/*
 * linux/arch/arm/plat-omap/dmtimer.c
 *
 * OMAP Dual-Mode Timers
 *
 * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
 * Tarun Kanti DebBarma <tarun.kanti@ti.com>
 * Thara Gopinath <thara@ti.com>
 *
 * dmtimer adaptation to platform_driver.
 *
 * Copyright (C) 2005 Nokia Corporation
 * OMAP2 support by Juha Yrjola
 * API improvements and OMAP2 clock framework support by Timo Teras
 *
 * Copyright (C) 2009 Texas Instruments
 * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.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.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * 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.,
 * 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/clk.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/platform_data/dmtimer-omap.h>

#include <plat/dmtimer.h>

static u32 omap_reserved_systimers;
static LIST_HEAD(omap_timer_list);
static DEFINE_SPINLOCK(dm_timer_lock);

enum {
        REQUEST_ANY = 0,
        REQUEST_BY_ID,
        REQUEST_BY_CAP,
        REQUEST_BY_NODE,
};

/**
 * omap_dm_timer_read_reg - read timer registers in posted and non-posted mode
 * @timer:      timer pointer over which read operation to perform
 * @reg:        lowest byte holds the register offset
 *
 * The posted mode bit is encoded in reg. Note that in posted mode write
 * pending bit must be checked. Otherwise a read of a non completed write
 * will produce an error.
 */
static inline u32 omap_dm_timer_read_reg(struct omap_dm_timer *timer, u32 reg)
{
        WARN_ON((reg & 0xff) < _OMAP_TIMER_WAKEUP_EN_OFFSET);
        return __omap_dm_timer_read(timer, reg, timer->posted);
}

/**
 * omap_dm_timer_write_reg - write timer registers in posted and non-posted mode
 * @timer:      timer pointer over which write operation is to perform
 * @reg:        lowest byte holds the register offset
 * @value:      data to write into the register
 *
 * The posted mode bit is encoded in reg. Note that in posted mode the write
 * pending bit must be checked. Otherwise a write on a register which has a
 * pending write will be lost.
 */
static void omap_dm_timer_write_reg(struct omap_dm_timer *timer, u32 reg,
                                                u32 value)
{
        WARN_ON((reg & 0xff) < _OMAP_TIMER_WAKEUP_EN_OFFSET);
        __omap_dm_timer_write(timer, reg, value, timer->posted);
}

static void omap_timer_restore_context(struct omap_dm_timer *timer)
{
        omap_dm_timer_write_reg(timer, OMAP_TIMER_WAKEUP_EN_REG,
                                timer->context.twer);
        omap_dm_timer_write_reg(timer, OMAP_TIMER_COUNTER_REG,
                                timer->context.tcrr);
        omap_dm_timer_write_reg(timer, OMAP_TIMER_LOAD_REG,
                                timer->context.tldr);
        omap_dm_timer_write_reg(timer, OMAP_TIMER_MATCH_REG,
                                timer->context.tmar);
        omap_dm_timer_write_reg(timer, OMAP_TIMER_IF_CTRL_REG,
                                timer->context.tsicr);
        __raw_writel(timer->context.tier, timer->irq_ena);
        omap_dm_timer_write_reg(timer, OMAP_TIMER_CTRL_REG,
                                timer->context.tclr);
}

static int omap_dm_timer_reset(struct omap_dm_timer *timer)
{
        u32 l, timeout = 100000;

        if (timer->revision != 1)
                return -EINVAL;

        omap_dm_timer_write_reg(timer, OMAP_TIMER_IF_CTRL_REG, 0x06);

        do {
                l = __omap_dm_timer_read(timer,
                                         OMAP_TIMER_V1_SYS_STAT_OFFSET, 0);
        } while (!l && timeout--);

        if (!timeout) {
                dev_err(&timer->pdev->dev, "Timer failed to reset\n");
                return -ETIMEDOUT;
        }

