priv != file->private_data);

        return videobuf_qbuf(&icf->vb_vidq, p);
}

static int soc_camera_dqbuf(struct file *file, void *priv,
                            struct v4l2_buffer *p)
{
        struct soc_camera_file *icf = file->private_data;

        WARN_ON(priv != file->private_data);

        return videobuf_dqbuf(&icf->vb_vidq, p, file->f_flags & O_NONBLOCK);
}

static int soc_camera_open(struct inode *inode, struct file *file)
{
        struct video_device *vdev;
        struct soc_camera_device *icd;
        struct soc_camera_host *ici;
        struct soc_camera_file *icf;
        int ret;

        icf = vmalloc(sizeof(*icf));
        if (!icf)
                return -ENOMEM;

        /* Protect against icd->remove() until we module_get() both drivers. */
        mutex_lock(&video_lock);

        vdev = video_devdata(file);
        icd = container_of(vdev->dev, struct soc_camera_device, dev);
        ici = to_soc_camera_host(icd->dev.parent);

        if (!try_module_get(icd->ops->owner)) {
                dev_err(&icd->dev, "Couldn't lock sensor driver.\n");
                ret = -EINVAL;
                goto emgd;
        }

        if (!try_module_get(ici->owner)) {
                dev_err(&icd->dev, "Couldn't lock capture bus driver.\n");
                ret = -EINVAL;
                goto emgi;
        }

        icd->use_count++;

        icf->icd = icd;

        /* Now we really have to activate the camera */
        if (icd->use_count == 1) {
                ret = ici->add(icd);
                if (ret < 0) {
                        dev_err(&icd->dev, "Couldn't activate the camera: %d\n", ret);
                        icd->use_count--;
                        goto eiciadd;
                }
        }

        mutex_unlock(&video_lock);

        file->private_data = icf;
        dev_dbg(&icd->dev, "camera device open\n");

        /* We must pass NULL as dev pointer, then all pci_* dma operations
         * transform to normal dma_* ones. Do we need an irqlock? */
        videobuf_queue_sg_init(&icf->vb_vidq, ici->vbq_ops, NULL, NULL,
                                V4L2_BUF_TYPE_VIDEO_CAPTURE, V4L2_FIELD_NONE,
                                ici->msize, icd);

        return 0;

        /* All errors are entered with the video_lock held */
eiciadd:
        module_put(ici->owner);
emgi:
        module_put(icd->ops->owner);
emgd:
        mutex_unlock(&video_lock);
        vfree(icf);
        return ret;
}

static int soc_camera_close(struct inode *inode, struct file *file)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        struct video_device *vdev = icd->vdev;

        mutex_lock(&video_lock);
        icd->use_count--;
        if (!icd->use_count)
                ici->remove(icd);
        module_put(icd->ops->owner);
        module_put(ici->owner);
        mutex_unlock(&video_lock);

        vfree(file->private_data);

        dev_dbg(vdev->dev, "camera device close\n");

        return 0;
}

static ssize_t soc_camera_read(struct file *file, char __user *buf,
                           size_t count, loff_t *ppos)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct video_device *vdev = icd->vdev;
        int err = -EINVAL;

        dev_err(vdev->dev, "camera device read not implemented\n");

        return err;
}

static int soc_camera_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        int err;

        dev_dbg(&icd->dev, "mmap called, vma=0x%08lx\n", (unsigned long)vma);

        err = videobuf_mmap_mapper(&icf->vb_vidq, vma);

        dev_dbg(&icd->dev, "vma start=0x%08lx, size=%ld, ret=%d\n",
                (unsigned long)vma->vm_start,
                (unsigned long)vma->vm_end - (unsigned long)vma->vm_start,
                err);

        return err;
}

static unsigned int soc_camera_poll(struct file *file, poll_table *pt)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici =
                to_soc_camera_host(icd->dev.parent);

