/*
 * 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/module.h>
#include <linux/mutex.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include <media/soc_camera.h>
#include <media/drv-intf/soc_mediabus.h>
#include <media/v4l2-async.h>
#include <media/v4l2-clk.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fwnode.h>
#include <media/videobuf2-v4l2.h>

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

#define MAP_MAX_NUM 32
static DECLARE_BITMAP(device_map, MAP_MAX_NUM);
static LIST_HEAD(hosts);
static LIST_HEAD(devices);
/*
 * Protects lists and bitmaps of hosts and devices.
 * Lock nesting: Ok to take ->host_lock under list_lock.
 */
static DEFINE_MUTEX(list_lock);

struct soc_camera_async_client {
        struct v4l2_async_subdev *sensor;
        struct v4l2_async_notifier notifier;
        struct platform_device *pdev;
        struct list_head list;          /* needed for clean up */
};

static int soc_camera_video_start(struct soc_camera_device *icd);
static int video_dev_create(struct soc_camera_device *icd);

int soc_camera_power_on(struct device *dev, struct soc_camera_subdev_desc *ssdd,
                        struct v4l2_clk *clk)
{
        int ret;
        bool clock_toggle;

        if (clk && (!ssdd->unbalanced_power ||
                    !test_and_set_bit(0, &ssdd->clock_state))) {
                ret = v4l2_clk_enable(clk);
                if (ret < 0) {
                        dev_err(dev, "Cannot enable clock: %d\n", ret);
                        return ret;
                }
                clock_toggle = true;
        } else {
                clock_toggle = false;
        }

        ret = regulator_bulk_enable(ssdd->sd_pdata.num_regulators,
                                    ssdd->sd_pdata.regulators);
        if (ret < 0) {
                dev_err(dev, "Cannot enable regulators\n");
                goto eregenable;
        }

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

        return 0;

epwron:
        regulator_bulk_disable(ssdd->sd_pdata.num_regulators,
                               ssdd->sd_pdata.regulators);
eregenable:
        if (clock_toggle)
                v4l2_clk_disable(clk);

        return ret;
}
EXPORT_SYMBOL(soc_camera_power_on);

int soc_camera_power_off(struct device *dev, struct soc_camera_subdev_desc *ssdd,
                         struct v4l2_clk *clk)
{
        int ret = 0;
        int err;

        if (ssdd->power) {
                err = ssdd->power(dev, 0);
                if (err < 0) {
                        dev_err(dev,
                                "Platform failed to power-off the camera.\n");
                        ret = err;
                }
        }

        err = regulator_bulk_disable(ssdd->sd_pdata.num_regulators,
                                     ssdd->sd_pdata.regulators);
        if (err < 0) {
                dev_err(dev, "Cannot disable regulators\n");
                ret = ret ? : err;
        }

        if (clk && (!ssdd->unbalanced_power || test_and_clear_bit(0, &ssdd->clock_state)))
                v4l2_clk_disable(clk);

        return ret;
}
EXPORT_SYMBOL(soc_camera_power_off);

int soc_camera_power_init(struct device *dev, struct soc_camera_subdev_desc *ssdd)
{
        /* Should not have any effect in synchronous case */
        return devm_regulator_bulk_get(dev, ssdd->sd_pdata.num_regulators,
                                       ssdd->sd_pdata.regulators);
}
EXPORT_SYMBOL(soc_camera_power_init);

static int __soc_camera_power_on(struct soc_camera_device *icd)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        int ret;

        ret = v4l2_subdev_call(sd, core, s_power, 1);
        if (ret < 0 && ret != -ENOIOCTLCMD && ret != -ENODEV)
                return ret;

        return 0;
}

static int __soc_camera_power_off(struct soc_camera_device *icd)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        int ret;

        ret = v4l2_subdev_call(sd, core, s_power, 0);
        if (ret < 0 && ret != -ENOIOCTLCMD && ret != -ENODEV)
                return ret;

        return 0;
}

static int soc_camera_clock_start(struct soc_camera_host *ici)
{
        int ret;

        if (!ici->ops->clock_start)
                return 0;

        mutex_lock(&ici->clk_lock);
        ret = ici->ops->clock_start(ici);
        mutex_unlock(&ici->clk_lock);

        return ret;
}

static void soc_camera_clock_stop(struct soc_camera_host *ici)
{
        if (!ici->ops->clock_stop)
                return;

        mutex_lock(&ici->clk_lock);
        ici->ops->clock_stop(ici);
        mutex_unlock(&ici->clk_lock);
}

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_board_flags() - apply platform SOCAM_SENSOR_INVERT_* flags
 * @ssdd:       camera platform parameters
 * @cfg:        media bus configuration
 * @return:     resulting flags
 */
unsigned long soc_camera_apply_board_flags(struct soc_camera_subdev_desc *ssdd,
                                           const struct v4l2_mbus_config *cfg)
{
        unsigned long f, flags = cfg->flags;

        /* If only one of the two polarities is supported, switch to the opposite */
        if (ssdd->flags & SOCAM_SENSOR_INVERT_HSYNC) {
                f = flags & (V4L2_MBUS_HSYNC_ACTIVE_HIGH | V4L2_MBUS_HSYNC_ACTIVE_LOW);
                if (f == V4L2_MBUS_HSYNC_ACTIVE_HIGH || f == V4L2_MBUS_HSYNC_ACTIVE_LOW)
                        flags ^= V4L2_MBUS_HSYNC_ACTIVE_HIGH | V4L2_MBUS_HSYNC_ACTIVE_LOW;
        }

        if (ssdd->flags & SOCAM_SENSOR_INVERT_VSYNC) {
                f = flags & (V4L2_MBUS_VSYNC_ACTIVE_HIGH | V4L2_MBUS_VSYNC_ACTIVE_LOW);
                if (f == V4L2_MBUS_VSYNC_ACTIVE_HIGH || f == V4L2_MBUS_VSYNC_ACTIVE_LOW)
                        flags ^= V4L2_MBUS_VSYNC_ACTIVE_HIGH | V4L2_MBUS_VSYNC_ACTIVE_LOW;
        }

        if (ssdd->flags & SOCAM_SENSOR_INVERT_PCLK) {
                f = flags & (V4L2_MBUS_PCLK_SAMPLE_RISING | V4L2_MBUS_PCLK_SAMPLE_FALLING);
                if (f == V4L2_MBUS_PCLK_SAMPLE_RISING || f == V4L2_MBUS_PCLK_SAMPLE_FALLING)
                        flags ^= V4L2_MBUS_PCLK_SAMPLE_RISING | V4L2_MBUS_PCLK_SAMPLE_FALLING;
        }

        return flags;
}
EXPORT_SYMBOL(soc_camera_apply_board_flags);