        /* Configure timer for smart-idle mode */
        l = __omap_dm_timer_read(timer, OMAP_TIMER_OCP_CFG_OFFSET, 0);
        l |= 0x2 << 0x3;
        __omap_dm_timer_write(timer, OMAP_TIMER_OCP_CFG_OFFSET, l, 0);

        timer->posted = 0;

        return 0;
}

static int omap_dm_timer_prepare(struct omap_dm_timer *timer)
{
        int rc;

        /*
         * FIXME: OMAP1 devices do not use the clock framework for dmtimers so
         * do not call clk_get() for these devices.
         */
        if (!(timer->capability & OMAP_TIMER_NEEDS_RESET)) {
                timer->fclk = clk_get(&timer->pdev->dev, "fck");
                if (WARN_ON_ONCE(IS_ERR(timer->fclk))) {
                        dev_err(&timer->pdev->dev, ": No fclk handle.\n");
                        return -EINVAL;
                }
        }

        omap_dm_timer_enable(timer);

        if (timer->capability & OMAP_TIMER_NEEDS_RESET) {
                rc = omap_dm_timer_reset(timer);
                if (rc) {
                        omap_dm_timer_disable(timer);
                        return rc;
                }
        }

        __omap_dm_timer_enable_posted(timer);
        omap_dm_timer_disable(timer);

        return omap_dm_timer_set_source(timer, OMAP_TIMER_SRC_32_KHZ);
}

static inline u32 omap_dm_timer_reserved_systimer(int id)
{
        return (omap_reserved_systimers & (1 << (id - 1))) ? 1 : 0;
}

int omap_dm_timer_reserve_systimer(int id)
{
        if (omap_dm_timer_reserved_systimer(id))
                return -ENODEV;

        omap_reserved_systimers |= (1 << (id - 1));

        return 0;
}

static struct omap_dm_timer *_omap_dm_timer_request(int req_type, void *data)
{
        struct omap_dm_timer *timer = NULL, *t;
        struct device_node *np = NULL;
        unsigned long flags;
        u32 cap = 0;
        int id = 0;

        switch (req_type) {
        case REQUEST_BY_ID:
                id = *(int *)data;
                break;
        case REQUEST_BY_CAP:
                cap = *(u32 *)data;
                break;
        case REQUEST_BY_NODE:
                np = (struct device_node *)data;
                break;
        default:
                /* REQUEST_ANY */
                break;
        }

        spin_lock_irqsave(&dm_timer_lock, flags);
        list_for_each_entry(t, &omap_timer_list, node) {
                if (t->reserved)
                        continue;

                switch (req_type) {
                case REQUEST_BY_ID:
                        if (id == t->pdev->id) {
                                timer = t;
                                timer->reserved = 1;
                                goto found;
                        }
                        break;
                case REQUEST_BY_CAP:
                        if (cap == (t->capability & cap)) {
                                /*
                                 * If timer is not NULL, we have already found
                                 * one timer but it was not an exact match
                                 * because it had more capabilites that what
                                 * was required. Therefore, unreserve the last
                                 * timer found and see if this one is a better
                                 * match.
                                 */
                                if (timer)
                                        timer->reserved = 0;
                                timer = t;
                                timer->reserved = 1;

                                /* Exit loop early if we find an exact match */
                                if (t->capability == cap)
                                        goto found;
                        }
                        break;
                case REQUEST_BY_NODE:
                        if (np == t->pdev->dev.of_node) {
                                timer = t;
                                timer->reserved = 1;
                                goto found;
                        }
                        break;
                default:
                        /* REQUEST_ANY */
                        timer = t;
                        timer->reserved = 1;
                        goto found;
                }
        }
found:
        spin_unlock_irqrestore(&dm_timer_lock, flags);

        if (timer && omap_dm_timer_prepare(timer)) {
                timer->reserved = 0;
                timer = NULL;
        }

        if (!timer)
                pr_debug("%s: timer request failed!\n", __func__);

        return timer;
}

struct omap_dm_timer *omap_dm_timer_request(void)
{
        return _omap_dm_timer_request(REQUEST_ANY, NULL);
}
EXPORT_SYMBOL_GPL(omap_dm_timer_request);

struct omap_dm_timer *omap_dm_timer_request_specific(int id)
{
        /* Requesting timer by ID is not supported when device tree is used */
        if (of_have_populated_dt()) {
                pr_warn("%s: Please use omap_dm_timer_request_by_cap/node()\n",
                        __func__);
                return NULL;
        }

        return _omap_dm_timer_request(REQUEST_BY_ID, &id);
}
EXPORT_SYMBOL_GPL(omap_dm_timer_request_specific);

