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         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
 139 fail_res:
 140         kfree(res);
 141 fail_device:
 142         platform_device_put(pdev);
 143 fail_alloc:
 144         return ret;
 145 }
 146
 147 int 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 }
 174 EXPORT_SYMBOL(mfd_add_devices);
 175
 176 static 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
 190 void 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 }
 197 EXPORT_SYMBOL(mfd_remove_devices);
 198
 199 int 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 }
 227 EXPORT_SYMBOL(mfd_clone_cell);
 228
 229 MODULE_LICENSE("GPL");
 230 MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");