power/reset/rmobile-reset.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Renesas R-Mobile Reset Driver
0004  *
0005  * Copyright (C) 2014 Glider bvba
0006  */
0007
0008 #include <linux/io.h>
0009 #include <linux/module.h>
0010 #include <linux/notifier.h>
0011 #include <linux/of_address.h>
0012 #include <linux/platform_device.h>
0013 #include <linux/printk.h>
0014 #include <linux/reboot.h>
0015
0016 /* SYSC Register Bank 2 */
0017 #define RESCNT2     0x20        /* Reset Control Register 2 */
0018
0019 /* Reset Control Register 2 */
0020 #define RESCNT2_PRES    0x80000000  /* Soft power-on reset */
0021
0022 static void __iomem *sysc_base2;
0023
0024 static int rmobile_reset_handler(struct notifier_block *this,
0025                  unsigned long mode, void *cmd)
0026 {
0027     pr_debug("%s %lu\n", __func__, mode);
0028
0029     /* Let's assume we have acquired the HPB semaphore */
0030     writel(RESCNT2_PRES, sysc_base2 + RESCNT2);
0031
0032     return NOTIFY_DONE;
0033 }
0034
0035 static struct notifier_block rmobile_reset_nb = {
0036     .notifier_call = rmobile_reset_handler,
0037     .priority = 192,
0038 };
0039
0040 static int rmobile_reset_probe(struct platform_device *pdev)
0041 {
0042     int error;
0043
0044     sysc_base2 = of_iomap(pdev->dev.of_node, 1);
0045     if (!sysc_base2)
0046         return -ENODEV;
0047
0048     error = register_restart_handler(&rmobile_reset_nb);
0049     if (error) {
0050         dev_err(&pdev->dev,
0051             "cannot register restart handler (err=%d)\n", error);
0052         goto fail_unmap;
0053     }
0054
0055     return 0;
0056
0057 fail_unmap:
0058     iounmap(sysc_base2);
0059     return error;
0060 }
0061
0062 static int rmobile_reset_remove(struct platform_device *pdev)
0063 {
0064     unregister_restart_handler(&rmobile_reset_nb);
0065     iounmap(sysc_base2);
0066     return 0;
0067 }
0068
0069 static const struct of_device_id rmobile_reset_of_match[] = {
0070     { .compatible = "renesas,sysc-rmobile", },
0071     { /* sentinel */ }
0072 };
0073 MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);
0074
0075 static struct platform_driver rmobile_reset_driver = {
0076     .probe = rmobile_reset_probe,
0077     .remove = rmobile_reset_remove,
0078     .driver = {
0079         .name = "rmobile_reset",
0080         .of_match_table = rmobile_reset_of_match,
0081     },
0082 };
0083
0084 module_platform_driver(rmobile_reset_driver);
0085
0086 MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
0087 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
0088 MODULE_LICENSE("GPL v2");