/**
 * omap_dm_timer_request_by_cap - Request a timer by capability
 * @cap:        Bit mask of capabilities to match
 *
 * Find a timer based upon capabilities bit mask. Callers of this function
 * should use the definitions found in the plat/dmtimer.h file under the
 * comment "timer capabilities used in hwmod database". Returns pointer to
 * timer handle on success and a NULL pointer on failure.
 */
struct omap_dm_timer *omap_dm_timer_request_by_cap(u32 cap)
{
        return _omap_dm_timer_request(REQUEST_BY_CAP, &cap);
}
EXPORT_SYMBOL_GPL(omap_dm_timer_request_by_cap);

/**
 * omap_dm_timer_request_by_node - Request a timer by device-tree node
 * @np:         Pointer to device-tree timer node
 *
 * Request a timer based upon a device node pointer. Returns pointer to
 * timer handle on success and a NULL pointer on failure.
 */
struct omap_dm_timer *omap_dm_timer_request_by_node(struct device_node *np)
{
        if (!np)
                return NULL;

        return _omap_dm_timer_request(REQUEST_BY_NODE, np);
}
EXPORT_SYMBOL_GPL(omap_dm_timer_request_by_node);

int omap_dm_timer_free(struct omap_dm_timer *timer)
{
        if (unlikely(!timer))
                return -EINVAL;

        clk_put(timer->fclk);

        WARN_ON(!timer->reserved);
        timer->reserved = 0;
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_free);

void omap_dm_timer_enable(struct omap_dm_timer *timer)
{
        int c;

        pm_runtime_get_sync(&timer->pdev->dev);

        if (!(timer->capability & OMAP_TIMER_ALWON)) {
                if (timer->get_context_loss_count) {
                        c = timer->get_context_loss_count(&timer->pdev->dev);
                        if (c != timer->ctx_loss_count) {
                                omap_timer_restore_context(timer);
                                timer->ctx_loss_count = c;
                        }
                } else {
                        omap_timer_restore_context(timer);
                }
        }
}
EXPORT_SYMBOL_GPL(omap_dm_timer_enable);

void omap_dm_timer_disable(struct omap_dm_timer *timer)
{
        pm_runtime_put_sync(&timer->pdev->dev);
}
EXPORT_SYMBOL_GPL(omap_dm_timer_disable);

int omap_dm_timer_get_irq(struct omap_dm_timer *timer)
{
        if (timer)
                return timer->irq;
        return -EINVAL;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_get_irq);

#if defined(CONFIG_ARCH_OMAP1)
#include <mach/hardware.h>
/**
 * omap_dm_timer_modify_idlect_mask - Check if any running timers use ARMXOR
 * @inputmask: current value of idlect mask
 */
__u32 omap_dm_timer_modify_idlect_mask(__u32 inputmask)
{
        int i = 0;
        struct omap_dm_timer *timer = NULL;
        unsigned long flags;

        /* If ARMXOR cannot be idled this function call is unnecessary */
        if (!(inputmask & (1 << 1)))
                return inputmask;

        /* If any active timer is using ARMXOR return modified mask */
        spin_lock_irqsave(&dm_timer_lock, flags);
        list_for_each_entry(timer, &omap_timer_list, node) {
                u32 l;

                l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
                if (l & OMAP_TIMER_CTRL_ST) {
                        if (((omap_readl(MOD_CONF_CTRL_1) >> (i * 2)) & 0x03) == 0)
                                inputmask &= ~(1 << 1);
                        else
                                inputmask &= ~(1 << 2);
                }
                i++;
        }
        spin_unlock_irqrestore(&dm_timer_lock, flags);

        return inputmask;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_modify_idlect_mask);

