+++ /dev/null
-.. SPDX-License-Identifier: GPL-2.0
-
-V4L2 clocks
------------
-
-.. attention::
-
- This is a temporary API and it shall be replaced by the generic
- clock API, when the latter becomes widely available.
-
-Many subdevices, like camera sensors, TV decoders and encoders, need a clock
-signal to be supplied by the system. Often this clock is supplied by the
-respective bridge device. The Linux kernel provides a Common Clock Framework for
-this purpose. However, it is not (yet) available on all architectures. Besides,
-the nature of the multi-functional (clock, data + synchronisation, I2C control)
-connection of subdevices to the system might impose special requirements on the
-clock API usage. E.g. V4L2 has to support clock provider driver unregistration
-while a subdevice driver is holding a reference to the clock. For these reasons
-a V4L2 clock helper API has been developed and is provided to bridge and
-subdevice drivers.
-
-The API consists of two parts: two functions to register and unregister a V4L2
-clock source: v4l2_clk_register() and v4l2_clk_unregister() and calls to control
-a clock object, similar to the respective generic clock API calls:
-v4l2_clk_get(), v4l2_clk_put(), v4l2_clk_enable(), v4l2_clk_disable(),
-v4l2_clk_get_rate(), and v4l2_clk_set_rate(). Clock suppliers have to provide
-clock operations that will be called when clock users invoke respective API
-methods.
-
-It is expected that once the CCF becomes available on all relevant
-architectures this API will be removed.
+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * V4L2 clock service
- *
- * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
- */
-
-#include <linux/atomic.h>
-#include <linux/clk.h>
-#include <linux/device.h>
-#include <linux/errno.h>
-#include <linux/list.h>
-#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/of.h>
-#include <linux/slab.h>
-#include <linux/string.h>
-
-#include <media/v4l2-clk.h>
-#include <media/v4l2-subdev.h>
-
-static DEFINE_MUTEX(clk_lock);
-static LIST_HEAD(clk_list);
-
-static struct v4l2_clk *v4l2_clk_find(const char *dev_id)
-{
- struct v4l2_clk *clk;
-
- list_for_each_entry(clk, &clk_list, list)
- if (!strcmp(dev_id, clk->dev_id))
- return clk;
-
- return ERR_PTR(-ENODEV);
-}
-
-struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id)
-{
- struct v4l2_clk *clk;
- struct clk *ccf_clk = clk_get(dev, id);
- char clk_name[V4L2_CLK_NAME_SIZE];
-
- if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
- return ERR_PTR(-EPROBE_DEFER);
-
- if (!IS_ERR_OR_NULL(ccf_clk)) {
- clk = kzalloc(sizeof(*clk), GFP_KERNEL);
- if (!clk) {
- clk_put(ccf_clk);
- return ERR_PTR(-ENOMEM);
- }
- clk->clk = ccf_clk;
-
- return clk;
- }
-
- mutex_lock(&clk_lock);
- clk = v4l2_clk_find(dev_name(dev));
-
- /* if dev_name is not found, try use the OF name to find again */
- if (PTR_ERR(clk) == -ENODEV && dev->of_node) {
- v4l2_clk_name_of(clk_name, sizeof(clk_name), dev->of_node);
- clk = v4l2_clk_find(clk_name);
- }
-
- 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;
-
- if (clk->clk) {
- clk_put(clk->clk);
- kfree(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;
-
- if (clk->clk)
- return clk_prepare_enable(clk->clk);
-
- 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;
-
- if (clk->clk)
- return clk_disable_unprepare(clk->clk);
-
- mutex_lock(&clk->lock);
-
- enable = --clk->enable;
- if (WARN(enable < 0, "Unbalanced %s() on %s!\n", __func__,
- clk->dev_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;
-
- if (clk->clk)
- return clk_get_rate(clk->clk);
-
- 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;
-
- if (clk->clk) {
- long r = clk_round_rate(clk->clk, rate);
- if (r < 0)
- return r;
- return clk_set_rate(clk->clk, r);
- }
-
- 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,
- 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->dev_id = kstrdup(dev_id, GFP_KERNEL);
- if (!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))) {
- 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->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 clock!\n",
- __func__, clk->dev_id))
- return;
-
- mutex_lock(&clk_lock);
- list_del(&clk->list);
- mutex_unlock(&clk_lock);
-
- kfree(clk->dev_id);
- kfree(clk);
-}
-EXPORT_SYMBOL(v4l2_clk_unregister);
-
-struct v4l2_clk_fixed {
- unsigned long rate;
- struct v4l2_clk_ops ops;
-};
-
-static unsigned long fixed_get_rate(struct v4l2_clk *clk)
-{
- struct v4l2_clk_fixed *priv = clk->priv;
- return priv->rate;
-}
-
-struct v4l2_clk *__v4l2_clk_register_fixed(const char *dev_id,
- unsigned long rate, struct module *owner)
-{
- struct v4l2_clk *clk;
- struct v4l2_clk_fixed *priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-
- if (!priv)
- return ERR_PTR(-ENOMEM);
-
- priv->rate = rate;
- priv->ops.get_rate = fixed_get_rate;
- priv->ops.owner = owner;
-
- clk = v4l2_clk_register(&priv->ops, dev_id, priv);
- if (IS_ERR(clk))
- kfree(priv);
-
- return clk;
-}
-EXPORT_SYMBOL(__v4l2_clk_register_fixed);
-
-void v4l2_clk_unregister_fixed(struct v4l2_clk *clk)
-{
- kfree(clk->priv);
- v4l2_clk_unregister(clk);
-}
-EXPORT_SYMBOL(v4l2_clk_unregister_fixed);
+++ /dev/null
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * V4L2 clock service
- *
- * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
- *
- * 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 <linux/atomic.h>
-#include <linux/export.h>
-#include <linux/list.h>
-#include <linux/mutex.h>
-
-struct module;
-struct device;
-
-struct clk;
-struct v4l2_clk {
- struct list_head list;
- const struct v4l2_clk_ops *ops;
- const char *dev_id;
- int enable;
- struct mutex lock; /* Protect the enable count */
- atomic_t use_count;
- struct clk *clk;
- 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,
- 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);
-
-struct module;
-
-struct v4l2_clk *__v4l2_clk_register_fixed(const char *dev_id,
- unsigned long rate, struct module *owner);
-void v4l2_clk_unregister_fixed(struct v4l2_clk *clk);
-
-static inline struct v4l2_clk *v4l2_clk_register_fixed(const char *dev_id,
- unsigned long rate)
-{
- return __v4l2_clk_register_fixed(dev_id, rate, THIS_MODULE);
-}
-
-#define V4L2_CLK_NAME_SIZE 64
-
-#define v4l2_clk_name_i2c(name, size, adap, client) snprintf(name, size, \
- "%d-%04x", adap, client)
-
-#define v4l2_clk_name_of(name, size, node) snprintf(name, size, \
- "of-%pOF", node)
-
-#endif
projects / users / hch / configfs.git / commitdiff