1 files changed, 1277 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
new file mode 100644
index 000000000000..0ef934fec364
--- /dev/null
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -0,0 +1,1277 @@
+/*
+ * 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 "omap_device.h"
+#include "omap_hwmod.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 */
+
+/**
+ * _omap_device_activate - increase device readiness
+ * @od: struct omap_device *
+ * @ignore_lat: increase to latency target (0) or full readiness (1)?
+ *
+ * Increase readiness of omap_device @od (thus decreasing device
+ * wakeup latency, but consuming more power).  If @ignore_lat is
+ * IGNORE_WAKEUP_LAT, make the omap_device fully active.  Otherwise,
+ * if @ignore_lat is USE_WAKEUP_LAT, and the device's maximum wakeup
+ * latency is greater than the requested maximum wakeup latency, step
+ * backwards in the omap_device_pm_latency table to ensure the
+ * device's maximum wakeup latency is less than or equal to the
+ * requested maximum wakeup latency.  Returns 0.
+ */
+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;
+}
+
+/**
+ * _omap_device_deactivate - decrease device readiness
+ * @od: struct omap_device *
+ * @ignore_lat: decrease to latency target (0) or full inactivity (1)?
+ *
+ * Decrease readiness of omap_device @od (thus increasing device
+ * wakeup latency, but conserving power).  If @ignore_lat is
+ * IGNORE_WAKEUP_LAT, make the omap_device fully inactive.  Otherwise,
+ * if @ignore_lat is USE_WAKEUP_LAT, and the device's maximum wakeup
+ * latency is less than the requested maximum wakeup latency, step
+ * forwards in the omap_device_pm_latency table to ensure the device's
+ * maximum wakeup latency is less than or equal to the requested
+ * maximum wakeup latency.  Returns 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);
+}
+
+/**
+ * _add_hwmod_clocks_clkdev - Add clkdev entry for hwmod optional clocks
+ * and main clock
+ * @od: struct omap_device *od
+ * @oh: struct omap_hwmod *oh
+ *
+ * For the main clock and every optional clock present per hwmod per
+ * omap_device, this function adds an entry in the clkdev table of the
+ * form <dev-id=dev_name, con-id=role> if it does not exist already.
+ *
+ * The function is called from inside omap_device_build_ss(), after
+ * omap_device_register.
+ *
+ * This allows drivers to get a pointer to its optional clocks based on its role
+ * by calling clk_get(<dev*>, <role>).
+ * In the case of the main clock, a "fck" alias is used.
+ *
+ * No return value.
+ */
+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);
+}
+
+
+/**
+ * omap_device_build_from_dt - build an omap_device with multiple hwmods
+ * @pdev_name: name of the platform_device driver to use
+ * @pdev_id: this platform_device's connection ID
+ * @oh: ptr to the single omap_hwmod that backs this omap_device
+ * @pdata: platform_data ptr to associate with the platform_device
+ * @pdata_len: amount of memory pointed to by @pdata
+ * @pm_lats: pointer to a omap_device_pm_latency array for this device
+ * @pm_lats_cnt: ARRAY_SIZE() of @pm_lats
+ * @is_early_device: should the device be registered as an early device or not
+ *
+ * Function for building an omap_device already registered from device-tree
+ *
+ * Returns 0 or PTR_ERR() on error.
+ */
+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 */
+
+/**
+ * omap_device_get_context_loss_count - get lost context count
+ * @od: struct omap_device *
+ *
+ * Using the primary hwmod, query the context loss count for this
+ * device.
+ *
+ * Callers should consider context for this device lost any time this
+ * function returns a value different than the value the caller got
+ * the last time it called this function.
+ *
+ * If any hwmods exist for the omap_device assoiated with @pdev,
+ * return the context loss counter for that hwmod, otherwise return
+ * zero.
+ */
+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;
+}
+
+/**
+ * omap_device_count_resources - count number of struct resource entries needed
+ * @od: struct omap_device *
+ *
+ * Count the number of struct resource entries needed for this
+ * omap_device @od.  Used by omap_device_build_ss() to determine how
+ * much memory to allocate before calling
+ * omap_device_fill_resources().  Returns the count.
+ */
+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;
+}
+
+/**
+ * omap_device_fill_resources - fill in array of struct resource
+ * @od: struct omap_device *
+ * @res: pointer to an array of struct resource to be filled in
+ *
+ * Populate one or more empty struct resource pointed to by @res with
+ * the resource data for this omap_device @od.  Used by
+ * omap_device_build_ss() after calling omap_device_count_resources().
+ * Ideally this function would not be needed at all.  If omap_device
+ * replaces platform_device, then we can specify our own
+ * get_resource()/ get_irq()/etc functions that use the underlying
+ * omap_hwmod information.  Or if platform_device is extended to use
+ * subarchitecture-specific function pointers, the various
+ * platform_device functions can simply call omap_device internal
+ * functions to get device resources.  Hacking around the existing
+ * platform_device code wastes memory.  Returns 0.
