[v10,16/21] V4L2: support asynchronous subdevice registration

Message ID	1370939028-8352-17-git-send-email-g.liakhovetski@gmx.de (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-media-owner@vger.kernel.org> From: Guennadi Liakhovetski <g.liakhovetski@gmx.de> To: linux-media@vger.kernel.org Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Sylwester Nawrocki <s.nawrocki@samsung.com>, Hans Verkuil <hverkuil@xs4all.nl>, linux-sh@vger.kernel.org, Magnus Damm <magnus.damm@gmail.com>, Sakari Ailus <sakari.ailus@iki.fi>, Prabhakar Lad <prabhakar.lad@ti.com>, Sascha Hauer <s.hauer@pengutronix.de>, Guennadi Liakhovetski <g.liakhovetski@gmx.de> Subject: [PATCH v10 16/21] V4L2: support asynchronous subdevice registration Date: Tue, 11 Jun 2013 10:23:43 +0200 Message-Id: <1370939028-8352-17-git-send-email-g.liakhovetski@gmx.de> In-Reply-To: <1370939028-8352-1-git-send-email-g.liakhovetski@gmx.de> References: <1370939028-8352-1-git-send-email-g.liakhovetski@gmx.de> Sender: linux-media-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile index 628c630..4c33b8d6 100644 --- a/drivers/media/v4l2-core/Makefile +++ b/drivers/media/v4l2-core/Makefile @@ -5,7 +5,8 @@ tuner-objs := tuner-core.o videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \ - v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o + v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o \ + v4l2-async.o ifeq ($(CONFIG_COMPAT),y) videodev-objs += v4l2-compat-ioctl32.o endif diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c new file mode 100644 index 0000000..3590ccc --- /dev/null +++ b/drivers/media/v4l2-core/v4l2-async.c @@ -0,0 +1,280 @@ +/* + * V4L2 asynchronous subdevice registration API + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de> + * + * 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/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/types.h> + +#include <media/v4l2-async.h> +#include <media/v4l2-device.h> +#include <media/v4l2-subdev.h> + +static bool match_i2c(struct device *dev, struct v4l2_async_subdev *asd) +{ + struct i2c_client *client = i2c_verify_client(dev); + return client && + asd->bus_type == V4L2_ASYNC_BUS_I2C && + asd->match.i2c.adapter_id == client->adapter->nr && + asd->match.i2c.address == client->addr; +} + +static bool match_platform(struct device *dev, struct v4l2_async_subdev *asd) +{ + return asd->bus_type == V4L2_ASYNC_BUS_PLATFORM && + !strcmp(asd->match.platform.name, dev_name(dev)); +} + +static LIST_HEAD(subdev_list); +static LIST_HEAD(notifier_list); +static DEFINE_MUTEX(list_lock); + +static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_notifier *notifier, + struct v4l2_async_subdev_list *asdl) +{ + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + struct v4l2_async_subdev *asd; + bool (*match)(struct device *, + struct v4l2_async_subdev *); + + list_for_each_entry(asd, &notifier->waiting, list) { + /* bus_type has been verified valid before */ + switch (asd->bus_type) { + case V4L2_ASYNC_BUS_CUSTOM: + match = asd->match.custom.match; + if (!match) + /* Match always */ + return asd; + break; + case V4L2_ASYNC_BUS_PLATFORM: + match = match_platform; + break; + case V4L2_ASYNC_BUS_I2C: + match = match_i2c; + break; + default: + /* Cannot happen, unless someone breaks us */ + WARN_ON(true); + return NULL; + } + + /* match cannot be NULL here */ + if (match(sd->dev, asd)) + return asd; + } + + return NULL; +} + +static int v4l2_async_test_notify(struct v4l2_async_notifier *notifier, + struct v4l2_async_subdev_list *asdl, + struct v4l2_async_subdev *asd) +{ + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + int ret; + + /* Remove from the waiting list */ + list_del(&asd->list); + asdl->asd = asd; + asdl->notifier = notifier; + + if (notifier->bound) { + ret = notifier->bound(notifier, sd, asd); + if (ret < 0) + return ret; + } + /* Move from the global subdevice list to notifier's done */ + list_move(&asdl->list, &notifier->done); + + ret = v4l2_device_register_subdev(notifier->v4l2_dev, sd); + if (ret < 0) { + if (notifier->unbind) + notifier->unbind(notifier, sd, asd); + return ret; + } + + if (list_empty(&notifier->waiting) && notifier->complete) + return notifier->complete(notifier); + + return 0; +} + +static void v4l2_async_cleanup(struct v4l2_async_subdev_list *asdl) +{ + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + + v4l2_device_unregister_subdev(sd); + /* Subdevice driver will reprobe and put asdl back onto the list */ + list_del_init(&asdl->list); + asdl->asd = NULL; + sd->dev = NULL; +} + +int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, + struct v4l2_async_notifier *notifier) +{ + struct v4l2_async_subdev_list *asdl, *tmp; + struct v4l2_async_subdev *asd; + int i; + + if (!notifier->subdev_num || notifier->subdev_num > V4L2_MAX_SUBDEVS) + return -EINVAL; + + notifier->v4l2_dev = v4l2_dev; + INIT_LIST_HEAD(&notifier->waiting); + INIT_LIST_HEAD(&notifier->done); + + for (i = 0; i < notifier->subdev_num; i++) { + asd = notifier->subdev[i]; + + switch (asd->bus_type) { + case V4L2_ASYNC_BUS_CUSTOM: + case V4L2_ASYNC_BUS_PLATFORM: + case V4L2_ASYNC_BUS_I2C: + break; + default: + dev_err(notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL, + "Invalid bus-type %u on %p\n", + asd->bus_type, asd); + return -EINVAL; + } + list_add_tail(&asd->list, &notifier->waiting); + } + + mutex_lock(&list_lock); + + /* Keep also completed notifiers on the list */ + list_add(&notifier->list, &notifier_list); + + list_for_each_entry_safe(asdl, tmp, &subdev_list, list) { + int ret; + + asd = v4l2_async_belongs(notifier, asdl); + if (!asd) + continue; + + ret = v4l2_async_test_notify(notifier, asdl, asd); + if (ret < 0) { + mutex_unlock(&list_lock); + return ret; + } + } + + mutex_unlock(&list_lock); + + return 0; +} +EXPORT_SYMBOL(v4l2_async_notifier_register); + +void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier) +{ + struct v4l2_async_subdev_list *asdl, *tmp; + unsigned int notif_n_subdev = notifier->subdev_num; + unsigned int n_subdev = min(notif_n_subdev, V4L2_MAX_SUBDEVS); + struct device *dev[n_subdev]; + int i = 0; + + mutex_lock(&list_lock); + + list_del(&notifier->list); + + list_for_each_entry_safe(asdl, tmp, &notifier->done, list) { + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + + dev[i] = get_device(sd->dev); + + v4l2_async_cleanup(asdl); + + /* If we handled USB devices, we'd have to lock the parent too */ + device_release_driver(dev[i++]); + + if (notifier->unbind) + notifier->unbind(notifier, sd, sd->asdl.asd); + } + + mutex_unlock(&list_lock); + + while (i--) { + struct device *d = dev[i]; + + if (d && device_attach(d) < 0) { + const char *name = "(none)"; + int lock = device_trylock(d); + + if (lock && d->driver) + name = d->driver->name; + dev_err(d, "Failed to re-probe to %s\n", name); + if (lock) + device_unlock(d); + } + put_device(d); + } + /* + * Don't care about the waiting list, it is initialised and populated + * upon notifier registration. + */ +} +EXPORT_SYMBOL(v4l2_async_notifier_unregister); + +int v4l2_async_register_subdev(struct v4l2_subdev *sd) +{ + struct v4l2_async_subdev_list *asdl = &sd->asdl; + struct v4l2_async_notifier *notifier; + + mutex_lock(&list_lock); + + INIT_LIST_HEAD(&asdl->list); + + list_for_each_entry(notifier, &notifier_list, list) { + struct v4l2_async_subdev *asd = v4l2_async_belongs(notifier, asdl); + if (asd) { + int ret = v4l2_async_test_notify(notifier, asdl, asd); + mutex_unlock(&list_lock); + return ret; + } + } + + /* None matched, wait for hot-plugging */ + list_add(&asdl->list, &subdev_list); + + mutex_unlock(&list_lock); + + return 0; +} +EXPORT_SYMBOL(v4l2_async_register_subdev); + +void v4l2_async_unregister_subdev(struct v4l2_subdev *sd) +{ + struct v4l2_async_subdev_list *asdl = &sd->asdl; + struct v4l2_async_notifier *notifier = asdl->notifier; + + if (!asdl->asd) { + if (!list_empty(&asdl->list)) + v4l2_async_cleanup(asdl); + return; + } + + mutex_lock(&list_lock); + + list_add(&asdl->asd->list, &notifier->waiting); + + v4l2_async_cleanup(asdl); + + if (notifier->unbind) + notifier->unbind(notifier, sd, sd->asdl.asd); + + mutex_unlock(&list_lock); +} +EXPORT_SYMBOL(v4l2_async_unregister_subdev); diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h