/*
 * arch/arm/mach-lpc32xx/clock.c
 *
 * Author: Kevin Wells <kevin.wells@nxp.com>
 *
 * Copyright (C) 2010 NXP Semiconductors
 *
 * 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.
 */

/*
 * LPC32xx clock management driver overview
 *
 * The LPC32XX contains a number of high level system clocks that can be
 * generated from different sources. These system clocks are used to
 * generate the CPU and bus rates and the individual peripheral clocks in
 * the system. When Linux is started by the boot loader, the system
 * clocks are already running. Stopping a system clock during normal
 * Linux operation should never be attempted, as peripherals that require
 * those clocks will quit working (ie, DRAM).
 *
 * The LPC32xx high level clock tree looks as follows. Clocks marked with
 * an asterisk are always on and cannot be disabled. Clocks marked with
 * an ampersand can only be disabled in CPU suspend mode. Clocks marked
 * with a caret are always on if it is the selected clock for the SYSCLK
 * source. The clock that isn't used for SYSCLK can be enabled and
 * disabled normally.
 *                               32KHz oscillator*
 *                               /      |      \
 *                             RTC*   PLL397^ TOUCH
 *                                     /
 *               Main oscillator^     /
 *                   |        \      /
 *                   |         SYSCLK&
 *                   |            \
 *                   |             \
 *                USB_PLL       HCLK_PLL&
 *                   |           |    |
 *            USB host/device  PCLK&  |
 *                               |    |
 *                             Peripherals
 *
 * The CPU and chip bus rates are derived from the HCLK PLL, which can
 * generate various clock rates up to 266MHz and beyond. The internal bus
 * rates (PCLK and HCLK) are generated from dividers based on the HCLK
 * PLL rate. HCLK can be a ratio of 1:1, 1:2, or 1:4 or HCLK PLL rate,
 * while PCLK can be 1:1 to 1:32 of HCLK PLL rate. Most peripherals high
 * level clocks are based on either HCLK or PCLK, but have their own
 * dividers as part of the IP itself. Because of this, the system clock
 * rates should not be changed.
 *
 * The HCLK PLL is clocked from SYSCLK, which can be derived from the
 * main oscillator or PLL397. PLL397 generates a rate that is 397 times
 * the 32KHz oscillator rate. The main oscillator runs at the selected
 * oscillator/crystal rate on the mosc_in pin of the LPC32xx. This rate
 * is normally 13MHz, but depends on the selection of external crystals
 * or oscillators. If USB operation is required, the main oscillator must
 * be used in the system.
 *
 * Switching SYSCLK between sources during normal Linux operation is not
 * supported. SYSCLK is preset in the bootloader. Because of the
 * complexities of clock management during clock frequency changes,
 * there are some limitations to the clock driver explained below:
 * - The PLL397 and main oscillator can be enabled and disabled by the
 *   clk_enable() and clk_disable() functions unless SYSCLK is based
 *   on that clock. This allows the other oscillator that isn't driving
 *   the HCLK PLL to be used as another system clock that can be routed
 *   to an external pin.
 * - The muxed SYSCLK input and HCLK_PLL rate cannot be changed with
 *   this driver.
 * - HCLK and PCLK rates cannot be changed as part of this driver.
 * - Most peripherals have their own dividers are part of the peripheral
 *   block. Changing SYSCLK, HCLK PLL, HCLK, or PCLK sources or rates
 *   will also impact the individual peripheral rates.
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/amba/bus.h>
#include <linux/amba/clcd.h>
#include <linux/clkdev.h>

#include <mach/hardware.h>
#include <mach/platform.h>
#include "clock.h"
#include "common.h"

static DEFINE_SPINLOCK(global_clkregs_lock);

static int usb_pll_enable, usb_pll_valid;

static struct clk clk_armpll;
static struct clk clk_usbpll;

/*
 * Post divider values for PLLs based on selected register value
 */
static const u32 pll_postdivs[4] = {1, 2, 4, 8};

static unsigned long local_return_parent_rate(struct clk *clk)
{
        /*
         * If a clock has a rate of 0, then it inherits it's parent
         * clock rate
         */
        while (clk->rate == 0)
                clk = clk->parent;

        return clk->rate;
}

/* 32KHz clock has a fixed rate and is not stoppable */
static struct clk osc_32KHz = {
        .rate           = LPC32XX_CLOCK_OSC_FREQ,
        .get_rate       = local_return_parent_rate,
};

static int local_pll397_enable(struct clk *clk, int enable)
{
        u32 reg;
        unsigned long timeout = jiffies + msecs_to_jiffies(10);

        reg = __raw_readl(LPC32XX_CLKPWR_PLL397_CTRL);

        if (enable == 0) {
                reg |= LPC32XX_CLKPWR_SYSCTRL_PLL397_DIS;
                __raw_writel(reg, LPC32XX_CLKPWR_PLL397_CTRL);
        } else {
                /* Enable PLL397 */
                reg &= ~LPC32XX_CLKPWR_SYSCTRL_PLL397_DIS;
                __raw_writel(reg, LPC32XX_CLKPWR_PLL397_CTRL);