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

static int soc_camera_try_fmt(struct soc_camera_device *icd,
                              struct v4l2_format *f)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        const struct soc_camera_format_xlate *xlate;
        struct v4l2_pix_format *pix = &f->fmt.pix;
        int ret;

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

        if (pix->pixelformat != V4L2_PIX_FMT_JPEG &&
            !(ici->capabilities & SOCAM_HOST_CAP_STRIDE)) {
                pix->bytesperline = 0;
                pix->sizeimage = 0;
        }

        ret = ici->ops->try_fmt(icd, f);
        if (ret < 0)
                return ret;

        xlate = soc_camera_xlate_by_fourcc(icd, pix->pixelformat);
        if (!xlate)
                return -EINVAL;

        ret = soc_mbus_bytes_per_line(pix->width, xlate->host_fmt);
        if (ret < 0)
                return ret;

        pix->bytesperline = max_t(u32, pix->bytesperline, ret);

        ret = soc_mbus_image_size(xlate->host_fmt, pix->bytesperline,
                                  pix->height);
        if (ret < 0)
                return ret;

        pix->sizeimage = max_t(u32, pix->sizeimage, ret);

        return 0;
}

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

        WARN_ON(priv != file->private_data);

        /* Only single-plane capture is supported so far */
        if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        /* limit format to hardware capabilities */
        return soc_camera_try_fmt(icd, f);
}

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

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

        /* default is camera */
        inp->type = V4L2_INPUT_TYPE_CAMERA;
        inp->std = icd->vdev->tvnorms;
        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)
{
        struct soc_camera_device *icd = file->private_data;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_subdev_call(sd, video, s_std, a);
}

static int soc_camera_g_std(struct file *file, void *priv, v4l2_std_id *a)
{
        struct soc_camera_device *icd = file->private_data;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_subdev_call(sd, video, g_std, a);
}

static int soc_camera_enum_framesizes(struct file *file, void *fh,
                                         struct v4l2_frmsizeenum *fsize)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);

        return ici->ops->enum_framesizes(icd, fsize);
}

static int soc_camera_reqbufs(struct file *file, void *priv,
                              struct v4l2_requestbuffers *p)
{
        int ret;
        struct soc_camera_device *icd = file->private_data;

        WARN_ON(priv != file->private_data);

        if (icd->streamer && icd->streamer != file)
                return -EBUSY;

        ret = vb2_reqbufs(&icd->vb2_vidq, p);
        if (!ret)
                icd->streamer = p->count ? file : NULL;
        return ret;
}

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

        WARN_ON(priv != file->private_data);

        return vb2_querybuf(&icd->vb2_vidq, p);
}

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

        WARN_ON(priv != file->private_data);

        if (icd->streamer != file)
                return -EBUSY;

        return vb2_qbuf(&icd->vb2_vidq, p);
}

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

        WARN_ON(priv != file->private_data);

        if (icd->streamer != file)
                return -EBUSY;

        return vb2_dqbuf(&icd->vb2_vidq, p, file->f_flags & O_NONBLOCK);
}

static int soc_camera_create_bufs(struct file *file, void *priv,
                            struct v4l2_create_buffers *create)
{
        struct soc_camera_device *icd = file->private_data;
        int ret;

        if (icd->streamer && icd->streamer != file)
                return -EBUSY;

        ret = vb2_create_bufs(&icd->vb2_vidq, create);
        if (!ret)
                icd->streamer = file;
        return ret;
}

static int soc_camera_prepare_buf(struct file *file, void *priv,
                                  struct v4l2_buffer *b)
{
        struct soc_camera_device *icd = file->private_data;

        return vb2_prepare_buf(&icd->vb2_vidq, b);
}

static int soc_camera_expbuf(struct file *file, void *priv,
                             struct v4l2_exportbuffer *p)
{
        struct soc_camera_device *icd = file->private_data;

        if (icd->streamer && icd->streamer != file)
                return -EBUSY;
        return vb2_expbuf(&icd->vb2_vidq, p);
}

/* Always entered with .host_lock held */
static int soc_camera_init_user_formats(struct soc_camera_device *icd)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        unsigned int i, fmts = 0, raw_fmts = 0;
        int ret;
        struct v4l2_subdev_mbus_code_enum code = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };

        while (!v4l2_subdev_call(sd, pad, enum_mbus_code, NULL, &code)) {
                raw_fmts++;
                code.index++;
        }

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

        if (!fmts)
                return -ENXIO;

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

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

        /* Second pass - actually fill data formats */
        fmts = 0;
        for (i = 0; i < raw_fmts; i++)
                if (!ici->ops->get_formats) {
                        code.index = i;
                        v4l2_subdev_call(sd, pad, enum_mbus_code, NULL, &code);
                        icd->user_formats[fmts].host_fmt =
                                soc_mbus_get_fmtdesc(code.code);
                        if (icd->user_formats[fmts].host_fmt)
                                icd->user_formats[fmts++].code = code.code;
                } else {
                        ret = ici->ops->get_formats(icd, i,
                                                    &icd->user_formats[fmts]);
                        if (ret < 0)
                                goto egfmt;
                        fmts += ret;
                }

        icd->num_user_formats = fmts;
        icd->current_fmt = &icd->user_formats[0];

        return 0;

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

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

/* Called with .vb_lock held, or from the first open(2), see comment there */
static int soc_camera_set_fmt(struct soc_camera_device *icd,
                              struct v4l2_format *f)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        struct v4l2_pix_format *pix = &f->fmt.pix;
        int ret;

        dev_dbg(icd->pdev, "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_selection() */
        ret = soc_camera_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->host_fmt->fourcc != pix->pixelformat) {
                dev_err(icd->pdev,
                        "Host driver hasn't set up current format correctly!\n");
                return -EINVAL;
        }

        icd->user_width         = pix->width;
        icd->user_height        = pix->height;
        icd->bytesperline       = pix->bytesperline;
        icd->sizeimage          = pix->sizeimage;
        icd->colorspace         = pix->colorspace;
        icd->field              = pix->field;

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

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

static int soc_camera_add_device(struct soc_camera_device *icd)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        int ret;

        if (ici->icd)
                return -EBUSY;

        if (!icd->clk) {
                ret = soc_camera_clock_start(ici);
                if (ret < 0)
                        return ret;
        }

