i2c: Fix userspace_device list corruption

[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/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/vmalloc.h>

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

/* Default to VGA resolution */
#define DEFAULT_WIDTH   640
#define DEFAULT_HEIGHT  480

static LIST_HEAD(hosts);
static LIST_HEAD(devices);
static DEFINE_MUTEX(list_lock);         /* Protects the list of hosts */

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

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

const struct soc_camera_format_xlate *soc_camera_xlate_by_fourcc(
        struct soc_camera_device *icd, unsigned int fourcc)
{
        unsigned int i;

        for (i = 0; i < icd->num_user_formats; i++)
                if (icd->user_formats[i].host_fmt->fourcc == fourcc)
                        return icd->user_formats + i;
        return NULL;
}
EXPORT_SYMBOL(soc_camera_xlate_by_fourcc);

/**
 * soc_camera_apply_sensor_flags() - apply platform SOCAM_SENSOR_INVERT_* flags
 * @icl:        camera platform parameters
 * @flags:      flags to be inverted according to platform configuration
 * @return:     resulting flags
 */
unsigned long soc_camera_apply_sensor_flags(struct soc_camera_link *icl,
                                            unsigned long flags)
{
        unsigned long f;

        /* If only one of the two polarities is supported, switch to the opposite */
        if (icl->flags & SOCAM_SENSOR_INVERT_HSYNC) {
                f = flags & (SOCAM_HSYNC_ACTIVE_HIGH | SOCAM_HSYNC_ACTIVE_LOW);
                if (f == SOCAM_HSYNC_ACTIVE_HIGH || f == SOCAM_HSYNC_ACTIVE_LOW)
                        flags ^= SOCAM_HSYNC_ACTIVE_HIGH | SOCAM_HSYNC_ACTIVE_LOW;
        }

        if (icl->flags & SOCAM_SENSOR_INVERT_VSYNC) {
                f = flags & (SOCAM_VSYNC_ACTIVE_HIGH | SOCAM_VSYNC_ACTIVE_LOW);
                if (f == SOCAM_VSYNC_ACTIVE_HIGH || f == SOCAM_VSYNC_ACTIVE_LOW)
                        flags ^= SOCAM_VSYNC_ACTIVE_HIGH | SOCAM_VSYNC_ACTIVE_LOW;
        }

        if (icl->flags & SOCAM_SENSOR_INVERT_PCLK) {
                f = flags & (SOCAM_PCLK_SAMPLE_RISING | SOCAM_PCLK_SAMPLE_FALLING);
                if (f == SOCAM_PCLK_SAMPLE_RISING || f == SOCAM_PCLK_SAMPLE_FALLING)
                        flags ^= SOCAM_PCLK_SAMPLE_RISING | SOCAM_PCLK_SAMPLE_FALLING;
        }

        return flags;
}
EXPORT_SYMBOL(soc_camera_apply_sensor_flags);

static int soc_camera_try_fmt_vid_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);

        WARN_ON(priv != file->private_data);

        /* limit format to hardware capabilities */
        return ici->ops->try_fmt(icd, f);
}

static int soc_camera_enum_input(struct file *file, void *priv,
                                 struct v4l2_input *inp)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        int ret = 0;

        if (inp->index != 0)
                return -EINVAL;

        if (icd->ops->enum_input)
                ret = icd->ops->enum_input(icd, inp);
        else {
                /* default is camera */
                inp->type = V4L2_INPUT_TYPE_CAMERA;
                inp->std  = V4L2_STD_UNKNOWN;
                strcpy(inp->name, "Camera");
        }

        return ret;
}

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)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_subdev_call(sd, core, s_std, *a);
}

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);

