Add support for asynchronous subdevice probing, using the v4l2-async API.
The legacy synchronous mode is still supported too, which allows to
gradually update drivers and platforms. The selected approach adds a
notifier for each struct soc_camera_device instance, i.e. for each video
device node, even when there are multiple such instances registered with a
single soc-camera host simultaneously.

Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de>
---
 drivers/media/platform/soc_camera/soc_camera.c |  527 ++++++++++++++++++++----
 include/media/soc_camera.h                     |   23 +-
 2 files changed, 464 insertions(+), 86 deletions(-)

diff --git a/drivers/media/platform/soc_camera/soc_camera.c 
b/drivers/media/platform/soc_camera/soc_camera.c
index 5845916..725e49d 100644
--- a/drivers/media/platform/soc_camera/soc_camera.c
+++ b/drivers/media/platform/soc_camera/soc_camera.c
@@ -21,22 +21,23 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/list.h>
-#include <linux/mutex.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
-#include <linux/pm_runtime.h>
 #include <linux/vmalloc.h>
 
 #include <media/soc_camera.h>
+#include <media/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/videobuf-core.h>
 #include <media/videobuf2-core.h>
-#include <media/soc_mediabus.h>
 
 /* Default to VGA resolution */
 #define DEFAULT_WIDTH  640
@@ -47,23 +48,39 @@
         (icd)->vb_vidq.streaming :                     \
         vb2_is_streaming(&(icd)->vb2_vidq))
 
+#define MAP_MAX_NUM 32
+static DECLARE_BITMAP(device_map, MAP_MAX_NUM);
 static LIST_HEAD(hosts);
 static LIST_HEAD(devices);
-static DEFINE_MUTEX(list_lock);                /* Protects the list of hosts */
+/*
+ * 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 = clk ? v4l2_clk_enable(clk) : 0;
        if (ret < 0) {
-               dev_err(dev, "Cannot enable clock\n");
+               dev_err(dev, "Cannot enable clock: %d\n", ret);
                return ret;
        }
        ret = regulator_bulk_enable(ssdd->num_regulators,
                                        ssdd->regulators);
        if (ret < 0) {
                dev_err(dev, "Cannot enable regulators\n");
-               goto eregenable;;
+               goto eregenable;
        }
 
        if (ssdd->power) {
@@ -117,6 +134,14 @@ int soc_camera_power_off(struct device *dev, struct 
soc_camera_subdev_desc *ssdd
 }
 EXPORT_SYMBOL(soc_camera_power_off);
 
+int soc_camera_power_init(struct device *dev, struct soc_camera_subdev_desc 
*ssdd)
+{
+
+       return devm_regulator_bulk_get(dev, ssdd->num_regulators,
+                                      ssdd->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);
@@ -533,7 +558,9 @@ static int soc_camera_add_device(struct soc_camera_device 
*icd)
                return -EBUSY;
 
        if (!icd->clk) {
+               mutex_lock(&ici->clk_lock);
                ret = ici->ops->clock_start(ici);
+               mutex_unlock(&ici->clk_lock);
                if (ret < 0)
                        return ret;
        }
@@ -549,8 +576,11 @@ static int soc_camera_add_device(struct soc_camera_device 
*icd)
        return 0;
 
 eadd:
-       if (!icd->clk)
+       if (!icd->clk) {
+               mutex_lock(&ici->clk_lock);
                ici->ops->clock_stop(ici);
+               mutex_unlock(&ici->clk_lock);
+       }
        return ret;
 }
 
@@ -563,8 +593,11 @@ static void soc_camera_remove_device(struct 
soc_camera_device *icd)
 
        if (ici->ops->remove)
                ici->ops->remove(icd);
-       if (!icd->clk)
+       if (!icd->clk) {
+               mutex_lock(&ici->clk_lock);
                ici->ops->clock_stop(ici);
+               mutex_unlock(&ici->clk_lock);
+       }
        ici->icd = NULL;
 }
 
@@ -673,8 +706,8 @@ static int soc_camera_open(struct file *file)
        return 0;
 
        /*
-        * First four errors are entered with the .host_lock held
-        * and use_count == 1
+        * All errors are entered with the .host_lock held, first four also
+        * with use_count == 1
         */
 einitvb:
 esfmt:
@@ -1128,7 +1161,8 @@ static int soc_camera_s_register(struct file *file, void 
*fh,
 }
 #endif
 
-static int soc_camera_probe(struct soc_camera_device *icd);
+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)
@@ -1137,12 +1171,20 @@ static void scan_add_host(struct soc_camera_host *ici)
 
        mutex_lock(&list_lock);
 