                /* Wait for PLL397 lock */
                while (((__raw_readl(LPC32XX_CLKPWR_PLL397_CTRL) &
                        LPC32XX_CLKPWR_SYSCTRL_PLL397_STS) == 0) &&
                        time_before(jiffies, timeout))
                        cpu_relax();

                if ((__raw_readl(LPC32XX_CLKPWR_PLL397_CTRL) &
                        LPC32XX_CLKPWR_SYSCTRL_PLL397_STS) == 0)
                        return -ENODEV;
        }

        return 0;
}

static int local_oscmain_enable(struct clk *clk, int enable)
{
        u32 reg;
        unsigned long timeout = jiffies + msecs_to_jiffies(10);

        reg = __raw_readl(LPC32XX_CLKPWR_MAIN_OSC_CTRL);

        if (enable == 0) {
                reg |= LPC32XX_CLKPWR_MOSC_DISABLE;
                __raw_writel(reg, LPC32XX_CLKPWR_MAIN_OSC_CTRL);
        } else {
                /* Enable main oscillator */
                reg &= ~LPC32XX_CLKPWR_MOSC_DISABLE;
                __raw_writel(reg, LPC32XX_CLKPWR_MAIN_OSC_CTRL);

                /* Wait for main oscillator to start */
                while (((__raw_readl(LPC32XX_CLKPWR_MAIN_OSC_CTRL) &
                        LPC32XX_CLKPWR_MOSC_DISABLE) != 0) &&
                        time_before(jiffies, timeout))
                        cpu_relax();

                if ((__raw_readl(LPC32XX_CLKPWR_MAIN_OSC_CTRL) &
                        LPC32XX_CLKPWR_MOSC_DISABLE) != 0)
                        return -ENODEV;
        }

        return 0;
}

static struct clk osc_pll397 = {
        .parent         = &osc_32KHz,
        .enable         = local_pll397_enable,
        .rate           = LPC32XX_CLOCK_OSC_FREQ * 397,
        .get_rate       = local_return_parent_rate,
};

static struct clk osc_main = {
        .enable         = local_oscmain_enable,
        .rate           = LPC32XX_MAIN_OSC_FREQ,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_sys;

/*
 * Convert a PLL register value to a PLL output frequency
 */
u32 clk_get_pllrate_from_reg(u32 inputclk, u32 regval)
{
        struct clk_pll_setup pllcfg;

        pllcfg.cco_bypass_b15 = 0;
        pllcfg.direct_output_b14 = 0;
        pllcfg.fdbk_div_ctrl_b13 = 0;
        if ((regval & LPC32XX_CLKPWR_HCLKPLL_CCO_BYPASS) != 0)
                pllcfg.cco_bypass_b15 = 1;
        if ((regval & LPC32XX_CLKPWR_HCLKPLL_POSTDIV_BYPASS) != 0)
                pllcfg.direct_output_b14 = 1;
        if ((regval & LPC32XX_CLKPWR_HCLKPLL_FDBK_SEL_FCLK) != 0)
                pllcfg.fdbk_div_ctrl_b13 = 1;
        pllcfg.pll_m = 1 + ((regval >> 1) & 0xFF);
        pllcfg.pll_n = 1 + ((regval >> 9) & 0x3);
        pllcfg.pll_p = pll_postdivs[((regval >> 11) & 0x3)];

        return clk_check_pll_setup(inputclk, &pllcfg);
}

/*
 * Setup the HCLK PLL with a PLL structure
 */
static u32 local_clk_pll_setup(struct clk_pll_setup *PllSetup)
{
        u32 tv, tmp = 0;

        if (PllSetup->analog_on != 0)
                tmp |= LPC32XX_CLKPWR_HCLKPLL_POWER_UP;
        if (PllSetup->cco_bypass_b15 != 0)
                tmp |= LPC32XX_CLKPWR_HCLKPLL_CCO_BYPASS;
        if (PllSetup->direct_output_b14 != 0)
                tmp |= LPC32XX_CLKPWR_HCLKPLL_POSTDIV_BYPASS;
        if (PllSetup->fdbk_div_ctrl_b13 != 0)
                tmp |= LPC32XX_CLKPWR_HCLKPLL_FDBK_SEL_FCLK;

        tv = ffs(PllSetup->pll_p) - 1;
        if ((!is_power_of_2(PllSetup->pll_p)) || (tv > 3))
                return 0;

        tmp |= LPC32XX_CLKPWR_HCLKPLL_POSTDIV_2POW(tv);
        tmp |= LPC32XX_CLKPWR_HCLKPLL_PREDIV_PLUS1(PllSetup->pll_n - 1);
        tmp |= LPC32XX_CLKPWR_HCLKPLL_PLLM(PllSetup->pll_m - 1);

        return tmp;
}

/*
 * Update the ARM core PLL frequency rate variable from the actual PLL setting
 */
static void local_update_armpll_rate(void)
{
        u32 clkin, pllreg;

        clkin = clk_armpll.parent->rate;
        pllreg = __raw_readl(LPC32XX_CLKPWR_HCLKPLL_CTRL) & 0x1FFFF;

        clk_armpll.rate = clk_get_pllrate_from_reg(clkin, pllreg);
}

/*
 * Find a PLL configuration for the selected input frequency
 */
static u32 local_clk_find_pll_cfg(u32 pllin_freq, u32 target_freq,
        struct clk_pll_setup *pllsetup)
{
        u32 ifreq, freqtol, m, n, p, fclkout;

        /* Determine frequency tolerance limits */
        freqtol = target_freq / 250;
        ifreq = pllin_freq;

