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 #include <linux/module.h>
  21
  22 int mfd_cell_enable(struct platform_device *pdev)
  23 {
  24         const struct mfd_cell *cell = mfd_get_cell(pdev);
  25         int err = 0;
  26
  27         /* only call enable hook if the cell wasn't previously enabled */
  28         if (atomic_inc_return(cell->usage_count) == 1)
  29                 err = cell->enable(pdev);
  30
  31         /* if the enable hook failed, decrement counter to allow retries */
  32         if (err)
  33                 atomic_dec(cell->usage_count);
  34
  35         return err;
  36 }
  37 EXPORT_SYMBOL(mfd_cell_enable);
  38
  39 int mfd_cell_disable(struct platform_device *pdev)
  40 {
  41         const struct mfd_cell *cell = mfd_get_cell(pdev);
  42         int err = 0;
  43
  44         /* only disable if no other clients are using it */
  45         if (atomic_dec_return(cell->usage_count) == 0)
  46                 err = cell->disable(pdev);
  47
  48         /* if the disable hook failed, increment to allow retries */
  49         if (err)
  50                 atomic_inc(cell->usage_count);
  51
  52         /* sanity check; did someone call disable too many times? */
  53         WARN_ON(atomic_read(cell->usage_count) < 0);
  54
  55         return err;
  56 }
  57 EXPORT_SYMBOL(mfd_cell_disable);
  58
  59 static int mfd_platform_add_cell(struct platform_device *pdev,
  60                                  const struct mfd_cell *cell)
  61 {
  62         if (!cell)
  63                 return 0;
  64
  65         pdev->mfd_cell = kmemdup(cell, sizeof(*cell), GFP_KERNEL);
  66         if (!pdev->mfd_cell)
  67                 return -ENOMEM;
  68
  69         return 0;
  70 }
  71
  72 static int mfd_add_device(struct device *parent, int id,
  73                           const struct mfd_cell *cell,
  74                           struct resource *mem_base,
  75                           int irq_base)
  76 {
  77         struct resource *res;
  78         struct platform_device *pdev;
  79         int ret = -ENOMEM;
  80         int r;
  81
  82         pdev = platform_device_alloc(cell->name, id + cell->id);
  83         if (!pdev)
  84                 goto fail_alloc;
  85
  86         res = kzalloc(sizeof(*res) * cell->num_resources, GFP_KERNEL);
  87         if (!res)
  88                 goto fail_device;
  89
  90         pdev->dev.parent = parent;
  91
  92         if (cell->pdata_size) {
  93                 ret = platform_device_add_data(pdev,
  94                                         cell->platform_data, cell->pdata_size);
  95                 if (ret)
  96                         goto fail_res;
  97         }
  98
  99         ret = mfd_platform_add_cell(pdev, cell);
 100         if (ret)
 101                 goto fail_res;
 102
 103         for (r = 0; r < cell->num_resources; r++) {
 104                 res[r].name = cell->resources[r].name;
 105                 res[r].flags = cell->resources[r].flags;
 106
 107                 /* Find out base to use */
 108                 if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) {
 109                         res[r].parent = mem_base;
 110                         res[r].start = mem_base->start +
 111                                 cell->resources[r].start;
 112                         res[r].end = mem_base->start +
 113                                 cell->resources[r].end;
 114                 } else if (cell->resources[r].flags & IORESOURCE_IRQ) {
 115                         res[r].start = irq_base +
 116                                 cell->resources[r].start;
 117                         res[r].end   = irq_base +
 118                                 cell->resources[r].end;
 119                 } else {
 120                         res[r].parent = cell->resources[r].parent;
 121                         res[r].start = cell->resources[r].start;
 122                         res[r].end   = cell->resources[r].end;
 123                 }
 124
 125                 if (!cell->ignore_resource_conflicts) {
 126                         ret = acpi_check_resource_conflict(res);
 127                         if (ret)
 128                                 goto fail_res;
 129                 }
 130         }
 131
 132         ret = platform_device_add_resources(pdev, res, cell->num_resources);
 133         if (ret)
 134                 goto fail_res;
 135
 136         ret = platform_device_add(pdev);
 137         if (ret)
 138                 goto fail_res;
 139
 140         if (cell->pm_runtime_no_callbacks)
 141                 pm_runtime_no_callbacks(&pdev->dev);
 142
 143         kfree(res);
 144
 145         return 0;
 146
 147 fail_res:
 148         kfree(res);
 149 fail_device:
 150         platform_device_put(pdev);
 151 fail_alloc:
 152         return ret;
 153 }
 154
 155 int mfd_add_devices(struct device *parent, int id,
 156                     struct mfd_cell *cells, int n_devs,
 157                     struct resource *mem_base,
 158                     int irq_base)
 159 {
 160         int i;
 161         int ret = 0;
 162         atomic_t *cnts;
 163
 164         /* initialize reference counting for all cells */
 165         cnts = kcalloc(sizeof(*cnts), n_devs, GFP_KERNEL);
 166         if (!cnts)
 167                 return -ENOMEM;
 168
 169         for (i = 0; i < n_devs; i++) {
 170                 atomic_set(&cnts[i], 0);
 171                 cells[i].usage_count = &cnts[i];
 172                 ret = mfd_add_device(parent, id, cells + i, mem_base, irq_base);
 173                 if (ret)
 174                         break;
 175         }
 176
 177         if (ret)
 178                 mfd_remove_devices(parent);
 179
 180         return ret;
 181 }
 182 EXPORT_SYMBOL(mfd_add_devices);
 183
 184 static int mfd_remove_devices_fn(struct device *dev, void *c)
 185 {
 186         struct platform_device *pdev = to_platform_device(dev);
 187         const struct mfd_cell *cell = mfd_get_cell(pdev);
 188         atomic_t **usage_count = c;
 189
 190         /* find the base address of usage_count pointers (for freeing) */
 191         if (!*usage_count || (cell->usage_count < *usage_count))
 192                 *usage_count = cell->usage_count;
 193
 194         platform_device_unregister(pdev);
 195         return 0;
 196 }
 197
 198 void mfd_remove_devices(struct device *parent)
 199 {
 200         atomic_t *cnts = NULL;
 201
 202         device_for_each_child(parent, &cnts, mfd_remove_devices_fn);
 203         kfree(cnts);
 204 }
 205 EXPORT_SYMBOL(mfd_remove_devices);
 206
 207 int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
 208 {
 209         struct mfd_cell cell_entry;
 210         struct device *dev;
 211         struct platform_device *pdev;
 212         int i;
 213
 214         /* fetch the parent cell's device (should already be registered!) */
 215         dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
 216         if (!dev) {
 217                 printk(KERN_ERR "failed to find device for cell %s\n", cell);
 218                 return -ENODEV;
 219         }
 220         pdev = to_platform_device(dev);
 221         memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));
 222
 223         WARN_ON(!cell_entry.enable);
 224
 225         for (i = 0; i < n_clones; i++) {
 226                 cell_entry.name = clones[i];
 227                 /* don't give up if a single call fails; just report error */
 228                 if (mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0))
 229                         dev_err(dev, "failed to create platform device '%s'\n",
 230                                         clones[i]);
 231         }
 232
 233         return 0;
 234 }
 235 EXPORT_SYMBOL(mfd_clone_cell);
 236
 237 MODULE_LICENSE("GPL");
 238 MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");