        if (list_empty(&icf->vb_vidq.stream)) {
                dev_err(&icd->dev, "Trying to poll with no queued buffers!\n");
                return POLLERR;
        }

        return ici->poll(file, pt);
}


static struct file_operations soc_camera_fops = {
        .owner          = THIS_MODULE,
        .open           = soc_camera_open,
        .release        = soc_camera_close,
        .ioctl          = video_ioctl2,
        .read           = soc_camera_read,
        .mmap           = soc_camera_mmap,
        .poll           = soc_camera_poll,
        .llseek         = no_llseek,
};


static int soc_camera_s_fmt_cap(struct file *file, void *priv,
                                struct v4l2_format *f)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici =
                to_soc_camera_host(icd->dev.parent);
        int ret;
        struct v4l2_rect rect;
        const static struct soc_camera_data_format *data_fmt;

        WARN_ON(priv != file->private_data);

        data_fmt = format_by_fourcc(icd, f->fmt.pix.pixelformat);
        if (!data_fmt)
                return -EINVAL;

        /* buswidth may be further adjusted by the ici */
        icd->buswidth = data_fmt->depth;

        ret = soc_camera_try_fmt_cap(file, icf, f);
        if (ret < 0)
                return ret;

        rect.left       = icd->x_current;
        rect.top        = icd->y_current;
        rect.width      = f->fmt.pix.width;
        rect.height     = f->fmt.pix.height;
        ret = ici->set_fmt_cap(icd, f->fmt.pix.pixelformat, &rect);
        if (ret < 0)
                return ret;

        icd->current_fmt        = data_fmt;
        icd->width              = rect.width;
        icd->height             = rect.height;
        icf->vb_vidq.field      = f->fmt.pix.field;
        if (V4L2_BUF_TYPE_VIDEO_CAPTURE != f->type)
                dev_warn(&icd->dev, "Attention! Wrong buf-type %d\n",
                         f->type);

        dev_dbg(&icd->dev, "set width: %d height: %d\n",
                icd->width, icd->height);

        /* set physical bus parameters */
        return ici->set_bus_param(icd, f->fmt.pix.pixelformat);
}

static int soc_camera_enum_fmt_cap(struct file *file, void  *priv,
                                   struct v4l2_fmtdesc *f)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        const struct soc_camera_data_format *format;

        WARN_ON(priv != file->private_data);

        if (f->index >= icd->ops->num_formats)
                return -EINVAL;

        format = &icd->ops->formats[f->index];

        strlcpy(f->description, format->name, sizeof(f->description));
        f->pixelformat = format->fourcc;
        return 0;
}

static int soc_camera_g_fmt_cap(struct file *file, void *priv,
                                struct v4l2_format *f)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        WARN_ON(priv != file->private_data);

        f->fmt.pix.width        = icd->width;
        f->fmt.pix.height       = icd->height;
        f->fmt.pix.field        = icf->vb_vidq.field;
        f->fmt.pix.pixelformat  = icd->current_fmt->fourcc;
        f->fmt.pix.bytesperline =
                (f->fmt.pix.width * icd->current_fmt->depth) >> 3;
        f->fmt.pix.sizeimage    =
                f->fmt.pix.height * f->fmt.pix.bytesperline;
        dev_dbg(&icd->dev, "current_fmt->fourcc: 0x%08x\n",
                icd->current_fmt->fourcc);
        return 0;
}

static int soc_camera_querycap(struct file *file, void  *priv,
                               struct v4l2_capability *cap)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici =
                to_soc_camera_host(icd->dev.parent);

        WARN_ON(priv != file->private_data);

        strlcpy(cap->driver, ici->drv_name, sizeof(cap->driver));
        return ici->querycap(ici, cap);
}

static int soc_camera_streamon(struct file *file, void *priv,
                               enum v4l2_buf_type i)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        WARN_ON(priv != file->private_data);

        dev_dbg(&icd->dev, "%s\n", __FUNCTION__);

        if (i != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        icd->ops->start_capture(icd);