        /* Is direct bypass mode possible? */
        if (abs(pllin_freq - target_freq) <= freqtol) {
                pllsetup->analog_on = 0;
                pllsetup->cco_bypass_b15 = 1;
                pllsetup->direct_output_b14 = 1;
                pllsetup->fdbk_div_ctrl_b13 = 1;
                pllsetup->pll_p = pll_postdivs[0];
                pllsetup->pll_n = 1;
                pllsetup->pll_m = 1;
                return clk_check_pll_setup(ifreq, pllsetup);
        } else if (target_freq <= ifreq) {
                pllsetup->analog_on = 0;
                pllsetup->cco_bypass_b15 = 1;
                pllsetup->direct_output_b14 = 0;
                pllsetup->fdbk_div_ctrl_b13 = 1;
                pllsetup->pll_n = 1;
                pllsetup->pll_m = 1;
                for (p = 0; p <= 3; p++) {
                        pllsetup->pll_p = pll_postdivs[p];
                        fclkout = clk_check_pll_setup(ifreq, pllsetup);
                        if (abs(target_freq - fclkout) <= freqtol)
                                return fclkout;
                }
        }

        /* Is direct mode possible? */
        pllsetup->analog_on = 1;
        pllsetup->cco_bypass_b15 = 0;
        pllsetup->direct_output_b14 = 1;
        pllsetup->fdbk_div_ctrl_b13 = 0;
        pllsetup->pll_p = pll_postdivs[0];
        for (m = 1; m <= 256; m++) {
                for (n = 1; n <= 4; n++) {
                        /* Compute output frequency for this value */
                        pllsetup->pll_n = n;
                        pllsetup->pll_m = m;
                        fclkout = clk_check_pll_setup(ifreq,
                                pllsetup);
                        if (abs(target_freq - fclkout) <=
                                freqtol)
                                return fclkout;
                }
        }

        /* Is integer mode possible? */
        pllsetup->analog_on = 1;
        pllsetup->cco_bypass_b15 = 0;
        pllsetup->direct_output_b14 = 0;
        pllsetup->fdbk_div_ctrl_b13 = 1;
        for (m = 1; m <= 256; m++) {
                for (n = 1; n <= 4; n++) {
                        for (p = 0; p < 4; p++) {
                                /* Compute output frequency */
                                pllsetup->pll_p = pll_postdivs[p];
                                pllsetup->pll_n = n;
                                pllsetup->pll_m = m;
                                fclkout = clk_check_pll_setup(
                                        ifreq, pllsetup);
                                if (abs(target_freq - fclkout) <= freqtol)
                                        return fclkout;
                        }
                }
        }

        /* Try non-integer mode */
        pllsetup->analog_on = 1;
        pllsetup->cco_bypass_b15 = 0;
        pllsetup->direct_output_b14 = 0;
        pllsetup->fdbk_div_ctrl_b13 = 0;
        for (m = 1; m <= 256; m++) {
                for (n = 1; n <= 4; n++) {
                        for (p = 0; p < 4; p++) {
                                /* Compute output frequency */
                                pllsetup->pll_p = pll_postdivs[p];
                                pllsetup->pll_n = n;
                                pllsetup->pll_m = m;
                                fclkout = clk_check_pll_setup(
                                        ifreq, pllsetup);
                                if (abs(target_freq - fclkout) <= freqtol)
                                        return fclkout;
                        }
                }
        }

        return 0;
}

static struct clk clk_armpll = {
        .parent         = &clk_sys,
        .get_rate       = local_return_parent_rate,
};

/*
 * Setup the USB PLL with a PLL structure
 */
static u32 local_clk_usbpll_setup(struct clk_pll_setup *pHCLKPllSetup)
{
        u32 reg, tmp = local_clk_pll_setup(pHCLKPllSetup);

        reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL) & ~0x1FFFF;
        reg |= tmp;
        __raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);

        return clk_check_pll_setup(clk_usbpll.parent->rate,
                pHCLKPllSetup);
}

static int local_usbpll_enable(struct clk *clk, int enable)
{
        u32 reg;
        int ret = 0;
        unsigned long timeout = jiffies + msecs_to_jiffies(20);

        reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL);

        __raw_writel(reg & ~(LPC32XX_CLKPWR_USBCTRL_CLK_EN2 |
                LPC32XX_CLKPWR_USBCTRL_PLL_PWRUP),
                LPC32XX_CLKPWR_USB_CTRL);
        __raw_writel(reg & ~LPC32XX_CLKPWR_USBCTRL_CLK_EN1,
                LPC32XX_CLKPWR_USB_CTRL);

        if (enable && usb_pll_valid && usb_pll_enable) {
                ret = -ENODEV;
                /*
                 * If the PLL rate has been previously set, then the rate
                 * in the PLL register is valid and can be enabled here.
                 * Otherwise, it needs to be enabled as part of setrate.
                 */

                /*
                 * Gate clock into PLL
                 */
                reg |= LPC32XX_CLKPWR_USBCTRL_CLK_EN1;
                __raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);

                /*
                 * Enable PLL
                 */
                reg |= LPC32XX_CLKPWR_USBCTRL_PLL_PWRUP;
                __raw_writel(reg, LPC32XX_CLKPWR_USB_CTRL);

                /*
                 * Wait for PLL to lock
                 */
                while (time_before(jiffies, timeout) && (ret == -ENODEV)) {
                        reg = __raw_readl(LPC32XX_CLKPWR_USB_CTRL);
                        if (reg & LPC32XX_CLKPWR_USBCTRL_PLL_STS)
                                ret = 0;
                        else
                                udelay(10);
                }