#else

struct clk *omap_dm_timer_get_fclk(struct omap_dm_timer *timer)
{
        if (timer && !IS_ERR(timer->fclk))
                return timer->fclk;
        return NULL;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_get_fclk);

__u32 omap_dm_timer_modify_idlect_mask(__u32 inputmask)
{
        BUG();

        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_modify_idlect_mask);

#endif

int omap_dm_timer_trigger(struct omap_dm_timer *timer)
{
        if (unlikely(!timer || pm_runtime_suspended(&timer->pdev->dev))) {
                pr_err("%s: timer not available or enabled.\n", __func__);
                return -EINVAL;
        }

        omap_dm_timer_write_reg(timer, OMAP_TIMER_TRIGGER_REG, 0);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_trigger);

int omap_dm_timer_start(struct omap_dm_timer *timer)
{
        u32 l;

        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);

        l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
        if (!(l & OMAP_TIMER_CTRL_ST)) {
                l |= OMAP_TIMER_CTRL_ST;
                omap_dm_timer_write_reg(timer, OMAP_TIMER_CTRL_REG, l);
        }

        /* Save the context */
        timer->context.tclr = l;
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_start);

int omap_dm_timer_stop(struct omap_dm_timer *timer)
{
        unsigned long rate = 0;

        if (unlikely(!timer))
                return -EINVAL;

        if (!(timer->capability & OMAP_TIMER_NEEDS_RESET))
                rate = clk_get_rate(timer->fclk);

        __omap_dm_timer_stop(timer, timer->posted, rate);

        /*
         * Since the register values are computed and written within
         * __omap_dm_timer_stop, we need to use read to retrieve the
         * context.
         */
        timer->context.tclr =
                        omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
        omap_dm_timer_disable(timer);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_stop);

int omap_dm_timer_set_source(struct omap_dm_timer *timer, int source)
{
        int ret;
        char *parent_name = NULL;
        struct clk *parent;
        struct dmtimer_platform_data *pdata;

        if (unlikely(!timer))
                return -EINVAL;

        pdata = timer->pdev->dev.platform_data;

        if (source < 0 || source >= 3)
                return -EINVAL;

        /*
         * FIXME: Used for OMAP1 devices only because they do not currently
         * use the clock framework to set the parent clock. To be removed
         * once OMAP1 migrated to using clock framework for dmtimers
         */
        if (pdata && pdata->set_timer_src)
                return pdata->set_timer_src(timer->pdev, source);

        if (IS_ERR(timer->fclk))
                return -EINVAL;

        switch (source) {
        case OMAP_TIMER_SRC_SYS_CLK:
                parent_name = "timer_sys_ck";
                break;

        case OMAP_TIMER_SRC_32_KHZ:
                parent_name = "timer_32k_ck";
                break;

        case OMAP_TIMER_SRC_EXT_CLK:
                parent_name = "timer_ext_ck";
                break;
        }

        parent = clk_get(&timer->pdev->dev, parent_name);
        if (IS_ERR(parent)) {
                pr_err("%s: %s not found\n", __func__, parent_name);
                return -EINVAL;
        }

        ret = clk_set_parent(timer->fclk, parent);
        if (ret < 0)
                pr_err("%s: failed to set %s as parent\n", __func__,
                        parent_name);

        clk_put(parent);

        return ret;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_source);

int omap_dm_timer_set_load(struct omap_dm_timer *timer, int autoreload,
                            unsigned int load)
{
        u32 l;

