omap_device.c

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/*
 * omap_device implementation
 *
 * Copyright (C) 2009-2010 Nokia Corporation
 * Paul Walmsley, Kevin Hilman
 *
 * Developed in collaboration with (alphabetical order): Benoit
 * Cousson, Thara Gopinath, Tony Lindgren, Rajendra Nayak, Vikram
 * Pandita, Sakari Poussa, Anand Sawant, Santosh Shilimkar, Richard
 * Woodruff
 *
 * 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.
 *
 * This code provides a consistent interface for OMAP device drivers
 * to control power management and interconnect properties of their
 * devices.
 *
 * In the medium- to long-term, this code should either be
 * a) implemented via arch-specific pointers in platform_data
 * or
 * b) implemented as a proper omap_bus/omap_device in Linux, no more
 *    platform_data func pointers
 *
 *
 * Guidelines for usage by driver authors:
 *
 * 1. These functions are intended to be used by device drivers via
 * function pointers in struct platform_data.  As an example,
 * omap_device_enable() should be passed to the driver as
 *
 * struct foo_driver_platform_data {
 * ...
 *      int (*device_enable)(struct platform_device *pdev);
 * ...
 * }
 *
 * Note that the generic "device_enable" name is used, rather than
 * "omap_device_enable".  This is so other architectures can pass in their
 * own enable/disable functions here.
 *
 * This should be populated during device setup:
 *
 * ...
 * pdata->device_enable = omap_device_enable;
 * ...
 *
 * 2. Drivers should first check to ensure the function pointer is not null
 * before calling it, as in:
 *
 * if (pdata->device_enable)
 *     pdata->device_enable(pdev);
 *
 * This allows other architectures that don't use similar device_enable()/
 * device_shutdown() functions to execute normally.
 *
 * ...
 *
 * Suggested usage by device drivers:
 *
 * During device initialization:
 * device_enable()
 *
 * During device idle:
 * (save remaining device context if necessary)
 * device_idle();
 *
 * During device resume:
 * device_enable();
 * (restore context if necessary)
 *
 * During device shutdown:
 * device_shutdown()
 * (device must be reinitialized at this point to use it again)
 *
 */
#undef DEBUG

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/notifier.h>

#include <plat/omap_device.h>
#include <plat/omap_hwmod.h>
#include <plat/clock.h>

/* These parameters are passed to _omap_device_{de,}activate() */
#define USE_WAKEUP_LAT          0
#define IGNORE_WAKEUP_LAT       1

static int omap_early_device_register(struct platform_device *pdev);

static struct omap_device_pm_latency omap_default_latency[] = {
    {
        .deactivate_func = omap_device_idle_hwmods,
        .activate_func   = omap_device_enable_hwmods,
        .flags = OMAP_DEVICE_LATENCY_AUTO_ADJUST,
    }
};

/* Private functions */

static int _omap_device_activate(struct omap_device *od, u8 ignore_lat)
{
    struct timespec a, b, c;

    dev_dbg(&od->pdev->dev, "omap_device: activating\n");

    while (od->pm_lat_level > 0) {
        struct omap_device_pm_latency *odpl;
        unsigned long long act_lat = 0;

        od->pm_lat_level--;

        odpl = od->pm_lats + od->pm_lat_level;

        if (!ignore_lat &&
            (od->dev_wakeup_lat <= od->_dev_wakeup_lat_limit))
            break;

        read_persistent_clock(&a);