        /* This calls buf_queue from host driver's videobuf_queue_ops */
        return videobuf_streamon(&icf->vb_vidq);
}

static int soc_camera_streamoff(struct file *file, void *priv,
                                enum v4l2_buf_type i)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        WARN_ON(priv != file->private_data);

        dev_dbg(&icd->dev, "%s\n", __FUNCTION__);

        if (i != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        /* This calls buf_release from host driver's videobuf_queue_ops for all
         * remaining buffers. When the last buffer is freed, stop capture */
        videobuf_streamoff(&icf->vb_vidq);

        icd->ops->stop_capture(icd);

        return 0;
}

static int soc_camera_queryctrl(struct file *file, void *priv,
                                struct v4l2_queryctrl *qc)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        int i;

        WARN_ON(priv != file->private_data);

        if (!qc->id)
                return -EINVAL;

        for (i = 0; i < icd->ops->num_controls; i++)
                if (qc->id == icd->ops->controls[i].id) {
                        memcpy(qc, &(icd->ops->controls[i]),
                                sizeof(*qc));
                        return 0;
                }

        return -EINVAL;
}

static int soc_camera_g_ctrl(struct file *file, void *priv,
                             struct v4l2_control *ctrl)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        WARN_ON(priv != file->private_data);

        switch (ctrl->id) {
        case V4L2_CID_GAIN:
                if (icd->gain == (unsigned short)~0)
                        return -EINVAL;
                ctrl->value = icd->gain;
                return 0;
        case V4L2_CID_EXPOSURE:
                if (icd->exposure == (unsigned short)~0)
                        return -EINVAL;
                ctrl->value = icd->exposure;
                return 0;
        }

        if (icd->ops->get_control)
                return icd->ops->get_control(icd, ctrl);
        return -EINVAL;
}

static int soc_camera_s_ctrl(struct file *file, void *priv,
                             struct v4l2_control *ctrl)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        WARN_ON(priv != file->private_data);

        if (icd->ops->set_control)
                return icd->ops->set_control(icd, ctrl);
        return -EINVAL;
}

static int soc_camera_cropcap(struct file *file, void *fh,
                              struct v4l2_cropcap *a)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        a->type                         = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        a->bounds.left                  = icd->x_min;
        a->bounds.top                   = icd->y_min;
        a->bounds.width                 = icd->width_max;
        a->bounds.height                = icd->height_max;
        a->defrect.left                 = icd->x_min;
        a->defrect.top                  = icd->y_min;
        a->defrect.width                = 640;
        a->defrect.height               = 480;
        a->pixelaspect.numerator        = 1;
        a->pixelaspect.denominator      = 1;

        return 0;
}

static int soc_camera_g_crop(struct file *file, void *fh,
                             struct v4l2_crop *a)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        a->type         = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        a->c.left       = icd->x_current;
        a->c.top        = icd->y_current;
        a->c.width      = icd->width;
        a->c.height     = icd->height;

        return 0;
}

static int soc_camera_s_crop(struct file *file, void *fh,
                             struct v4l2_crop *a)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici =
                to_soc_camera_host(icd->dev.parent);
        int ret;

        if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        ret = ici->set_fmt_cap(icd, 0, &a->c);
        if (!ret) {
                icd->width      = a->c.width;
                icd->height     = a->c.height;
                icd->x_current  = a->c.left;
                icd->y_current  = a->c.top;
        }

        return ret;
}

static int soc_camera_g_chip_ident(struct file *file, void *fh,
                                   struct v4l2_chip_ident *id)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        if (!icd->ops->get_chip_id)
                return -EINVAL;

        return icd->ops->get_chip_id(icd, id);
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int soc_camera_g_register(struct file *file, void *fh,
                                 struct v4l2_register *reg)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        if (!icd->ops->get_register)
                return -EINVAL;

