diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile index aa50c46314b7..628c6307e978 100644 --- a/drivers/media/v4l2-core/Makefile +++ b/drivers/media/v4l2-core/Makefile @@ -5,7 +5,7 @@ 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-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o ifeq ($(CONFIG_COMPAT),y) videodev-objs += v4l2-compat-ioctl32.o endif diff --git a/drivers/media/v4l2-core/v4l2-clk.c b/drivers/media/v4l2-core/v4l2-clk.c new file mode 100644 index 000000000000..b67de8642b5a --- /dev/null +++ b/drivers/media/v4l2-core/v4l2-clk.c @@ -0,0 +1,242 @@ +/* + * V4L2 clock service + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski + * + * 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 +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +static DEFINE_MUTEX(clk_lock); +static LIST_HEAD(clk_list); + +static struct v4l2_clk *v4l2_clk_find(const char *dev_id, const char *id) +{ + struct v4l2_clk *clk; + + list_for_each_entry(clk, &clk_list, list) { + if (strcmp(dev_id, clk->dev_id)) + continue; + + if (!id || !clk->id || !strcmp(clk->id, id)) + return clk; + } + + return ERR_PTR(-ENODEV); +} + +struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id) +{ + struct v4l2_clk *clk; + + mutex_lock(&clk_lock); + clk = v4l2_clk_find(dev_name(dev), id); + + if (!IS_ERR(clk)) + atomic_inc(&clk->use_count); + mutex_unlock(&clk_lock); + + return clk; +} +EXPORT_SYMBOL(v4l2_clk_get); + +void v4l2_clk_put(struct v4l2_clk *clk) +{ + struct v4l2_clk *tmp; + + if (IS_ERR(clk)) + return; + + mutex_lock(&clk_lock); + + list_for_each_entry(tmp, &clk_list, list) + if (tmp == clk) + atomic_dec(&clk->use_count); + + mutex_unlock(&clk_lock); +} +EXPORT_SYMBOL(v4l2_clk_put); + +static int v4l2_clk_lock_driver(struct v4l2_clk *clk) +{ + struct v4l2_clk *tmp; + int ret = -ENODEV; + + mutex_lock(&clk_lock); + + list_for_each_entry(tmp, &clk_list, list) + if (tmp == clk) { + ret = !try_module_get(clk->ops->owner); + if (ret) + ret = -EFAULT; + break; + } + + mutex_unlock(&clk_lock); + + return ret; +} + +static void v4l2_clk_unlock_driver(struct v4l2_clk *clk) +{ + module_put(clk->ops->owner); +} + +int v4l2_clk_enable(struct v4l2_clk *clk) +{ + int ret = v4l2_clk_lock_driver(clk); + + if (ret < 0) + return ret; + + mutex_lock(&clk->lock); + + if (++clk->enable == 1 && clk->ops->enable) { + ret = clk->ops->enable(clk); + if (ret < 0) + clk->enable--; + } + + mutex_unlock(&clk->lock); + + return ret; +} +EXPORT_SYMBOL(v4l2_clk_enable); + +/* + * You might Oops if you try to disabled a disabled clock, because then the + * driver isn't locked and could have been unloaded by now, so, don't do that + */ +void v4l2_clk_disable(struct v4l2_clk *clk) +{ + int enable; + + mutex_lock(&clk->lock); + + enable = --clk->enable; + if (WARN(enable < 0, "Unbalanced %s() on %s:%s!