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

        return ici->ops->reqbufs(icf, p);
}

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);
}

/* Always entered with .video_lock held */
static int soc_camera_init_user_formats(struct soc_camera_device *icd)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        int i, fmts = 0, ret;

        if (!ici->ops->get_formats)
                /*
                 * Fallback mode - the host will have to serve all
                 * sensor-provided formats one-to-one to the user
                 */
                fmts = icd->num_formats;
        else
                /*
                 * First pass - only count formats this host-sensor
                 * configuration can provide
                 */
                for (i = 0; i < icd->num_formats; i++) {
                        ret = ici->ops->get_formats(icd, i, NULL);
                        if (ret < 0)
                                return ret;
                        fmts += ret;
                }

        if (!fmts)
                return -ENXIO;

        icd->user_formats =
                vmalloc(fmts * sizeof(struct soc_camera_format_xlate));
        if (!icd->user_formats)
                return -ENOMEM;

        icd->num_user_formats = fmts;

        dev_dbg(&icd->dev, "Found %d supported formats.\n", fmts);

        /* Second pass - actually fill data formats */
        fmts = 0;
        for (i = 0; i < icd->num_formats; i++)
                if (!ici->ops->get_formats) {
                        icd->user_formats[i].host_fmt = icd->formats + i;
                        icd->user_formats[i].cam_fmt = icd->formats + i;
                        icd->user_formats[i].buswidth = icd->formats[i].depth;
                } else {
                        ret = ici->ops->get_formats(icd, i,
                                                    &icd->user_formats[fmts]);
                        if (ret < 0)
                                goto egfmt;
                        fmts += ret;
                }

        icd->current_fmt = icd->user_formats[0].host_fmt;

        return 0;

egfmt:
        icd->num_user_formats = 0;
        vfree(icd->user_formats);
        return ret;
}

/* Always entered with .video_lock held */
static void soc_camera_free_user_formats(struct soc_camera_device *icd)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);

        if (ici->ops->put_formats)
                ici->ops->put_formats(icd);
        icd->current_fmt = NULL;
        icd->num_user_formats = 0;
        vfree(icd->user_formats);
        icd->user_formats = NULL;
}

#define pixfmtstr(x) (x) & 0xff, ((x) >> 8) & 0xff, ((x) >> 16) & 0xff, \
        ((x) >> 24) & 0xff

/* Called with .vb_lock held */
static int soc_camera_set_fmt(struct soc_camera_file *icf,
                              struct v4l2_format *f)
{
        struct soc_camera_device *icd = icf->icd;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        struct v4l2_pix_format *pix = &f->fmt.pix;
        int ret;

        dev_dbg(&icd->dev, "S_FMT(%c%c%c%c, %ux%u)\n",
                pixfmtstr(pix->pixelformat), pix->width, pix->height);

        /* We always call try_fmt() before set_fmt() or set_crop() */
        ret = ici->ops->try_fmt(icd, f);
        if (ret < 0)
                return ret;

        ret = ici->ops->set_fmt(icd, f);
        if (ret < 0) {
                return ret;
        } else if (!icd->current_fmt ||
                   icd->current_fmt->fourcc != pix->pixelformat) {
                dev_err(&icd->dev,
                        "Host driver hasn't set up current format correctly!\n");
                return -EINVAL;
        }

        icd->user_width         = pix->width;
        icd->user_height        = pix->height;
        icf->vb_vidq.field      =
                icd->field      = pix->field;

        if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                dev_warn(&icd->dev, "Attention! Wrong buf-type %d\n",
                         f->type);

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

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

static int soc_camera_open(struct file *file)
{
        struct video_device *vdev = video_devdata(file);
        struct soc_camera_device *icd = container_of(vdev->parent,
                                                     struct soc_camera_device,
                                                     dev);
        struct soc_camera_link *icl = to_soc_camera_link(icd);
        struct soc_camera_host *ici;
        struct soc_camera_file *icf;
        int ret;

        if (!icd->ops)
                /* No device driver attached */
                return -ENODEV;

        ici = to_soc_camera_host(icd->dev.parent);

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

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

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

        icf->icd = icd;
        icd->use_count++;

        /* Now we really have to activate the camera */
        if (icd->use_count == 1) {
                /* Restore parameters before the last close() per V4L2 API */
                struct v4l2_format f = {
                        .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
                        .fmt.pix = {
                                .width          = icd->user_width,
                                .height         = icd->user_height,
                                .field          = icd->field,
                                .pixelformat    = icd->current_fmt->fourcc,
                                .colorspace     = icd->current_fmt->colorspace,
                        },
                };

                if (icl->power) {
                        ret = icl->power(icd->pdev, 1);
                        if (ret < 0)
                                goto epower;
                }