                /*
                 * Gate clock from PLL if PLL is locked
                 */
                if (ret == 0) {
                        __raw_writel(reg | LPC32XX_CLKPWR_USBCTRL_CLK_EN2,
                                LPC32XX_CLKPWR_USB_CTRL);
                } else {
                        __raw_writel(reg & ~(LPC32XX_CLKPWR_USBCTRL_CLK_EN1 |
                                LPC32XX_CLKPWR_USBCTRL_PLL_PWRUP),
                                LPC32XX_CLKPWR_USB_CTRL);
                }
        } else if ((enable == 0) && usb_pll_valid  && usb_pll_enable) {
                usb_pll_valid = 0;
                usb_pll_enable = 0;
        }

        return ret;
}

static unsigned long local_usbpll_round_rate(struct clk *clk,
        unsigned long rate)
{
        u32 clkin, usbdiv;
        struct clk_pll_setup pllsetup;

        /*
         * Unlike other clocks, this clock has a KHz input rate, so bump
         * it up to work with the PLL function
         */
        rate = rate * 1000;

        clkin = clk->get_rate(clk);
        usbdiv = (__raw_readl(LPC32XX_CLKPWR_USBCLK_PDIV) &
                LPC32XX_CLKPWR_USBPDIV_PLL_MASK) + 1;
        clkin = clkin / usbdiv;

        /* Try to find a good rate setup */
        if (local_clk_find_pll_cfg(clkin, rate, &pllsetup) == 0)
                return 0;

        return clk_check_pll_setup(clkin, &pllsetup);
}

static int local_usbpll_set_rate(struct clk *clk, unsigned long rate)
{
        int ret = -ENODEV;
        u32 clkin, usbdiv;
        struct clk_pll_setup pllsetup;

        /*
         * Unlike other clocks, this clock has a KHz input rate, so bump
         * it up to work with the PLL function
         */
        rate = rate * 1000;

        clkin = clk->get_rate(clk->parent);
        usbdiv = (__raw_readl(LPC32XX_CLKPWR_USBCLK_PDIV) &
                LPC32XX_CLKPWR_USBPDIV_PLL_MASK) + 1;
        clkin = clkin / usbdiv;

        /* Try to find a good rate setup */
        if (local_clk_find_pll_cfg(clkin, rate, &pllsetup) == 0)
                return -EINVAL;

        /*
         * Disable PLL clocks during PLL change
         */
        local_usbpll_enable(clk, 0);
        pllsetup.analog_on = 0;
        local_clk_usbpll_setup(&pllsetup);

        /*
         * Start USB PLL and check PLL status
         */

        usb_pll_valid = 1;
        usb_pll_enable = 1;

        ret = local_usbpll_enable(clk, 1);
        if (ret >= 0)
                clk->rate = clk_check_pll_setup(clkin, &pllsetup);

        return ret;
}

static struct clk clk_usbpll = {
        .parent         = &osc_main,
        .set_rate       = local_usbpll_set_rate,
        .enable         = local_usbpll_enable,
        .rate           = 48000, /* In KHz */
        .get_rate       = local_return_parent_rate,
        .round_rate     = local_usbpll_round_rate,
};

static u32 clk_get_hclk_div(void)
{
        static const u32 hclkdivs[4] = {1, 2, 4, 4};
        return hclkdivs[LPC32XX_CLKPWR_HCLKDIV_DIV_2POW(
                __raw_readl(LPC32XX_CLKPWR_HCLK_DIV))];
}

static struct clk clk_hclk = {
        .parent         = &clk_armpll,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_pclk = {
        .parent         = &clk_armpll,
        .get_rate       = local_return_parent_rate,
};

static int local_onoff_enable(struct clk *clk, int enable)
{
        u32 tmp;

        tmp = __raw_readl(clk->enable_reg);

        if (enable == 0)
                tmp &= ~clk->enable_mask;
        else
                tmp |= clk->enable_mask;

