Moritz Fischer | 8a57760 | 2015-03-11 17:37:18 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Generic Syscon Poweroff Driver |
| 3 | * |
| 4 | * Copyright (c) 2015, National Instruments Corp. |
| 5 | * Author: Moritz Fischer <moritz.fischer@ettus.com> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License as |
| 9 | * published by the Free Software Foundation; either version 2 of |
| 10 | * the License, or (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | */ |
| 17 | |
| 18 | #include <linux/kallsyms.h> |
| 19 | #include <linux/delay.h> |
| 20 | #include <linux/io.h> |
| 21 | #include <linux/notifier.h> |
| 22 | #include <linux/mfd/syscon.h> |
| 23 | #include <linux/of_address.h> |
| 24 | #include <linux/of_device.h> |
| 25 | #include <linux/platform_device.h> |
| 26 | #include <linux/pm.h> |
| 27 | #include <linux/regmap.h> |
| 28 | |
| 29 | static struct regmap *map; |
| 30 | static u32 offset; |
| 31 | static u32 mask; |
| 32 | |
| 33 | void syscon_poweroff(void) |
| 34 | { |
| 35 | /* Issue the poweroff */ |
| 36 | regmap_write(map, offset, mask); |
| 37 | |
| 38 | mdelay(1000); |
| 39 | |
| 40 | pr_emerg("Unable to poweroff system\n"); |
| 41 | } |
| 42 | |
| 43 | static int syscon_poweroff_probe(struct platform_device *pdev) |
| 44 | { |
| 45 | char symname[KSYM_NAME_LEN]; |
| 46 | |
| 47 | map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap"); |
| 48 | if (IS_ERR(map)) { |
| 49 | dev_err(&pdev->dev, "unable to get syscon"); |
| 50 | return PTR_ERR(map); |
| 51 | } |
| 52 | |
| 53 | if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) { |
| 54 | dev_err(&pdev->dev, "unable to read 'offset'"); |
| 55 | return -EINVAL; |
| 56 | } |
| 57 | |
| 58 | if (of_property_read_u32(pdev->dev.of_node, "mask", &mask)) { |
| 59 | dev_err(&pdev->dev, "unable to read 'mask'"); |
| 60 | return -EINVAL; |
| 61 | } |
| 62 | |
| 63 | if (pm_power_off) { |
| 64 | lookup_symbol_name((ulong)pm_power_off, symname); |
| 65 | dev_err(&pdev->dev, |
| 66 | "pm_power_off already claimed %p %s", |
| 67 | pm_power_off, symname); |
| 68 | return -EBUSY; |
| 69 | } |
| 70 | |
| 71 | pm_power_off = syscon_poweroff; |
| 72 | |
| 73 | return 0; |
| 74 | } |
| 75 | |
| 76 | static int syscon_poweroff_remove(struct platform_device *pdev) |
| 77 | { |
| 78 | if (pm_power_off == syscon_poweroff) |
| 79 | pm_power_off = NULL; |
| 80 | |
| 81 | return 0; |
| 82 | } |
| 83 | |
| 84 | static const struct of_device_id syscon_poweroff_of_match[] = { |
| 85 | { .compatible = "syscon-poweroff" }, |
| 86 | {} |
| 87 | }; |
| 88 | |
| 89 | static struct platform_driver syscon_poweroff_driver = { |
| 90 | .probe = syscon_poweroff_probe, |
| 91 | .remove = syscon_poweroff_remove, |
| 92 | .driver = { |
| 93 | .name = "syscon-poweroff", |
| 94 | .of_match_table = syscon_poweroff_of_match, |
| 95 | }, |
| 96 | }; |
| 97 | |
| 98 | static int __init syscon_poweroff_register(void) |
| 99 | { |
| 100 | return platform_driver_register(&syscon_poweroff_driver); |
| 101 | } |
| 102 | device_initcall(syscon_poweroff_register); |