                /* The camera could have been already on, try to reset */
                if (icl->reset)
                        icl->reset(icd->pdev);

                ret = ici->ops->add(icd);
                if (ret < 0) {
                        dev_err(&icd->dev, "Couldn't activate the camera: %d\n", ret);
                        goto eiciadd;
                }

                /* Try to configure with default parameters */
                ret = soc_camera_set_fmt(icf, &f);
                if (ret < 0)
                        goto esfmt;
        }

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

        ici->ops->init_videobuf(&icf->vb_vidq, icd);

        mutex_unlock(&icd->video_lock);

        return 0;

        /*
         * First five errors are entered with the .video_lock held
         * and use_count == 1
         */
esfmt:
        ici->ops->remove(icd);
eiciadd:
        if (icl->power)
                icl->power(icd->pdev, 0);
epower:
        icd->use_count--;
        mutex_unlock(&icd->video_lock);
        module_put(ici->ops->owner);
emgi:
        vfree(icf);
        return ret;
}

static int soc_camera_close(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);

        mutex_lock(&icd->video_lock);
        icd->use_count--;
        if (!icd->use_count) {
                struct soc_camera_link *icl = to_soc_camera_link(icd);

                ici->ops->remove(icd);
                if (icl->power)
                        icl->power(icd->pdev, 0);
        }

        mutex_unlock(&icd->video_lock);

        module_put(ici->ops->owner);

        vfree(icf);

        dev_dbg(&icd->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;
        int err = -EINVAL;

        dev_err(&icd->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->ops->poll(file, pt);
}

static struct v4l2_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,
};

static int soc_camera_s_fmt_vid_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;
        int ret;

        WARN_ON(priv != file->private_data);

        mutex_lock(&icf->vb_vidq.vb_lock);

        if (icf->vb_vidq.bufs[0]) {
                dev_err(&icd->dev, "S_FMT denied: queue initialised\n");
                ret = -EBUSY;
                goto unlock;
        }

        ret = soc_camera_set_fmt(icf, f);

unlock:
        mutex_unlock(&icf->vb_vidq.vb_lock);

        return ret;
}

static int soc_camera_enum_fmt_vid_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->num_user_formats)
                return -EINVAL;

        format = icd->user_formats[f->index].host_fmt;

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

static int soc_camera_g_fmt_vid_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 v4l2_pix_format *pix = &f->fmt.pix;

        WARN_ON(priv != file->private_data);

        pix->width              = icd->user_width;
        pix->height             = icd->user_height;
        pix->field              = icf->vb_vidq.field;
        pix->pixelformat        = icd->current_fmt->fourcc;
        pix->bytesperline       = pix->width *
                DIV_ROUND_UP(icd->current_fmt->depth, 8);
        pix->sizeimage          = pix->height * 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->ops->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;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        int ret;

        WARN_ON(priv != file->private_data);

        if (i != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        mutex_lock(&icd->video_lock);

        v4l2_subdev_call(sd, video, s_stream, 1);

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

        mutex_unlock(&icd->video_lock);

        return ret;
}

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;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        WARN_ON(priv != file->private_data);

        if (i != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        mutex_lock(&icd->video_lock);

        /* 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);

        v4l2_subdev_call(sd, video, s_stream, 0);

        mutex_unlock(&icd->video_lock);

        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;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        int i;

        WARN_ON(priv != file->private_data);

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

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

        /* Then device controls */
        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;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        int ret;

        WARN_ON(priv != file->private_data);

        if (ici->ops->get_ctrl) {
                ret = ici->ops->get_ctrl(icd, ctrl);
                if (ret != -ENOIOCTLCMD)
                        return ret;
        }

        return v4l2_subdev_call(sd, core, g_ctrl, ctrl);
}

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;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        int ret;

