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/*
* rcar-fcp.c -- R-Car Frame Compression Processor Driver
*
* Copyright (C) 2016 Renesas Electronics Corporation
*
* Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/device.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <media/rcar-fcp.h>
struct rcar_fcp_device {
struct list_head list;
struct device *dev;
};
static LIST_HEAD(fcp_devices);
static DEFINE_MUTEX(fcp_lock);
/* -----------------------------------------------------------------------------
* Public API
*/
/**
* rcar_fcp_get - Find and acquire a reference to an FCP instance
* @np: Device node of the FCP instance
*
* Search the list of registered FCP instances for the instance corresponding to
* the given device node.
*
* Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be
* found.
*/
struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
{
struct rcar_fcp_device *fcp;
mutex_lock(&fcp_lock);
list_for_each_entry(fcp, &fcp_devices, list) {
if (fcp->dev->of_node != np)
continue;
/*
* Make sure the module won't be unloaded behind our back. This
* is a poor man's safety net, the module should really not be
* unloaded while FCP users can be active.
*/
if (!try_module_get(fcp->dev->driver->owner))
fcp = NULL;
goto done;
}
fcp = ERR_PTR(-EPROBE_DEFER);
done:
mutex_unlock(&fcp_lock);
return fcp;
}
EXPORT_SYMBOL_GPL(rcar_fcp_get);
/**
* rcar_fcp_put - Release a reference to an FCP instance
* @fcp: The FCP instance
*
* Release the FCP instance acquired by a call to rcar_fcp_get().
*/
void rcar_fcp_put(struct rcar_fcp_device *fcp)
{
if (fcp)
module_put(fcp->dev->driver->owner);
}
EXPORT_SYMBOL_GPL(rcar_fcp_put);
/**
* rcar_fcp_enable - Enable an FCP
* @fcp: The FCP instance
*
* Before any memory access through an FCP is performed by a module, the FCP
* must be enabled by a call to this function. The enable calls are reference
* counted, each successful call must be followed by one rcar_fcp_disable()
* call when no more memory transfer can occur through the FCP.
*
* Return 0 on success or a negative error code if an error occurs. The enable
* reference count isn't increased when this function returns an error.
*/
int rcar_fcp_enable(struct rcar_fcp_device *fcp)
{
int error;
if (!fcp)
return 0;
error = pm_runtime_get_sync(fcp->dev);
if (error < 0)
return error;
return 0;
}
EXPORT_SYMBOL_GPL(rcar_fcp_enable);
/**
* rcar_fcp_disable - Disable an FCP
* @fcp: The FCP instance
*
* This function is the counterpart of rcar_fcp_enable(). As enable calls are
* reference counted a disable call may not disable the FCP synchronously.
*/
void rcar_fcp_disable(struct rcar_fcp_device *fcp)
{
if (fcp)
pm_runtime_put(fcp->dev);
}
EXPORT_SYMBOL_GPL(rcar_fcp_disable);
/* -----------------------------------------------------------------------------
* Platform Driver
*/
static int rcar_fcp_probe(struct platform_device *pdev)
{
struct rcar_fcp_device *fcp;
fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL);
if (fcp == NULL)
return -ENOMEM;
fcp->dev = &pdev->dev;
pm_runtime_enable(&pdev->dev);
mutex_lock(&fcp_lock);
list_add_tail(&fcp->list, &fcp_devices);
mutex_unlock(&fcp_lock);
platform_set_drvdata(pdev, fcp);
return 0;
}
static int rcar_fcp_remove(struct platform_device *pdev)
{
struct rcar_fcp_device *fcp = platform_get_drvdata(pdev);
mutex_lock(&fcp_lock);
list_del(&fcp->list);
mutex_unlock(&fcp_lock);
pm_runtime_disable(&pdev->dev);
return 0;
}
static const struct of_device_id rcar_fcp_of_match[] = {
{ .compatible = "renesas,fcpv" },
{ },
};
static struct platform_driver rcar_fcp_platform_driver = {
.probe = rcar_fcp_probe,
.remove = rcar_fcp_remove,
.driver = {
.name = "rcar-fcp",
.of_match_table = rcar_fcp_of_match,
.suppress_bind_attrs = true,
},
};
module_platform_driver(rcar_fcp_platform_driver);
MODULE_ALIAS("rcar-fcp");
MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
MODULE_DESCRIPTION("Renesas FCP Driver");
MODULE_LICENSE("GPL");
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