text: /*
   * 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)
  		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_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);
  
  	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_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);
  	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;
  
  	strlcpy(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");
  