        __raw_writel(tmp, clk->enable_reg);

        return 0;
}

/* Peripheral clock sources */
static struct clk clk_timer0 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
        .enable_mask    = LPC32XX_CLKPWR_TMRPWMCLK_TIMER0_EN,
        .get_rate       = local_return_parent_rate,
};
static struct clk clk_timer1 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
        .enable_mask    = LPC32XX_CLKPWR_TMRPWMCLK_TIMER1_EN,
        .get_rate       = local_return_parent_rate,
};
static struct clk clk_timer2 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
        .enable_mask    = LPC32XX_CLKPWR_TMRPWMCLK_TIMER2_EN,
        .get_rate       = local_return_parent_rate,
};
static struct clk clk_timer3 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
        .enable_mask    = LPC32XX_CLKPWR_TMRPWMCLK_TIMER3_EN,
        .get_rate       = local_return_parent_rate,
};
static struct clk clk_mpwm = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1,
        .enable_mask    = LPC32XX_CLKPWR_TMRPWMCLK_MPWM_EN,
        .get_rate       = local_return_parent_rate,
};
static struct clk clk_wdt = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_TIMER_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_PWMCLK_WDOG_EN,
        .get_rate       = local_return_parent_rate,
};
static struct clk clk_vfp9 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_DEBUG_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_VFP_CLOCK_ENABLE_BIT,
        .get_rate       = local_return_parent_rate,
};
static struct clk clk_dma = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_DMA_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_DMACLKCTRL_CLK_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_pwm = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_PWM_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_PWMCLK_PWM1CLK_EN |
                          LPC32XX_CLKPWR_PWMCLK_PWM1SEL_PCLK |
                          LPC32XX_CLKPWR_PWMCLK_PWM1_DIV(1) |
                          LPC32XX_CLKPWR_PWMCLK_PWM2CLK_EN |
                          LPC32XX_CLKPWR_PWMCLK_PWM2SEL_PCLK |
                          LPC32XX_CLKPWR_PWMCLK_PWM2_DIV(1),
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_uart3 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_UART_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_UARTCLKCTRL_UART3_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_uart4 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_UART_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_UARTCLKCTRL_UART4_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_uart5 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_UART_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_UARTCLKCTRL_UART5_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_uart6 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_UART_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_UARTCLKCTRL_UART6_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_i2c0 = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_I2C_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_I2CCLK_I2C1CLK_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_i2c1 = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_I2C_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_I2CCLK_I2C2CLK_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_i2c2 = {
        .parent         = &clk_pclk,
        .enable         = local_onoff_enable,
        .enable_reg     = io_p2v(LPC32XX_USB_BASE + 0xFF4),
        .enable_mask    = 0x4,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_ssp0 = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_SSP_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_SSPCTRL_SSPCLK0_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_ssp1 = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_SSP_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_SSPCTRL_SSPCLK1_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_kscan = {
        .parent         = &osc_32KHz,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_KEY_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_KEYCLKCTRL_CLK_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_nand = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_NAND_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_NANDCLK_SLCCLK_EN |
                          LPC32XX_CLKPWR_NANDCLK_SEL_SLC,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_nand_mlc = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_NAND_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_NANDCLK_MLCCLK_EN |
                          LPC32XX_CLKPWR_NANDCLK_DMA_INT |
                          LPC32XX_CLKPWR_NANDCLK_INTSEL_MLC,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_i2s0 = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_I2S_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_I2SCTRL_I2SCLK0_EN,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_i2s1 = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_I2S_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_I2SCTRL_I2SCLK1_EN |
                          LPC32XX_CLKPWR_I2SCTRL_I2S1_USE_DMA,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_net = {
        .parent         = &clk_hclk,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_MACCLK_CTRL,
        .enable_mask    = (LPC32XX_CLKPWR_MACCTRL_DMACLK_EN |
                LPC32XX_CLKPWR_MACCTRL_MMIOCLK_EN |
                LPC32XX_CLKPWR_MACCTRL_HRCCLK_EN),
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_rtc = {
        .parent         = &osc_32KHz,
        .rate           = 1, /* 1 Hz */
        .get_rate       = local_return_parent_rate,
};

static int local_usb_enable(struct clk *clk, int enable)
{
        u32 tmp;

        if (enable) {
                /* Set up I2C pull levels */
                tmp = __raw_readl(LPC32XX_CLKPWR_I2C_CLK_CTRL);
                tmp |= LPC32XX_CLKPWR_I2CCLK_USBI2CHI_DRIVE;
                __raw_writel(tmp, LPC32XX_CLKPWR_I2C_CLK_CTRL);
        }

        return local_onoff_enable(clk, enable);
}

static struct clk clk_usbd = {
        .parent         = &clk_usbpll,
        .enable         = local_usb_enable,
        .enable_reg     = LPC32XX_CLKPWR_USB_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_USBCTRL_HCLK_EN,
        .get_rate       = local_return_parent_rate,
};

#define OTG_ALWAYS_MASK         (LPC32XX_USB_OTG_OTG_CLOCK_ON | \
                                 LPC32XX_USB_OTG_I2C_CLOCK_ON)

static int local_usb_otg_enable(struct clk *clk, int enable)
{
        int to = 1000;

        if (enable) {
                __raw_writel(clk->enable_mask, clk->enable_reg);

                while (((__raw_readl(LPC32XX_USB_OTG_CLK_STAT) &
                        clk->enable_mask) != clk->enable_mask) && (to > 0))
                        to--;
        } else {
                __raw_writel(OTG_ALWAYS_MASK, clk->enable_reg);

                while (((__raw_readl(LPC32XX_USB_OTG_CLK_STAT) &
                        OTG_ALWAYS_MASK) != OTG_ALWAYS_MASK) && (to > 0))
                        to--;
        }

        if (to)
                return 0;
        else
                return -1;
}

static struct clk clk_usb_otg_dev = {
        .parent         = &clk_usbpll,
        .enable         = local_usb_otg_enable,
        .enable_reg     = LPC32XX_USB_OTG_CLK_CTRL,
        .enable_mask    = LPC32XX_USB_OTG_AHB_M_CLOCK_ON |
                          LPC32XX_USB_OTG_OTG_CLOCK_ON |
                          LPC32XX_USB_OTG_DEV_CLOCK_ON |
                          LPC32XX_USB_OTG_I2C_CLOCK_ON,
        .get_rate       = local_return_parent_rate,
};

static struct clk clk_usb_otg_host = {
        .parent         = &clk_usbpll,
        .enable         = local_usb_otg_enable,
        .enable_reg     = LPC32XX_USB_OTG_CLK_CTRL,
        .enable_mask    = LPC32XX_USB_OTG_AHB_M_CLOCK_ON |
                          LPC32XX_USB_OTG_OTG_CLOCK_ON |
                          LPC32XX_USB_OTG_HOST_CLOCK_ON |
                          LPC32XX_USB_OTG_I2C_CLOCK_ON,
        .get_rate       = local_return_parent_rate,
};

static int tsc_onoff_enable(struct clk *clk, int enable)
{
        u32 tmp;