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

        ici->icd = icd;

        return 0;

eadd:
        if (!icd->clk)
                soc_camera_clock_stop(ici);
        return ret;
}

static void soc_camera_remove_device(struct soc_camera_device *icd)
{
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);

        if (WARN_ON(icd != ici->icd))
                return;

        if (ici->ops->remove)
                ici->ops->remove(icd);
        if (!icd->clk)
                soc_camera_clock_stop(ici);
        ici->icd = NULL;
}

static int soc_camera_open(struct file *file)
{
        struct video_device *vdev = video_devdata(file);
        struct soc_camera_device *icd;
        struct soc_camera_host *ici;
        int ret;

        /*
         * Don't mess with the host during probe: wait until the loop in
         * scan_add_host() completes. Also protect against a race with
         * soc_camera_host_unregister().
         */
        if (mutex_lock_interruptible(&list_lock))
                return -ERESTARTSYS;

        if (!vdev || !video_is_registered(vdev)) {
                mutex_unlock(&list_lock);
                return -ENODEV;
        }

        icd = video_get_drvdata(vdev);
        ici = to_soc_camera_host(icd->parent);

        ret = try_module_get(ici->ops->owner) ? 0 : -ENODEV;
        mutex_unlock(&list_lock);

        if (ret < 0) {
                dev_err(icd->pdev, "Couldn't lock capture bus driver.\n");
                return ret;
        }

        if (!to_soc_camera_control(icd)) {
                /* No device driver attached */
                ret = -ENODEV;
                goto econtrol;
        }

        if (mutex_lock_interruptible(&ici->host_lock)) {
                ret = -ERESTARTSYS;
                goto elockhost;
        }
        icd->use_count++;

        /* Now we really have to activate the camera */
        if (icd->use_count == 1) {
                struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);
                /* 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,
                                .colorspace     = icd->colorspace,
                                .pixelformat    =
                                        icd->current_fmt->host_fmt->fourcc,
                        },
                };

                /* The camera could have been already on, try to reset */
                if (sdesc->subdev_desc.reset)
                        if (icd->control)
                                sdesc->subdev_desc.reset(icd->control);

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

                ret = __soc_camera_power_on(icd);
                if (ret < 0)
                        goto epower;

                pm_runtime_enable(&icd->vdev->dev);
                ret = pm_runtime_resume(&icd->vdev->dev);
                if (ret < 0 && ret != -ENOSYS)
                        goto eresume;

                /*
                 * Try to configure with default parameters. Notice: this is the
                 * very first open, so, we cannot race against other calls,
                 * apart from someone else calling open() simultaneously, but
                 * .host_lock is protecting us against it.
                 */
                ret = soc_camera_set_fmt(icd, &f);
                if (ret < 0)
                        goto esfmt;

                ret = ici->ops->init_videobuf2(&icd->vb2_vidq, icd);
                if (ret < 0)
                        goto einitvb;
                v4l2_ctrl_handler_setup(&icd->ctrl_handler);
        }
        mutex_unlock(&ici->host_lock);

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

        return 0;

        /*
         * All errors are entered with the .host_lock held, first four also
         * with use_count == 1
         */
einitvb:
esfmt:
        pm_runtime_disable(&icd->vdev->dev);
eresume:
        __soc_camera_power_off(icd);
epower:
        soc_camera_remove_device(icd);
eiciadd:
        icd->use_count--;
        mutex_unlock(&ici->host_lock);
elockhost:
econtrol:
        module_put(ici->ops->owner);

        return ret;
}

static int soc_camera_close(struct file *file)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);

        mutex_lock(&ici->host_lock);
        if (icd->streamer == file) {
                if (ici->ops->init_videobuf2)
                        vb2_queue_release(&icd->vb2_vidq);
                icd->streamer = NULL;
        }
        icd->use_count--;
        if (!icd->use_count) {
                pm_runtime_suspend(&icd->vdev->dev);
                pm_runtime_disable(&icd->vdev->dev);

                __soc_camera_power_off(icd);

                soc_camera_remove_device(icd);
        }

        mutex_unlock(&ici->host_lock);

        module_put(ici->ops->owner);

        dev_dbg(icd->pdev, "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_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);

        dev_dbg(icd->pdev, "read called, buf %p\n", buf);

        if (ici->ops->init_videobuf2 && icd->vb2_vidq.io_modes & VB2_READ)
                return vb2_read(&icd->vb2_vidq, buf, count, ppos,
                                file->f_flags & O_NONBLOCK);

        dev_err(icd->pdev, "camera device read not implemented\n");

        return -EINVAL;
}

static int soc_camera_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        int err;

        dev_dbg(icd->pdev, "mmap called, vma=%p\n", vma);

        if (icd->streamer != file)
                return -EBUSY;

        if (mutex_lock_interruptible(&ici->host_lock))
                return -ERESTARTSYS;
        err = vb2_mmap(&icd->vb2_vidq, vma);
        mutex_unlock(&ici->host_lock);

        dev_dbg(icd->pdev, "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 __poll_t soc_camera_poll(struct file *file, poll_table *pt)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        __poll_t res = EPOLLERR;

        if (icd->streamer != file)
                return EPOLLERR;

        mutex_lock(&ici->host_lock);
        res = ici->ops->poll(file, pt);
        mutex_unlock(&ici->host_lock);
        return res;
}

static const struct v4l2_file_operations soc_camera_fops = {
        .owner          = THIS_MODULE,
        .open           = soc_camera_open,
        .release        = soc_camera_close,
        .unlocked_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_device *icd = file->private_data;
        int ret;

        WARN_ON(priv != file->private_data);

        if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE) {
                dev_warn(icd->pdev, "Wrong buf-type %d\n", f->type);
                return -EINVAL;
        }

        if (icd->streamer && icd->streamer != file)
                return -EBUSY;

        if (vb2_is_streaming(&icd->vb2_vidq)) {
                dev_err(icd->pdev, "S_FMT denied: queue initialised\n");
                return -EBUSY;
        }

        ret = soc_camera_set_fmt(icd, f);

        if (!ret && !icd->streamer)
                icd->streamer = file;

        return ret;
}

static int soc_camera_enum_fmt_vid_cap(struct file *file, void  *priv,
                                       struct v4l2_fmtdesc *f)
{
        struct soc_camera_device *icd = file->private_data;
        const struct soc_mbus_pixelfmt *format;

        WARN_ON(priv != file->private_data);

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

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

        if (format->name)
                strscpy(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_device *icd = file->private_data;
        struct v4l2_pix_format *pix = &f->fmt.pix;

        WARN_ON(priv != file->private_data);

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

        pix->width              = icd->user_width;
        pix->height             = icd->user_height;
        pix->bytesperline       = icd->bytesperline;
        pix->sizeimage          = icd->sizeimage;
        pix->field              = icd->field;
        pix->pixelformat        = icd->current_fmt->host_fmt->fourcc;
        pix->colorspace         = icd->colorspace;
        dev_dbg(icd->pdev, "current_fmt->fourcc: 0x%08x\n",
                icd->current_fmt->host_fmt->fourcc);
        return 0;
}

