V4L/DVB (11221): gspca - sonixj: Prefer sonixj instead of sn9c102 for 0471:0327.

[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-ioctl.h>
#include <media/v4l2-dev.h>
#include <media/videobuf-core.h>
#include <media/soc_camera.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);

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;
        int ret = 0;

        if (icd->ops->set_std)
                ret = icd->ops->set_std(icd, a);

        return ret;
}

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", __func__, p->memory);

        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);
}

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;

        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++)
                        fmts += ici->ops->get_formats(icd, i, NULL);

        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;
        fmts = 0;

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

        /* Second pass - actually fill data formats */
        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 {
                        fmts += ici->ops->get_formats(icd, i,
                                                      &icd->user_formats[fmts]);
                }

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

        return 0;
}

static void soc_camera_free_user_formats(struct soc_camera_device *icd)
{
        vfree(icd->user_formats);
}

/* 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;

        /* 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(&ici->dev,
                        "Host driver hasn't set up current format correctly!\n");
                return -EINVAL;
        }

        icd->width              = pix->width;
        icd->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->width, icd->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;
        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;

        /*
         * It is safe to dereference these pointers now as long as a user has
         * the video device open - we are protected by the held cdev reference.
         */

        vdev = video_devdata(file);
        icd = container_of(vdev->parent, 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->ops->owner)) {
                dev_err(&icd->dev, "Couldn't lock capture bus driver.\n");
                ret = -EINVAL;
                goto emgi;
        }

        /* Protect against icd->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->width,
                                .height         = icd->height,
                                .field          = icd->field,
                                .pixelformat    = icd->current_fmt->fourcc,
                                .colorspace     = icd->current_fmt->colorspace,
                        },
                };

                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;
        }

        mutex_unlock(&icd->video_lock);

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

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

        return 0;

        /*
         * First three errors are entered with the .video_lock held
         * and use_count == 1
         */
esfmt:
        ici->ops->remove(icd);
eiciadd:
        icd->use_count--;
        mutex_unlock(&icd->video_lock);
        module_put(ici->ops->owner);
emgi:
        module_put(icd->ops->owner);
emgd:
        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);
        struct video_device *vdev = icd->vdev;

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

        mutex_unlock(&icd->video_lock);

        module_put(icd->ops->owner);
        module_put(ici->ops->owner);

        vfree(icf);

        dev_dbg(vdev->parent, "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->parent, "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 (videobuf_queue_is_busy(&icf->vb_vidq)) {
                dev_err(&icd->dev, "S_FMT denied: queue busy\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->width;
        pix->height             = icd->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;
        int ret;

        WARN_ON(priv != file->private_data);

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

        if (i != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        mutex_lock(&icd->video_lock);

        icd->ops->start_capture(icd);

        /* 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;

        WARN_ON(priv != file->private_data);

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

        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);

        icd->ops->stop_capture(icd);

        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;
        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                = DEFAULT_WIDTH;
        a->defrect.height               = DEFAULT_HEIGHT;
        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;

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

        ret = ici->ops->set_crop(icd, &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;
        }

        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;

        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_dbg_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_dbg_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;

        /*
         * Possible race scenario:
         * modprobe <camera-host-driver> triggers __func__
         * at this moment respective <camera-sensor-driver> gets rmmod'ed
         * to protect take module references.
         */

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

        mutex_lock(&icd->video_lock);

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

        ret = icd->ops->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;

                ret = soc_camera_init_user_formats(icd);
                if (ret < 0)
                        goto eiufmt;

                icd->height     = DEFAULT_HEIGHT;
                icd->width      = DEFAULT_WIDTH;
                icd->field      = V4L2_FIELD_ANY;
        }

eiufmt:
        ici->ops->remove(icd);
eiadd:
        mutex_unlock(&icd->video_lock);
        module_put(ici->ops->owner);
emgi:
        module_put(icd->ops->owner);
emgd:
        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->ops->remove)
                icd->ops->remove(icd);

        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)
{
}

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

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

        /* Number might be equal to the platform device ID */
        dev_set_name(&ici->dev, "camera_host%d", ici->nr);

        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->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->ops->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 || !icd->ops ||
            !icd->ops->probe ||
            !icd->ops->init ||
            !icd->ops->release ||
            !icd->ops->start_capture ||
            !icd->ops->stop_capture ||
            !icd->ops->set_crop ||
            !icd->ops->set_fmt ||
            !icd->ops->try_fmt ||
            !icd->ops->query_bus_param ||
            !icd->ops->set_bus_param)
                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;
        dev_set_name(&icd->dev, "%u-%u", icd->iface, icd->devnum);

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

        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);

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
};

/*
 * Usually called from the struct soc_camera_ops .probe() method, i.e., from
 * soc_camera_probe() above with .video_lock held
 */
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));

        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,

        err = video_register_device(vdev, VFL_TYPE_GRABBER, vdev->minor);
        if (err < 0) {
                dev_err(vdev->parent, "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", __func__);

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

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

        return 0;

edrvr:
        bus_unregister(&soc_camera_bus_type);
        return ret;
}

static void __exit soc_camera_exit(void)
{
        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");