        return icd->ops->get_register(icd, reg);
}

static int soc_camera_s_register(struct file *file, void *fh,
                                 struct v4l2_register *reg)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;

        if (!icd->ops->set_register)
                return -EINVAL;

        return icd->ops->set_register(icd, reg);
}
#endif

static int device_register_link(struct soc_camera_device *icd)
{
        int ret = device_register(&icd->dev);

        if (ret < 0) {
                /* Prevent calling device_unregister() */
                icd->dev.parent = NULL;
                dev_err(&icd->dev, "Cannot register device: %d\n", ret);
        /* Even if probe() was unsuccessful for all registered drivers,
         * device_register() returns 0, and we add the link, just to
         * document this camera's control device */
        } else if (icd->control)
                /* Have to sysfs_remove_link() before device_unregister()? */
                if (sysfs_create_link(&icd->dev.kobj, &icd->control->kobj,
                                      "control"))
                        dev_warn(&icd->dev,
                                 "Failed creating the control symlink\n");
        return ret;
}

/* So far this function cannot fail */
static void scan_add_host(struct soc_camera_host *ici)
{
        struct soc_camera_device *icd;

        mutex_lock(&list_lock);

        list_for_each_entry(icd, &devices, list) {
                if (icd->iface == ici->nr) {
                        icd->dev.parent = &ici->dev;
                        device_register_link(icd);
                }
        }

        mutex_unlock(&list_lock);
}

/* return: 0 if no match found or a match found and
 * device_register() successful, error code otherwise */
static int scan_add_device(struct soc_camera_device *icd)
{
        struct soc_camera_host *ici;
        int ret = 0;

        mutex_lock(&list_lock);

        list_add_tail(&icd->list, &devices);

        /* Watch out for class_for_each_device / class_find_device API by
         * Dave Young <hidave.darkstar@gmail.com> */
        list_for_each_entry(ici, &hosts, list) {
                if (icd->iface == ici->nr) {
                        ret = 1;
                        icd->dev.parent = &ici->dev;
                        break;
                }
        }

        mutex_unlock(&list_lock);

        if (ret)
                ret = device_register_link(icd);

        return ret;
}

static int soc_camera_probe(struct device *dev)
{
        struct soc_camera_device *icd = to_soc_camera_dev(dev);
        struct soc_camera_host *ici =
                to_soc_camera_host(icd->dev.parent);
        int ret;

        if (!icd->probe)
                return -ENODEV;

        /* We only call ->add() here to activate and probe the camera.
         * We shall ->remove() and deactivate it immediately afterwards. */
        ret = ici->add(icd);
        if (ret < 0)
                return ret;

        ret = icd->probe(icd);
        if (ret >= 0) {
                const struct v4l2_queryctrl *qctrl;

                qctrl = soc_camera_find_qctrl(icd->ops, V4L2_CID_GAIN);
                icd->gain = qctrl ? qctrl->default_value : (unsigned short)~0;
                qctrl = soc_camera_find_qctrl(icd->ops, V4L2_CID_EXPOSURE);
                icd->exposure = qctrl ? qctrl->default_value :
                        (unsigned short)~0;
        }
        ici->remove(icd);

        return ret;
}

/* This is called on device_unregister, which only means we have to disconnect
 * from the host, but not remove ourselves from the device list */
static int soc_camera_remove(struct device *dev)
{
        struct soc_camera_device *icd = to_soc_camera_dev(dev);

        if (icd->remove)
                icd->remove(icd);

        return 0;
}

static struct bus_type soc_camera_bus_type = {
        .name           = "soc-camera",
        .probe          = soc_camera_probe,
        .remove         = soc_camera_remove,
};

static struct device_driver ic_drv = {
        .name   = "camera",
        .bus    = &soc_camera_bus_type,
        .owner  = THIS_MODULE,
};

