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1// SPDX-License-Identifier: GPL-2.0-only2/*3 *4 * Copyright (C) 2012 ARM Limited5 */6 7#include <linux/delay.h>8#include <linux/notifier.h>9#include <linux/of.h>10#include <linux/platform_device.h>11#include <linux/property.h>12#include <linux/reboot.h>13#include <linux/stat.h>14#include <linux/vexpress.h>15 16static void vexpress_reset_do(struct device *dev, const char *what)17{18 int err = -ENOENT;19 struct regmap *reg = dev_get_drvdata(dev);20 21 if (reg) {22 err = regmap_write(reg, 0, 0);23 if (!err)24 mdelay(1000);25 }26 27 dev_emerg(dev, "Unable to %s (%d)\n", what, err);28}29 30static struct device *vexpress_power_off_device;31static atomic_t vexpress_restart_nb_refcnt = ATOMIC_INIT(0);32 33static void vexpress_power_off(void)34{35 vexpress_reset_do(vexpress_power_off_device, "power off");36}37 38static struct device *vexpress_restart_device;39 40static int vexpress_restart(struct notifier_block *this, unsigned long mode,41 void *cmd)42{43 vexpress_reset_do(vexpress_restart_device, "restart");44 45 return NOTIFY_DONE;46}47 48static struct notifier_block vexpress_restart_nb = {49 .notifier_call = vexpress_restart,50 .priority = 128,51};52 53static ssize_t vexpress_reset_active_show(struct device *dev,54 struct device_attribute *attr, char *buf)55{56 return sprintf(buf, "%d\n", vexpress_restart_device == dev);57}58 59static ssize_t vexpress_reset_active_store(struct device *dev,60 struct device_attribute *attr, const char *buf, size_t count)61{62 long value;63 int err = kstrtol(buf, 0, &value);64 65 if (!err && value)66 vexpress_restart_device = dev;67 68 return err ? err : count;69}70 71static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,72 vexpress_reset_active_store);73 74 75enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };76 77static const struct of_device_id vexpress_reset_of_match[] = {78 {79 .compatible = "arm,vexpress-reset",80 .data = (void *)FUNC_RESET,81 }, {82 .compatible = "arm,vexpress-shutdown",83 .data = (void *)FUNC_SHUTDOWN84 }, {85 .compatible = "arm,vexpress-reboot",86 .data = (void *)FUNC_REBOOT87 },88 {}89};90 91static int _vexpress_register_restart_handler(struct device *dev)92{93 int err;94 95 vexpress_restart_device = dev;96 if (atomic_inc_return(&vexpress_restart_nb_refcnt) == 1) {97 err = register_restart_handler(&vexpress_restart_nb);98 if (err) {99 dev_err(dev, "cannot register restart handler (err=%d)\n", err);100 atomic_dec(&vexpress_restart_nb_refcnt);101 return err;102 }103 }104 device_create_file(dev, &dev_attr_active);105 106 return 0;107}108 109static int vexpress_reset_probe(struct platform_device *pdev)110{111 enum vexpress_reset_func func;112 struct regmap *regmap;113 int ret = 0;114 115 regmap = devm_regmap_init_vexpress_config(&pdev->dev);116 if (IS_ERR(regmap))117 return PTR_ERR(regmap);118 dev_set_drvdata(&pdev->dev, regmap);119 120 func = (uintptr_t)device_get_match_data(&pdev->dev);121 switch (func) {122 case FUNC_SHUTDOWN:123 vexpress_power_off_device = &pdev->dev;124 pm_power_off = vexpress_power_off;125 break;126 case FUNC_RESET:127 if (!vexpress_restart_device)128 ret = _vexpress_register_restart_handler(&pdev->dev);129 break;130 case FUNC_REBOOT:131 ret = _vexpress_register_restart_handler(&pdev->dev);132 break;133 }134 135 return ret;136}137 138static struct platform_driver vexpress_reset_driver = {139 .probe = vexpress_reset_probe,140 .driver = {141 .name = "vexpress-reset",142 .of_match_table = vexpress_reset_of_match,143 .suppress_bind_attrs = true,144 },145};146builtin_platform_driver(vexpress_reset_driver);147