drivers/reset/reset-sunxi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Allwinner SoCs Reset Controller driver
   4  *
   5  * Copyright 2013 Maxime Ripard
   6  *
   7  * Maxime Ripard <maxime.ripard@free-electrons.com>
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/io.h>
  12 #include <linux/init.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/reset-controller.h>
  17 #include <linux/reset/sunxi.h>
  18 #include <linux/slab.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/types.h>
  21
  22 #include "reset-simple.h"
  23
  24 static int sunxi_reset_init(struct device_node *np)
  25 {
  26         struct reset_simple_data *data;
  27         struct resource res;
  28         resource_size_t size;
  29         int ret;
  30
  31         data = kzalloc(sizeof(*data), GFP_KERNEL);
  32         if (!data)
  33                 return -ENOMEM;
  34
  35         ret = of_address_to_resource(np, 0, &res);
  36         if (ret)
  37                 goto err_alloc;
  38
  39         size = resource_size(&res);
  40         if (!request_mem_region(res.start, size, np->name)) {
  41                 ret = -EBUSY;
  42                 goto err_alloc;
  43         }
  44
  45         data->membase = ioremap(res.start, size);
  46         if (!data->membase) {
  47                 ret = -ENOMEM;
  48                 goto err_alloc;
  49         }
  50
  51         spin_lock_init(&data->lock);
  52
  53         data->rcdev.owner = THIS_MODULE;
  54         data->rcdev.nr_resets = size * 8;
  55         data->rcdev.ops = &reset_simple_ops;
  56         data->rcdev.of_node = np;
  57         data->active_low = true;
  58
  59         return reset_controller_register(&data->rcdev);
  60
  61 err_alloc:
  62         kfree(data);
  63         return ret;
  64 };
  65
  66 /*
  67  * These are the reset controller we need to initialize early on in
  68  * our system, before we can even think of using a regular device
  69  * driver for it.
  70  * The controllers that we can register through the regular device
  71  * model are handled by the simple reset driver directly.
  72  */
  73 static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = {
  74         { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
  75         { /* sentinel */ },
  76 };
  77
  78 void __init sun6i_reset_init(void)
  79 {
  80         struct device_node *np;
  81
  82         for_each_matching_node(np, sunxi_early_reset_dt_ids)
  83                 sunxi_reset_init(np);
  84 }