\n", __func__, + clk->dev_id, clk->id)) + clk->enable++; + else if (!enable && clk->ops->disable) + clk->ops->disable(clk); + + mutex_unlock(&clk->lock); + + v4l2_clk_unlock_driver(clk); +} +EXPORT_SYMBOL(v4l2_clk_disable); + +unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk) +{ + int ret = v4l2_clk_lock_driver(clk); + + if (ret < 0) + return ret; + + mutex_lock(&clk->lock); + if (!clk->ops->get_rate) + ret = -ENOSYS; + else + ret = clk->ops->get_rate(clk); + mutex_unlock(&clk->lock); + + v4l2_clk_unlock_driver(clk); + + return ret; +} +EXPORT_SYMBOL(v4l2_clk_get_rate); + +int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate) +{ + int ret = v4l2_clk_lock_driver(clk); + + if (ret < 0) + return ret; + + mutex_lock(&clk->lock); + if (!clk->ops->set_rate) + ret = -ENOSYS; + else + ret = clk->ops->set_rate(clk, rate); + mutex_unlock(&clk->lock); + + v4l2_clk_unlock_driver(clk); + + return ret; +} +EXPORT_SYMBOL(v4l2_clk_set_rate); + +struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops, + const char *dev_id, + const char *id, void *priv) +{ + struct v4l2_clk *clk; + int ret; + + if (!ops || !dev_id) + return ERR_PTR(-EINVAL); + + clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL); + if (!clk) + return ERR_PTR(-ENOMEM); + + clk->id = kstrdup(id, GFP_KERNEL); + clk->dev_id = kstrdup(dev_id, GFP_KERNEL); + if ((id && !clk->id) || !clk->dev_id) { + ret = -ENOMEM; + goto ealloc; + } + clk->ops = ops; + clk->priv = priv; + atomic_set(&clk->use_count, 0); + mutex_init(&clk->lock); + + mutex_lock(&clk_lock); + if (!IS_ERR(v4l2_clk_find(dev_id, id))) { + mutex_unlock(&clk_lock); + ret = -EEXIST; + goto eexist; + } + list_add_tail(&clk->list, &clk_list); + mutex_unlock(&clk_lock); + + return clk; + +eexist: +ealloc: + kfree(clk->id); + kfree(clk->dev_id); + kfree(clk); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(v4l2_clk_register); + +void v4l2_clk_unregister(struct v4l2_clk *clk) +{ + if (WARN(atomic_read(&clk->use_count), + "%s(): Refusing to unregister ref-counted %s:%s clock!\n", + __func__, clk->dev_id, clk->id)) + return; + + mutex_lock(&clk_lock); + list_del(&clk->list); + mutex_unlock(&clk_lock); + + kfree(clk->id); + kfree(clk->dev_id); + kfree(clk); +} +EXPORT_SYMBOL(v4l2_clk_unregister); diff --git a/include/media/v4l2-clk.h b/include/media/v4l2-clk.h new file mode 100644 index 000000000000..0503a90b48bb --- /dev/null +++ b/include/media/v4l2-clk.h @@ -0,0 +1,54 @@ +/* + * V4L2 clock service + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski + * + * 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. + * + * ATTENTION: This is a temporary API and it shall be replaced by the generic + * clock API, when the latter becomes widely available. + */ + +#ifndef MEDIA_V4L2_CLK_H +#define MEDIA_V4L2_CLK_H + +#include +#include +#include + +struct module; +struct device; + +struct v4l2_clk { + struct list_head list; + const struct v4l2_clk_ops *ops; + const char *dev_id; + const char *id; + int enable; + struct mutex lock; /* Protect the enable count */ + atomic_t use_count; + void *priv; +}; + +struct v4l2_clk_ops { + struct module *owner; + int (*enable)(struct v4l2_clk *clk); + void (*disable)(struct v4l2_clk *clk); + unsigned long (*get_rate)(struct v4l2_clk *clk); + int (*set_rate)(struct v4l2_clk *clk, unsigned long); +}; + +struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops, + const char *dev_name, + const char *name, void *priv); +void v4l2_clk_unregister(struct v4l2_clk *clk); +struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id); +void v4l2_clk_put(struct v4l2_clk *clk); +int v4l2_clk_enable(struct v4l2_clk *clk); +void v4l2_clk_disable(struct v4l2_clk *clk); +unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk); +int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate); + +#endif