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 /* STiH407 */ 32 #define STIH407_SYSCFG_4000 0x0 33 #define STIH407_SYSCFG_4008 0x20 34 35 static struct reset_syscfg stih407_reset = { 36 .offset_rst = STIH407_SYSCFG_4000, 37 .mask_rst = BIT(0), 38 .offset_rst_msk = STIH407_SYSCFG_4008, 39 .mask_rst_msk = BIT(0) 40 }; 41 42 43 static struct reset_syscfg *st_restart_syscfg; 44 45 static int st_restart(struct notifier_block *this, unsigned long mode, 46 void *cmd) 47 { 48 /* reset syscfg updated */ 49 regmap_update_bits(st_restart_syscfg->regmap, 50 st_restart_syscfg->offset_rst, 51 st_restart_syscfg->mask_rst, 52 0); 53 54 /* unmask the reset */ 55 regmap_update_bits(st_restart_syscfg->regmap, 56 st_restart_syscfg->offset_rst_msk, 57 st_restart_syscfg->mask_rst_msk, 58 0); 59 60 return NOTIFY_DONE; 61 } 62 63 static struct notifier_block st_restart_nb = { 64 .notifier_call = st_restart, 65 .priority = 192, 66 }; 67 68 static const struct of_device_id st_reset_of_match[] = { 69 { 70 .compatible = "st,stih407-restart", 71 .data = (void *)&stih407_reset, 72 }, 73 {} 74 }; 75 76 static int st_reset_probe(struct platform_device *pdev) 77 { 78 struct device_node *np = pdev->dev.of_node; 79 const struct of_device_id *match; 80 struct device *dev = &pdev->dev; 81 82 match = of_match_device(st_reset_of_match, dev); 83 if (!match) 84 return -ENODEV; 85 86 st_restart_syscfg = (struct reset_syscfg *)match->data; 87 88 st_restart_syscfg->regmap = 89 syscon_regmap_lookup_by_phandle(np, "st,syscfg"); 90 if (IS_ERR(st_restart_syscfg->regmap)) { 91 dev_err(dev, "No syscfg phandle specified\n"); 92 return PTR_ERR(st_restart_syscfg->regmap); 93 } 94 95 return register_restart_handler(&st_restart_nb); 96 } 97 98 static struct platform_driver st_reset_driver = { 99 .probe = st_reset_probe, 100 .driver = { 101 .name = "st_reset", 102 .of_match_table = st_reset_of_match, 103 }, 104 }; 105 106 static int __init st_reset_init(void) 107 { 108 return platform_driver_register(&st_reset_driver); 109 } 110 111 device_initcall(st_reset_init); 112 113 MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>"); 114 MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver"); 115 MODULE_LICENSE("GPL v2"); 116