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_add_device(struct device *parent, int id,
  59                           const struct mfd_cell *cell,
  60                           struct resource *mem_base,
  61                           int irq_base)
  62 {
  63         struct resource *res;
  64         struct platform_device *pdev;
  65         int ret = -ENOMEM;
  66         int r;
  67
  68         pdev = platform_device_alloc(cell->name, id + cell->id);
  69         if (!pdev)
  70                 goto fail_alloc;
  71
  72         res = kzalloc(sizeof(*res) * cell->num_resources, GFP_KERNEL);
  73         if (!res)
  74                 goto fail_device;
  75
  76         pdev->dev.parent = parent;
  77
  78         ret = platform_device_add_data(pdev, cell, sizeof(*cell));
  79         if (ret)
  80                 goto fail_res;
  81
  82         for (r = 0; r < cell->num_resources; r++) {
  83                 res[r].name = cell->resources[r].name;
  84                 res[r].flags = cell->resources[r].flags;
  85
  86                 /* Find out base to use */
  87                 if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) {
  88                         res[r].parent = mem_base;
  89                         res[r].start = mem_base->start +
  90                                 cell->resources[r].start;
  91                         res[r].end = mem_base->start +
  92                                 cell->resources[r].end;
  93                 } else if (cell->resources[r].flags & IORESOURCE_IRQ) {
  94                         res[r].start = irq_base +
  95                                 cell->resources[r].start;
  96                         res[r].end   = irq_base +
  97                                 cell->resources[r].end;
  98                 } else {
  99                         res[r].parent = cell->resources[r].parent;
 100                         res[r].start = cell->resources[r].start;
 101                         res[r].end   = cell->resources[r].end;
 102                 }
 103
 104                 if (!cell->ignore_resource_conflicts) {
 105                         ret = acpi_check_resource_conflict(res);
 106                         if (ret)
 107                                 goto fail_res;
 108                 }
 109         }
 110
 111         ret = platform_device_add_resources(pdev, res, cell->num_resources);
 112         if (ret)
 113                 goto fail_res;
 114
 115         ret = platform_device_add(pdev);
 116         if (ret)
 117                 goto fail_res;
 118
 119         if (cell->pm_runtime_no_callbacks)
 120                 pm_runtime_no_callbacks(&pdev->dev);
 121
 122         kfree(res);
 123
 124         return 0;
 125
 126 /*      platform_device_del(pdev); */
 127 fail_res:
 128         kfree(res);
 129 fail_device:
 130         platform_device_put(pdev);
 131 fail_alloc:
 132         return ret;
 133 }
 134
 135 int mfd_add_devices(struct device *parent, int id,
 136                     struct mfd_cell *cells, int n_devs,
 137                     struct resource *mem_base,
 138                     int irq_base)
 139 {
 140         int i;
 141         int ret = 0;
 142         atomic_t *cnts;
 143
 144         /* initialize reference counting for all cells */
 145         cnts = kcalloc(sizeof(*cnts), n_devs, GFP_KERNEL);
 146         if (!cnts)
 147                 return -ENOMEM;
 148
 149         for (i = 0; i < n_devs; i++) {
 150                 atomic_set(&cnts[i], 0);
 151                 cells[i].usage_count = &cnts[i];
 152                 ret = mfd_add_device(parent, id, cells + i, mem_base, irq_base);
 153                 if (ret)
 154                         break;
 155         }
 156
 157         if (ret)
 158                 mfd_remove_devices(parent);
 159
 160         return ret;
 161 }
 162 EXPORT_SYMBOL(mfd_add_devices);
 163
 164 static int mfd_remove_devices_fn(struct device *dev, void *c)
 165 {
 166         struct platform_device *pdev = to_platform_device(dev);
 167         const struct mfd_cell *cell = mfd_get_cell(pdev);
 168         atomic_t **usage_count = c;
 169
 170         /* find the base address of usage_count pointers (for freeing) */
 171         if (!*usage_count || (cell->usage_count < *usage_count))
 172                 *usage_count = cell->usage_count;
 173
 174         platform_device_unregister(pdev);
 175         return 0;
 176 }
 177
 178 void mfd_remove_devices(struct device *parent)
 179 {
 180         atomic_t *cnts = NULL;
 181
 182         device_for_each_child(parent, &cnts, mfd_remove_devices_fn);
 183         kfree(cnts);
 184 }
 185 EXPORT_SYMBOL(mfd_remove_devices);
 186
 187 int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
 188 {
 189         struct mfd_cell cell_entry;
 190         struct device *dev;
 191         struct platform_device *pdev;
 192         int i;
 193
 194         /* fetch the parent cell's device (should already be registered!) */
 195         dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
 196         if (!dev) {
 197                 printk(KERN_ERR "failed to find device for cell %s\n", cell);
 198                 return -ENODEV;
 199         }
 200         pdev = to_platform_device(dev);
 201         memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));
 202
 203         WARN_ON(!cell_entry.enable);
 204
 205         for (i = 0; i < n_clones; i++) {
 206                 cell_entry.name = clones[i];
 207                 /* don't give up if a single call fails; just report error */
 208                 if (mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0))
 209                         dev_err(dev, "failed to create platform device '%s'\n",
 210                                         clones[i]);
 211         }
 212
 213         return 0;
 214 }
 215 EXPORT_SYMBOL(mfd_clone_cell);
 216
 217 MODULE_LICENSE("GPL");
 218 MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");