        WARN_ON(priv != file->private_data);

        if (ici->ops->set_ctrl) {
                ret = ici->ops->set_ctrl(icd, ctrl);
                if (ret != -ENOIOCTLCMD)
                        return ret;
        }

        return v4l2_subdev_call(sd, core, s_ctrl, ctrl);
}

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;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);

        return ici->ops->cropcap(icd, a);
}

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;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        int ret;

        mutex_lock(&icf->vb_vidq.vb_lock);
        ret = ici->ops->get_crop(icd, a);
        mutex_unlock(&icf->vb_vidq.vb_lock);

        return ret;
}

/*
 * According to the V4L2 API, drivers shall not update the struct v4l2_crop
 * argument with the actual geometry, instead, the user shall use G_CROP to
 * retrieve it. However, we expect camera host and client drivers to update
 * the argument, which we then use internally, but do not return to the user.
 */
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);
        struct v4l2_rect *rect = &a->c;
        struct v4l2_crop current_crop;
        int ret;

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

        dev_dbg(&icd->dev, "S_CROP(%ux%u@%u:%u)\n",
                rect->width, rect->height, rect->left, rect->top);

        /* Cropping is allowed during a running capture, guard consistency */
        mutex_lock(&icf->vb_vidq.vb_lock);

        /* If get_crop fails, we'll let host and / or client drivers decide */
        ret = ici->ops->get_crop(icd, &current_crop);

        /* Prohibit window size change with initialised buffers */
        if (icf->vb_vidq.bufs[0] && !ret &&
            (a->c.width != current_crop.c.width ||
             a->c.height != current_crop.c.height)) {
                dev_err(&icd->dev,
                        "S_CROP denied: queue initialised and sizes differ\n");
                ret = -EBUSY;
        } else {
                ret = ici->ops->set_crop(icd, a);
        }

        mutex_unlock(&icf->vb_vidq.vb_lock);

        return ret;
}

static int soc_camera_g_chip_ident(struct file *file, void *fh,
                                   struct v4l2_dbg_chip_ident *id)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_subdev_call(sd, core, g_chip_ident, id);
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int soc_camera_g_register(struct file *file, void *fh,
                                 struct v4l2_dbg_register *reg)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_subdev_call(sd, core, g_register, reg);
}

static int soc_camera_s_register(struct file *file, void *fh,
                                 struct v4l2_dbg_register *reg)
{
        struct soc_camera_file *icf = file->private_data;
        struct soc_camera_device *icd = icf->icd;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_subdev_call(sd, core, s_register, reg);
}
#endif

/* 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) {
                        int ret;
                        icd->dev.parent = ici->v4l2_dev.dev;
                        dev_set_name(&icd->dev, "%u-%u", icd->iface,
                                     icd->devnum);
                        ret = device_register(&icd->dev);
                        if (ret < 0) {
                                icd->dev.parent = NULL;
                                dev_err(&icd->dev,
                                        "Cannot register device: %d\n", ret);
                        }
                }
        }

        mutex_unlock(&list_lock);
}

#ifdef CONFIG_I2C_BOARDINFO
static int soc_camera_init_i2c(struct soc_camera_device *icd,
                               struct soc_camera_link *icl)
{
        struct i2c_client *client;
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        struct i2c_adapter *adap = i2c_get_adapter(icl->i2c_adapter_id);
        struct v4l2_subdev *subdev;
        int ret;

        if (!adap) {
                ret = -ENODEV;
                dev_err(&icd->dev, "Cannot get I2C adapter #%d. No driver?\n",
                        icl->i2c_adapter_id);
                goto ei2cga;
        }

        icl->board_info->platform_data = icd;

        subdev = v4l2_i2c_new_subdev_board(&ici->v4l2_dev, adap,
                                icl->module_name, icl->board_info, NULL);
        if (!subdev) {
                ret = -ENOMEM;
                goto ei2cnd;
        }

        client = subdev->priv;