/*
 * Image capture host - this is a host device, not a bus device, so,
 * no bus reference, no probing.
 */
static struct class soc_camera_host_class = {
        .owner          = THIS_MODULE,
        .name           = "camera_host",
};

static void dummy_release(struct device *dev)
{
}

int soc_camera_host_register(struct soc_camera_host *ici, struct module *owner)
{
        int ret;
        struct soc_camera_host *ix;

        if (!ici->vbq_ops || !ici->add || !ici->remove || !owner)
                return -EINVAL;

        /* Number might be equal to the platform device ID */
        sprintf(ici->dev.bus_id, "camera_host%d", ici->nr);
        ici->dev.class = &soc_camera_host_class;

        mutex_lock(&list_lock);
        list_for_each_entry(ix, &hosts, list) {
                if (ix->nr == ici->nr) {
                        mutex_unlock(&list_lock);
                        return -EBUSY;
                }
        }

        list_add_tail(&ici->list, &hosts);
        mutex_unlock(&list_lock);

        ici->owner = owner;
        ici->dev.release = dummy_release;

        ret = device_register(&ici->dev);

        if (ret)
                goto edevr;

        scan_add_host(ici);

        return 0;

edevr:
        mutex_lock(&list_lock);
        list_del(&ici->list);
        mutex_unlock(&list_lock);

        return ret;
}
EXPORT_SYMBOL(soc_camera_host_register);

/* Unregister all clients! */
void soc_camera_host_unregister(struct soc_camera_host *ici)
{
        struct soc_camera_device *icd;

        mutex_lock(&list_lock);

        list_del(&ici->list);

        list_for_each_entry(icd, &devices, list) {
                if (icd->dev.parent == &ici->dev) {
                        device_unregister(&icd->dev);
                        /* Not before device_unregister(), .remove
                         * needs parent to call ici->remove() */
                        icd->dev.parent = NULL;
                        memset(&icd->dev.kobj, 0, sizeof(icd->dev.kobj));
                }
        }

        mutex_unlock(&list_lock);

        device_unregister(&ici->dev);
}
EXPORT_SYMBOL(soc_camera_host_unregister);

/* Image capture device */
int soc_camera_device_register(struct soc_camera_device *icd)
{
        struct soc_camera_device *ix;
        int num = -1, i;

        if (!icd)
                return -EINVAL;

        for (i = 0; i < 256 && num < 0; i++) {
                num = i;
                list_for_each_entry(ix, &devices, list) {
                        if (ix->iface == icd->iface && ix->devnum == i) {
                                num = -1;
                                break;
                        }
                }
        }

        if (num < 0)
                /* ok, we have 256 cameras on this host...
                 * man, stay reasonable... */
                return -ENOMEM;

        icd->devnum = num;
        icd->dev.bus = &soc_camera_bus_type;
        snprintf(icd->dev.bus_id, sizeof(icd->dev.bus_id),
                 "%u-%u", icd->iface, icd->devnum);

        icd->dev.release = dummy_release;

        return scan_add_device(icd);
}
EXPORT_SYMBOL(soc_camera_device_register);

void soc_camera_device_unregister(struct soc_camera_device *icd)
{
        mutex_lock(&list_lock);
        list_del(&icd->list);

        /* The bus->remove will be eventually called */
        if (icd->dev.parent)
                device_unregister(&icd->dev);
        mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(soc_camera_device_unregister);

int soc_camera_video_start(struct soc_camera_device *icd)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        int err = -ENOMEM;
        struct video_device *vdev;

        if (!icd->dev.parent)
                return -ENODEV;

        vdev = video_device_alloc();
        if (!vdev)
                goto evidallocd;
        dev_dbg(&ici->dev, "Allocated video_device %p\n", vdev);

