linux/drivers/mfd/mfd-core.c
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   1/*
   2 * drivers/mfd/mfd-core.c
   3 *
   4 * core MFD support
   5 * Copyright (c) 2006 Ian Molton
   6 * Copyright (c) 2007,2008 Dmitry Baryshkov
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 *
  12 */
  13
  14#include <linux/kernel.h>
  15#include <linux/platform_device.h>
  16#include <linux/acpi.h>
  17#include <linux/mfd/core.h>
  18#include <linux/pm_runtime.h>
  19#include <linux/slab.h>
  20
  21int mfd_cell_enable(struct platform_device *pdev)
  22{
  23        const struct mfd_cell *cell = mfd_get_cell(pdev);
  24        int err = 0;
  25
  26        /* only call enable hook if the cell wasn't previously enabled */
  27        if (atomic_inc_return(cell->usage_count) == 1)
  28                err = cell->enable(pdev);
  29
  30        /* if the enable hook failed, decrement counter to allow retries */
  31        if (err)
  32                atomic_dec(cell->usage_count);
  33
  34        return err;
  35}
  36EXPORT_SYMBOL(mfd_cell_enable);
  37
  38int mfd_cell_disable(struct platform_device *pdev)
  39{
  40        const struct mfd_cell *cell = mfd_get_cell(pdev);
  41        int err = 0;
  42
  43        /* only disable if no other clients are using it */
  44        if (atomic_dec_return(cell->usage_count) == 0)
  45                err = cell->disable(pdev);
  46
  47        /* if the disable hook failed, increment to allow retries */
  48        if (err)
  49                atomic_inc(cell->usage_count);
  50
  51        /* sanity check; did someone call disable too many times? */
  52        WARN_ON(atomic_read(cell->usage_count) < 0);
  53
  54        return err;
  55}
  56EXPORT_SYMBOL(mfd_cell_disable);
  57
  58static int mfd_platform_add_cell(struct platform_device *pdev,
  59                                 const struct mfd_cell *cell)
  60{
  61        if (!cell)
  62                return 0;
  63
  64        pdev->mfd_cell = kmemdup(cell, sizeof(*cell), GFP_KERNEL);
  65        if (!pdev->mfd_cell)
  66                return -ENOMEM;
  67
  68        return 0;
  69}
  70
  71static int mfd_add_device(struct device *parent, int id,
  72                          const struct mfd_cell *cell,
  73                          struct resource *mem_base,
  74                          int irq_base)
  75{
  76        struct resource *res;
  77        struct platform_device *pdev;
  78        int ret = -ENOMEM;
  79        int r;
  80
  81        pdev = platform_device_alloc(cell->name, id + cell->id);
  82        if (!pdev)
  83                goto fail_alloc;
  84
  85        res = kzalloc(sizeof(*res) * cell->num_resources, GFP_KERNEL);
  86        if (!res)
  87                goto fail_device;
  88
  89        pdev->dev.parent = parent;
  90
  91        ret = mfd_platform_add_cell(pdev, cell);
  92        if (ret)
  93                goto fail_res;
  94
  95        for (r = 0; r < cell->num_resources; r++) {
  96                res[r].name = cell->resources[r].name;
  97                res[r].flags = cell->resources[r].flags;
  98
  99                /* Find out base to use */
 100                if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) {
 101                        res[r].parent = mem_base;
 102                        res[r].start = mem_base->start +
 103                                cell->resources[r].start;
 104                        res[r].end = mem_base->start +
 105                                cell->resources[r].end;
 106                } else if (cell->resources[r].flags & IORESOURCE_IRQ) {
 107                        res[r].start = irq_base +
 108                                cell->resources[r].start;
 109                        res[r].end   = irq_base +
 110                                cell->resources[r].end;
 111                } else {
 112                        res[r].parent = cell->resources[r].parent;
 113                        res[r].start = cell->resources[r].start;
 114                        res[r].end   = cell->resources[r].end;
 115                }
 116
 117                if (!cell->ignore_resource_conflicts) {
 118                        ret = acpi_check_resource_conflict(res);
 119                        if (ret)
 120                                goto fail_res;
 121                }
 122        }
 123
 124        ret = platform_device_add_resources(pdev, res, cell->num_resources);
 125        if (ret)
 126                goto fail_res;
 127
 128        ret = platform_device_add(pdev);
 129        if (ret)
 130                goto fail_res;
 131
 132        if (cell->pm_runtime_no_callbacks)
 133                pm_runtime_no_callbacks(&pdev->dev);
 134
 135        kfree(res);
 136
 137        return 0;
 138
 139fail_res:
 140        kfree(res);
 141fail_device:
 142        platform_device_put(pdev);
 143fail_alloc:
 144        return ret;
 145}
 146
 147int mfd_add_devices(struct device *parent, int id,
 148                    struct mfd_cell *cells, int n_devs,
 149                    struct resource *mem_base,
 150                    int irq_base)
 151{
 152        int i;
 153        int ret = 0;
 154        atomic_t *cnts;
 155
 156        /* initialize reference counting for all cells */
 157        cnts = kcalloc(sizeof(*cnts), n_devs, GFP_KERNEL);
 158        if (!cnts)
 159                return -ENOMEM;
 160
 161        for (i = 0; i < n_devs; i++) {
 162                atomic_set(&cnts[i], 0);
 163                cells[i].usage_count = &cnts[i];
 164                ret = mfd_add_device(parent, id, cells + i, mem_base, irq_base);
 165                if (ret)
 166                        break;
 167        }
 168
 169        if (ret)
 170                mfd_remove_devices(parent);
 171
 172        return ret;
 173}
 174EXPORT_SYMBOL(mfd_add_devices);
 175
 176static int mfd_remove_devices_fn(struct device *dev, void *c)
 177{
 178        struct platform_device *pdev = to_platform_device(dev);
 179        const struct mfd_cell *cell = mfd_get_cell(pdev);
 180        atomic_t **usage_count = c;
 181
 182        /* find the base address of usage_count pointers (for freeing) */
 183        if (!*usage_count || (cell->usage_count < *usage_count))
 184                *usage_count = cell->usage_count;
 185
 186        platform_device_unregister(pdev);
 187        return 0;
 188}
 189
 190void mfd_remove_devices(struct device *parent)
 191{
 192        atomic_t *cnts = NULL;
 193
 194        device_for_each_child(parent, &cnts, mfd_remove_devices_fn);
 195        kfree(cnts);
 196}
 197EXPORT_SYMBOL(mfd_remove_devices);
 198
 199int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
 200{
 201        struct mfd_cell cell_entry;
 202        struct device *dev;
 203        struct platform_device *pdev;
 204        int i;
 205
 206        /* fetch the parent cell's device (should already be registered!) */
 207        dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
 208        if (!dev) {
 209                printk(KERN_ERR "failed to find device for cell %s\n", cell);
 210                return -ENODEV;
 211        }
 212        pdev = to_platform_device(dev);
 213        memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));
 214
 215        WARN_ON(!cell_entry.enable);
 216
 217        for (i = 0; i < n_clones; i++) {
 218                cell_entry.name = clones[i];
 219                /* don't give up if a single call fails; just report error */
 220                if (mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0))
 221                        dev_err(dev, "failed to create platform device '%s'\n",
 222                                        clones[i]);
 223        }
 224
 225        return 0;
 226}
 227EXPORT_SYMBOL(mfd_clone_cell);
 228
 229MODULE_LICENSE("GPL");
 230MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");
 231