1 /* 2 * Copyright (C) 2014 STMicroelectronics 3 * 4 * Power off Restart driver, used in STMicroelectronics devices. 5 * 6 * Author: Christophe Kerello <christophe.kerello@st.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2, as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/of_platform.h> 16 #include <linux/platform_device.h> 17 #include <linux/mfd/syscon.h> 18 #include <linux/reboot.h> 19 #include <linux/regmap.h> 20 21 struct reset_syscfg { 22 struct regmap *regmap; 23 /* syscfg used for reset */ 24 unsigned int offset_rst; 25 unsigned int mask_rst; 26 /* syscfg used for unmask the reset */ 27 unsigned int offset_rst_msk; 28 unsigned int mask_rst_msk; 29 }; 30 31 /* STiH415 */ 32 #define STIH415_SYSCFG_11 0x2c 33 #define STIH415_SYSCFG_15 0x3c 34 35 static struct reset_syscfg stih415_reset = { 36 .offset_rst = STIH415_SYSCFG_11, 37 .mask_rst = BIT(0), 38 .offset_rst_msk = STIH415_SYSCFG_15, 39 .mask_rst_msk = BIT(0) 40 }; 41 42 /* STiH416 */ 43 #define STIH416_SYSCFG_500 0x7d0 44 #define STIH416_SYSCFG_504 0x7e0 45 46 static struct reset_syscfg stih416_reset = { 47 .offset_rst = STIH416_SYSCFG_500, 48 .mask_rst = BIT(0), 49 .offset_rst_msk = STIH416_SYSCFG_504, 50 .mask_rst_msk = BIT(0) 51 }; 52 53 /* STiH407 */ 54 #define STIH407_SYSCFG_4000 0x0 55 #define STIH407_SYSCFG_4008 0x20 56 57 static struct reset_syscfg stih407_reset = { 58 .offset_rst = STIH407_SYSCFG_4000, 59 .mask_rst = BIT(0), 60 .offset_rst_msk = STIH407_SYSCFG_4008, 61 .mask_rst_msk = BIT(0) 62 }; 63 64 /* STiD127 */ 65 #define STID127_SYSCFG_700 0x0 66 #define STID127_SYSCFG_773 0x124 67 68 static struct reset_syscfg stid127_reset = { 69 .offset_rst = STID127_SYSCFG_773, 70 .mask_rst = BIT(0), 71 .offset_rst_msk = STID127_SYSCFG_700, 72 .mask_rst_msk = BIT(8) 73 }; 74 75 static struct reset_syscfg *st_restart_syscfg; 76 77 static int st_restart(struct notifier_block *this, unsigned long mode, 78 void *cmd) 79 { 80 /* reset syscfg updated */ 81 regmap_update_bits(st_restart_syscfg->regmap, 82 st_restart_syscfg->offset_rst, 83 st_restart_syscfg->mask_rst, 84 0); 85 86 /* unmask the reset */ 87 regmap_update_bits(st_restart_syscfg->regmap, 88 st_restart_syscfg->offset_rst_msk, 89 st_restart_syscfg->mask_rst_msk, 90 0); 91 92 return NOTIFY_DONE; 93 } 94 95 static struct notifier_block st_restart_nb = { 96 .notifier_call = st_restart, 97 .priority = 192, 98 }; 99 100 static const struct of_device_id st_reset_of_match[] = { 101 { 102 .compatible = "st,stih415-restart", 103 .data = (void *)&stih415_reset, 104 }, { 105 .compatible = "st,stih416-restart", 106 .data = (void *)&stih416_reset, 107 }, { 108 .compatible = "st,stih407-restart", 109 .data = (void *)&stih407_reset, 110 }, { 111 .compatible = "st,stid127-restart", 112 .data = (void *)&stid127_reset, 113 }, 114 {} 115 }; 116 117 static int st_reset_probe(struct platform_device *pdev) 118 { 119 struct device_node *np = pdev->dev.of_node; 120 const struct of_device_id *match; 121 struct device *dev = &pdev->dev; 122 123 match = of_match_device(st_reset_of_match, dev); 124 if (!match) 125 return -ENODEV; 126 127 st_restart_syscfg = (struct reset_syscfg *)match->data; 128 129 st_restart_syscfg->regmap = 130 syscon_regmap_lookup_by_phandle(np, "st,syscfg"); 131 if (IS_ERR(st_restart_syscfg->regmap)) { 132 dev_err(dev, "No syscfg phandle specified\n"); 133 return PTR_ERR(st_restart_syscfg->regmap); 134 } 135 136 return register_restart_handler(&st_restart_nb); 137 } 138 139 static struct platform_driver st_reset_driver = { 140 .probe = st_reset_probe, 141 .driver = { 142 .name = "st_reset", 143 .of_match_table = st_reset_of_match, 144 }, 145 }; 146 147 static int __init st_reset_init(void) 148 { 149 return platform_driver_register(&st_reset_driver); 150 } 151 152 device_initcall(st_reset_init); 153 154 MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>"); 155 MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver"); 156 MODULE_LICENSE("GPL v2"); 157