        /* Make sure 32KHz clock is the selected clock */
        tmp = __raw_readl(LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
        tmp &= ~LPC32XX_CLKPWR_ADCCTRL1_PCLK_SEL;
        __raw_writel(tmp, LPC32XX_CLKPWR_ADC_CLK_CTRL_1);

        if (enable == 0)
                __raw_writel(0, clk->enable_reg);
        else
                __raw_writel(clk->enable_mask, clk->enable_reg);

        return 0;
}

static struct clk clk_tsc = {
        .parent         = &osc_32KHz,
        .enable         = tsc_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_ADC_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_ADC32CLKCTRL_CLK_EN,
        .get_rate       = local_return_parent_rate,
};

static int adc_onoff_enable(struct clk *clk, int enable)
{
        u32 tmp;
        u32 divider;

        /* Use PERIPH_CLOCK */
        tmp = __raw_readl(LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
        tmp |= LPC32XX_CLKPWR_ADCCTRL1_PCLK_SEL;
        /*
         * Set clock divider so that we have equal to or less than
         * 4.5MHz clock at ADC
         */
        divider = clk->get_rate(clk) / 4500000 + 1;
        tmp |= divider;
        __raw_writel(tmp, LPC32XX_CLKPWR_ADC_CLK_CTRL_1);

        /* synchronize rate of this clock w/ actual HW setting */
        clk->rate = clk->get_rate(clk->parent) / divider;

        if (enable == 0)
                __raw_writel(0, clk->enable_reg);
        else
                __raw_writel(clk->enable_mask, clk->enable_reg);

        return 0;
}

static struct clk clk_adc = {
        .parent         = &clk_pclk,
        .enable         = adc_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_ADC_CLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_ADC32CLKCTRL_CLK_EN,
        .get_rate       = local_return_parent_rate,
};

static int mmc_onoff_enable(struct clk *clk, int enable)
{
        u32 tmp;

        tmp = __raw_readl(LPC32XX_CLKPWR_MS_CTRL) &
                ~(LPC32XX_CLKPWR_MSCARD_SDCARD_EN |
                  LPC32XX_CLKPWR_MSCARD_MSDIO_PU_EN |
                  LPC32XX_CLKPWR_MSCARD_MSDIO_PIN_DIS |
                  LPC32XX_CLKPWR_MSCARD_MSDIO0_DIS |
                  LPC32XX_CLKPWR_MSCARD_MSDIO1_DIS |
                  LPC32XX_CLKPWR_MSCARD_MSDIO23_DIS);

        /* If rate is 0, disable clock */
        if (enable != 0)
                tmp |= LPC32XX_CLKPWR_MSCARD_SDCARD_EN |
                        LPC32XX_CLKPWR_MSCARD_MSDIO_PU_EN;

        __raw_writel(tmp, LPC32XX_CLKPWR_MS_CTRL);

        return 0;
}

static unsigned long mmc_get_rate(struct clk *clk)
{
        u32 div, rate, oldclk;

        /* The MMC clock must be on when accessing an MMC register */
        oldclk = __raw_readl(LPC32XX_CLKPWR_MS_CTRL);
        __raw_writel(oldclk | LPC32XX_CLKPWR_MSCARD_SDCARD_EN,
                LPC32XX_CLKPWR_MS_CTRL);
        div = __raw_readl(LPC32XX_CLKPWR_MS_CTRL);
        __raw_writel(oldclk, LPC32XX_CLKPWR_MS_CTRL);

        /* Get the parent clock rate */
        rate = clk->parent->get_rate(clk->parent);

        /* Get the MMC controller clock divider value */
        div = div & LPC32XX_CLKPWR_MSCARD_SDCARD_DIV(0xf);

        if (!div)
                div = 1;

        return rate / div;
}

static unsigned long mmc_round_rate(struct clk *clk, unsigned long rate)
{
        unsigned long div, prate;

        /* Get the parent clock rate */
        prate = clk->parent->get_rate(clk->parent);

        if (rate >= prate)
                return prate;

        div = prate / rate;
        if (div > 0xf)
                div = 0xf;

        return prate / div;
}

static int mmc_set_rate(struct clk *clk, unsigned long rate)
{
        u32 tmp;
        unsigned long prate, div, crate = mmc_round_rate(clk, rate);

        prate = clk->parent->get_rate(clk->parent);

        div = prate / crate;

        /* The MMC clock must be on when accessing an MMC register */
        tmp = __raw_readl(LPC32XX_CLKPWR_MS_CTRL) &
                ~LPC32XX_CLKPWR_MSCARD_SDCARD_DIV(0xf);
        tmp |= LPC32XX_CLKPWR_MSCARD_SDCARD_DIV(div) |
                LPC32XX_CLKPWR_MSCARD_SDCARD_EN;
        __raw_writel(tmp, LPC32XX_CLKPWR_MS_CTRL);

        return 0;
}

static struct clk clk_mmc = {
        .parent         = &clk_armpll,
        .set_rate       = mmc_set_rate,
        .get_rate       = mmc_get_rate,
        .round_rate     = mmc_round_rate,
        .enable         = mmc_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_MS_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_MSCARD_SDCARD_EN,
};

static unsigned long clcd_get_rate(struct clk *clk)
{
        u32 tmp, div, rate, oldclk;

