--- /dev/null
+/*
+ * V4L2 clock service
+ *
+ * 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/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/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);
+
+ 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 (!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);
Code Review / kvmfornfv.git / blobdiff