mfd-core.c

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/*
 * drivers/mfd/mfd-core.c
 *
 * core MFD support
 * Copyright (c) 2006 Ian Molton
 * Copyright (c) 2007,2008 Dmitry Baryshkov
 *
 * 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.
 *
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <linux/mfd/core.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/irqdomain.h>
#include <linux/of.h>

int mfd_cell_enable(struct platform_device *pdev)
{
    const struct mfd_cell *cell = mfd_get_cell(pdev);
    int err = 0;

    /* only call enable hook if the cell wasn't previously enabled */
    if (atomic_inc_return(cell->usage_count) == 1)
        err = cell->enable(pdev);

    /* if the enable hook failed, decrement counter to allow retries */
    if (err)
        atomic_dec(cell->usage_count);

    return err;
}
EXPORT_SYMBOL(mfd_cell_enable);

int mfd_cell_disable(struct platform_device *pdev)
{
    const struct mfd_cell *cell = mfd_get_cell(pdev);
    int err = 0;

    /* only disable if no other clients are using it */
    if (atomic_dec_return(cell->usage_count) == 0)
        err = cell->disable(pdev);

    /* if the disable hook failed, increment to allow retries */
    if (err)
        atomic_inc(cell->usage_count);

    /* sanity check; did someone call disable too many times? */
    WARN_ON(atomic_read(cell->usage_count) < 0);

    return err;
}
EXPORT_SYMBOL(mfd_cell_disable);

static int mfd_platform_add_cell(struct platform_device *pdev,
                 const struct mfd_cell *cell)
{
    if (!cell)
        return 0;

    pdev->mfd_cell = kmemdup(cell, sizeof(*cell), GFP_KERNEL);
    if (!pdev->mfd_cell)
        return -ENOMEM;

    return 0;
}

static int mfd_add_device(struct device *parent, int id,
              const struct mfd_cell *cell,
              struct resource *mem_base,
              int irq_base, struct irq_domain *domain)
{
    struct resource *res;
    struct platform_device *pdev;
    struct device_node *np = NULL;
    int ret = -ENOMEM;
    int r;

    pdev = platform_device_alloc(cell->name, id + cell->id);
    if (!pdev)
        goto fail_alloc;

    res = kzalloc(sizeof(*res) * cell->num_resources, GFP_KERNEL);
    if (!res)
        goto fail_device;

    pdev->dev.parent = parent;

    if (parent->of_node && cell->of_compatible) {
        for_each_child_of_node(parent->of_node, np) {
            if (of_device_is_compatible(np, cell->of_compatible)) {
                pdev->dev.of_node = np;
                break;
            }
        }
    }

    if (cell->pdata_size) {
        ret = platform_device_add_data(pdev,
                    cell->platform_data, cell->pdata_size);
        if (ret)
            goto fail_res;
    }

    ret = mfd_platform_add_cell(pdev, cell);
    if (ret)
        goto fail_res;

    for (r = 0; r < cell->num_resources; r++) {
        res[r].name = cell->resources[r].name;
        res[r].flags = cell->resources[r].flags;

        /* Find out base to use */
        if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) {
            res[r].parent = mem_base;
            res[r].start = mem_base->start +
                cell->resources[r].start;
            res[r].end = mem_base->start +
                cell->resources[r].end;
        } else if (cell->resources[r].flags & IORESOURCE_IRQ) {
            if (domain) {
                /* Unable to create mappings for IRQ ranges. */
                WARN_ON(cell->resources[r].start !=
                    cell->resources[r].end);
                res[r].start = res[r].end = irq_create_mapping(
                    domain, cell->resources[r].start);
            } else {
                res[r].start = irq_base +
                    cell->resources[r].start;
                res[r].end   = irq_base +
                    cell->resources[r].end;
            }
        } else {
            res[r].parent = cell->resources[r].parent;
            res[r].start = cell->resources[r].start;
            res[r].end   = cell->resources[r].end;
        }

        if (!cell->ignore_resource_conflicts) {
            ret = acpi_check_resource_conflict(&res[r]);
            if (ret)
                goto fail_res;
        }
    }

    ret = platform_device_add_resources(pdev, res, cell->num_resources);
    if (ret)
        goto fail_res;

    ret = platform_device_add(pdev);
    if (ret)
        goto fail_res;

    if (cell->pm_runtime_no_callbacks)
        pm_runtime_no_callbacks(&pdev->dev);

    kfree(res);

    return 0;

fail_res:
    kfree(res);
fail_device:
    platform_device_put(pdev);
fail_alloc:
    return ret;
}

int mfd_add_devices(struct device *parent, int id,
            struct mfd_cell *cells, int n_devs,
            struct resource *mem_base,
            int irq_base, struct irq_domain *domain)
{
    int i;
    int ret = 0;
    atomic_t *cnts;

    /* initialize reference counting for all cells */
    cnts = kcalloc(n_devs, sizeof(*cnts), GFP_KERNEL);
    if (!cnts)
        return -ENOMEM;

    for (i = 0; i < n_devs; i++) {
        atomic_set(&cnts[i], 0);
        cells[i].usage_count = &cnts[i];
        ret = mfd_add_device(parent, id, cells + i, mem_base,
                     irq_base, domain);
        if (ret)
            break;
    }

    if (ret)
        mfd_remove_devices(parent);

    return ret;
}
EXPORT_SYMBOL(mfd_add_devices);

static int mfd_remove_devices_fn(struct device *dev, void *c)
{
    struct platform_device *pdev = to_platform_device(dev);
    const struct mfd_cell *cell = mfd_get_cell(pdev);
    atomic_t **usage_count = c;

    /* find the base address of usage_count pointers (for freeing) */
    if (!*usage_count || (cell->usage_count < *usage_count))
        *usage_count = cell->usage_count;

    platform_device_unregister(pdev);
    return 0;
}

void mfd_remove_devices(struct device *parent)
{
    atomic_t *cnts = NULL;

    device_for_each_child(parent, &cnts, mfd_remove_devices_fn);
    kfree(cnts);
}
EXPORT_SYMBOL(mfd_remove_devices);

int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
{
    struct mfd_cell cell_entry;
    struct device *dev;
    struct platform_device *pdev;
    int i;

    /* fetch the parent cell's device (should already be registered!) */
    dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
    if (!dev) {
        printk(KERN_ERR "failed to find device for cell %s\n", cell);
        return -ENODEV;
    }
    pdev = to_platform_device(dev);
    memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));

    WARN_ON(!cell_entry.enable);

    for (i = 0; i < n_clones; i++) {
        cell_entry.name = clones[i];
        /* don't give up if a single call fails; just report error */
        if (mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0,
                   NULL))
            dev_err(dev, "failed to create platform device '%s'\n",
                    clones[i]);
    }

    return 0;
}
EXPORT_SYMBOL(mfd_clone_cell);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");