        /* Use to_i2c_client(dev) to recover the i2c client */
        dev_set_drvdata(&icd->dev, &client->dev);

        return 0;
ei2cnd:
        i2c_put_adapter(adap);
ei2cga:
        return ret;
}

static void soc_camera_free_i2c(struct soc_camera_device *icd)
{
        struct i2c_client *client =
                to_i2c_client(to_soc_camera_control(icd));
        dev_set_drvdata(&icd->dev, NULL);
        v4l2_device_unregister_subdev(i2c_get_clientdata(client));
        i2c_unregister_device(client);
        i2c_put_adapter(client->adapter);
}
#else
#define soc_camera_init_i2c(icd, icl)   (-ENODEV)
#define soc_camera_free_i2c(icd)        do {} while (0)
#endif

static int soc_camera_video_start(struct soc_camera_device *icd);
static int video_dev_create(struct soc_camera_device *icd);
/* Called during host-driver probe */
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(dev->parent);
        struct soc_camera_link *icl = to_soc_camera_link(icd);
        struct device *control = NULL;
        struct v4l2_subdev *sd;
        struct v4l2_format f = {.type = V4L2_BUF_TYPE_VIDEO_CAPTURE};
        int ret;

        dev_info(dev, "Probing %s\n", dev_name(dev));

        if (icl->power) {
                ret = icl->power(icd->pdev, 1);
                if (ret < 0) {
                        dev_err(dev,
                                "Platform failed to power-on the camera.\n");
                        goto epower;
                }
        }

        /* The camera could have been already on, try to reset */
        if (icl->reset)
                icl->reset(icd->pdev);

        ret = ici->ops->add(icd);
        if (ret < 0)
                goto eadd;

        /* Must have icd->vdev before registering the device */
        ret = video_dev_create(icd);
        if (ret < 0)
                goto evdc;

        /* Non-i2c cameras, e.g., soc_camera_platform, have no board_info */
        if (icl->board_info) {
                ret = soc_camera_init_i2c(icd, icl);
                if (ret < 0)
                        goto eadddev;
        } else if (!icl->add_device || !icl->del_device) {
                ret = -EINVAL;
                goto eadddev;
        } else {
                if (icl->module_name)
                        ret = request_module(icl->module_name);

                ret = icl->add_device(icl, &icd->dev);
                if (ret < 0)
                        goto eadddev;

                /*
                 * FIXME: this is racy, have to use driver-binding notification,
                 * when it is available
                 */
                control = to_soc_camera_control(icd);
                if (!control || !control->driver || !dev_get_drvdata(control) ||
                    !try_module_get(control->driver->owner)) {
                        icl->del_device(icl);
                        goto enodrv;
                }
        }

        /* At this point client .probe() should have run already */
        ret = soc_camera_init_user_formats(icd);
        if (ret < 0)
                goto eiufmt;

        icd->field = V4L2_FIELD_ANY;

        /* ..._video_start() will create a device node, so we have to protect */
        mutex_lock(&icd->video_lock);

        ret = soc_camera_video_start(icd);
        if (ret < 0)
                goto evidstart;

        /* Try to improve our guess of a reasonable window format */
        sd = soc_camera_to_subdev(icd);
        if (!v4l2_subdev_call(sd, video, g_fmt, &f)) {
                icd->user_width         = f.fmt.pix.width;
                icd->user_height        = f.fmt.pix.height;
        }

        /* Do we have to sysfs_remove_link() before device_unregister()? */
        if (sysfs_create_link(&icd->dev.kobj, &to_soc_camera_control(icd)->kobj,
                              "control"))
                dev_warn(&icd->dev, "Failed creating the control symlink\n");

        ici->ops->remove(icd);

        if (icl->power)
                icl->power(icd->pdev, 0);

        mutex_unlock(&icd->video_lock);

        return 0;

evidstart:
        mutex_unlock(&icd->video_lock);
        soc_camera_free_user_formats(icd);
eiufmt:
        if (icl->board_info) {
                soc_camera_free_i2c(icd);
        } else {
                icl->del_device(icl);
                module_put(control->driver->owner);
        }
enodrv:
eadddev:
        video_device_release(icd->vdev);
evdc:
        ici->ops->remove(icd);
eadd:
        if (icl->power)
                icl->power(icd->pdev, 0);
epower:
        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);
        struct soc_camera_link *icl = to_soc_camera_link(icd);
        struct video_device *vdev = icd->vdev;