-       list_for_each_entry(icd, &devices, list) {
+       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)
+                               ssdd->reset(icd->pdev);
+
                        icd->parent = ici->v4l2_dev.dev;
-                       soc_camera_probe(icd);
+
+                       /* Ignore errors */
+                       soc_camera_probe(ici, icd);
                }
-       }
 
        mutex_unlock(&list_lock);
 }
@@ -1155,6 +1197,7 @@ static int soc_camera_clk_enable(struct v4l2_clk *clk)
 {
        struct soc_camera_device *icd = clk->priv;
        struct soc_camera_host *ici;
+       int ret;
 
        if (!icd || !icd->parent)
                return -ENODEV;
@@ -1168,7 +1211,10 @@ static int soc_camera_clk_enable(struct v4l2_clk *clk)
         * If a different client is currently being probed, the host will tell
         * you to go
         */
-       return ici->ops->clock_start(ici);
+       mutex_lock(&ici->clk_lock);
+       ret = ici->ops->clock_start(ici);
+       mutex_unlock(&ici->clk_lock);
+       return ret;
 }
 
 static void soc_camera_clk_disable(struct v4l2_clk *clk)
@@ -1181,7 +1227,9 @@ static void soc_camera_clk_disable(struct v4l2_clk *clk)
 
        ici = to_soc_camera_host(icd->parent);
 
+       mutex_lock(&ici->clk_lock);
        ici->ops->clock_stop(ici);
+       mutex_unlock(&ici->clk_lock);
 
        module_put(ici->ops->owner);
 }
@@ -1198,18 +1246,117 @@ static const struct v4l2_clk_ops soc_camera_clk_ops = {
        .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_mbus_framefmt mf;
+       int ret;
+
+       sd->grp_id = soc_camera_grp_id(icd);
+       v4l2_set_subdev_hostdata(sd, icd);
+
+       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, video, g_mbus_fmt, &mf)) {
+               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_init_i2c(struct soc_camera_device *icd,
+static int soc_camera_i2c_init(struct soc_camera_device *icd,
                               struct soc_camera_desc *sdesc)
 {
        struct i2c_client *client;
-       struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
+       struct soc_camera_host *ici;
        struct soc_camera_host_desc *shd = &sdesc->host_desc;
-       struct i2c_adapter *adap = i2c_get_adapter(shd->i2c_adapter_id);
+       struct i2c_adapter *adap;
        struct v4l2_subdev *subdev;
        char clk_name[V4L2_SUBDEV_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);
@@ -1242,42 +1389,202 @@ static int soc_camera_init_i2c(struct 
soc_camera_device *icd,
        return 0;
 ei2cnd:
        v4l2_clk_unregister(icd->clk);
-       icd->clk = NULL;
 eclkreg:
+       icd->clk = NULL;
        i2c_put_adapter(adap);
        return ret;
 }
 
-static void soc_camera_free_i2c(struct soc_camera_device *icd)
+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 = client->adapter;
+       struct i2c_adapter *adap;
 
        icd->control = NULL;
+       if (icd->sasc)
+               return;
+
+       adap = client->adapter;
        v4l2_device_unregister_subdev(i2c_get_clientdata(client));
        i2c_unregister_device(client);
        i2c_put_adapter(adap);
        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(icd->pdev);
+                       }
+
+                       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);
+
+       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 int scan_async_group(struct soc_camera_host *ici,
+                           struct v4l2_async_subdev **asd, 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_SUBDEV_NAME_SIZE];
+       int ret, i;
+
+       /* 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]->bus_type != V4L2_ASYNC_BUS_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)
+               return ret;
+
+       sasc->sensor = &sasd->asd;
+
+       icd = soc_camera_add_pdev(sasc);
+       if (!icd) {
+               platform_device_put(sasc->pdev);
+               return -ENOMEM;
+       }
+
+       sasc->notifier.subdev = asd;
+       sasc->notifier.subdev_num = size;
+       sasc->notifier.bound = soc_camera_async_bound;
+       sasc->notifier.unbind = soc_camera_async_unbind;
+       sasc->notifier.complete = soc_camera_async_complete;
+
+       icd->sasc = sasc;
+       icd->parent = ici->v4l2_dev.dev;
+
+       snprintf(clk_name, sizeof(clk_name), "%d-%04x",
+                sasd->asd.match.i2c.adapter_id, sasd->asd.match.i2c.address);
+
+       icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, "mclk", 
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_unregister(sasc->pdev);
+       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_init_i2c(icd, sdesc)        (-ENODEV)
-#define soc_camera_free_i2c(icd)       do {} while (0)
+#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
 