        strlcpy(vdev->name, ici->drv_name, sizeof(vdev->name));
        /* Maybe better &ici->dev */
        vdev->dev               = &icd->dev;
        vdev->type              = VID_TYPE_CAPTURE;
        vdev->current_norm      = V4L2_STD_UNKNOWN;
        vdev->fops              = &soc_camera_fops;
        vdev->release           = video_device_release;
        vdev->minor             = -1;
        vdev->tvnorms           = V4L2_STD_UNKNOWN,
        vdev->vidioc_querycap   = soc_camera_querycap;
        vdev->vidioc_g_fmt_cap  = soc_camera_g_fmt_cap;
        vdev->vidioc_enum_fmt_cap = soc_camera_enum_fmt_cap;
        vdev->vidioc_s_fmt_cap  = soc_camera_s_fmt_cap;
        vdev->vidioc_enum_input = soc_camera_enum_input;
        vdev->vidioc_g_input    = soc_camera_g_input;
        vdev->vidioc_s_input    = soc_camera_s_input;
        vdev->vidioc_s_std      = soc_camera_s_std;
        vdev->vidioc_reqbufs    = soc_camera_reqbufs;
        vdev->vidioc_try_fmt_cap = soc_camera_try_fmt_cap;
        vdev->vidioc_querybuf   = soc_camera_querybuf;
        vdev->vidioc_qbuf       = soc_camera_qbuf;
        vdev->vidioc_dqbuf      = soc_camera_dqbuf;
        vdev->vidioc_streamon   = soc_camera_streamon;
        vdev->vidioc_streamoff  = soc_camera_streamoff;
        vdev->vidioc_queryctrl  = soc_camera_queryctrl;
        vdev->vidioc_g_ctrl     = soc_camera_g_ctrl;
        vdev->vidioc_s_ctrl     = soc_camera_s_ctrl;
        vdev->vidioc_cropcap    = soc_camera_cropcap;
        vdev->vidioc_g_crop     = soc_camera_g_crop;
        vdev->vidioc_s_crop     = soc_camera_s_crop;
        vdev->vidioc_g_chip_ident = soc_camera_g_chip_ident;
#ifdef CONFIG_VIDEO_ADV_DEBUG
        vdev->vidioc_g_register = soc_camera_g_register;
        vdev->vidioc_s_register = soc_camera_s_register;
#endif

        icd->current_fmt = &icd->ops->formats[0];

        err = video_register_device(vdev, VFL_TYPE_GRABBER, vdev->minor);
        if (err < 0) {
                dev_err(vdev->dev, "video_register_device failed\n");
                goto evidregd;
        }
        icd->vdev = vdev;

        return 0;

evidregd:
        video_device_release(vdev);
evidallocd:
        return err;
}
EXPORT_SYMBOL(soc_camera_video_start);

void soc_camera_video_stop(struct soc_camera_device *icd)
{
        struct video_device *vdev = icd->vdev;

        dev_dbg(&icd->dev, "%s\n", __FUNCTION__);

        if (!icd->dev.parent || !vdev)
                return;

        mutex_lock(&video_lock);
        video_unregister_device(vdev);
        icd->vdev = NULL;
        mutex_unlock(&video_lock);
}
EXPORT_SYMBOL(soc_camera_video_stop);

static int __init soc_camera_init(void)
{
        int ret = bus_register(&soc_camera_bus_type);
        if (ret)
                return ret;
        ret = driver_register(&ic_drv);
        if (ret)
                goto edrvr;
        ret = class_register(&soc_camera_host_class);
        if (ret)
                goto eclr;

        return 0;

eclr:
        driver_unregister(&ic_drv);
edrvr:
        bus_unregister(&soc_camera_bus_type);
        return ret;
}

static void __exit soc_camera_exit(void)
{
        class_unregister(&soc_camera_host_class);
        driver_unregister(&ic_drv);
        bus_unregister(&soc_camera_bus_type);
}

module_init(soc_camera_init);
module_exit(soc_camera_exit);

MODULE_DESCRIPTION("Image capture bus driver");
MODULE_AUTHOR("Guennadi Liakhovetski <kernel@pengutronix.de>");
MODULE_LICENSE("GPL");