1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Generic Syscon Poweroff Driver 4 * 5 * Copyright (c) 2015, National Instruments Corp. 6 * Author: Moritz Fischer <moritz.fischer@ettus.com> 7 */ 8 9 #include <linux/delay.h> 10 #include <linux/io.h> 11 #include <linux/notifier.h> 12 #include <linux/mfd/syscon.h> 13 #include <linux/of.h> 14 #include <linux/platform_device.h> 15 #include <linux/pm.h> 16 #include <linux/reboot.h> 17 #include <linux/regmap.h> 18 19 struct syscon_poweroff_data { 20 struct regmap *map; 21 u32 offset; 22 u32 value; 23 u32 mask; 24 }; 25 26 static int syscon_poweroff(struct sys_off_data *off_data) 27 { 28 struct syscon_poweroff_data *data = off_data->cb_data; 29 30 /* Issue the poweroff */ 31 regmap_update_bits(data->map, data->offset, data->mask, data->value); 32 33 mdelay(1000); 34 35 pr_emerg("Unable to poweroff system\n"); 36 37 return NOTIFY_DONE; 38 } 39 40 static int syscon_poweroff_probe(struct platform_device *pdev) 41 { 42 struct device *dev = &pdev->dev; 43 struct syscon_poweroff_data *data; 44 int mask_err, value_err; 45 46 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 47 if (!data) 48 return -ENOMEM; 49 50 data->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap"); 51 if (IS_ERR(data->map)) { 52 data->map = syscon_node_to_regmap(dev->parent->of_node); 53 if (IS_ERR(data->map)) { 54 dev_err(dev, "unable to get syscon"); 55 return PTR_ERR(data->map); 56 } 57 } 58 59 if (of_property_read_u32(dev->of_node, "offset", &data->offset)) { 60 dev_err(dev, "unable to read 'offset'"); 61 return -EINVAL; 62 } 63 64 value_err = of_property_read_u32(dev->of_node, "value", &data->value); 65 mask_err = of_property_read_u32(dev->of_node, "mask", &data->mask); 66 if (value_err && mask_err) { 67 dev_err(dev, "unable to read 'value' and 'mask'"); 68 return -EINVAL; 69 } 70 71 if (value_err) { 72 /* support old binding */ 73 data->value = data->mask; 74 data->mask = 0xFFFFFFFF; 75 } else if (mask_err) { 76 /* support value without mask*/ 77 data->mask = 0xFFFFFFFF; 78 } 79 80 return devm_register_sys_off_handler(&pdev->dev, 81 SYS_OFF_MODE_POWER_OFF, 82 SYS_OFF_PRIO_DEFAULT, 83 syscon_poweroff, data); 84 } 85 86 static const struct of_device_id syscon_poweroff_of_match[] = { 87 { .compatible = "syscon-poweroff" }, 88 {} 89 }; 90 91 static struct platform_driver syscon_poweroff_driver = { 92 .probe = syscon_poweroff_probe, 93 .driver = { 94 .name = "syscon-poweroff", 95 .of_match_table = syscon_poweroff_of_match, 96 }, 97 }; 98 builtin_platform_driver(syscon_poweroff_driver); 99