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

        WARN_ON(priv != file->private_data);

        strscpy(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_device *icd = file->private_data;
        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;

        if (icd->streamer != file)
                return -EBUSY;

        /* This calls buf_queue from host driver's videobuf2_queue_ops */
        ret = vb2_streamon(&icd->vb2_vidq, i);
        if (!ret)
                v4l2_subdev_call(sd, video, s_stream, 1);

        return ret;
}

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

        if (icd->streamer != file)
                return -EBUSY;

        /*
         * This calls buf_release from host driver's videobuf2_queue_ops for all
         * remaining buffers. When the last buffer is freed, stop capture
         */
        ret = vb2_streamoff(&icd->vb2_vidq, i);

        v4l2_subdev_call(sd, video, s_stream, 0);

        return ret;
}

static int soc_camera_g_selection(struct file *file, void *fh,
                                  struct v4l2_selection *s)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);

        /* With a wrong type no need to try to fall back to cropping */
        if (s->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        return ici->ops->get_selection(icd, s);
}

static int soc_camera_s_selection(struct file *file, void *fh,
                                  struct v4l2_selection *s)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        int ret;

        /* In all these cases cropping emulation will not help */
        if (s->type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
            (s->target != V4L2_SEL_TGT_COMPOSE &&
             s->target != V4L2_SEL_TGT_CROP))
                return -EINVAL;

        if (s->target == V4L2_SEL_TGT_COMPOSE) {
                /* No output size change during a running capture! */
                if (vb2_is_streaming(&icd->vb2_vidq) &&
                    (icd->user_width != s->r.width ||
                     icd->user_height != s->r.height))
                        return -EBUSY;

                /*
                 * Only one user is allowed to change the output format, touch

                 * buffers, start / stop streaming, poll for data
                 */
                if (icd->streamer && icd->streamer != file)
                        return -EBUSY;
        }

        if (s->target == V4L2_SEL_TGT_CROP &&
            vb2_is_streaming(&icd->vb2_vidq) &&
            ici->ops->set_liveselection)
                ret = ici->ops->set_liveselection(icd, s);
        else
                ret = ici->ops->set_selection(icd, s);
        if (!ret &&
            s->target == V4L2_SEL_TGT_COMPOSE) {
                icd->user_width = s->r.width;
                icd->user_height = s->r.height;
                if (!icd->streamer)
                        icd->streamer = file;
        }

        return ret;
}

static int soc_camera_g_parm(struct file *file, void *fh,
                             struct v4l2_streamparm *a)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);

        if (ici->ops->get_parm)
                return ici->ops->get_parm(icd, a);

        return -ENOIOCTLCMD;
}

static int soc_camera_s_parm(struct file *file, void *fh,
                             struct v4l2_streamparm *a)
{
        struct soc_camera_device *icd = file->private_data;
        struct soc_camera_host *ici = to_soc_camera_host(icd->parent);

        if (ici->ops->set_parm)
                return ici->ops->set_parm(icd, a);

        return -ENOIOCTLCMD;
}

static int soc_camera_probe(struct soc_camera_host *ici,
                            struct soc_camera_device *icd);

/* 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) {
                        struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);
                        struct soc_camera_subdev_desc *ssdd = &sdesc->subdev_desc;

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

                        icd->parent = ici->v4l2_dev.dev;

                        /* Ignore errors */
                        soc_camera_probe(ici, icd);
                }

        mutex_unlock(&list_lock);
}

/*
 * It is invalid to call v4l2_clk_enable() after a successful probing
 * asynchronously outside of V4L2 operations, i.e. with .host_lock not held.
 */
static int soc_camera_clk_enable(struct v4l2_clk *clk)
{
        struct soc_camera_device *icd = clk->priv;
        struct soc_camera_host *ici;

        if (!icd || !icd->parent)
                return -ENODEV;

        ici = to_soc_camera_host(icd->parent);

        if (!try_module_get(ici->ops->owner))
                return -ENODEV;

        /*
         * If a different client is currently being probed, the host will tell
         * you to go
         */
        return soc_camera_clock_start(ici);
}

static void soc_camera_clk_disable(struct v4l2_clk *clk)
{
        struct soc_camera_device *icd = clk->priv;
        struct soc_camera_host *ici;

        if (!icd || !icd->parent)
                return;

        ici = to_soc_camera_host(icd->parent);

        soc_camera_clock_stop(ici);

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

/*
 * Eventually, it would be more logical to make the respective host the clock
 * owner, but then we would have to copy this struct for each ici. Besides, it
 * would introduce the circular dependency problem, unless we port all client
 * drivers to release the clock, when not in use.
 */
static const struct v4l2_clk_ops soc_camera_clk_ops = {
        .owner = THIS_MODULE,
        .enable = soc_camera_clk_enable,
        .disable = soc_camera_clk_disable,
};

static int soc_camera_dyn_pdev(struct soc_camera_desc *sdesc,
                               struct soc_camera_async_client *sasc)
{
        struct platform_device *pdev;
        int ret, i;

        mutex_lock(&list_lock);
        i = find_first_zero_bit(device_map, MAP_MAX_NUM);
        if (i < MAP_MAX_NUM)
                set_bit(i, device_map);
        mutex_unlock(&list_lock);
        if (i >= MAP_MAX_NUM)
                return -ENOMEM;

        pdev = platform_device_alloc("soc-camera-pdrv", i);
        if (!pdev)
                return -ENOMEM;

        ret = platform_device_add_data(pdev, sdesc, sizeof(*sdesc));
        if (ret < 0) {
                platform_device_put(pdev);
                return ret;
        }

        sasc->pdev = pdev;

        return 0;
}

static struct soc_camera_device *soc_camera_add_pdev(struct soc_camera_async_client *sasc)
{
        struct platform_device *pdev = sasc->pdev;
        int ret;

        ret = platform_device_add(pdev);
        if (ret < 0 || !pdev->dev.driver)
                return NULL;

        return platform_get_drvdata(pdev);
}

/* Locking: called with .host_lock held */
static int soc_camera_probe_finish(struct soc_camera_device *icd)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        struct v4l2_subdev_format fmt = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };
        struct v4l2_mbus_framefmt *mf = &fmt.format;
        int ret;

        sd->grp_id = soc_camera_grp_id(icd);
        v4l2_set_subdev_hostdata(sd, icd);

        v4l2_subdev_call(sd, video, g_tvnorms, &icd->vdev->tvnorms);

        ret = v4l2_ctrl_add_handler(&icd->ctrl_handler, sd->ctrl_handler,
                                    NULL, true);
        if (ret < 0)
                return ret;

        ret = soc_camera_add_device(icd);
        if (ret < 0) {
                dev_err(icd->pdev, "Couldn't activate the camera: %d\n", ret);
                return ret;
        }

