LXR linux/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
  21struct 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
  35static 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
  43static struct reset_syscfg *st_restart_syscfg;
  44
  45static 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
  63static struct notifier_block st_restart_nb = {
  64        .notifier_call = st_restart,
  65        .priority = 192,
  66};
  67
  68static const struct of_device_id st_reset_of_match[] = {
  69        {
  70                .compatible = "st,stih407-restart",
  71                .data = (void *)&stih407_reset,
  72        },
  73        {}
  74};
  75
  76static 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
  98static 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
 106static int __init st_reset_init(void)
 107{
 108        return platform_driver_register(&st_reset_driver);
 109}
 110
 111device_initcall(st_reset_init);
 112
 113MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");
 114MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");
 115MODULE_LICENSE("GPL v2");
 116