drivers/power/reset/rmobile-reset.c

   1 /*
   2  * Renesas R-Mobile Reset Driver
   3  *
   4  * Copyright (C) 2014 Glider bvba
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/notifier.h>
  14 #include <linux/of_address.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/printk.h>
  17 #include <linux/reboot.h>
  18
  19 /* SYSC Register Bank 2 */
  20 #define RESCNT2         0x20            /* Reset Control Register 2 */
  21
  22 /* Reset Control Register 2 */
  23 #define RESCNT2_PRES    0x80000000      /* Soft power-on reset */
  24
  25 static void __iomem *sysc_base2;
  26
  27 static int rmobile_reset_handler(struct notifier_block *this,
  28                                  unsigned long mode, void *cmd)
  29 {
  30         pr_debug("%s %lu\n", __func__, mode);
  31
  32         /* Let's assume we have acquired the HPB semaphore */
  33         writel(RESCNT2_PRES, sysc_base2 + RESCNT2);
  34
  35         return NOTIFY_DONE;
  36 }
  37
  38 static struct notifier_block rmobile_reset_nb = {
  39         .notifier_call = rmobile_reset_handler,
  40         .priority = 192,
  41 };
  42
  43 static int rmobile_reset_probe(struct platform_device *pdev)
  44 {
  45         int error;
  46
  47         sysc_base2 = of_iomap(pdev->dev.of_node, 1);
  48         if (!sysc_base2)
  49                 return -ENODEV;
  50
  51         error = register_restart_handler(&rmobile_reset_nb);
  52         if (error) {
  53                 dev_err(&pdev->dev,
  54                         "cannot register restart handler (err=%d)\n", error);
  55                 goto fail_unmap;
  56         }
  57
  58         return 0;
  59
  60 fail_unmap:
  61         iounmap(sysc_base2);
  62         return error;
  63 }
  64
  65 static int rmobile_reset_remove(struct platform_device *pdev)
  66 {
  67         unregister_restart_handler(&rmobile_reset_nb);
  68         iounmap(sysc_base2);
  69         return 0;
  70 }
  71
  72 static const struct of_device_id rmobile_reset_of_match[] = {
  73         { .compatible = "renesas,sysc-rmobile", },
  74         { /* sentinel */ }
  75 };
  76 MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);
  77
  78 static struct platform_driver rmobile_reset_driver = {
  79         .probe = rmobile_reset_probe,
  80         .remove = rmobile_reset_remove,
  81         .driver = {
  82                 .name = "rmobile_reset",
  83                 .of_match_table = rmobile_reset_of_match,
  84         },
  85 };
  86
  87 module_platform_driver(rmobile_reset_driver);
  88
  89 MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
  90 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
  91 MODULE_LICENSE("GPL v2");