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

        icd->field = V4L2_FIELD_ANY;

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

        /* Try to improve our guess of a reasonable window format */
        if (!v4l2_subdev_call(sd, pad, get_fmt, NULL, &fmt)) {
                icd->user_width         = mf->width;
                icd->user_height        = mf->height;
                icd->colorspace         = mf->colorspace;
                icd->field              = mf->field;
        }
        soc_camera_remove_device(icd);

        return 0;

evidstart:
        soc_camera_free_user_formats(icd);
eusrfmt:
        soc_camera_remove_device(icd);

        return ret;
}

#ifdef CONFIG_I2C_BOARDINFO
static int soc_camera_i2c_init(struct soc_camera_device *icd,
                               struct soc_camera_desc *sdesc)
{
        struct soc_camera_subdev_desc *ssdd;
        struct i2c_client *client;
        struct soc_camera_host *ici;
        struct soc_camera_host_desc *shd = &sdesc->host_desc;
        struct i2c_adapter *adap;
        struct v4l2_subdev *subdev;
        char clk_name[V4L2_CLK_NAME_SIZE];
        int ret;

        /* First find out how we link the main client */
        if (icd->sasc) {
                /* Async non-OF probing handled by the subdevice list */
                return -EPROBE_DEFER;
        }

        ici = to_soc_camera_host(icd->parent);
        adap = i2c_get_adapter(shd->i2c_adapter_id);
        if (!adap) {
                dev_err(icd->pdev, "Cannot get I2C adapter #%d. No driver?\n",
                        shd->i2c_adapter_id);
                return -ENODEV;
        }

        ssdd = kmemdup(&sdesc->subdev_desc, sizeof(*ssdd), GFP_KERNEL);
        if (!ssdd) {
                ret = -ENOMEM;
                goto ealloc;
        }
        /*
         * In synchronous case we request regulators ourselves in
         * soc_camera_pdrv_probe(), make sure the subdevice driver doesn't try
         * to allocate them again.
         */
        ssdd->sd_pdata.num_regulators = 0;
        ssdd->sd_pdata.regulators = NULL;
        shd->board_info->platform_data = ssdd;

        v4l2_clk_name_i2c(clk_name, sizeof(clk_name),
                          shd->i2c_adapter_id, shd->board_info->addr);

        icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, icd);
        if (IS_ERR(icd->clk)) {
                ret = PTR_ERR(icd->clk);
                goto eclkreg;
        }

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

        client = v4l2_get_subdevdata(subdev);

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

        return 0;
ei2cnd:
        v4l2_clk_unregister(icd->clk);
        icd->clk = NULL;
eclkreg:
        kfree(ssdd);
ealloc:
        i2c_put_adapter(adap);
        return ret;
}

static void soc_camera_i2c_free(struct soc_camera_device *icd)
{
        struct i2c_client *client =
                to_i2c_client(to_soc_camera_control(icd));
        struct i2c_adapter *adap;
        struct soc_camera_subdev_desc *ssdd;

        icd->control = NULL;
        if (icd->sasc)
                return;

        adap = client->adapter;
        ssdd = client->dev.platform_data;
        v4l2_device_unregister_subdev(i2c_get_clientdata(client));
        i2c_unregister_device(client);
        i2c_put_adapter(adap);
        kfree(ssdd);
        v4l2_clk_unregister(icd->clk);
        icd->clk = NULL;
}

/*
 * V4L2 asynchronous notifier callbacks. They are all called under a v4l2-async
 * internal global mutex, therefore cannot race against other asynchronous
 * events. Until notifier->complete() (soc_camera_async_complete()) is called,
 * the video device node is not registered and no V4L fops can occur. Unloading
 * of the host driver also calls a v4l2-async function, so also there we're
 * protected.
 */
static int soc_camera_async_bound(struct v4l2_async_notifier *notifier,
                                  struct v4l2_subdev *sd,
                                  struct v4l2_async_subdev *asd)
{
        struct soc_camera_async_client *sasc = container_of(notifier,
                                        struct soc_camera_async_client, notifier);
        struct soc_camera_device *icd = platform_get_drvdata(sasc->pdev);

        if (asd == sasc->sensor && !WARN_ON(icd->control)) {
                struct i2c_client *client = v4l2_get_subdevdata(sd);

                /*
                 * Only now we get subdevice-specific information like
                 * regulators, flags, callbacks, etc.
                 */
                if (client) {
                        struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);
                        struct soc_camera_subdev_desc *ssdd =
                                soc_camera_i2c_to_desc(client);
                        if (ssdd) {
                                memcpy(&sdesc->subdev_desc, ssdd,
                                       sizeof(sdesc->subdev_desc));
                                if (ssdd->reset)
                                        ssdd->reset(&client->dev);
                        }

                        icd->control = &client->dev;
                }
        }

        return 0;
}

static void soc_camera_async_unbind(struct v4l2_async_notifier *notifier,
                                    struct v4l2_subdev *sd,
                                    struct v4l2_async_subdev *asd)
{
        struct soc_camera_async_client *sasc = container_of(notifier,
                                        struct soc_camera_async_client, notifier);
        struct soc_camera_device *icd = platform_get_drvdata(sasc->pdev);

        icd->control = NULL;

        if (icd->clk) {
                v4l2_clk_unregister(icd->clk);
                icd->clk = NULL;
        }
}

static int soc_camera_async_complete(struct v4l2_async_notifier *notifier)
{
        struct soc_camera_async_client *sasc = container_of(notifier,
                                        struct soc_camera_async_client, notifier);
        struct soc_camera_device *icd = platform_get_drvdata(sasc->pdev);

        if (to_soc_camera_control(icd)) {
                struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
                int ret;

                mutex_lock(&list_lock);
                ret = soc_camera_probe(ici, icd);
                mutex_unlock(&list_lock);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static const struct v4l2_async_notifier_operations soc_camera_async_ops = {
        .bound = soc_camera_async_bound,
        .unbind = soc_camera_async_unbind,
        .complete = soc_camera_async_complete,
};

static int scan_async_group(struct soc_camera_host *ici,
                            struct v4l2_async_subdev **asd, unsigned int size)
{
        struct soc_camera_async_subdev *sasd;
        struct soc_camera_async_client *sasc;
        struct soc_camera_device *icd;
        struct soc_camera_desc sdesc = {.host_desc.bus_id = ici->nr,};
        char clk_name[V4L2_CLK_NAME_SIZE];
        unsigned int i;
        int ret;

