1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License version 2 as 4 * published by the Free Software Foundation. 5 * 6 * This program is distributed in the hope that it will be useful, 7 * but WITHOUT ANY WARRANTY; without even the implied warranty of 8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 9 * GNU General Public License for more details. 10 * 11 * Copyright (C) 2012 ARM Limited 12 */ 13 14 #include <linux/delay.h> 15 #include <linux/notifier.h> 16 #include <linux/of.h> 17 #include <linux/of_device.h> 18 #include <linux/platform_device.h> 19 #include <linux/reboot.h> 20 #include <linux/stat.h> 21 #include <linux/vexpress.h> 22 23 static void vexpress_reset_do(struct device *dev, const char *what) 24 { 25 int err = -ENOENT; 26 struct regmap *reg = dev_get_drvdata(dev); 27 28 if (reg) { 29 err = regmap_write(reg, 0, 0); 30 if (!err) 31 mdelay(1000); 32 } 33 34 dev_emerg(dev, "Unable to %s (%d)\n", what, err); 35 } 36 37 static struct device *vexpress_power_off_device; 38 39 static void vexpress_power_off(void) 40 { 41 vexpress_reset_do(vexpress_power_off_device, "power off"); 42 } 43 44 static struct device *vexpress_restart_device; 45 46 static int vexpress_restart(struct notifier_block *this, unsigned long mode, 47 void *cmd) 48 { 49 vexpress_reset_do(vexpress_restart_device, "restart"); 50 51 return NOTIFY_DONE; 52 } 53 54 static struct notifier_block vexpress_restart_nb = { 55 .notifier_call = vexpress_restart, 56 .priority = 128, 57 }; 58 59 static ssize_t vexpress_reset_active_show(struct device *dev, 60 struct device_attribute *attr, char *buf) 61 { 62 return sprintf(buf, "%d\n", vexpress_restart_device == dev); 63 } 64 65 static ssize_t vexpress_reset_active_store(struct device *dev, 66 struct device_attribute *attr, const char *buf, size_t count) 67 { 68 long value; 69 int err = kstrtol(buf, 0, &value); 70 71 if (!err && value) 72 vexpress_restart_device = dev; 73 74 return err ? err : count; 75 } 76 77 static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show, 78 vexpress_reset_active_store); 79 80 81 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT }; 82 83 static const struct of_device_id vexpress_reset_of_match[] = { 84 { 85 .compatible = "arm,vexpress-reset", 86 .data = (void *)FUNC_RESET, 87 }, { 88 .compatible = "arm,vexpress-shutdown", 89 .data = (void *)FUNC_SHUTDOWN 90 }, { 91 .compatible = "arm,vexpress-reboot", 92 .data = (void *)FUNC_REBOOT 93 }, 94 {} 95 }; 96 97 static int _vexpress_register_restart_handler(struct device *dev) 98 { 99 int err; 100 101 vexpress_restart_device = dev; 102 err = register_restart_handler(&vexpress_restart_nb); 103 if (err) { 104 dev_err(dev, "cannot register restart handler (err=%d)\n", err); 105 return err; 106 } 107 device_create_file(dev, &dev_attr_active); 108 109 return 0; 110 } 111 112 static int vexpress_reset_probe(struct platform_device *pdev) 113 { 114 const struct of_device_id *match = 115 of_match_device(vexpress_reset_of_match, &pdev->dev); 116 struct regmap *regmap; 117 int ret = 0; 118 119 if (!match) 120 return -EINVAL; 121 122 regmap = devm_regmap_init_vexpress_config(&pdev->dev); 123 if (IS_ERR(regmap)) 124 return PTR_ERR(regmap); 125 dev_set_drvdata(&pdev->dev, regmap); 126 127 switch ((enum vexpress_reset_func)match->data) { 128 case FUNC_SHUTDOWN: 129 vexpress_power_off_device = &pdev->dev; 130 pm_power_off = vexpress_power_off; 131 break; 132 case FUNC_RESET: 133 if (!vexpress_restart_device) 134 ret = _vexpress_register_restart_handler(&pdev->dev); 135 break; 136 case FUNC_REBOOT: 137 ret = _vexpress_register_restart_handler(&pdev->dev); 138 break; 139 }; 140 141 return ret; 142 } 143 144 static struct platform_driver vexpress_reset_driver = { 145 .probe = vexpress_reset_probe, 146 .driver = { 147 .name = "vexpress-reset", 148 .of_match_table = vexpress_reset_of_match, 149 }, 150 }; 151 152 static int __init vexpress_reset_init(void) 153 { 154 return platform_driver_register(&vexpress_reset_driver); 155 } 156 device_initcall(vexpress_reset_init); 157