        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);
        l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
        if (autoreload)
                l |= OMAP_TIMER_CTRL_AR;
        else
                l &= ~OMAP_TIMER_CTRL_AR;
        omap_dm_timer_write_reg(timer, OMAP_TIMER_CTRL_REG, l);
        omap_dm_timer_write_reg(timer, OMAP_TIMER_LOAD_REG, load);

        omap_dm_timer_write_reg(timer, OMAP_TIMER_TRIGGER_REG, 0);
        /* Save the context */
        timer->context.tclr = l;
        timer->context.tldr = load;
        omap_dm_timer_disable(timer);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_load);

/* Optimized set_load which removes costly spin wait in timer_start */
int omap_dm_timer_set_load_start(struct omap_dm_timer *timer, int autoreload,
                            unsigned int load)
{
        u32 l;

        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);

        l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
        if (autoreload) {
                l |= OMAP_TIMER_CTRL_AR;
                omap_dm_timer_write_reg(timer, OMAP_TIMER_LOAD_REG, load);
        } else {
                l &= ~OMAP_TIMER_CTRL_AR;
        }
        l |= OMAP_TIMER_CTRL_ST;

        __omap_dm_timer_load_start(timer, l, load, timer->posted);

        /* Save the context */
        timer->context.tclr = l;
        timer->context.tldr = load;
        timer->context.tcrr = load;
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_load_start);

int omap_dm_timer_set_match(struct omap_dm_timer *timer, int enable,
                             unsigned int match)
{
        u32 l;

        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);
        l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
        if (enable)
                l |= OMAP_TIMER_CTRL_CE;
        else
                l &= ~OMAP_TIMER_CTRL_CE;
        omap_dm_timer_write_reg(timer, OMAP_TIMER_MATCH_REG, match);
        omap_dm_timer_write_reg(timer, OMAP_TIMER_CTRL_REG, l);

        /* Save the context */
        timer->context.tclr = l;
        timer->context.tmar = match;
        omap_dm_timer_disable(timer);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_match);

int omap_dm_timer_set_pwm(struct omap_dm_timer *timer, int def_on,
                           int toggle, int trigger)
{
        u32 l;

        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);
        l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
        l &= ~(OMAP_TIMER_CTRL_GPOCFG | OMAP_TIMER_CTRL_SCPWM |
               OMAP_TIMER_CTRL_PT | (0x03 << 10));
        if (def_on)
                l |= OMAP_TIMER_CTRL_SCPWM;
        if (toggle)
                l |= OMAP_TIMER_CTRL_PT;
        l |= trigger << 10;
        omap_dm_timer_write_reg(timer, OMAP_TIMER_CTRL_REG, l);

        /* Save the context */
        timer->context.tclr = l;
        omap_dm_timer_disable(timer);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_pwm);

int omap_dm_timer_set_prescaler(struct omap_dm_timer *timer, int prescaler)
{
        u32 l;

        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);
        l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
        l &= ~(OMAP_TIMER_CTRL_PRE | (0x07 << 2));
        if (prescaler >= 0x00 && prescaler <= 0x07) {
                l |= OMAP_TIMER_CTRL_PRE;
                l |= prescaler << 2;
        }
        omap_dm_timer_write_reg(timer, OMAP_TIMER_CTRL_REG, l);

        /* Save the context */
        timer->context.tclr = l;
        omap_dm_timer_disable(timer);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_prescaler);

int omap_dm_timer_set_int_enable(struct omap_dm_timer *timer,
                                  unsigned int value)
{
        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);
        __omap_dm_timer_int_enable(timer, value);

        /* Save the context */
        timer->context.tier = value;
        timer->context.twer = value;
        omap_dm_timer_disable(timer);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_int_enable);

/**
 * omap_dm_timer_set_int_disable - disable timer interrupts
 * @timer:      pointer to timer handle
 * @mask:       bit mask of interrupts to be disabled
 *
 * Disables the specified timer interrupts for a timer.
 */
int omap_dm_timer_set_int_disable(struct omap_dm_timer *timer, u32 mask)
{
        u32 l = mask;

        if (unlikely(!timer))
                return -EINVAL;

        omap_dm_timer_enable(timer);

        if (timer->revision == 1)
                l = __raw_readl(timer->irq_ena) & ~mask;