        /* XXX check return code */
        odpl->activate_func(od);

        read_persistent_clock(&b);

        c = timespec_sub(b, a);
        act_lat = timespec_to_ns(&c);

        dev_dbg(&od->pdev->dev,
            "omap_device: pm_lat %d: activate: elapsed time %llu nsec\n",
            od->pm_lat_level, act_lat);

        if (act_lat > odpl->activate_lat) {
            odpl->activate_lat_worst = act_lat;
            if (odpl->flags & OMAP_DEVICE_LATENCY_AUTO_ADJUST) {
                odpl->activate_lat = act_lat;
                dev_dbg(&od->pdev->dev,
                    "new worst case activate latency %d: %llu\n",
                    od->pm_lat_level, act_lat);
            } else
                dev_warn(&od->pdev->dev,
                     "activate latency %d higher than expected. (%llu > %d)\n",
                     od->pm_lat_level, act_lat,
                     odpl->activate_lat);
        }

        od->dev_wakeup_lat -= odpl->activate_lat;
    }

    return 0;
}

static int _omap_device_deactivate(struct omap_device *od, u8 ignore_lat)
{
    struct timespec a, b, c;

    dev_dbg(&od->pdev->dev, "omap_device: deactivating\n");

    while (od->pm_lat_level < od->pm_lats_cnt) {
        struct omap_device_pm_latency *odpl;
        unsigned long long deact_lat = 0;

        odpl = od->pm_lats + od->pm_lat_level;

        if (!ignore_lat &&
            ((od->dev_wakeup_lat + odpl->activate_lat) >
             od->_dev_wakeup_lat_limit))
            break;

        read_persistent_clock(&a);

        /* XXX check return code */
        odpl->deactivate_func(od);

        read_persistent_clock(&b);

        c = timespec_sub(b, a);
        deact_lat = timespec_to_ns(&c);

        dev_dbg(&od->pdev->dev,
            "omap_device: pm_lat %d: deactivate: elapsed time %llu nsec\n",
            od->pm_lat_level, deact_lat);

        if (deact_lat > odpl->deactivate_lat) {
            odpl->deactivate_lat_worst = deact_lat;
            if (odpl->flags & OMAP_DEVICE_LATENCY_AUTO_ADJUST) {
                odpl->deactivate_lat = deact_lat;
                dev_dbg(&od->pdev->dev,
                    "new worst case deactivate latency %d: %llu\n",
                    od->pm_lat_level, deact_lat);
            } else
                dev_warn(&od->pdev->dev,
                     "deactivate latency %d higher than expected. (%llu > %d)\n",
                     od->pm_lat_level, deact_lat,
                     odpl->deactivate_lat);
        }

        od->dev_wakeup_lat += odpl->activate_lat;

        od->pm_lat_level++;
    }

    return 0;
}

static void _add_clkdev(struct omap_device *od, const char *clk_alias,
               const char *clk_name)
{
    struct clk *r;
    struct clk_lookup *l;

    if (!clk_alias || !clk_name)
        return;

    dev_dbg(&od->pdev->dev, "Creating %s -> %s\n", clk_alias, clk_name);

    r = clk_get_sys(dev_name(&od->pdev->dev), clk_alias);
    if (!IS_ERR(r)) {
        dev_warn(&od->pdev->dev,
             "alias %s already exists\n", clk_alias);
        clk_put(r);
        return;
    }

    r = clk_get(NULL, clk_name);
    if (IS_ERR(r)) {
        dev_err(&od->pdev->dev,
            "clk_get for %s failed\n", clk_name);
        return;
    }

    l = clkdev_alloc(r, clk_alias, dev_name(&od->pdev->dev));
    if (!l) {
        dev_err(&od->pdev->dev,
            "clkdev_alloc for %s failed\n", clk_alias);
        return;
    }

    clkdev_add(l);
}

static void _add_hwmod_clocks_clkdev(struct omap_device *od,
                     struct omap_hwmod *oh)
{
    int i;