        /* First look for a sensor */
        for (i = 0; i < size; i++) {
                sasd = container_of(asd[i], struct soc_camera_async_subdev, asd);
                if (sasd->role == SOCAM_SUBDEV_DATA_SOURCE)
                        break;
        }

        if (i >= size || asd[i]->match_type != V4L2_ASYNC_MATCH_I2C) {
                /* All useless */
                dev_err(ici->v4l2_dev.dev, "No I2C data source found!\n");
                return -ENODEV;
        }

        /* Or shall this be managed by the soc-camera device? */
        sasc = devm_kzalloc(ici->v4l2_dev.dev, sizeof(*sasc), GFP_KERNEL);
        if (!sasc)
                return -ENOMEM;

        /* HACK: just need a != NULL */
        sdesc.host_desc.board_info = ERR_PTR(-ENODATA);

        ret = soc_camera_dyn_pdev(&sdesc, sasc);
        if (ret < 0)
                goto eallocpdev;

        sasc->sensor = &sasd->asd;

        icd = soc_camera_add_pdev(sasc);
        if (!icd) {
                ret = -ENOMEM;
                goto eaddpdev;
        }

        sasc->notifier.subdevs = asd;
        sasc->notifier.num_subdevs = size;
        sasc->notifier.ops = &soc_camera_async_ops;

        icd->sasc = sasc;
        icd->parent = ici->v4l2_dev.dev;

        v4l2_clk_name_i2c(clk_name, sizeof(clk_name),
                          sasd->asd.match.i2c.adapter_id,
                          sasd->asd.match.i2c.address);

        icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, icd);
        if (IS_ERR(icd->clk)) {
                ret = PTR_ERR(icd->clk);
                goto eclkreg;
        }

        ret = v4l2_async_notifier_register(&ici->v4l2_dev, &sasc->notifier);
        if (!ret)
                return 0;

        v4l2_clk_unregister(icd->clk);
eclkreg:
        icd->clk = NULL;
        platform_device_del(sasc->pdev);
eaddpdev:
        platform_device_put(sasc->pdev);
eallocpdev:
        devm_kfree(ici->v4l2_dev.dev, sasc);
        dev_err(ici->v4l2_dev.dev, "group probe failed: %d\n", ret);

        return ret;
}

static void scan_async_host(struct soc_camera_host *ici)
{
        struct v4l2_async_subdev **asd;
        int j;

        for (j = 0, asd = ici->asd; ici->asd_sizes[j]; j++) {
                scan_async_group(ici, asd, ici->asd_sizes[j]);
                asd += ici->asd_sizes[j];
        }
}
#else
#define soc_camera_i2c_init(icd, sdesc) (-ENODEV)
#define soc_camera_i2c_free(icd)        do {} while (0)
#define scan_async_host(ici)            do {} while (0)
#endif

#ifdef CONFIG_OF

struct soc_of_info {
        struct soc_camera_async_subdev  sasd;
        struct soc_camera_async_client  sasc;
        struct v4l2_async_subdev        *subdev;
};

static int soc_of_bind(struct soc_camera_host *ici,
                       struct device_node *ep,
                       struct device_node *remote)
{
        struct soc_camera_device *icd;
        struct soc_camera_desc sdesc = {.host_desc.bus_id = ici->nr,};
        struct soc_camera_async_client *sasc;
        struct soc_of_info *info;
        struct i2c_client *client;
        char clk_name[V4L2_CLK_NAME_SIZE];
        int ret;

        /* allocate a new subdev and add match info to it */
        info = devm_kzalloc(ici->v4l2_dev.dev, sizeof(struct soc_of_info),
                            GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        info->sasd.asd.match.fwnode = of_fwnode_handle(remote);
        info->sasd.asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
        info->subdev = &info->sasd.asd;

        /* Or shall this be managed by the soc-camera device? */
        sasc = &info->sasc;

        /* HACK: just need a != NULL */
        sdesc.host_desc.board_info = ERR_PTR(-ENODATA);

        ret = soc_camera_dyn_pdev(&sdesc, sasc);
        if (ret < 0)
                goto eallocpdev;

        sasc->sensor = &info->sasd.asd;

        icd = soc_camera_add_pdev(sasc);
        if (!icd) {
                ret = -ENOMEM;
                goto eaddpdev;
        }

        sasc->notifier.subdevs = &info->subdev;
        sasc->notifier.num_subdevs = 1;
        sasc->notifier.ops = &soc_camera_async_ops;

        icd->sasc = sasc;
        icd->parent = ici->v4l2_dev.dev;

        client = of_find_i2c_device_by_node(remote);

        if (client)
                v4l2_clk_name_i2c(clk_name, sizeof(clk_name),
                                  client->adapter->nr, client->addr);
        else
                v4l2_clk_name_of(clk_name, sizeof(clk_name), remote);

        icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, icd);
        if (IS_ERR(icd->clk)) {
                ret = PTR_ERR(icd->clk);
                goto eclkreg;
        }

        ret = v4l2_async_notifier_register(&ici->v4l2_dev, &sasc->notifier);
        if (!ret)
                return 0;

        v4l2_clk_unregister(icd->clk);
eclkreg:
        icd->clk = NULL;
        platform_device_del(sasc->pdev);
eaddpdev:
        platform_device_put(sasc->pdev);
eallocpdev:
        devm_kfree(ici->v4l2_dev.dev, info);
        dev_err(ici->v4l2_dev.dev, "group probe failed: %d\n", ret);

        return ret;
}

static void scan_of_host(struct soc_camera_host *ici)
{
        struct device *dev = ici->v4l2_dev.dev;
        struct device_node *np = dev->of_node;
        struct device_node *epn = NULL, *ren;
        unsigned int i;

        for (i = 0; ; i++) {
                epn = of_graph_get_next_endpoint(np, epn);
                if (!epn)
                        break;

                ren = of_graph_get_remote_port(epn);
                if (!ren) {
                        dev_notice(dev, "no remote for %pOF\n", epn);
                        continue;
                }

                /* so we now have a remote node to connect */
                if (!i)
                        soc_of_bind(ici, epn, ren->parent);

                of_node_put(ren);

                if (i) {
                        dev_err(dev, "multiple subdevices aren't supported yet!\n");
                        break;
                }
        }

        of_node_put(epn);
}

#else
static inline void scan_of_host(struct soc_camera_host *ici) { }
#endif

/* Called during host-driver probe */
static int soc_camera_probe(struct soc_camera_host *ici,
                            struct soc_camera_device *icd)
{
        struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);
        struct soc_camera_host_desc *shd = &sdesc->host_desc;
        struct device *control = NULL;
        int ret;

        dev_info(icd->pdev, "Probing %s\n", dev_name(icd->pdev));