        __raw_writel(l, timer->irq_dis);
        l = omap_dm_timer_read_reg(timer, OMAP_TIMER_WAKEUP_EN_REG) & ~mask;
        omap_dm_timer_write_reg(timer, OMAP_TIMER_WAKEUP_EN_REG, l);

        /* Save the context */
        timer->context.tier &= ~mask;
        timer->context.twer &= ~mask;
        omap_dm_timer_disable(timer);
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_set_int_disable);

unsigned int omap_dm_timer_read_status(struct omap_dm_timer *timer)
{
        unsigned int l;

        if (unlikely(!timer || pm_runtime_suspended(&timer->pdev->dev))) {
                pr_err("%s: timer not available or enabled.\n", __func__);
                return 0;
        }

        l = __raw_readl(timer->irq_stat);

        return l;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_read_status);

int omap_dm_timer_write_status(struct omap_dm_timer *timer, unsigned int value)
{
        if (unlikely(!timer || pm_runtime_suspended(&timer->pdev->dev)))
                return -EINVAL;

        __omap_dm_timer_write_status(timer, value);

        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_write_status);

unsigned int omap_dm_timer_read_counter(struct omap_dm_timer *timer)
{
        if (unlikely(!timer || pm_runtime_suspended(&timer->pdev->dev))) {
                pr_err("%s: timer not iavailable or enabled.\n", __func__);
                return 0;
        }

        return __omap_dm_timer_read_counter(timer, timer->posted);
}
EXPORT_SYMBOL_GPL(omap_dm_timer_read_counter);

int omap_dm_timer_write_counter(struct omap_dm_timer *timer, unsigned int value)
{
        if (unlikely(!timer || pm_runtime_suspended(&timer->pdev->dev))) {
                pr_err("%s: timer not available or enabled.\n", __func__);
                return -EINVAL;
        }

        omap_dm_timer_write_reg(timer, OMAP_TIMER_COUNTER_REG, value);

        /* Save the context */
        timer->context.tcrr = value;
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timer_write_counter);

int omap_dm_timers_active(void)
{
        struct omap_dm_timer *timer;

        list_for_each_entry(timer, &omap_timer_list, node) {
                if (!timer->reserved)
                        continue;

                if (omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG) &
                    OMAP_TIMER_CTRL_ST) {
                        return 1;
                }
        }
        return 0;
}
EXPORT_SYMBOL_GPL(omap_dm_timers_active);

static const struct of_device_id omap_timer_match[];

/**
 * omap_dm_timer_probe - probe function called for every registered device
 * @pdev:       pointer to current timer platform device
 *
 * Called by driver framework at the end of device registration for all
 * timer devices.
 */
static int omap_dm_timer_probe(struct platform_device *pdev)
{
        unsigned long flags;
        struct omap_dm_timer *timer;
        struct resource *mem, *irq;
        struct device *dev = &pdev->dev;
        const struct of_device_id *match;
        const struct dmtimer_platform_data *pdata;

        match = of_match_device(of_match_ptr(omap_timer_match), dev);
        pdata = match ? match->data : dev->platform_data;

        if (!pdata && !dev->of_node) {
                dev_err(dev, "%s: no platform data.\n", __func__);
                return -ENODEV;
        }

        irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (unlikely(!irq)) {
                dev_err(dev, "%s: no IRQ resource.\n", __func__);
                return -ENODEV;
        }