        /* The LCD clock must be on when accessing an LCD register */
        oldclk = __raw_readl(LPC32XX_CLKPWR_LCDCLK_CTRL);
        __raw_writel(oldclk | LPC32XX_CLKPWR_LCDCTRL_CLK_EN,
                LPC32XX_CLKPWR_LCDCLK_CTRL);
        tmp = __raw_readl(io_p2v(LPC32XX_LCD_BASE + CLCD_TIM2));
        __raw_writel(oldclk, LPC32XX_CLKPWR_LCDCLK_CTRL);

        rate = clk->parent->get_rate(clk->parent);

        /* Only supports internal clocking */
        if (tmp & TIM2_BCD)
                return rate;

        div = (tmp & 0x1F) | ((tmp & 0xF8) >> 22);
        tmp = rate / (2 + div);

        return tmp;
}

static int clcd_set_rate(struct clk *clk, unsigned long rate)
{
        u32 tmp, prate, div, oldclk;

        /* The LCD clock must be on when accessing an LCD register */
        oldclk = __raw_readl(LPC32XX_CLKPWR_LCDCLK_CTRL);
        __raw_writel(oldclk | LPC32XX_CLKPWR_LCDCTRL_CLK_EN,
                LPC32XX_CLKPWR_LCDCLK_CTRL);

        tmp = __raw_readl(io_p2v(LPC32XX_LCD_BASE + CLCD_TIM2)) | TIM2_BCD;
        prate = clk->parent->get_rate(clk->parent);

        if (rate < prate) {
                /* Find closest divider */
                div = prate / rate;
                if (div >= 2) {
                        div -= 2;
                        tmp &= ~TIM2_BCD;
                }

                tmp &= ~(0xF800001F);
                tmp |= (div & 0x1F);
                tmp |= (((div >> 5) & 0x1F) << 27);
        }

        __raw_writel(tmp, io_p2v(LPC32XX_LCD_BASE + CLCD_TIM2));
        __raw_writel(oldclk, LPC32XX_CLKPWR_LCDCLK_CTRL);

        return 0;
}

static unsigned long clcd_round_rate(struct clk *clk, unsigned long rate)
{
        u32 prate, div;

        prate = clk->parent->get_rate(clk->parent);

        if (rate >= prate)
                rate = prate;
        else {
                div = prate / rate;
                if (div > 0x3ff)
                        div = 0x3ff;

                rate = prate / div;
        }

        return rate;
}

static struct clk clk_lcd = {
        .parent         = &clk_hclk,
        .set_rate       = clcd_set_rate,
        .get_rate       = clcd_get_rate,
        .round_rate     = clcd_round_rate,
        .enable         = local_onoff_enable,
        .enable_reg     = LPC32XX_CLKPWR_LCDCLK_CTRL,
        .enable_mask    = LPC32XX_CLKPWR_LCDCTRL_CLK_EN,
};

static void local_clk_disable(struct clk *clk)
{
        /* Don't attempt to disable clock if it has no users */
        if (clk->usecount > 0) {
                clk->usecount--;

                /* Only disable clock when it has no more users */
                if ((clk->usecount == 0) && (clk->enable))
                        clk->enable(clk, 0);

                /* Check parent clocks, they may need to be disabled too */
                if (clk->parent)
                        local_clk_disable(clk->parent);
        }
}

static int local_clk_enable(struct clk *clk)
{
        int ret = 0;

        /* Enable parent clocks first and update use counts */
        if (clk->parent)
                ret = local_clk_enable(clk->parent);

        if (!ret) {
                /* Only enable clock if it's currently disabled */
                if ((clk->usecount == 0) && (clk->enable))
                        ret = clk->enable(clk, 1);

                if (!ret)
                        clk->usecount++;
                else if (clk->parent)
                        local_clk_disable(clk->parent);
        }

        return ret;
}

/*
 * clk_enable - inform the system when the clock source should be running.
 */
int clk_enable(struct clk *clk)
{
        int ret;
        unsigned long flags;

        spin_lock_irqsave(&global_clkregs_lock, flags);
        ret = local_clk_enable(clk);
        spin_unlock_irqrestore(&global_clkregs_lock, flags);

        return ret;
}
EXPORT_SYMBOL(clk_enable);

/*
 * clk_disable - inform the system when the clock source is no longer required
 */
void clk_disable(struct clk *clk)
{
        unsigned long flags;

        spin_lock_irqsave(&global_clkregs_lock, flags);
        local_clk_disable(clk);
        spin_unlock_irqrestore(&global_clkregs_lock, flags);
}
EXPORT_SYMBOL(clk_disable);

/*
 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source
 */
unsigned long clk_get_rate(struct clk *clk)
{
        return clk->get_rate(clk);
}
EXPORT_SYMBOL(clk_get_rate);

/*
 * clk_set_rate - set the clock rate for a clock source
 */
int clk_set_rate(struct clk *clk, unsigned long rate)
{
        int ret = -EINVAL;

        /*
         * Most system clocks can only be enabled or disabled, with
         * the actual rate set as part of the peripheral dividers
         * instead of high level clock control
         */
        if (clk->set_rate)
                ret = clk->set_rate(clk, rate);

        return ret;
}
EXPORT_SYMBOL(clk_set_rate);

/*
 * clk_round_rate - adjust a rate to the exact rate a clock can provide
 */
long clk_round_rate(struct clk *clk, unsigned long rate)
{
        if (clk->round_rate)
                rate = clk->round_rate(clk, rate);
        else
                rate = clk->get_rate(clk);

        return rate;
}
EXPORT_SYMBOL(clk_round_rate);

/*
 * clk_set_parent - set the parent clock source for this clock
 */
int clk_set_parent(struct clk *clk, struct clk *parent)
{
        /* Clock re-parenting is not supported */
        return -EINVAL;
}
EXPORT_SYMBOL(clk_set_parent);

