/* * Generic Syscon Poweroff Driver * * Copyright (c) 2015, National Instruments Corp. * Author: Moritz Fischer <moritz.fischer@ettus.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/kallsyms.h> #include <linux/delay.h> #include <linux/io.h> #include <linux/notifier.h> #include <linux/mfd/syscon.h> #include <linux/of_address.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/pm.h> #include <linux/regmap.h> static struct regmap *map; static u32 offset; static u32 value; static u32 mask; static void syscon_poweroff(void) { /* Issue the poweroff */ regmap_update_bits(map, offset, mask, value); mdelay(1000); pr_emerg("Unable to poweroff system\n"); } static int syscon_poweroff_probe(struct platform_device *pdev) { char symname[KSYM_NAME_LEN]; int mask_err, value_err; map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap"); if (IS_ERR(map)) { dev_err(&pdev->dev, "unable to get syscon"); return PTR_ERR(map); } if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) { dev_err(&pdev->dev, "unable to read 'offset'"); return -EINVAL; } value_err = of_property_read_u32(pdev->dev.of_node, "value", &value); mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &mask); if (value_err && mask_err) { dev_err(&pdev->dev, "unable to read 'value' and 'mask'"); return -EINVAL; } if (value_err) { /* support old binding */ value = mask; mask = 0xFFFFFFFF; } else if (mask_err) { /* support value without mask*/ mask = 0xFFFFFFFF; } if (pm_power_off) { lookup_symbol_name((ulong)pm_power_off, symname); dev_err(&pdev->dev, "pm_power_off already claimed %p %s", pm_power_off, symname); return -EBUSY; } pm_power_off = syscon_poweroff; return 0; } static int syscon_poweroff_remove(struct platform_device *pdev) { if (pm_power_off == syscon_poweroff) pm_power_off = NULL; return 0; } static const struct of_device_id syscon_poweroff_of_match[] = { { .compatible = "syscon-poweroff" }, {} }; static struct platform_driver syscon_poweroff_driver = { .probe = syscon_poweroff_probe, .remove = syscon_poweroff_remove, .driver = { .name = "syscon-poweroff", .of_match_table = syscon_poweroff_of_match, }, }; static int __init syscon_poweroff_register(void) { return platform_driver_register(&syscon_poweroff_driver); } device_initcall(syscon_poweroff_register);