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