1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Reset driver for Axxia devices 4 * 5 * Copyright (C) 2014 LSI 6 */ 7 #include <linux/init.h> 8 #include <linux/err.h> 9 #include <linux/io.h> 10 #include <linux/kernel.h> 11 #include <linux/mfd/syscon.h> 12 #include <linux/module.h> 13 #include <linux/notifier.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 #include <linux/reboot.h> 17 #include <linux/regmap.h> 18 19 #define SC_CRIT_WRITE_KEY 0x1000 20 #define SC_LATCH_ON_RESET 0x1004 21 #define SC_RESET_CONTROL 0x1008 22 #define RSTCTL_RST_ZERO (1<<3) 23 #define RSTCTL_RST_FAB (1<<2) 24 #define RSTCTL_RST_CHIP (1<<1) 25 #define RSTCTL_RST_SYS (1<<0) 26 #define SC_EFUSE_INT_STATUS 0x180c 27 #define EFUSE_READ_DONE (1<<31) 28 29 static int axxia_restart_handler(struct sys_off_data *data) 30 { 31 struct regmap *syscon = data->cb_data; 32 33 /* Access Key (0xab) */ 34 regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab); 35 /* Select internal boot from 0xffff0000 */ 36 regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040); 37 /* Assert ResetReadDone (to avoid hanging in boot ROM) */ 38 regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE); 39 /* Assert chip reset */ 40 regmap_update_bits(syscon, SC_RESET_CONTROL, 41 RSTCTL_RST_CHIP, RSTCTL_RST_CHIP); 42 43 return NOTIFY_DONE; 44 } 45 46 static int axxia_reset_probe(struct platform_device *pdev) 47 { 48 struct device *dev = &pdev->dev; 49 struct regmap *syscon; 50 int err; 51 52 syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon"); 53 if (IS_ERR(syscon)) { 54 pr_err("%pOFn: syscon lookup failed\n", dev->of_node); 55 return PTR_ERR(syscon); 56 } 57 58 err = devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART, 59 128, axxia_restart_handler, syscon); 60 if (err) 61 dev_err(dev, "cannot register restart handler (err=%d)\n", err); 62 63 return err; 64 } 65 66 static const struct of_device_id of_axxia_reset_match[] = { 67 { .compatible = "lsi,axm55xx-reset", }, 68 {}, 69 }; 70 MODULE_DEVICE_TABLE(of, of_axxia_reset_match); 71 72 static struct platform_driver axxia_reset_driver = { 73 .probe = axxia_reset_probe, 74 .driver = { 75 .name = "axxia-reset", 76 .of_match_table = of_match_ptr(of_axxia_reset_match), 77 }, 78 }; 79 builtin_platform_driver(axxia_reset_driver); 80