        /*
         * Currently the subdev with the largest number of controls (13) is
         * ov6550. So let's pick 16 as a hint for the control handler. Note
         * that this is a hint only: too large and you waste some memory, too
         * small and there is a (very) small performance hit when looking up
         * controls in the internal hash.
         */
        ret = v4l2_ctrl_handler_init(&icd->ctrl_handler, 16);
        if (ret < 0)
                return ret;

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

        /*
         * ..._video_start() will create a device node, video_register_device()
         * itself is protected against concurrent open() calls, but we also have
         * to protect our data also during client probing.
         */

        /* Non-i2c cameras, e.g., soc_camera_platform, have no board_info */
        if (shd->board_info) {
                ret = soc_camera_i2c_init(icd, sdesc);
                if (ret < 0 && ret != -EPROBE_DEFER)
                        goto eadd;
        } else if (!shd->add_device || !shd->del_device) {
                ret = -EINVAL;
                goto eadd;
        } else {
                ret = soc_camera_clock_start(ici);
                if (ret < 0)
                        goto eadd;

                if (shd->module_name)
                        ret = request_module(shd->module_name);

                ret = shd->add_device(icd);
                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)) {
                        shd->del_device(icd);
                        ret = -ENODEV;
                        goto enodrv;
                }
        }

        mutex_lock(&ici->host_lock);
        ret = soc_camera_probe_finish(icd);
        mutex_unlock(&ici->host_lock);
        if (ret < 0)
                goto efinish;

        return 0;

efinish:
        if (shd->board_info) {
                soc_camera_i2c_free(icd);
        } else {
                shd->del_device(icd);
                module_put(control->driver->owner);
enodrv:
eadddev:
                soc_camera_clock_stop(ici);
        }
eadd:
        if (icd->vdev) {
                video_device_release(icd->vdev);
                icd->vdev = NULL;
        }
evdc:
        v4l2_ctrl_handler_free(&icd->ctrl_handler);
        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. With
 * asynchronous client probing this can also be called without
 * soc_camera_probe_finish() having run. Careful with clean up.
 */
static int soc_camera_remove(struct soc_camera_device *icd)
{
        struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);
        struct video_device *vdev = icd->vdev;

        v4l2_ctrl_handler_free(&icd->ctrl_handler);
        if (vdev) {
                video_unregister_device(vdev);
                icd->vdev = NULL;
        }

        if (sdesc->host_desc.board_info) {
                soc_camera_i2c_free(icd);
        } else {
                struct device *dev = to_soc_camera_control(icd);
                struct device_driver *drv = dev ? dev->driver : NULL;
                if (drv) {
                        sdesc->host_desc.del_device(icd);
                        module_put(drv->owner);
                }
        }

        if (icd->num_user_formats)
                soc_camera_free_user_formats(icd);

        if (icd->clk) {
                /* For the synchronous case */
                v4l2_clk_unregister(icd->clk);
                icd->clk = NULL;
        }

        if (icd->sasc)
                platform_device_unregister(icd->sasc->pdev);

        return 0;
}

static int default_g_selection(struct soc_camera_device *icd,
                               struct v4l2_selection *sel)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        struct v4l2_subdev_selection sdsel = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
                .target = sel->target,
        };
        int ret;

        ret = v4l2_subdev_call(sd, pad, get_selection, NULL, &sdsel);
        if (ret)
                return ret;
        sel->r = sdsel.r;
        return 0;
}

static int default_s_selection(struct soc_camera_device *icd,
                               struct v4l2_selection *sel)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        struct v4l2_subdev_selection sdsel = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
                .target = sel->target,
                .flags = sel->flags,
                .r = sel->r,
        };
        int ret;

        ret = v4l2_subdev_call(sd, pad, set_selection, NULL, &sdsel);
        if (ret)
                return ret;
        sel->r = sdsel.r;
        return 0;
}

static int default_g_parm(struct soc_camera_device *icd,
                          struct v4l2_streamparm *a)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_g_parm_cap(icd->vdev, sd, a);
}

static int default_s_parm(struct soc_camera_device *icd,
                          struct v4l2_streamparm *a)
{
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);

        return v4l2_s_parm_cap(icd->vdev, sd, a);
}

static int default_enum_framesizes(struct soc_camera_device *icd,
                                   struct v4l2_frmsizeenum *fsize)
{
        int ret;
        struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
        const struct soc_camera_format_xlate *xlate;
        struct v4l2_subdev_frame_size_enum fse = {
                .index = fsize->index,
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
        };

        xlate = soc_camera_xlate_by_fourcc(icd, fsize->pixel_format);
        if (!xlate)
                return -EINVAL;
        fse.code = xlate->code;

        ret = v4l2_subdev_call(sd, pad, enum_frame_size, NULL, &fse);
        if (ret < 0)
                return ret;

        if (fse.min_width == fse.max_width &&
            fse.min_height == fse.max_height) {
                fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
                fsize->discrete.width = fse.min_width;
                fsize->discrete.height = fse.min_height;
                return 0;
        }
        fsize->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
        fsize->stepwise.min_width = fse.min_width;
        fsize->stepwise.max_width = fse.max_width;
        fsize->stepwise.min_height = fse.min_height;
        fsize->stepwise.max_height = fse.max_height;
        fsize->stepwise.step_width = 1;
        fsize->stepwise.step_height = 1;
        return 0;
}

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_videobuf2 ||
            !ici->ops->poll ||
            !ici->v4l2_dev.dev)
                return -EINVAL;

        if (!ici->ops->set_selection)
                ici->ops->set_selection = default_s_selection;
        if (!ici->ops->get_selection)
                ici->ops->get_selection = default_g_selection;
        if (!ici->ops->set_parm)
                ici->ops->set_parm = default_s_parm;
        if (!ici->ops->get_parm)
                ici->ops->get_parm = default_g_parm;
        if (!ici->ops->enum_framesizes)
                ici->ops->enum_framesizes = default_enum_framesizes;

