drivers/power/reset/st-poweroff.c

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