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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2014 STMicroelectronics4 *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_device.h>13#include <linux/platform_device.h>14#include <linux/mfd/syscon.h>15#include <linux/reboot.h>16#include <linux/regmap.h>17 18struct 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 0x030#define STIH407_SYSCFG_4008 0x2031 32static 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 40static struct reset_syscfg *st_restart_syscfg;41 42static 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 60static struct notifier_block st_restart_nb = {61 .notifier_call = st_restart,62 .priority = 192,63};64 65static const struct of_device_id st_reset_of_match[] = {66 {67 .compatible = "st,stih407-restart",68 .data = (void *)&stih407_reset,69 },70 {}71};72 73static 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 95static 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 103builtin_platform_driver(st_reset_driver);104 105MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");106MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");107MODULE_LICENSE("GPL v2");108