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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Generic Syscon Poweroff Driver4 *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 19struct syscon_poweroff_data {20 struct regmap *map;21 u32 offset;22 u32 value;23 u32 mask;24};25 26static 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 40static 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 86static const struct of_device_id syscon_poweroff_of_match[] = {87 { .compatible = "syscon-poweroff" },88 {}89};90 91static 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};98builtin_platform_driver(syscon_poweroff_driver);99