    _add_clkdev(od, "fck", oh->main_clk);

    for (i = 0; i < oh->opt_clks_cnt; i++)
        _add_clkdev(od, oh->opt_clks[i].role, oh->opt_clks[i].clk);
}


static int omap_device_build_from_dt(struct platform_device *pdev)
{
    struct omap_hwmod **hwmods;
    struct omap_device *od;
    struct omap_hwmod *oh;
    struct device_node *node = pdev->dev.of_node;
    const char *oh_name;
    int oh_cnt, i, ret = 0;

    oh_cnt = of_property_count_strings(node, "ti,hwmods");
    if (!oh_cnt || IS_ERR_VALUE(oh_cnt)) {
        dev_dbg(&pdev->dev, "No 'hwmods' to build omap_device\n");
        return -ENODEV;
    }

    hwmods = kzalloc(sizeof(struct omap_hwmod *) * oh_cnt, GFP_KERNEL);
    if (!hwmods) {
        ret = -ENOMEM;
        goto odbfd_exit;
    }

    for (i = 0; i < oh_cnt; i++) {
        of_property_read_string_index(node, "ti,hwmods", i, &oh_name);
        oh = omap_hwmod_lookup(oh_name);
        if (!oh) {
            dev_err(&pdev->dev, "Cannot lookup hwmod '%s'\n",
                oh_name);
            ret = -EINVAL;
            goto odbfd_exit1;
        }
        hwmods[i] = oh;
    }

    od = omap_device_alloc(pdev, hwmods, oh_cnt, NULL, 0);
    if (!od) {
        dev_err(&pdev->dev, "Cannot allocate omap_device for :%s\n",
            oh_name);
        ret = PTR_ERR(od);
        goto odbfd_exit1;
    }

    /* Fix up missing resource names */
    for (i = 0; i < pdev->num_resources; i++) {
        struct resource *r = &pdev->resource[i];

        if (r->name == NULL)
            r->name = dev_name(&pdev->dev);
    }

    if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
        omap_device_disable_idle_on_suspend(pdev);

    pdev->dev.pm_domain = &omap_device_pm_domain;

odbfd_exit1:
    kfree(hwmods);
odbfd_exit:
    return ret;
}

static int _omap_device_notifier_call(struct notifier_block *nb,
                      unsigned long event, void *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct omap_device *od;

    switch (event) {
    case BUS_NOTIFY_DEL_DEVICE:
        if (pdev->archdata.od)
            omap_device_delete(pdev->archdata.od);
        break;
    case BUS_NOTIFY_ADD_DEVICE:
        if (pdev->dev.of_node)
            omap_device_build_from_dt(pdev);
        /* fall through */
    default:
        od = to_omap_device(pdev);
        if (od)
            od->_driver_status = event;
    }

    return NOTIFY_DONE;
}


/* Public functions for use by core code */

int omap_device_get_context_loss_count(struct platform_device *pdev)
{
    struct omap_device *od;
    u32 ret = 0;

    od = to_omap_device(pdev);

    if (od->hwmods_cnt)
        ret = omap_hwmod_get_context_loss_count(od->hwmods[0]);

    return ret;
}

static int omap_device_count_resources(struct omap_device *od)
{
    int c = 0;
    int i;

    for (i = 0; i < od->hwmods_cnt; i++)
        c += omap_hwmod_count_resources(od->hwmods[i]);

    pr_debug("omap_device: %s: counted %d total resources across %d hwmods\n",
         od->pdev->name, c, od->hwmods_cnt);

    return c;
}

static int omap_device_fill_resources(struct omap_device *od,
                      struct resource *res)
{
    int i, r;

    for (i = 0; i < od->hwmods_cnt; i++) {
        r = omap_hwmod_fill_resources(od->hwmods[i], res);
        res += r;
    }

    return 0;
}

static int _od_fill_dma_resources(struct omap_device *od,
                      struct resource *res)
{
    int i, r;

    for (i = 0; i < od->hwmods_cnt; i++) {
        r = omap_hwmod_fill_dma_resources(od->hwmods[i], res);
        res += r;
    }

    return 0;
}

struct omap_device *omap_device_alloc(struct platform_device *pdev,
                    struct omap_hwmod **ohs, int oh_cnt,
                    struct omap_device_pm_latency *pm_lats,
                    int pm_lats_cnt)
{
    int ret = -ENOMEM;
    struct omap_device *od;
    struct resource *res = NULL;
    int i, res_count;
    struct omap_hwmod **hwmods;