/*
 * clk_get_parent - get the parent clock source for this clock
 */
struct clk *clk_get_parent(struct clk *clk)
{
        return clk->parent;
}
EXPORT_SYMBOL(clk_get_parent);

static struct clk_lookup lookups[] = {
        CLKDEV_INIT(NULL, "osc_32KHz", &osc_32KHz),
        CLKDEV_INIT(NULL, "osc_pll397", &osc_pll397),
        CLKDEV_INIT(NULL, "osc_main", &osc_main),
        CLKDEV_INIT(NULL, "sys_ck", &clk_sys),
        CLKDEV_INIT(NULL, "arm_pll_ck", &clk_armpll),
        CLKDEV_INIT(NULL, "ck_pll5", &clk_usbpll),
        CLKDEV_INIT(NULL, "hclk_ck", &clk_hclk),
        CLKDEV_INIT(NULL, "pclk_ck", &clk_pclk),
        CLKDEV_INIT(NULL, "timer0_ck", &clk_timer0),
        CLKDEV_INIT(NULL, "timer1_ck", &clk_timer1),
        CLKDEV_INIT(NULL, "timer2_ck", &clk_timer2),
        CLKDEV_INIT(NULL, "timer3_ck", &clk_timer3),
        CLKDEV_INIT(NULL, "vfp9_ck", &clk_vfp9),
        CLKDEV_INIT("pl08xdmac", NULL, &clk_dma),
        CLKDEV_INIT("4003c000.watchdog", NULL, &clk_wdt),
        CLKDEV_INIT("4005c000.pwm", NULL, &clk_pwm),
        CLKDEV_INIT("400e8000.mpwm", NULL, &clk_mpwm),
        CLKDEV_INIT(NULL, "uart3_ck", &clk_uart3),
        CLKDEV_INIT(NULL, "uart4_ck", &clk_uart4),
        CLKDEV_INIT(NULL, "uart5_ck", &clk_uart5),
        CLKDEV_INIT(NULL, "uart6_ck", &clk_uart6),
        CLKDEV_INIT("400a0000.i2c", NULL, &clk_i2c0),
        CLKDEV_INIT("400a8000.i2c", NULL, &clk_i2c1),
        CLKDEV_INIT("31020300.i2c", NULL, &clk_i2c2),
        CLKDEV_INIT("dev:ssp0", NULL, &clk_ssp0),
        CLKDEV_INIT("dev:ssp1", NULL, &clk_ssp1),
        CLKDEV_INIT("40050000.key", NULL, &clk_kscan),
        CLKDEV_INIT("20020000.flash", NULL, &clk_nand),
        CLKDEV_INIT("200a8000.flash", NULL, &clk_nand_mlc),
        CLKDEV_INIT("40048000.adc", NULL, &clk_adc),
        CLKDEV_INIT(NULL, "i2s0_ck", &clk_i2s0),
        CLKDEV_INIT(NULL, "i2s1_ck", &clk_i2s1),
        CLKDEV_INIT("40048000.tsc", NULL, &clk_tsc),
        CLKDEV_INIT("20098000.sd", NULL, &clk_mmc),
        CLKDEV_INIT("31060000.ethernet", NULL, &clk_net),
        CLKDEV_INIT("dev:clcd", NULL, &clk_lcd),
        CLKDEV_INIT("31020000.usbd", "ck_usbd", &clk_usbd),
        CLKDEV_INIT("31020000.ohci", "ck_usbd", &clk_usbd),
        CLKDEV_INIT("31020000.usbd", "ck_usb_otg", &clk_usb_otg_dev),
        CLKDEV_INIT("31020000.ohci", "ck_usb_otg", &clk_usb_otg_host),
        CLKDEV_INIT("lpc32xx_rtc", NULL, &clk_rtc),
};

static int __init clk_init(void)
{
        clkdev_add_table(lookups, ARRAY_SIZE(lookups));

        /*
         * Setup muxed SYSCLK for HCLK PLL base -this selects the
         * parent clock used for the ARM PLL and is used to derive
         * the many system clock rates in the device.
         */
        if (clk_is_sysclk_mainosc() != 0)
                clk_sys.parent = &osc_main;
        else
                clk_sys.parent = &osc_pll397;

        clk_sys.rate = clk_sys.parent->rate;

        /* Compute the current ARM PLL and USB PLL frequencies */
        local_update_armpll_rate();

        /* Compute HCLK and PCLK bus rates */
        clk_hclk.rate = clk_hclk.parent->rate / clk_get_hclk_div();
        clk_pclk.rate = clk_pclk.parent->rate / clk_get_pclk_div();

        /*
         * Enable system clocks - this step is somewhat formal, as the
         * clocks are already running, but it does get the clock data
         * inline with the actual system state. Never disable these
         * clocks as they will only stop if the system is going to sleep.
         * In that case, the chip/system power management functions will
         * handle clock gating.
         */
        if (clk_enable(&clk_hclk) || clk_enable(&clk_pclk))
                printk(KERN_ERR "Error enabling system HCLK and PCLK\n");

        /*
         * Timers 0 and 1 were enabled and are being used by the high
         * resolution tick function prior to this driver being initialized.
         * Tag them now as used.
         */
        if (clk_enable(&clk_timer0) || clk_enable(&clk_timer1))
                printk(KERN_ERR "Error enabling timer tick clocks\n");

        return 0;
}
core_initcall(clk_init);