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/reset/sunxi.h>
  22 #include <linux/slab.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/types.h>
  25
  26 #include "reset-simple.h"
  27
  28 static int sunxi_reset_init(struct device_node *np)
  29 {
  30         struct reset_simple_data *data;
  31         struct resource res;
  32         resource_size_t size;
  33         int ret;
  34
  35         data = kzalloc(sizeof(*data), GFP_KERNEL);
  36         if (!data)
  37                 return -ENOMEM;
  38
  39         ret = of_address_to_resource(np, 0, &res);
  40         if (ret)
  41                 goto err_alloc;
  42
  43         size = resource_size(&res);
  44         if (!request_mem_region(res.start, size, np->name)) {
  45                 ret = -EBUSY;
  46                 goto err_alloc;
  47         }
  48
  49         data->membase = ioremap(res.start, size);
  50         if (!data->membase) {
  51                 ret = -ENOMEM;
  52                 goto err_alloc;
  53         }
  54
  55         spin_lock_init(&data->lock);
  56
  57         data->rcdev.owner = THIS_MODULE;
  58         data->rcdev.nr_resets = size * 8;
  59         data->rcdev.ops = &reset_simple_ops;
  60         data->rcdev.of_node = np;
  61         data->active_low = true;
  62
  63         return reset_controller_register(&data->rcdev);
  64
  65 err_alloc:
  66         kfree(data);
  67         return ret;
  68 };
  69
  70 /*
  71  * These are the reset controller we need to initialize early on in
  72  * our system, before we can even think of using a regular device
  73  * driver for it.
  74  * The controllers that we can register through the regular device
  75  * model are handled by the simple reset driver directly.
  76  */
  77 static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = {
  78         { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
  79         { /* sentinel */ },
  80 };
  81
  82 void __init sun6i_reset_init(void)
  83 {
  84         struct device_node *np;
  85
  86         for_each_matching_node(np, sunxi_early_reset_dt_ids)
  87                 sunxi_reset_init(np);
  88 }