    od = kzalloc(sizeof(struct omap_device), GFP_KERNEL);
    if (!od) {
        ret = -ENOMEM;
        goto oda_exit1;
    }
    od->hwmods_cnt = oh_cnt;

    hwmods = kmemdup(ohs, sizeof(struct omap_hwmod *) * oh_cnt, GFP_KERNEL);
    if (!hwmods)
        goto oda_exit2;

    od->hwmods = hwmods;
    od->pdev = pdev;

    res_count = omap_device_count_resources(od);
    /*
     * DT Boot:
     *   OF framework will construct the resource structure (currently
     *   does for MEM & IRQ resource) and we should respect/use these
     *   resources, killing hwmod dependency.
     *   If pdev->num_resources > 0, we assume that MEM & IRQ resources
     *   have been allocated by OF layer already (through DTB).
     *
     * Non-DT Boot:
     *   Here, pdev->num_resources = 0, and we should get all the
     *   resources from hwmod.
     *
     * TODO: Once DMA resource is available from OF layer, we should
     *   kill filling any resources from hwmod.
     */
    if (res_count > pdev->num_resources) {
        /* Allocate resources memory to account for new resources */
        res = kzalloc(sizeof(struct resource) * res_count, GFP_KERNEL);
        if (!res)
            goto oda_exit3;

        /*
         * If pdev->num_resources > 0, then assume that,
         * MEM and IRQ resources will only come from DT and only
         * fill DMA resource from hwmod layer.
         */
        if (pdev->num_resources && pdev->resource) {
            dev_dbg(&pdev->dev, "%s(): resources already allocated %d\n",
                __func__, res_count);
            memcpy(res, pdev->resource,
                   sizeof(struct resource) * pdev->num_resources);
            _od_fill_dma_resources(od, &res[pdev->num_resources]);
        } else {
            dev_dbg(&pdev->dev, "%s(): using resources from hwmod %d\n",
                __func__, res_count);
            omap_device_fill_resources(od, res);
        }

        ret = platform_device_add_resources(pdev, res, res_count);
        kfree(res);

        if (ret)
            goto oda_exit3;
    }

    if (!pm_lats) {
        pm_lats = omap_default_latency;
        pm_lats_cnt = ARRAY_SIZE(omap_default_latency);
    }

    od->pm_lats_cnt = pm_lats_cnt;
    od->pm_lats = kmemdup(pm_lats,
            sizeof(struct omap_device_pm_latency) * pm_lats_cnt,
            GFP_KERNEL);
    if (!od->pm_lats)
        goto oda_exit3;

    pdev->archdata.od = od;

    for (i = 0; i < oh_cnt; i++) {
        hwmods[i]->od = od;
        _add_hwmod_clocks_clkdev(od, hwmods[i]);
    }

    return od;

oda_exit3:
    kfree(hwmods);
oda_exit2:
    kfree(od);
oda_exit1:
    dev_err(&pdev->dev, "omap_device: build failed (%d)\n", ret);

    return ERR_PTR(ret);
}

void omap_device_delete(struct omap_device *od)
{
    if (!od)
        return;

    od->pdev->archdata.od = NULL;
    kfree(od->pm_lats);
    kfree(od->hwmods);
    kfree(od);
}

struct platform_device __init *omap_device_build(const char *pdev_name, int pdev_id,
                      struct omap_hwmod *oh, void *pdata,
                      int pdata_len,
                      struct omap_device_pm_latency *pm_lats,
                      int pm_lats_cnt, int is_early_device)
{
    struct omap_hwmod *ohs[] = { oh };

    if (!oh)
        return ERR_PTR(-EINVAL);

    return omap_device_build_ss(pdev_name, pdev_id, ohs, 1, pdata,
                    pdata_len, pm_lats, pm_lats_cnt,
                    is_early_device);
}

struct platform_device __init *omap_device_build_ss(const char *pdev_name, int pdev_id,
                     struct omap_hwmod **ohs, int oh_cnt,
                     void *pdata, int pdata_len,
                     struct omap_device_pm_latency *pm_lats,
                     int pm_lats_cnt, int is_early_device)
{
    int ret = -ENOMEM;
    struct platform_device *pdev;
    struct omap_device *od;

    if (!ohs || oh_cnt == 0 || !pdev_name)
        return ERR_PTR(-EINVAL);

    if (!pdata && pdata_len > 0)
        return ERR_PTR(-EINVAL);

    pdev = platform_device_alloc(pdev_name, pdev_id);
    if (!pdev) {
        ret = -ENOMEM;
        goto odbs_exit;
    }

