drivers/power/reset/st-poweroff.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2014 STMicroelectronics
   4  *
   5  * Power off Restart driver, used in STMicroelectronics devices.
   6  *
   7  * Author: Christophe Kerello <christophe.kerello@st.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/reboot.h>
  16 #include <linux/regmap.h>
  17
  18 struct reset_syscfg {
  19         struct regmap *regmap;
  20         /* syscfg used for reset */
  21         unsigned int offset_rst;
  22         unsigned int mask_rst;
  23         /* syscfg used for unmask the reset */
  24         unsigned int offset_rst_msk;
  25         unsigned int mask_rst_msk;
  26 };
  27
  28 /* STiH407 */
  29 #define STIH407_SYSCFG_4000     0x0
  30 #define STIH407_SYSCFG_4008     0x20
  31
  32 static struct reset_syscfg stih407_reset = {
  33         .offset_rst = STIH407_SYSCFG_4000,
  34         .mask_rst = BIT(0),
  35         .offset_rst_msk = STIH407_SYSCFG_4008,
  36         .mask_rst_msk = BIT(0)
  37 };
  38
  39
  40 static struct reset_syscfg *st_restart_syscfg;
  41
  42 static int st_restart(struct notifier_block *this, unsigned long mode,
  43                       void *cmd)
  44 {
  45         /* reset syscfg updated */
  46         regmap_update_bits(st_restart_syscfg->regmap,
  47                            st_restart_syscfg->offset_rst,
  48                            st_restart_syscfg->mask_rst,
  49                            0);
  50
  51         /* unmask the reset */
  52         regmap_update_bits(st_restart_syscfg->regmap,
  53                            st_restart_syscfg->offset_rst_msk,
  54                            st_restart_syscfg->mask_rst_msk,
  55                            0);
  56
  57         return NOTIFY_DONE;
  58 }
  59
  60 static struct notifier_block st_restart_nb = {
  61         .notifier_call = st_restart,
  62         .priority = 192,
  63 };
  64
  65 static const struct of_device_id st_reset_of_match[] = {
  66         {
  67                 .compatible = "st,stih407-restart",
  68                 .data = (void *)&stih407_reset,
  69         },
  70         {}
  71 };
  72
  73 static int st_reset_probe(struct platform_device *pdev)
  74 {
  75         struct device_node *np = pdev->dev.of_node;
  76         const struct of_device_id *match;
  77         struct device *dev = &pdev->dev;
  78
  79         match = of_match_device(st_reset_of_match, dev);
  80         if (!match)
  81                 return -ENODEV;
  82
  83         st_restart_syscfg = (struct reset_syscfg *)match->data;
  84
  85         st_restart_syscfg->regmap =
  86                 syscon_regmap_lookup_by_phandle(np, "st,syscfg");
  87         if (IS_ERR(st_restart_syscfg->regmap)) {
  88                 dev_err(dev, "No syscfg phandle specified\n");
  89                 return PTR_ERR(st_restart_syscfg->regmap);
  90         }
  91
  92         return register_restart_handler(&st_restart_nb);
  93 }
  94
  95 static struct platform_driver st_reset_driver = {
  96         .probe = st_reset_probe,
  97         .driver = {
  98                 .name = "st_reset",
  99                 .of_match_table = st_reset_of_match,
 100         },
 101 };
 102
 103 static int __init st_reset_init(void)
 104 {
 105         return platform_driver_register(&st_reset_driver);
 106 }
 107
 108 device_initcall(st_reset_init);
 109
 110 MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");
 111 MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");
 112 MODULE_LICENSE("GPL v2");