drivers/reset/reset-sunxi.c

   1 /*
   2  * Allwinner SoCs Reset Controller driver
   3  *
   4  * Copyright 2013 Maxime Ripard
   5  *
   6  * Maxime Ripard <maxime.ripard@free-electrons.com>
   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 as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include <linux/err.h>
  15 #include <linux/io.h>
  16 #include <linux/init.h>
  17 #include <linux/of.h>
  18 #include <linux/of_address.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/reset-controller.h>
  21 #include <linux/slab.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/types.h>
  24
  25 #include "reset-simple.h"
  26
  27 static int sunxi_reset_init(struct device_node *np)
  28 {
  29         struct reset_simple_data *data;
  30         struct resource res;
  31         resource_size_t size;
  32         int ret;
  33
  34         data = kzalloc(sizeof(*data), GFP_KERNEL);
  35         if (!data)
  36                 return -ENOMEM;
  37
  38         ret = of_address_to_resource(np, 0, &res);
  39         if (ret)
  40                 goto err_alloc;
  41
  42         size = resource_size(&res);
  43         if (!request_mem_region(res.start, size, np->name)) {
  44                 ret = -EBUSY;
  45                 goto err_alloc;
  46         }
  47
  48         data->membase = ioremap(res.start, size);
  49         if (!data->membase) {
  50                 ret = -ENOMEM;
  51                 goto err_alloc;
  52         }
  53
  54         spin_lock_init(&data->lock);
  55
  56         data->rcdev.owner = THIS_MODULE;
  57         data->rcdev.nr_resets = size * 8;
  58         data->rcdev.ops = &reset_simple_ops;
  59         data->rcdev.of_node = np;
  60         data->active_low = true;
  61
  62         return reset_controller_register(&data->rcdev);
  63
  64 err_alloc:
  65         kfree(data);
  66         return ret;
  67 };
  68
  69 /*
  70  * These are the reset controller we need to initialize early on in
  71  * our system, before we can even think of using a regular device
  72  * driver for it.
  73  * The controllers that we can register through the regular device
  74  * model are handled by the simple reset driver directly.
  75  */
  76 static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = {
  77         { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
  78         { /* sentinel */ },
  79 };
  80
  81 void __init sun6i_reset_init(void)
  82 {
  83         struct device_node *np;
  84
  85         for_each_matching_node(np, sunxi_early_reset_dt_ids)
  86                 sunxi_reset_init(np);
  87 }