    /* Set the dev_name early to allow dev_xxx in omap_device_alloc */
    if (pdev->id != -1)
        dev_set_name(&pdev->dev, "%s.%d", pdev->name,  pdev->id);
    else
        dev_set_name(&pdev->dev, "%s", pdev->name);

    od = omap_device_alloc(pdev, ohs, oh_cnt, pm_lats, pm_lats_cnt);
    if (IS_ERR(od))
        goto odbs_exit1;

    ret = platform_device_add_data(pdev, pdata, pdata_len);
    if (ret)
        goto odbs_exit2;

    if (is_early_device)
        ret = omap_early_device_register(pdev);
    else
        ret = omap_device_register(pdev);
    if (ret)
        goto odbs_exit2;

    return pdev;

odbs_exit2:
    omap_device_delete(od);
odbs_exit1:
    platform_device_put(pdev);
odbs_exit:

    pr_err("omap_device: %s: build failed (%d)\n", pdev_name, ret);

    return ERR_PTR(ret);
}

static int __init omap_early_device_register(struct platform_device *pdev)
{
    struct platform_device *devices[1];

    devices[0] = pdev;
    early_platform_add_devices(devices, 1);
    return 0;
}

#ifdef CONFIG_PM_RUNTIME
static int _od_runtime_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    int ret;

    ret = pm_generic_runtime_suspend(dev);

    if (!ret)
        omap_device_idle(pdev);

    return ret;
}

static int _od_runtime_idle(struct device *dev)
{
    return pm_generic_runtime_idle(dev);
}

static int _od_runtime_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);

    omap_device_enable(pdev);

    return pm_generic_runtime_resume(dev);
}
#endif

#ifdef CONFIG_SUSPEND
static int _od_suspend_noirq(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct omap_device *od = to_omap_device(pdev);
    int ret;

    /* Don't attempt late suspend on a driver that is not bound */
    if (od->_driver_status != BUS_NOTIFY_BOUND_DRIVER)
        return 0;

    ret = pm_generic_suspend_noirq(dev);

    if (!ret && !pm_runtime_status_suspended(dev)) {
        if (pm_generic_runtime_suspend(dev) == 0) {
            if (!(od->flags & OMAP_DEVICE_NO_IDLE_ON_SUSPEND))
                omap_device_idle(pdev);
            od->flags |= OMAP_DEVICE_SUSPENDED;
        }
    }

    return ret;
}

static int _od_resume_noirq(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct omap_device *od = to_omap_device(pdev);

    if ((od->flags & OMAP_DEVICE_SUSPENDED) &&
        !pm_runtime_status_suspended(dev)) {
        od->flags &= ~OMAP_DEVICE_SUSPENDED;
        if (!(od->flags & OMAP_DEVICE_NO_IDLE_ON_SUSPEND))
            omap_device_enable(pdev);
        pm_generic_runtime_resume(dev);
    }

    return pm_generic_resume_noirq(dev);
}
#else
#define _od_suspend_noirq NULL
#define _od_resume_noirq NULL
#endif

struct dev_pm_domain omap_device_pm_domain = {
    .ops = {
        SET_RUNTIME_PM_OPS(_od_runtime_suspend, _od_runtime_resume,
                   _od_runtime_idle)
        USE_PLATFORM_PM_SLEEP_OPS
        .suspend_noirq = _od_suspend_noirq,
        .resume_noirq = _od_resume_noirq,
    }
};

int omap_device_register(struct platform_device *pdev)
{
    pr_debug("omap_device: %s: registering\n", pdev->name);

    pdev->dev.pm_domain = &omap_device_pm_domain;
    return platform_device_add(pdev);
}