+ */
+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;
+}
+
+/**
+ * _od_fill_dma_resources - fill in array of struct resource with dma resources
+ * @od: struct omap_device *
+ * @res: pointer to an array of struct resource to be filled in
+ *
+ * Populate one or more empty struct resource pointed to by @res with
+ * the dma resource data for this omap_device @od.  Used by
+ * omap_device_alloc() after calling omap_device_count_resources().
+ *
+ * Ideally this function would not be needed at all.  If we have
+ * mechanism to get dma resources from DT.
+ *
+ * Returns 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;
+}
+
+/**
+ * omap_device_alloc - allocate an omap_device
+ * @pdev: platform_device that will be included in this omap_device
+ * @oh: ptr to the single omap_hwmod that backs this omap_device
+ * @pdata: platform_data ptr to associate with the platform_device
+ * @pdata_len: amount of memory pointed to by @pdata
+ * @pm_lats: pointer to a omap_device_pm_latency array for this device
+ * @pm_lats_cnt: ARRAY_SIZE() of @pm_lats
+ *
+ * Convenience function for allocating an omap_device structure and filling
+ * hwmods, resources and pm_latency attributes.
+ *
+ * Returns an struct omap_device pointer or ERR_PTR() on error;
+ */
+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);
+}
+
+/**
+ * omap_device_build - build and register an omap_device with one omap_hwmod
+ * @pdev_name: name of the platform_device driver to use
+ * @pdev_id: this platform_device's connection ID
+ * @oh: ptr to the single omap_hwmod that backs this omap_device
+ * @pdata: platform_data ptr to associate with the platform_device
+ * @pdata_len: amount of memory pointed to by @pdata
+ * @pm_lats: pointer to a omap_device_pm_latency array for this device
+ * @pm_lats_cnt: ARRAY_SIZE() of @pm_lats
+ * @is_early_device: should the device be registered as an early device or not
+ *
+ * Convenience function for building and registering a single
+ * omap_device record, which in turn builds and registers a
+ * platform_device record.  See omap_device_build_ss() for more
+ * information.  Returns ERR_PTR(-EINVAL) if @oh is NULL; otherwise,
+ * passes along the return value of omap_device_build_ss().
+ */
+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);
+}
+
+/**
+ * omap_device_build_ss - build and register an omap_device with multiple hwmods
+ * @pdev_name: name of the platform_device driver to use
+ * @pdev_id: this platform_device's connection ID
+ * @oh: ptr to the single omap_hwmod that backs this omap_device
+ * @pdata: platform_data ptr to associate with the platform_device
+ * @pdata_len: amount of memory pointed to by @pdata
+ * @pm_lats: pointer to a omap_device_pm_latency array for this device
+ * @pm_lats_cnt: ARRAY_SIZE() of @pm_lats
+ * @is_early_device: should the device be registered as an early device or not
+ *
+ * Convenience function for building and registering an omap_device
+ * subsystem record.  Subsystem records consist of multiple
+ * omap_hwmods.  This function in turn builds and registers a
+ * platform_device record.  Returns an ERR_PTR() on error, or passes
+ * along the return value of omap_device_register().
+ */
+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);
+}
+
+/**
+ * omap_early_device_register - register an omap_device as an early platform
+ * device.
+ * @od: struct omap_device * to register
+ *
+ * Register the omap_device structure.  This currently just calls
+ * platform_early_add_device() on the underlying platform_device.
+ * Returns 0 by default.
+ */
+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,
+        }
+};
+
+/**
+ * omap_device_register - register an omap_device with one omap_hwmod
+ * @od: struct omap_device * to register
+ *
+ * Register the omap_device structure.  This currently just calls
+ * platform_device_register() on the underlying platform_device.
+ * Returns the return value of platform_device_register().
+ */
+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 */
+
+/**
+ * omap_device_enable - fully activate an omap_device
+ * @od: struct omap_device * to activate
+ *
+ * Do whatever is necessary for the hwmods underlying omap_device @od
+ * to be accessible and ready to operate.  This generally involves
+ * enabling clocks, setting SYSCONFIG registers; and in the future may
+ * involve remuxing pins.  Device drivers should call this function
+ * (through platform_data function pointers) where they would normally
+ * enable clocks, etc.  Returns -EINVAL if called when the omap_device
+ * is already enabled, or passes along the return value of
+ * _omap_device_activate().
+ */
+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;
+}
+
+/**
+ * omap_device_idle - idle an omap_device
+ * @od: struct omap_device * to idle
+ *
+ * Idle omap_device @od by calling as many .deactivate_func() entries
+ * in the omap_device's pm_lats table as is possible without exceeding
+ * the device's maximum wakeup latency limit, pm_lat_limit.  Device
+ * drivers should call this function (through platform_data function
+ * pointers) where they would normally disable clocks after operations
+ * complete, etc..  Returns -EINVAL if the omap_device is not
+ * currently enabled, or passes along the return value of
+ * _omap_device_deactivate().