        BUG_ON(!dev->parent);

        if (vdev) {
                mutex_lock(&icd->video_lock);
                video_unregister_device(vdev);
                icd->vdev = NULL;
                mutex_unlock(&icd->video_lock);
        }

        if (icl->board_info) {
                soc_camera_free_i2c(icd);
        } else {
                struct device_driver *drv = to_soc_camera_control(icd) ?
                        to_soc_camera_control(icd)->driver : NULL;
                if (drv) {
                        icl->del_device(icl);
                        module_put(drv->owner);
                }
        }
        soc_camera_free_user_formats(icd);

        return 0;
}

static int soc_camera_suspend(struct device *dev, pm_message_t state)
{
        struct soc_camera_device *icd = to_soc_camera_dev(dev);
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        int ret = 0;

        if (ici->ops->suspend)
                ret = ici->ops->suspend(icd, state);

        return ret;
}

static int soc_camera_resume(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 = 0;

        if (ici->ops->resume)
                ret = ici->ops->resume(icd);

        return ret;
}

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

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

static void dummy_release(struct device *dev)
{
}

static int default_cropcap(struct soc_camera_device *icd,
                           struct v4l2_cropcap *a)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        return v4l2_subdev_call(sd, video, cropcap, a);
}

static int default_g_crop(struct soc_camera_device *icd, struct v4l2_crop *a)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        return v4l2_subdev_call(sd, video, g_crop, a);
}

static int default_s_crop(struct soc_camera_device *icd, struct v4l2_crop *a)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        return v4l2_subdev_call(sd, video, s_crop, a);
}

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

        if (!ici || !ici->ops ||
            !ici->ops->try_fmt ||
            !ici->ops->set_fmt ||
            !ici->ops->set_bus_param ||
            !ici->ops->querycap ||
            !ici->ops->init_videobuf ||
            !ici->ops->reqbufs ||
            !ici->ops->add ||
            !ici->ops->remove ||
            !ici->ops->poll ||
            !ici->v4l2_dev.dev)
                return -EINVAL;

        if (!ici->ops->set_crop)
                ici->ops->set_crop = default_s_crop;
        if (!ici->ops->get_crop)
                ici->ops->get_crop = default_g_crop;
        if (!ici->ops->cropcap)
                ici->ops->cropcap = default_cropcap;

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

        ret = v4l2_device_register(ici->v4l2_dev.dev, &ici->v4l2_dev);
        if (ret < 0)
                goto edevreg;

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

        scan_add_host(ici);

        return 0;

edevreg:
        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->iface == ici->nr) {
                        /* The bus->remove will be called */
                        device_unregister(&icd->dev);
                        /*
                         * Not before device_unregister(), .remove
                         * needs parent to call ici->ops->remove().
                         * If the host module is loaded again, device_register()
                         * would complain "already initialised," since 2.6.32
                         * this is also needed to prevent use-after-free of the
                         * device private data.
                         */
                        memset(&icd->dev, 0, sizeof(icd->dev));
                }
        }

        mutex_unlock(&list_lock);

        v4l2_device_unregister(&ici->v4l2_dev);
}
EXPORT_SYMBOL(soc_camera_host_unregister);

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

        for (i = 0; i < 256 && num < 0; i++) {
                num = i;
                /* Check if this index is available on this interface */
                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;

        icd->dev.release        = dummy_release;
        icd->use_count          = 0;
        icd->host_priv          = NULL;
        mutex_init(&icd->video_lock);

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

        return 0;
}

static void soc_camera_device_unregister(struct soc_camera_device *icd)
{
        list_del(&icd->list);
}