/* Public functions for use by device drivers through struct platform_data */

int omap_device_enable(struct platform_device *pdev)
{
    int ret;
    struct omap_device *od;

    od = to_omap_device(pdev);

    if (od->_state == OMAP_DEVICE_STATE_ENABLED) {
        dev_warn(&pdev->dev,
             "omap_device: %s() called from invalid state %d\n",
             __func__, od->_state);
        return -EINVAL;
    }

    /* Enable everything if we're enabling this device from scratch */
    if (od->_state == OMAP_DEVICE_STATE_UNKNOWN)
        od->pm_lat_level = od->pm_lats_cnt;

    ret = _omap_device_activate(od, IGNORE_WAKEUP_LAT);

    od->dev_wakeup_lat = 0;
    od->_dev_wakeup_lat_limit = UINT_MAX;
    od->_state = OMAP_DEVICE_STATE_ENABLED;

    return ret;
}

int omap_device_idle(struct platform_device *pdev)
{
    int ret;
    struct omap_device *od;

    od = to_omap_device(pdev);

    if (od->_state != OMAP_DEVICE_STATE_ENABLED) {
        dev_warn(&pdev->dev,
             "omap_device: %s() called from invalid state %d\n",
             __func__, od->_state);
        return -EINVAL;
    }

    ret = _omap_device_deactivate(od, USE_WAKEUP_LAT);

    od->_state = OMAP_DEVICE_STATE_IDLE;

    return ret;
}

int omap_device_shutdown(struct platform_device *pdev)
{
    int ret, i;
    struct omap_device *od;

    od = to_omap_device(pdev);

    if (od->_state != OMAP_DEVICE_STATE_ENABLED &&
        od->_state != OMAP_DEVICE_STATE_IDLE) {
        dev_warn(&pdev->dev,
             "omap_device: %s() called from invalid state %d\n",
             __func__, od->_state);
        return -EINVAL;
    }

    ret = _omap_device_deactivate(od, IGNORE_WAKEUP_LAT);

    for (i = 0; i < od->hwmods_cnt; i++)
        omap_hwmod_shutdown(od->hwmods[i]);

    od->_state = OMAP_DEVICE_STATE_SHUTDOWN;

    return ret;
}

int omap_device_assert_hardreset(struct platform_device *pdev, const char *name)
{
    struct omap_device *od = to_omap_device(pdev);
    int ret = 0;
    int i;

    for (i = 0; i < od->hwmods_cnt; i++) {
        ret = omap_hwmod_assert_hardreset(od->hwmods[i], name);
        if (ret)
            break;
    }

    return ret;
}

int omap_device_deassert_hardreset(struct platform_device *pdev,
                   const char *name)
{
    struct omap_device *od = to_omap_device(pdev);
    int ret = 0;
    int i;

    for (i = 0; i < od->hwmods_cnt; i++) {
        ret = omap_hwmod_deassert_hardreset(od->hwmods[i], name);
        if (ret)
            break;
    }

    return ret;
}

int omap_device_align_pm_lat(struct platform_device *pdev,
                 u32 new_wakeup_lat_limit)
{
    int ret = -EINVAL;
    struct omap_device *od;

    od = to_omap_device(pdev);

    if (new_wakeup_lat_limit == od->dev_wakeup_lat)
        return 0;

    od->_dev_wakeup_lat_limit = new_wakeup_lat_limit;

    if (od->_state != OMAP_DEVICE_STATE_IDLE)
        return 0;
    else if (new_wakeup_lat_limit > od->dev_wakeup_lat)
        ret = _omap_device_deactivate(od, USE_WAKEUP_LAT);
    else if (new_wakeup_lat_limit < od->dev_wakeup_lat)
        ret = _omap_device_activate(od, USE_WAKEUP_LAT);

