/*
 * Copyright (C) ST-Ericsson SA 2011
 *
 * Author: Hemant Gupta <hemant.gupta@stericsson.com>
 * Author: Tomasz Hliwiak <tomasz.hliwiak@tieto.com>
 *
 * 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 <asm/mach-types.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/skbuff.h>
#include "clock.h"
#include "cg2900.h"

static DEFINE_MUTEX(cg2900_clk_mutex);

static struct cg2900_user_data *pf_data;
static struct clk_lookup *cg2900_clk_lookup;

/**
 * cg2900_clk_enable() - Enables CG2900 Clock
 *
 * Enables CG2900 Clock by starting CG2900.
 *
 * Returns:
 *  0 if success.
 *  -EINVAL if stored pf_data is NULL.
 *  Error codes generated by open.
 */

static int cg2900_clk_enable(struct clk *clk)
{
	int err = -EINVAL;
	if (pf_data)
		err = pf_data->open(pf_data);

	return err;
}

/**
 * cg2900_clk_disable() - Disables CG2900 Clock
 *
 * Disables CG2900 Clock by switching off CG2900.
 */
static void cg2900_clk_disable(struct clk *clk)
{
	if (pf_data)
		pf_data->close(pf_data);
}

static struct clkops cg2900_clk_ops = {
	.enable		= cg2900_clk_enable,
	.disable	= cg2900_clk_disable,
};

static struct clk cg2900_clk = {
	.name	= "cg2900_clk",
	.ops	= &cg2900_clk_ops,
	.mutex	= &cg2900_clk_mutex,
};

/**
 * cg2900_read_cb() - Dummy callback for cg2900 core read.
 *
 * Function is required by cg2900_core->open().
 */
static void cg2900_read_cb(struct cg2900_user_data *user, struct sk_buff *skb)
{
	kfree_skb(skb);
}

/**
 * cg2900_core_probe() - Initialize resources.
 *
 * Function initializes pf_data structure and also adds the cg2900
 * clock source.
 */
static int __devinit cg2900_core_probe(struct platform_device *pdev)
{
	cg2900_clk_lookup = clkdev_alloc(&cg2900_clk, "sys_clk_out",
			"cw1200_wlan");

	if (!cg2900_clk_lookup)
		return -ENOMEM;

	clkdev_add(cg2900_clk_lookup);
	pf_data = dev_get_platdata(&pdev->dev);
	pf_data->dev = &pdev->dev;
	pf_data->read_cb = cg2900_read_cb;

	return 0;
}

/**
 * cg2900_core_remove() - Clean resources.
 *
 * Function cleans pf_data structure and removes the clock source.
 */
static int __devexit cg2900_core_remove(struct platform_device *pdev)
{
	clkdev_drop(cg2900_clk_lookup);
	pf_data = NULL;

	return 0;
}

static struct platform_driver cg2900_core_ctrl_driver = {
	.driver = {
		.name      = "cg2900-core",
		.owner     = THIS_MODULE,
	},
	.probe     = cg2900_core_probe,
	.remove    = __devexit_p(cg2900_core_remove),
};

/**
 * clock_cg2900_init() - Register Platform Data
 *
 * Registers the platform data.
 */
static int __init clock_cg2900_init(void)
{
	return platform_driver_register(&cg2900_core_ctrl_driver);
}

/**
 * clock_cg2900_exit() - Unregister Platform Data
 *
 * Unregister Platform Data
 */
static void __exit clock_cg2900_exit(void)
{
	platform_driver_unregister(&cg2900_core_ctrl_driver);
}

module_init(clock_cg2900_init);
module_exit(clock_cg2900_exit);