-static int soc_camera_video_start(struct soc_camera_device *icd);
-static int video_dev_create(struct soc_camera_device *icd);
 /* Called during host-driver probe */
-static int soc_camera_probe(struct soc_camera_device *icd)
+static int soc_camera_probe(struct soc_camera_host *ici,
+                           struct soc_camera_device *icd)
 {
-       struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
        struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);
        struct soc_camera_host_desc *shd = &sdesc->host_desc;
-       struct soc_camera_subdev_desc *ssdd = &sdesc->subdev_desc;
        struct device *control = NULL;
-       struct v4l2_subdev *sd;
-       struct v4l2_mbus_framefmt mf;
        int ret;
 
        dev_info(icd->pdev, "Probing %s\n", dev_name(icd->pdev));
@@ -1293,10 +1600,6 @@ static int soc_camera_probe(struct soc_camera_device 
*icd)
        if (ret < 0)
                return ret;
 
-       /* The camera could have been already on, try to reset */
-       if (ssdd->reset)
-               ssdd->reset(icd->pdev);
-
        /* Must have icd->vdev before registering the device */
        ret = video_dev_create(icd);
        if (ret < 0)
@@ -1307,18 +1610,19 @@ static int soc_camera_probe(struct soc_camera_device 
*icd)
         * itself is protected against concurrent open() calls, but we also have
         * to protect our data also during client probing.
         */
-       mutex_lock(&ici->host_lock);
 
        /* Non-i2c cameras, e.g., soc_camera_platform, have no board_info */
        if (shd->board_info) {
-               ret = soc_camera_init_i2c(icd, sdesc);
-               if (ret < 0)
+               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 {
+               mutex_lock(&ici->clk_lock);
                ret = ici->ops->clock_start(ici);
+               mutex_unlock(&ici->clk_lock);
                if (ret < 0)
                        goto eadd;
 
@@ -1342,57 +1646,33 @@ static int soc_camera_probe(struct soc_camera_device 
*icd)
                }
        }
 
-       sd = soc_camera_to_subdev(icd);
-       sd->grp_id = soc_camera_grp_id(icd);
-       v4l2_set_subdev_hostdata(sd, icd);
-
-       ret = v4l2_ctrl_add_handler(&icd->ctrl_handler, sd->ctrl_handler, NULL);
-       if (ret < 0)
-               goto ectrl;
-
-       /* At this point client .probe() should have run already */
-       ret = soc_camera_init_user_formats(icd);
-       if (ret < 0)
-               goto eiufmt;
-
-       icd->field = V4L2_FIELD_ANY;
-
-       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, video, g_mbus_fmt, &mf)) {
-               icd->user_width         = mf.width;
-               icd->user_height        = mf.height;
-               icd->colorspace         = mf.colorspace;
-               icd->field              = mf.field;
-       }
-
-       if (!shd->board_info)
-               ici->ops->clock_stop(ici);
-
+       mutex_lock(&ici->host_lock);
+       ret = soc_camera_probe_finish(icd);
        mutex_unlock(&ici->host_lock);
+       if (ret < 0)
+               goto efinish;
 
        return 0;
 
-evidstart:
-       soc_camera_free_user_formats(icd);
-eiufmt:
-ectrl:
+efinish:
        if (shd->board_info) {
-               soc_camera_free_i2c(icd);
+               soc_camera_i2c_free(icd);
        } else {
                shd->del_device(icd);
                module_put(control->driver->owner);
 enodrv:
 eadddev:
+               mutex_lock(&ici->clk_lock);
                ici->ops->clock_stop(ici);
+               mutex_unlock(&ici->clk_lock);
        }
 eadd:
        video_device_release(icd->vdev);
        icd->vdev = NULL;
-       mutex_unlock(&ici->host_lock);
+       if (icd->vdev) {
+               video_device_release(icd->vdev);
+               icd->vdev = NULL;
+       }
 evdc:
        v4l2_ctrl_handler_free(&icd->ctrl_handler);
        return ret;
@@ -1400,15 +1680,15 @@ evdc:
 
 /*
  * This is called on device_unregister, which only means we have to disconnect
- * from the host, but not remove ourselves from the device list
+ * 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;
 
-       BUG_ON(!icd->parent);
-
        v4l2_ctrl_handler_free(&icd->ctrl_handler);
        if (vdev) {
                video_unregister_device(vdev);
@@ -1416,15 +1696,27 @@ static int soc_camera_remove(struct soc_camera_device 
*icd)
        }
 
        if (sdesc->host_desc.board_info) {
-               soc_camera_free_i2c(icd);
+               soc_camera_i2c_free(icd);
        } else {
-               struct device_driver *drv = to_soc_camera_control(icd)->driver;
+               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);
                }
        }
-       soc_camera_free_user_formats(icd);
+
+       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;
 }
@@ -1535,7 +1827,18 @@ int soc_camera_host_register(struct soc_camera_host *ici)
        mutex_unlock(&list_lock);
 
        mutex_init(&ici->host_lock);
-       scan_add_host(ici);
+       mutex_init(&ici->clk_lock);
+
+       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;
 
