drivers/mfd/mfd-core.c

   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
  21 int 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 }
  36 EXPORT_SYMBOL(mfd_cell_enable);
  37
  38 int 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 }
  56 EXPORT_SYMBOL(mfd_cell_disable);
  57
  58 static 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
  71 static 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         if (cell->pdata_size) {
  92                 ret = platform_device_add_data(pdev,
  93                                         cell->platform_data, cell->pdata_size);
  94                 if (ret)
  95                         goto fail_res;
  96         }
  97
  98         ret = mfd_platform_add_cell(pdev, cell);
  99         if (ret)
 100                 goto fail_res;
 101
 102         for (r = 0; r < cell->num_resources; r++) {
 103                 res[r].name = cell->resources[r].name;
 104                 res[r].flags = cell->resources[r].flags;
 105
 106                 /* Find out base to use */
 107                 if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) {
 108                         res[r].parent = mem_base;
 109                         res[r].start = mem_base->start +
 110                                 cell->resources[r].start;
 111                         res[r].end = mem_base->start +
 112                                 cell->resources[r].end;
 113                 } else if (cell->resources[r].flags & IORESOURCE_IRQ) {
 114                         res[r].start = irq_base +
 115                                 cell->resources[r].start;
 116                         res[r].end   = irq_base +
 117                                 cell->resources[r].end;
 118                 } else {
 119                         res[r].parent = cell->resources[r].parent;
 120                         res[r].start = cell->resources[r].start;
 121                         res[r].end   = cell->resources[r].end;
 122                 }
 123
 124                 if (!cell->ignore_resource_conflicts) {
 125                         ret = acpi_check_resource_conflict(res);
 126                         if (ret)
 127                                 goto fail_res;
 128                 }
 129         }
 130
 131         ret = platform_device_add_resources(pdev, res, cell->num_resources);
 132         if (ret)
 133                 goto fail_res;
 134
 135         ret = platform_device_add(pdev);
 136         if (ret)
 137                 goto fail_res;
 138
 139         if (cell->pm_runtime_no_callbacks)
 140                 pm_runtime_no_callbacks(&pdev->dev);
 141
 142         kfree(res);
 143
 144         return 0;
 145
 146 fail_res:
 147         kfree(res);
 148 fail_device:
 149         platform_device_put(pdev);
 150 fail_alloc:
 151         return ret;
 152 }
 153
 154 int mfd_add_devices(struct device *parent, int id,
 155                     struct mfd_cell *cells, int n_devs,
 156                     struct resource *mem_base,
 157                     int irq_base)
 158 {
 159         int i;
 160         int ret = 0;
 161         atomic_t *cnts;
 162
 163         /* initialize reference counting for all cells */
 164         cnts = kcalloc(sizeof(*cnts), n_devs, GFP_KERNEL);
 165         if (!cnts)
 166                 return -ENOMEM;
 167
 168         for (i = 0; i < n_devs; i++) {
 169                 atomic_set(&cnts[i], 0);
 170                 cells[i].usage_count = &cnts[i];
 171                 ret = mfd_add_device(parent, id, cells + i, mem_base, irq_base);
 172                 if (ret)
 173                         break;
 174         }
 175
 176         if (ret)
 177                 mfd_remove_devices(parent);
 178
 179         return ret;
 180 }
 181 EXPORT_SYMBOL(mfd_add_devices);
 182
 183 static int mfd_remove_devices_fn(struct device *dev, void *c)
 184 {
 185         struct platform_device *pdev = to_platform_device(dev);
 186         const struct mfd_cell *cell = mfd_get_cell(pdev);
 187         atomic_t **usage_count = c;
 188
 189         /* find the base address of usage_count pointers (for freeing) */
 190         if (!*usage_count || (cell->usage_count < *usage_count))
 191                 *usage_count = cell->usage_count;
 192
 193         platform_device_unregister(pdev);
 194         return 0;
 195 }
 196
 197 void mfd_remove_devices(struct device *parent)
 198 {
 199         atomic_t *cnts = NULL;
 200
 201         device_for_each_child(parent, &cnts, mfd_remove_devices_fn);
 202         kfree(cnts);
 203 }
 204 EXPORT_SYMBOL(mfd_remove_devices);
 205
 206 int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
 207 {
 208         struct mfd_cell cell_entry;
 209         struct device *dev;
 210         struct platform_device *pdev;
 211         int i;
 212
 213         /* fetch the parent cell's device (should already be registered!) */
 214         dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
 215         if (!dev) {
 216                 printk(KERN_ERR "failed to find device for cell %s\n", cell);
 217                 return -ENODEV;
 218         }
 219         pdev = to_platform_device(dev);
 220         memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));
 221
 222         WARN_ON(!cell_entry.enable);
 223
 224         for (i = 0; i < n_clones; i++) {
 225                 cell_entry.name = clones[i];
 226                 /* don't give up if a single call fails; just report error */
 227                 if (mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0))
 228                         dev_err(dev, "failed to create platform device '%s'\n",
 229                                         clones[i]);
 230         }
 231
 232         return 0;
 233 }
 234 EXPORT_SYMBOL(mfd_clone_cell);
 235
 236 MODULE_LICENSE("GPL");
 237 MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");