        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);

        mutex_init(&ici->host_lock);
        mutex_init(&ici->clk_lock);

        if (ici->v4l2_dev.dev->of_node)
                scan_of_host(ici);
        else if (ici->asd_sizes)
                /*
                 * No OF, host with a list of subdevices. Don't try to mix
                 * modes by initialising some groups statically and some
                 * dynamically!
                 */
                scan_async_host(ici);
        else
                /* Legacy: static platform devices from board data */
                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, *tmp;
        struct soc_camera_async_client *sasc;
        LIST_HEAD(notifiers);

        mutex_lock(&list_lock);
        list_del(&ici->list);
        list_for_each_entry(icd, &devices, list)
                if (icd->iface == ici->nr && icd->sasc) {
                        /* as long as we hold the device, sasc won't be freed */
                        get_device(icd->pdev);
                        list_add(&icd->sasc->list, &notifiers);
                }
        mutex_unlock(&list_lock);

        list_for_each_entry(sasc, &notifiers, list) {
                /* Must call unlocked to avoid AB-BA dead-lock */
                v4l2_async_notifier_unregister(&sasc->notifier);
                put_device(&sasc->pdev->dev);
        }

        mutex_lock(&list_lock);

        list_for_each_entry_safe(icd, tmp, &devices, list)
                if (icd->iface == ici->nr)
                        soc_camera_remove(icd);

        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;

        mutex_lock(&list_lock);
        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...
                 */
                mutex_unlock(&list_lock);
                return -ENOMEM;
        }

        icd->devnum             = num;
        icd->use_count          = 0;
        icd->host_priv          = NULL;

        /*
         * Dynamically allocated devices set the bit earlier, but it doesn't hurt setting
         * it again
         */
        i = to_platform_device(icd->pdev)->id;
        if (i < 0)
                /* One static (legacy) soc-camera platform device */
                i = 0;
        if (i >= MAP_MAX_NUM) {
                mutex_unlock(&list_lock);
                return -EBUSY;
        }
        set_bit(i, device_map);
        list_add_tail(&icd->list, &devices);
        mutex_unlock(&list_lock);

        return 0;
}

static const struct v4l2_ioctl_ops soc_camera_ioctl_ops = {
        .vidioc_querycap         = soc_camera_querycap,
        .vidioc_try_fmt_vid_cap  = soc_camera_try_fmt_vid_cap,
        .vidioc_g_fmt_vid_cap    = soc_camera_g_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap    = soc_camera_s_fmt_vid_cap,
        .vidioc_enum_fmt_vid_cap = soc_camera_enum_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_g_std            = soc_camera_g_std,
        .vidioc_enum_framesizes  = soc_camera_enum_framesizes,
        .vidioc_reqbufs          = soc_camera_reqbufs,
        .vidioc_querybuf         = soc_camera_querybuf,
        .vidioc_qbuf             = soc_camera_qbuf,
        .vidioc_dqbuf            = soc_camera_dqbuf,
        .vidioc_create_bufs      = soc_camera_create_bufs,
        .vidioc_prepare_buf      = soc_camera_prepare_buf,
        .vidioc_expbuf           = soc_camera_expbuf,
        .vidioc_streamon         = soc_camera_streamon,
        .vidioc_streamoff        = soc_camera_streamoff,
        .vidioc_g_selection      = soc_camera_g_selection,
        .vidioc_s_selection      = soc_camera_s_selection,
        .vidioc_g_parm           = soc_camera_g_parm,
        .vidioc_s_parm           = soc_camera_s_parm,
};

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

        if (!vdev)
                return -ENOMEM;

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

        vdev->v4l2_dev          = &ici->v4l2_dev;
        vdev->fops              = &soc_camera_fops;
        vdev->ioctl_ops         = &soc_camera_ioctl_ops;
        vdev->release           = video_device_release;
        vdev->ctrl_handler      = &icd->ctrl_handler;
        vdev->lock              = &ici->host_lock;

        icd->vdev = vdev;

        return 0;
}

/*
 * Called from soc_camera_probe() above with .host_lock held
 */
static int soc_camera_video_start(struct soc_camera_device *icd)
{
        const struct device_type *type = icd->vdev->dev.type;
        int ret;

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

        video_set_drvdata(icd->vdev, icd);
        if (icd->vdev->tvnorms == 0) {
                /* disable the STD API if there are no tvnorms defined */
                v4l2_disable_ioctl(icd->vdev, VIDIOC_G_STD);
                v4l2_disable_ioctl(icd->vdev, VIDIOC_S_STD);
                v4l2_disable_ioctl(icd->vdev, VIDIOC_ENUMSTD);
        }
        ret = video_register_device(icd->vdev, VFL_TYPE_GRABBER, -1);
        if (ret < 0) {
                dev_err(icd->pdev, "video_register_device failed: %d\n", ret);
                return ret;
        }

        /* Restore device type, possibly set by the subdevice driver */
        icd->vdev->dev.type = type;

        return 0;
}

static int soc_camera_pdrv_probe(struct platform_device *pdev)
{
        struct soc_camera_desc *sdesc = pdev->dev.platform_data;
        struct soc_camera_subdev_desc *ssdd = &sdesc->subdev_desc;
        struct soc_camera_device *icd;
        int ret;

        if (!sdesc)
                return -EINVAL;

        icd = devm_kzalloc(&pdev->dev, sizeof(*icd), GFP_KERNEL);
        if (!icd)
                return -ENOMEM;

        /*
         * In the asynchronous case ssdd->num_regulators == 0 yet, so, the below
         * regulator allocation is a dummy. They are actually requested by the
         * subdevice driver, using soc_camera_power_init(). Also note, that in
         * that case regulators are attached to the I2C device and not to the
         * camera platform device.
         */
        ret = devm_regulator_bulk_get(&pdev->dev, ssdd->sd_pdata.num_regulators,
                                      ssdd->sd_pdata.regulators);
        if (ret < 0)
                return ret;

        icd->iface = sdesc->host_desc.bus_id;
        icd->sdesc = sdesc;
        icd->pdev = &pdev->dev;
        platform_set_drvdata(pdev, icd);

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

        return soc_camera_device_register(icd);
}

/*
 * 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 soc_camera_pdrv_remove(struct platform_device *pdev)
{
        struct soc_camera_device *icd = platform_get_drvdata(pdev);
        int i;

        if (!icd)
                return -EINVAL;

        i = pdev->id;
        if (i < 0)
                i = 0;

        /*
         * In synchronous mode with static platform devices this is called in a
         * loop from drivers/base/dd.c::driver_detach(), no parallel execution,
         * no need to lock. In asynchronous case the caller -
         * soc_camera_host_unregister() - already holds the lock
         */
        if (test_bit(i, device_map)) {
                clear_bit(i, device_map);
                list_del(&icd->list);
        }

        return 0;
}

static struct platform_driver __refdata soc_camera_pdrv = {
        .probe = soc_camera_pdrv_probe,
        .remove  = soc_camera_pdrv_remove,
        .driver  = {
                .name   = "soc-camera-pdrv",
        },
};

module_platform_driver(soc_camera_pdrv);

MODULE_DESCRIPTION("Image capture bus driver");
MODULE_AUTHOR("Guennadi Liakhovetski <kernel@pengutronix.de>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:soc-camera-pdrv");