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/of.h> 16 #include <linux/of_device.h> 17 #include <linux/platform_device.h> 18 #include <linux/stat.h> 19 #include <linux/vexpress.h> 20 21 #include <asm/system_misc.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 void vexpress_restart(enum reboot_mode reboot_mode, const char *cmd) 47 { 48 vexpress_reset_do(vexpress_restart_device, "restart"); 49 } 50 51 static ssize_t vexpress_reset_active_show(struct device *dev, 52 struct device_attribute *attr, char *buf) 53 { 54 return sprintf(buf, "%d\n", vexpress_restart_device == dev); 55 } 56 57 static ssize_t vexpress_reset_active_store(struct device *dev, 58 struct device_attribute *attr, const char *buf, size_t count) 59 { 60 long value; 61 int err = kstrtol(buf, 0, &value); 62 63 if (!err && value) 64 vexpress_restart_device = dev; 65 66 return err ? err : count; 67 } 68 69 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show, 70 vexpress_reset_active_store); 71 72 73 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT }; 74 75 static struct of_device_id vexpress_reset_of_match[] = { 76 { 77 .compatible = "arm,vexpress-reset", 78 .data = (void *)FUNC_RESET, 79 }, { 80 .compatible = "arm,vexpress-shutdown", 81 .data = (void *)FUNC_SHUTDOWN 82 }, { 83 .compatible = "arm,vexpress-reboot", 84 .data = (void *)FUNC_REBOOT 85 }, 86 {} 87 }; 88 89 static int vexpress_reset_probe(struct platform_device *pdev) 90 { 91 enum vexpress_reset_func func; 92 const struct of_device_id *match = 93 of_match_device(vexpress_reset_of_match, &pdev->dev); 94 struct regmap *regmap; 95 96 if (match) 97 func = (enum vexpress_reset_func)match->data; 98 else 99 func = pdev->id_entry->driver_data; 100 101 regmap = devm_regmap_init_vexpress_config(&pdev->dev); 102 if (IS_ERR(regmap)) 103 return PTR_ERR(regmap); 104 dev_set_drvdata(&pdev->dev, regmap); 105 106 switch (func) { 107 case FUNC_SHUTDOWN: 108 vexpress_power_off_device = &pdev->dev; 109 pm_power_off = vexpress_power_off; 110 break; 111 case FUNC_RESET: 112 if (!vexpress_restart_device) 113 vexpress_restart_device = &pdev->dev; 114 arm_pm_restart = vexpress_restart; 115 device_create_file(&pdev->dev, &dev_attr_active); 116 break; 117 case FUNC_REBOOT: 118 vexpress_restart_device = &pdev->dev; 119 arm_pm_restart = vexpress_restart; 120 device_create_file(&pdev->dev, &dev_attr_active); 121 break; 122 }; 123 124 return 0; 125 } 126 127 static const struct platform_device_id vexpress_reset_id_table[] = { 128 { .name = "vexpress-reset", .driver_data = FUNC_RESET, }, 129 { .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, }, 130 { .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, }, 131 {} 132 }; 133 134 static struct platform_driver vexpress_reset_driver = { 135 .probe = vexpress_reset_probe, 136 .driver = { 137 .name = "vexpress-reset", 138 .of_match_table = vexpress_reset_of_match, 139 }, 140 .id_table = vexpress_reset_id_table, 141 }; 142 143 static int __init vexpress_reset_init(void) 144 { 145 return platform_driver_register(&vexpress_reset_driver); 146 } 147 device_initcall(vexpress_reset_init); 148