/*
 *  Copyright (C) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/math64.h>
#include <linux/err.h>
#include <linux/io.h>

#include <mach/hardware.h>

/*
 * Very simple approach: We can't disable clocks, so we do
 * not need refcounting
 */

struct clk {
        struct list_head node;
        const char *name;
        unsigned long (*get_rate)(void);
};

/*
 *  get the system pll clock in Hz
 *
 *                  mfi + mfn / (mfd +1)
 *  f = 2 * f_ref * --------------------
 *                        pd + 1
 */
static unsigned long imx_decode_pll(unsigned int pll, u32 f_ref)
{
        unsigned long long ll;
        unsigned long quot;

        u32 mfi = (pll >> 10) & 0xf;
        u32 mfn = pll & 0x3ff;
        u32 mfd = (pll >> 16) & 0x3ff;
        u32 pd =  (pll >> 26) & 0xf;

        mfi = mfi <= 5 ? 5 : mfi;

        ll = 2 * (unsigned long long)f_ref *
                ((mfi << 16) + (mfn << 16) / (mfd + 1));
        quot = (pd + 1) * (1 << 16);
        ll += quot / 2;
        do_div(ll, quot);
        return (unsigned long)ll;
}

static unsigned long imx_get_system_clk(void)
{
        u32 f_ref = (CSCR & CSCR_SYSTEM_SEL) ? 16000000 : (CLK32 * 512);

        return imx_decode_pll(SPCTL0, f_ref);
}

static unsigned long imx_get_mcu_clk(void)
{
        return imx_decode_pll(MPCTL0, CLK32 * 512);
}

/*
 *  get peripheral clock 1 ( UART[12], Timer[12], PWM )
 */
static unsigned long imx_get_perclk1(void)
{
        return imx_get_system_clk() / (((PCDR) & 0xf)+1);
}

/*
 *  get peripheral clock 2 ( LCD, SD, SPI[12] )
 */
static unsigned long imx_get_perclk2(void)
{
        return imx_get_system_clk() / (((PCDR>>4) & 0xf)+1);
}

/*
 *  get peripheral clock 3 ( SSI )
 */
static unsigned long imx_get_perclk3(void)
{
        return imx_get_system_clk() / (((PCDR>>16) & 0x7f)+1);
}

/*
 *  get hclk ( SDRAM, CSI, Memory Stick, I2C, DMA )
 */
static unsigned long imx_get_hclk(void)
{
        return imx_get_system_clk() / (((CSCR>>10) & 0xf)+1);
}

static struct clk clk_system_clk = {
        .name = "system_clk",
        .get_rate = imx_get_system_clk,
};

static struct clk clk_hclk = {
        .name = "hclk",
        .get_rate = imx_get_hclk,
};

static struct clk clk_mcu_clk = {
        .name = "mcu_clk",
        .get_rate = imx_get_mcu_clk,
};

static struct clk clk_perclk1 = {
        .name = "perclk1",
        .get_rate = imx_get_perclk1,
};

static struct clk clk_uart_clk = {
        .name = "uart_clk",
        .get_rate = imx_get_perclk1,
};

static struct clk clk_perclk2 = {
        .name = "perclk2",
        .get_rate = imx_get_perclk2,
};

static struct clk clk_perclk3 = {
        .name = "perclk3",
        .get_rate = imx_get_perclk3,
};

static struct clk *clks[] = {
        &clk_perclk1,
        &clk_perclk2,
        &clk_perclk3,
        &clk_system_clk,
        &clk_hclk,
        &clk_mcu_clk,
        &clk_uart_clk,
};

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);

struct clk *clk_get(struct device *dev, const char *id)
{
        struct clk *p, *clk = ERR_PTR(-ENOENT);

        mutex_lock(&clocks_mutex);
        list_for_each_entry(p, &clocks, node) {
                if (!strcmp(p->name, id)) {
                        clk = p;
                        goto found;
                }
        }

found:
        mutex_unlock(&clocks_mutex);

        return clk;
}
EXPORT_SYMBOL(clk_get);

void clk_put(struct clk *clk)
{
}
EXPORT_SYMBOL(clk_put);

int clk_enable(struct clk *clk)
{
        return 0;
}
EXPORT_SYMBOL(clk_enable);

void clk_disable(struct clk *clk)
{
}
EXPORT_SYMBOL(clk_disable);

unsigned long clk_get_rate(struct clk *clk)
{
        return clk->get_rate();
}
EXPORT_SYMBOL(clk_get_rate);

int imx_clocks_init(void)
{
        int i;

        mutex_lock(&clocks_mutex);
        for (i = 0; i < ARRAY_SIZE(clks); i++)
                list_add(&clks[i]->node, &clocks);
        mutex_unlock(&clocks_mutex);

        return 0;
}