@@ -1548,13 +1851,30 @@ EXPORT_SYMBOL(soc_camera_host_register);
 /* Unregister all clients! */
 void soc_camera_host_unregister(struct soc_camera_host *ici)
 {
-       struct soc_camera_device *icd;
+       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 && to_soc_camera_control(icd))
+               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);
@@ -1569,6 +1889,7 @@ 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 */
@@ -1580,18 +1901,34 @@ static int soc_camera_device_register(struct 
soc_camera_device *icd)
                }
        }
 
-       if (num < 0)
+       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;
 }
@@ -1691,6 +2028,12 @@ static int soc_camera_pdrv_probe(struct platform_device 
*pdev)
        if (!icd)
                return -ENOMEM;
 
+       /*
+        * In the asynchronous case ssdd->num_regulators == 0 yet, so, the below
+        * regulator allocation is a dummy. They will be really requested later
+        * in soc_camera_async_bind(). 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->num_regulators,
                                      ssdd->regulators);
        if (ret < 0)
@@ -1715,11 +2058,25 @@ static int soc_camera_pdrv_probe(struct platform_device 
*pdev)
 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;
 
-       list_del(&icd->list);
+       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;
 }
diff --git a/include/media/soc_camera.h b/include/media/soc_camera.h
index f8c1ffe..2d3c939 100644
--- a/include/media/soc_camera.h
+++ b/include/media/soc_camera.h
@@ -19,11 +19,13 @@
 #include <linux/videodev2.h>
 #include <media/videobuf-core.h>
 #include <media/videobuf2-core.h>
+#include <media/v4l2-async.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 
 struct file;
 struct soc_camera_desc;
+struct soc_camera_async_client;
 
 struct soc_camera_device {
        struct list_head list;          /* list of all registered devices */
@@ -50,6 +52,9 @@ struct soc_camera_device {
        int use_count;
        struct file *streamer;          /* stream owner */
        struct v4l2_clk *clk;
+       /* Asynchronous subdevice management */
+       struct soc_camera_async_client *sasc;
+       /* video buffer queue */
        union {
                struct videobuf_queue vb_vidq;
                struct vb2_queue vb2_vidq;
@@ -59,16 +64,30 @@ struct soc_camera_device {
 /* Host supports programmable stride */
 #define SOCAM_HOST_CAP_STRIDE          (1 << 0)
 
+enum soc_camera_subdev_role {
+       SOCAM_SUBDEV_DATA_SOURCE = 1,
+       SOCAM_SUBDEV_DATA_SINK,
+       SOCAM_SUBDEV_DATA_PROCESSOR,
+};
+
+struct soc_camera_async_subdev {
+       struct v4l2_async_subdev asd;
+       enum soc_camera_subdev_role role;
+};
+
 struct soc_camera_host {
        struct v4l2_device v4l2_dev;
        struct list_head list;
-       struct mutex host_lock;         /* Protect pipeline modifications */
+       struct mutex host_lock;         /* Main synchronisation lock */
+       struct mutex clk_lock;          /* Protect pipeline modifications */
        unsigned char nr;               /* Host number */
        u32 capabilities;
        struct soc_camera_device *icd;  /* Currently attached client */
        void *priv;
        const char *drv_name;
        struct soc_camera_host_ops *ops;
+       struct v4l2_async_subdev **asd; /* Flat array, arranged in groups */
+       int *asd_sizes;                 /* 0-terminated array of asd group 
sizes */
 };
 
 struct soc_camera_host_ops {
@@ -161,6 +180,7 @@ struct soc_camera_host_desc {
 };
 
 /*
+ * Platform data for "soc-camera-pdrv"
  * This MUST be kept binary-identical to struct soc_camera_link below, until
  * it is completely replaced by this one, after which we can split it into its
  * two components.
@@ -326,6 +346,7 @@ static inline void soc_camera_limit_side(int *start, int 
*length,
 unsigned long soc_camera_apply_board_flags(struct soc_camera_subdev_desc *ssdd,
                                           const struct v4l2_mbus_config *cfg);
 
+int soc_camera_power_init(struct device *dev, struct soc_camera_subdev_desc 
*ssdd);
 int soc_camera_power_on(struct device *dev, struct soc_camera_subdev_desc 
*ssdd,
                        struct v4l2_clk *clk);
 int soc_camera_power_off(struct device *dev, struct soc_camera_subdev_desc 
*ssdd,
-- 
1.7.2.5

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