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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Reset driver for Axxia devices4 *5 * Copyright (C) 2014 LSI6 */7#include <linux/init.h>8#include <linux/err.h>9#include <linux/io.h>10#include <linux/kernel.h>11#include <linux/mfd/syscon.h>12#include <linux/module.h>13#include <linux/notifier.h>14#include <linux/of.h>15#include <linux/platform_device.h>16#include <linux/reboot.h>17#include <linux/regmap.h>18 19#define SC_CRIT_WRITE_KEY 0x100020#define SC_LATCH_ON_RESET 0x100421#define SC_RESET_CONTROL 0x100822#define RSTCTL_RST_ZERO (1<<3)23#define RSTCTL_RST_FAB (1<<2)24#define RSTCTL_RST_CHIP (1<<1)25#define RSTCTL_RST_SYS (1<<0)26#define SC_EFUSE_INT_STATUS 0x180c27#define EFUSE_READ_DONE (1<<31)28 29static int axxia_restart_handler(struct sys_off_data *data)30{31 struct regmap *syscon = data->cb_data;32 33 /* Access Key (0xab) */34 regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);35 /* Select internal boot from 0xffff0000 */36 regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);37 /* Assert ResetReadDone (to avoid hanging in boot ROM) */38 regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);39 /* Assert chip reset */40 regmap_update_bits(syscon, SC_RESET_CONTROL,41 RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);42 43 return NOTIFY_DONE;44}45 46static int axxia_reset_probe(struct platform_device *pdev)47{48 struct device *dev = &pdev->dev;49 struct regmap *syscon;50 int err;51 52 syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");53 if (IS_ERR(syscon)) {54 pr_err("%pOFn: syscon lookup failed\n", dev->of_node);55 return PTR_ERR(syscon);56 }57 58 err = devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART,59 128, axxia_restart_handler, syscon);60 if (err)61 dev_err(dev, "cannot register restart handler (err=%d)\n", err);62 63 return err;64}65 66static const struct of_device_id of_axxia_reset_match[] = {67 { .compatible = "lsi,axm55xx-reset", },68 {},69};70MODULE_DEVICE_TABLE(of, of_axxia_reset_match);71 72static struct platform_driver axxia_reset_driver = {73 .probe = axxia_reset_probe,74 .driver = {75 .name = "axxia-reset",76 .of_match_table = of_match_ptr(of_axxia_reset_match),77 },78};79builtin_platform_driver(axxia_reset_driver);80