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (unlikely(!mem)) {
                dev_err(dev, "%s: no memory resource.\n", __func__);
                return -ENODEV;
        }

        timer = devm_kzalloc(dev, sizeof(struct omap_dm_timer), GFP_KERNEL);
        if (!timer) {
                dev_err(dev, "%s: memory alloc failed!\n", __func__);
                return  -ENOMEM;
        }

        timer->fclk = ERR_PTR(-ENODEV);
        timer->io_base = devm_ioremap_resource(dev, mem);
        if (IS_ERR(timer->io_base))
                return PTR_ERR(timer->io_base);

        if (dev->of_node) {
                if (of_find_property(dev->of_node, "ti,timer-alwon", NULL))
                        timer->capability |= OMAP_TIMER_ALWON;
                if (of_find_property(dev->of_node, "ti,timer-dsp", NULL))
                        timer->capability |= OMAP_TIMER_HAS_DSP_IRQ;
                if (of_find_property(dev->of_node, "ti,timer-pwm", NULL))
                        timer->capability |= OMAP_TIMER_HAS_PWM;
                if (of_find_property(dev->of_node, "ti,timer-secure", NULL))
                        timer->capability |= OMAP_TIMER_SECURE;
        } else {
                timer->id = pdev->id;
                timer->capability = pdata->timer_capability;
                timer->reserved = omap_dm_timer_reserved_systimer(timer->id);
                timer->get_context_loss_count = pdata->get_context_loss_count;
        }

        if (pdata)
                timer->errata = pdata->timer_errata;

        timer->irq = irq->start;
        timer->pdev = pdev;

        /* Skip pm_runtime_enable for OMAP1 */
        if (!(timer->capability & OMAP_TIMER_NEEDS_RESET)) {
                pm_runtime_enable(dev);
                pm_runtime_irq_safe(dev);
        }

        if (!timer->reserved) {
                pm_runtime_get_sync(dev);
                __omap_dm_timer_init_regs(timer);
                pm_runtime_put(dev);
        }

        /* add the timer element to the list */
        spin_lock_irqsave(&dm_timer_lock, flags);
        list_add_tail(&timer->node, &omap_timer_list);
        spin_unlock_irqrestore(&dm_timer_lock, flags);

        dev_dbg(dev, "Device Probed.\n");

        return 0;
}

/**
 * omap_dm_timer_remove - cleanup a registered timer device
 * @pdev:       pointer to current timer platform device
 *
 * Called by driver framework whenever a timer device is unregistered.
 * In addition to freeing platform resources it also deletes the timer
 * entry from the local list.
 */
static int omap_dm_timer_remove(struct platform_device *pdev)
{
        struct omap_dm_timer *timer;
        unsigned long flags;
        int ret = -EINVAL;

        spin_lock_irqsave(&dm_timer_lock, flags);
        list_for_each_entry(timer, &omap_timer_list, node)
                if (!strcmp(dev_name(&timer->pdev->dev),
                            dev_name(&pdev->dev))) {
                        list_del(&timer->node);
                        ret = 0;
                        break;
                }
        spin_unlock_irqrestore(&dm_timer_lock, flags);

        return ret;
}

static const struct dmtimer_platform_data omap3plus_pdata = {
        .timer_errata = OMAP_TIMER_ERRATA_I103_I767,
};

static const struct of_device_id omap_timer_match[] = {
        {
                .compatible = "ti,omap2420-timer",
        },
        {
                .compatible = "ti,omap3430-timer",
                .data = &omap3plus_pdata,
        },
        {
                .compatible = "ti,omap4430-timer",
                .data = &omap3plus_pdata,
        },
        {
                .compatible = "ti,omap5430-timer",
                .data = &omap3plus_pdata,
        },
        {
                .compatible = "ti,am335x-timer",
                .data = &omap3plus_pdata,
        },
        {
                .compatible = "ti,am335x-timer-1ms",
                .data = &omap3plus_pdata,
        },
        {},
};
MODULE_DEVICE_TABLE(of, omap_timer_match);

static struct platform_driver omap_dm_timer_driver = {
        .probe  = omap_dm_timer_probe,
        .remove = omap_dm_timer_remove,
        .driver = {
                .name   = "omap_timer",
                .of_match_table = of_match_ptr(omap_timer_match),
        },
};

early_platform_init("earlytimer", &omap_dm_timer_driver);
module_platform_driver(omap_dm_timer_driver);

MODULE_DESCRIPTION("OMAP Dual-Mode Timer Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_AUTHOR("Texas Instruments Inc");