drivers/power/reset/rmobile-reset.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Renesas R-Mobile Reset Driver
   4  *
   5  * Copyright (C) 2014 Glider bvba
   6  */
   7
   8 #include <linux/io.h>
   9 #include <linux/module.h>
  10 #include <linux/notifier.h>
  11 #include <linux/of_address.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/printk.h>
  14 #include <linux/reboot.h>
  15
  16 /* SYSC Register Bank 2 */
  17 #define RESCNT2         0x20            /* Reset Control Register 2 */
  18
  19 /* Reset Control Register 2 */
  20 #define RESCNT2_PRES    0x80000000      /* Soft power-on reset */
  21
  22 static int rmobile_reset_handler(struct sys_off_data *data)
  23 {
  24         void __iomem *sysc_base2 = (void __iomem *)data->cb_data;
  25
  26         /* Let's assume we have acquired the HPB semaphore */
  27         writel(RESCNT2_PRES, sysc_base2 + RESCNT2);
  28
  29         return NOTIFY_DONE;
  30 }
  31
  32 static int rmobile_reset_probe(struct platform_device *pdev)
  33 {
  34         void __iomem *sysc_base2;
  35         int error;
  36
  37         sysc_base2 = devm_platform_ioremap_resource(pdev, 1);
  38         if (IS_ERR(sysc_base2))
  39                 return PTR_ERR(sysc_base2);
  40
  41         error = devm_register_sys_off_handler(&pdev->dev,
  42                                               SYS_OFF_MODE_RESTART,
  43                                               SYS_OFF_PRIO_HIGH,
  44                                               rmobile_reset_handler,
  45                                               (__force void *)sysc_base2);
  46         if (error) {
  47                 dev_err(&pdev->dev,
  48                         "cannot register restart handler (err=%d)\n", error);
  49                 return error;
  50         }
  51
  52         return 0;
  53 }
  54
  55 static const struct of_device_id rmobile_reset_of_match[] = {
  56         { .compatible = "renesas,sysc-rmobile", },
  57         { /* sentinel */ }
  58 };
  59 MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);
  60
  61 static struct platform_driver rmobile_reset_driver = {
  62         .probe = rmobile_reset_probe,
  63         .driver = {
  64                 .name = "rmobile_reset",
  65                 .of_match_table = rmobile_reset_of_match,
  66         },
  67 };
  68
  69 module_platform_driver(rmobile_reset_driver);
  70
  71 MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
  72 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
  73 MODULE_LICENSE("GPL v2");