static const struct v4l2_ioctl_ops soc_camera_ioctl_ops = {
        .vidioc_querycap         = soc_camera_querycap,
        .vidioc_g_fmt_vid_cap    = soc_camera_g_fmt_vid_cap,
        .vidioc_enum_fmt_vid_cap = soc_camera_enum_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap    = soc_camera_s_fmt_vid_cap,
        .vidioc_enum_input       = soc_camera_enum_input,
        .vidioc_g_input          = soc_camera_g_input,
        .vidioc_s_input          = soc_camera_s_input,
        .vidioc_s_std            = soc_camera_s_std,
        .vidioc_reqbufs          = soc_camera_reqbufs,
        .vidioc_try_fmt_vid_cap  = soc_camera_try_fmt_vid_cap,
        .vidioc_querybuf         = soc_camera_querybuf,
        .vidioc_qbuf             = soc_camera_qbuf,
        .vidioc_dqbuf            = soc_camera_dqbuf,
        .vidioc_streamon         = soc_camera_streamon,
        .vidioc_streamoff        = soc_camera_streamoff,
        .vidioc_queryctrl        = soc_camera_queryctrl,
        .vidioc_g_ctrl           = soc_camera_g_ctrl,
        .vidioc_s_ctrl           = soc_camera_s_ctrl,
        .vidioc_cropcap          = soc_camera_cropcap,
        .vidioc_g_crop           = soc_camera_g_crop,
        .vidioc_s_crop           = soc_camera_s_crop,
        .vidioc_g_chip_ident     = soc_camera_g_chip_ident,
#ifdef CONFIG_VIDEO_ADV_DEBUG
        .vidioc_g_register       = soc_camera_g_register,
        .vidioc_s_register       = soc_camera_s_register,
#endif
};

static int video_dev_create(struct soc_camera_device *icd)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
        struct video_device *vdev = video_device_alloc();

        if (!vdev)
                return -ENOMEM;

        strlcpy(vdev->name, ici->drv_name, sizeof(vdev->name));

        vdev->parent            = &icd->dev;
        vdev->current_norm      = V4L2_STD_UNKNOWN;
        vdev->fops              = &soc_camera_fops;
        vdev->ioctl_ops         = &soc_camera_ioctl_ops;
        vdev->release           = video_device_release;
        vdev->minor             = -1;
        vdev->tvnorms           = V4L2_STD_UNKNOWN;

        icd->vdev = vdev;

        return 0;
}

/*
 * Called from soc_camera_probe() above (with .video_lock held???)
 */
static int soc_camera_video_start(struct soc_camera_device *icd)
{
        int ret;

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

        if (!icd->ops ||
            !icd->ops->query_bus_param ||
            !icd->ops->set_bus_param)
                return -EINVAL;

        ret = video_register_device(icd->vdev, VFL_TYPE_GRABBER,
                                    icd->vdev->minor);
        if (ret < 0) {
                dev_err(&icd->dev, "video_register_device failed: %d\n", ret);
                return ret;
        }

        return 0;
}

static int __devinit soc_camera_pdrv_probe(struct platform_device *pdev)
{
        struct soc_camera_link *icl = pdev->dev.platform_data;
        struct soc_camera_device *icd;
        int ret;

        if (!icl)
                return -EINVAL;

        icd = kzalloc(sizeof(*icd), GFP_KERNEL);
        if (!icd)
                return -ENOMEM;

        icd->iface = icl->bus_id;
        icd->pdev = &pdev->dev;
        platform_set_drvdata(pdev, icd);
        icd->dev.platform_data = icl;

        ret = soc_camera_device_register(icd);
        if (ret < 0)
                goto escdevreg;

        icd->user_width         = DEFAULT_WIDTH;
        icd->user_height        = DEFAULT_HEIGHT;

        return 0;

escdevreg:
        kfree(icd);

        return ret;
}

/* Only called on rmmod for each platform device, since they are not
 * hot-pluggable. Now we know, that all our users - hosts and devices have
 * been unloaded already */
static int __devexit soc_camera_pdrv_remove(struct platform_device *pdev)
{
        struct soc_camera_device *icd = platform_get_drvdata(pdev);

        if (!icd)
                return -EINVAL;

        soc_camera_device_unregister(icd);

        kfree(icd);

        return 0;
}

static struct platform_driver __refdata soc_camera_pdrv = {
        .remove  = __devexit_p(soc_camera_pdrv_remove),
        .driver  = {
                .name   = "soc-camera-pdrv",
                .owner  = THIS_MODULE,
        },
};

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 = platform_driver_probe(&soc_camera_pdrv, soc_camera_pdrv_probe);
        if (ret)
                goto epdr;

        return 0;

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

static void __exit soc_camera_exit(void)
{
        platform_driver_unregister(&soc_camera_pdrv);
        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");
MODULE_ALIAS("platform:soc-camera-pdrv");