new file mode 100644 index 0000000..12bd39c --- /dev/null +++ b/include/media/v4l2-async.h @@ -0,0 +1,105 @@ +/* + * V4L2 asynchronous subdevice registration API + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de> + * + * 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. + */ + +#ifndef V4L2_ASYNC_H +#define V4L2_ASYNC_H + +#include <linux/list.h> +#include <linux/mutex.h> + +struct device; +struct v4l2_device; +struct v4l2_subdev; +struct v4l2_async_notifier; + +/* A random max subdevice number, used to allocate an array on stack */ +#define V4L2_MAX_SUBDEVS 128U + +enum v4l2_async_bus_type { + V4L2_ASYNC_BUS_CUSTOM, + V4L2_ASYNC_BUS_PLATFORM, + V4L2_ASYNC_BUS_I2C, +}; + +/** + * struct v4l2_async_subdev - sub-device descriptor, as known to a bridge + * @bus_type: subdevice bus type to select the appropriate matching method + * @match: union of per-bus type matching data sets + * @list: used to link struct v4l2_async_subdev objects, waiting to be + * probed, to a notifier->waiting list + */ +struct v4l2_async_subdev { + enum v4l2_async_bus_type bus_type; + union { + struct { + const char *name; + } platform; + struct { + int adapter_id; + unsigned short address; + } i2c; + struct { + bool (*match)(struct device *, + struct v4l2_async_subdev *); + void *priv; + } custom; + } match; + + /* v4l2-async core private: not to be used by drivers */ + struct list_head list; +}; + +/** + * v4l2_async_subdev_list - provided by subdevices + * @list: links struct v4l2_async_subdev_list objects to a global list + * before probing, and onto notifier->done after probing + * @asd: pointer to respective struct v4l2_async_subdev + * @notifier: pointer to managing notifier + */ +struct v4l2_async_subdev_list { + struct list_head list; + struct v4l2_async_subdev *asd; + struct v4l2_async_notifier *notifier; +}; + +/** + * v4l2_async_notifier - v4l2_device notifier data + * @subdev_num: number of subdevices + * @subdev: array of pointers to subdevices + * @v4l2_dev: pointer to struct v4l2_device + * @waiting: list of struct v4l2_async_subdev, waiting for their drivers + * @done: list of struct v4l2_async_subdev_list, already probed + * @list: member in a global list of notifiers + * @bound: a subdevice driver has successfully probed one of subdevices + * @complete: all subdevices have been probed successfully + * @unbind: a subdevice is leaving + */ +struct v4l2_async_notifier { + unsigned int subdev_num; + struct v4l2_async_subdev **subdev; + struct v4l2_device *v4l2_dev; + struct list_head waiting; + struct list_head done; + struct list_head list; + int (*bound)(struct v4l2_async_notifier *notifier, + struct v4l2_subdev *subdev, + struct v4l2_async_subdev *asd); + int (*complete)(struct v4l2_async_notifier *notifier); + void (*unbind)(struct v4l2_async_notifier *notifier, + struct v4l2_subdev *subdev, + struct v4l2_async_subdev *asd); +}; + +int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, + struct v4l2_async_notifier *notifier); +void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier); +int v4l2_async_register_subdev(struct v4l2_subdev *sd); +void v4l2_async_unregister_subdev(struct v4l2_subdev *sd); +#endif diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index d8756fa..21174af 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -24,6 +24,7 @@ #include <linux/types.h> #include <linux/v4l2-subdev.h> #include <media/media-entity.h> +#include <media/v4l2-async.h> #include <media/v4l2-common.h> #include <media/v4l2-dev.h> #include <media/v4l2-fh.h> @@ -587,8 +588,15 @@ struct v4l2_subdev { struct video_device *devnode; /* pointer to the physical device */ struct device *dev; + struct v4l2_async_subdev_list asdl; }; +static inline struct v4l2_subdev *v4l2_async_to_subdev( + struct v4l2_async_subdev_list *asdl) +{ + return container_of(asdl, struct v4l2_subdev, asdl); +} + #define media_entity_to_v4l2_subdev(ent) \ container_of(ent, struct v4l2_subdev, entity) #define vdev_to_v4l2_subdev(vdev) \

[v10,16/21] V4L2: support asynchronous subdevice registration

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