1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2014 STMicroelectronics 4 * 5 * Power off Restart driver, used in STMicroelectronics devices. 6 * 7 * Author: Christophe Kerello <christophe.kerello@st.com> 8 */ 9 10 #include <linux/module.h> 11 #include <linux/of.h> 12 #include <linux/of_platform.h> 13 #include <linux/platform_device.h> 14 #include <linux/mfd/syscon.h> 15 #include <linux/reboot.h> 16 #include <linux/regmap.h> 17 18 struct reset_syscfg { 19 struct regmap *regmap; 20 /* syscfg used for reset */ 21 unsigned int offset_rst; 22 unsigned int mask_rst; 23 /* syscfg used for unmask the reset */ 24 unsigned int offset_rst_msk; 25 unsigned int mask_rst_msk; 26 }; 27 28 /* STiH407 */ 29 #define STIH407_SYSCFG_4000 0x0 30 #define STIH407_SYSCFG_4008 0x20 31 32 static struct reset_syscfg stih407_reset = { 33 .offset_rst = STIH407_SYSCFG_4000, 34 .mask_rst = BIT(0), 35 .offset_rst_msk = STIH407_SYSCFG_4008, 36 .mask_rst_msk = BIT(0) 37 }; 38 39 40 static struct reset_syscfg *st_restart_syscfg; 41 42 static int st_restart(struct notifier_block *this, unsigned long mode, 43 void *cmd) 44 { 45 /* reset syscfg updated */ 46 regmap_update_bits(st_restart_syscfg->regmap, 47 st_restart_syscfg->offset_rst, 48 st_restart_syscfg->mask_rst, 49 0); 50 51 /* unmask the reset */ 52 regmap_update_bits(st_restart_syscfg->regmap, 53 st_restart_syscfg->offset_rst_msk, 54 st_restart_syscfg->mask_rst_msk, 55 0); 56 57 return NOTIFY_DONE; 58 } 59 60 static struct notifier_block st_restart_nb = { 61 .notifier_call = st_restart, 62 .priority = 192, 63 }; 64 65 static const struct of_device_id st_reset_of_match[] = { 66 { 67 .compatible = "st,stih407-restart", 68 .data = (void *)&stih407_reset, 69 }, 70 {} 71 }; 72 73 static int st_reset_probe(struct platform_device *pdev) 74 { 75 struct device_node *np = pdev->dev.of_node; 76 const struct of_device_id *match; 77 struct device *dev = &pdev->dev; 78 79 match = of_match_device(st_reset_of_match, dev); 80 if (!match) 81 return -ENODEV; 82 83 st_restart_syscfg = (struct reset_syscfg *)match->data; 84 85 st_restart_syscfg->regmap = 86 syscon_regmap_lookup_by_phandle(np, "st,syscfg"); 87 if (IS_ERR(st_restart_syscfg->regmap)) { 88 dev_err(dev, "No syscfg phandle specified\n"); 89 return PTR_ERR(st_restart_syscfg->regmap); 90 } 91 92 return register_restart_handler(&st_restart_nb); 93 } 94 95 static struct platform_driver st_reset_driver = { 96 .probe = st_reset_probe, 97 .driver = { 98 .name = "st_reset", 99 .of_match_table = st_reset_of_match, 100 }, 101 }; 102 103 static int __init st_reset_init(void) 104 { 105 return platform_driver_register(&st_reset_driver); 106 } 107 108 device_initcall(st_reset_init); 109 110 MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>"); 111 MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver"); 112 MODULE_LICENSE("GPL v2"); 113