+ */
+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;
+}
+
+/**
+ * omap_device_shutdown - shut down an omap_device
+ * @od: struct omap_device * to shut down
+ *
+ * Shut down omap_device @od by calling all .deactivate_func() entries
+ * in the omap_device's pm_lats table and then shutting down all of
+ * the underlying omap_hwmods.  Used when a device is being "removed"
+ * or a device driver is being unloaded.  Returns -EINVAL if the
+ * omap_device is not currently enabled or idle, or passes along the
+ * return value of _omap_device_deactivate().
+ */
+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;
+}
+
+/**
+ * omap_device_assert_hardreset - set a device's hardreset line
+ * @pdev: struct platform_device * to reset
+ * @name: const char * name of the reset line
+ *
+ * Set the hardreset line identified by @name on the IP blocks
+ * associated with the hwmods backing the platform_device @pdev.  All
+ * of the hwmods associated with @pdev must have the same hardreset
+ * line linked to them for this to work.  Passes along the return value
+ * of omap_hwmod_assert_hardreset() in the event of any failure, or
+ * returns 0 upon success.
+ */
+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;
+}
+
+/**
+ * omap_device_deassert_hardreset - release a device's hardreset line
+ * @pdev: struct platform_device * to reset
+ * @name: const char * name of the reset line
+ *
+ * Release the hardreset line identified by @name on the IP blocks
+ * associated with the hwmods backing the platform_device @pdev.  All
+ * of the hwmods associated with @pdev must have the same hardreset
+ * line linked to them for this to work.  Passes along the return
+ * value of omap_hwmod_deassert_hardreset() in the event of any
+ * failure, or returns 0 upon success.
+ */
+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;
+}
+
+/**
+ * omap_device_align_pm_lat - activate/deactivate device to match wakeup lat lim
+ * @od: struct omap_device *
+ *
+ * When a device's maximum wakeup latency limit changes, call some of
+ * the .activate_func or .deactivate_func function pointers in the
+ * omap_device's pm_lats array to ensure that the device's maximum
+ * wakeup latency is less than or equal to the new latency limit.
+ * Intended to be called by OMAP PM code whenever a device's maximum
+ * wakeup latency limit changes (e.g., via
+ * omap_pm_set_dev_wakeup_lat()).  Returns 0 if nothing needs to be
+ * done (e.g., if the omap_device is not currently idle, or if the
+ * wakeup latency is already current with the new limit) or passes
+ * along the return value of _omap_device_deactivate() or
+ * _omap_device_activate().
+ */
+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;
+}
+
+/**
+ * omap_device_get_pwrdm - return the powerdomain * associated with @od
+ * @od: struct omap_device *
+ *
+ * Return the powerdomain associated with the first underlying
+ * omap_hwmod for this omap_device.  Intended for use by core OMAP PM
+ * code.  Returns NULL on error or a struct powerdomain * upon
+ * success.
+ */
+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]);
+}
+
+/**
+ * omap_device_get_mpu_rt_va - return the MPU's virtual addr for the hwmod base
+ * @od: struct omap_device *
+ *
+ * Return the MPU's virtual address for the base of the hwmod, from
+ * the ioremap() that the hwmod code does.  Only valid if there is one
+ * hwmod associated with this device.  Returns NULL if there are zero
+ * or more than one hwmods associated with this omap_device;
+ * otherwise, passes along the return value from
+ * omap_hwmod_get_mpu_rt_va().
+ */
+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]);
+}
+
+/**
+ * omap_device_get_by_hwmod_name() - convert a hwmod name to
+ * device pointer.
+ * @oh_name: name of the hwmod device
+ *
+ * Returns back a struct device * pointer associated with a hwmod
+ * device represented by a hwmod_name
+ */
+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
+ */
+
+/**
+ * omap_device_enable_hwmods - call omap_hwmod_enable() on all hwmods
+ * @od: struct omap_device *od
+ *
+ * Enable all underlying hwmods.  Returns 0.
+ */
+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;
+}
+
+/**
+ * omap_device_idle_hwmods - call omap_hwmod_idle() on all hwmods
+ * @od: struct omap_device *od
+ *
+ * Idle all underlying hwmods.  Returns 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;
+}
+
+/**
+ * omap_device_disable_clocks - disable all main and interface clocks
+ * @od: struct omap_device *od
+ *
+ * Disable the main functional clock and interface clock for all of the
+ * omap_hwmods associated with the omap_device.  Returns 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;
+}
+
+/**
+ * omap_device_enable_clocks - enable all main and interface clocks
+ * @od: struct omap_device *od
+ *
+ * Enable the main functional clock and interface clock for all of the
+ * omap_hwmods associated with the omap_device.  Returns 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);
+
+/**
+ * omap_device_late_idle - idle devices without drivers
+ * @dev: struct device * associated with omap_device
+ * @data: unused
+ *
+ * Check the driver bound status of this device, and idle it
+ * if there is no driver attached.
+ */
+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);