    return ret;
}

struct powerdomain *omap_device_get_pwrdm(struct omap_device *od)
{
    /*
     * XXX Assumes that all omap_hwmod powerdomains are identical.
     * This may not necessarily be true.  There should be a sanity
     * check in here to WARN() if any difference appears.
     */
    if (!od->hwmods_cnt)
        return NULL;

    return omap_hwmod_get_pwrdm(od->hwmods[0]);
}

void __iomem *omap_device_get_rt_va(struct omap_device *od)
{
    if (od->hwmods_cnt != 1)
        return NULL;

    return omap_hwmod_get_mpu_rt_va(od->hwmods[0]);
}

struct device *omap_device_get_by_hwmod_name(const char *oh_name)
{
    struct omap_hwmod *oh;

    if (!oh_name) {
        WARN(1, "%s: no hwmod name!\n", __func__);
        return ERR_PTR(-EINVAL);
    }

    oh = omap_hwmod_lookup(oh_name);
    if (IS_ERR_OR_NULL(oh)) {
        WARN(1, "%s: no hwmod for %s\n", __func__,
            oh_name);
        return ERR_PTR(oh ? PTR_ERR(oh) : -ENODEV);
    }
    if (IS_ERR_OR_NULL(oh->od)) {
        WARN(1, "%s: no omap_device for %s\n", __func__,
            oh_name);
        return ERR_PTR(oh->od ? PTR_ERR(oh->od) : -ENODEV);
    }

    if (IS_ERR_OR_NULL(oh->od->pdev))
        return ERR_PTR(oh->od->pdev ? PTR_ERR(oh->od->pdev) : -ENODEV);

    return &oh->od->pdev->dev;
}
EXPORT_SYMBOL(omap_device_get_by_hwmod_name);

/*
 * Public functions intended for use in omap_device_pm_latency
 * .activate_func and .deactivate_func function pointers
 */

int omap_device_enable_hwmods(struct omap_device *od)
{
    int i;

    for (i = 0; i < od->hwmods_cnt; i++)
        omap_hwmod_enable(od->hwmods[i]);

    /* XXX pass along return value here? */
    return 0;
}

int omap_device_idle_hwmods(struct omap_device *od)
{
    int i;

    for (i = 0; i < od->hwmods_cnt; i++)
        omap_hwmod_idle(od->hwmods[i]);

    /* XXX pass along return value here? */
    return 0;
}

int omap_device_disable_clocks(struct omap_device *od)
{
    int i;

    for (i = 0; i < od->hwmods_cnt; i++)
        omap_hwmod_disable_clocks(od->hwmods[i]);

    /* XXX pass along return value here? */
    return 0;
}

int omap_device_enable_clocks(struct omap_device *od)
{
    int i;

    for (i = 0; i < od->hwmods_cnt; i++)
        omap_hwmod_enable_clocks(od->hwmods[i]);

    /* XXX pass along return value here? */
    return 0;
}

static struct notifier_block platform_nb = {
    .notifier_call = _omap_device_notifier_call,
};

static int __init omap_device_init(void)
{
    bus_register_notifier(&platform_bus_type, &platform_nb);
    return 0;
}
core_initcall(omap_device_init);

static int __init omap_device_late_idle(struct device *dev, void *data)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct omap_device *od = to_omap_device(pdev);

    if (!od)
        return 0;

    /*
     * If omap_device state is enabled, but has no driver bound,
     * idle it.
     */
    if (od->_driver_status != BUS_NOTIFY_BOUND_DRIVER) {
        if (od->_state == OMAP_DEVICE_STATE_ENABLED) {
            dev_warn(dev, "%s: enabled but no driver.  Idling\n",
                 __func__);
            omap_device_idle(pdev);
        }
    }

    return 0;
}

static int __init omap_device_late_init(void)
{
    bus_for_each_dev(&platform_bus_type, NULL, NULL, omap_device_late_idle);
    return 0;
}
late_initcall(omap_device_late_init);