107 lines
2.4 KiB
C
107 lines
2.4 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Generic Syscon Poweroff Driver
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*
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* Copyright (c) 2015, National Instruments Corp.
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* Author: Moritz Fischer <moritz.fischer@ettus.com>
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*/
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#include <linux/kallsyms.h>
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/notifier.h>
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#include <linux/mfd/syscon.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/pm.h>
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#include <linux/regmap.h>
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static struct regmap *map;
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static u32 offset;
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static u32 value;
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static u32 mask;
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static void syscon_poweroff(void)
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{
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/* Issue the poweroff */
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regmap_update_bits(map, offset, mask, value);
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mdelay(1000);
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pr_emerg("Unable to poweroff system\n");
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}
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static int syscon_poweroff_probe(struct platform_device *pdev)
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{
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char symname[KSYM_NAME_LEN];
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int mask_err, value_err;
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map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
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if (IS_ERR(map)) {
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dev_err(&pdev->dev, "unable to get syscon");
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return PTR_ERR(map);
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}
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if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) {
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dev_err(&pdev->dev, "unable to read 'offset'");
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return -EINVAL;
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}
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value_err = of_property_read_u32(pdev->dev.of_node, "value", &value);
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mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &mask);
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if (value_err && mask_err) {
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dev_err(&pdev->dev, "unable to read 'value' and 'mask'");
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return -EINVAL;
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}
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if (value_err) {
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/* support old binding */
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value = mask;
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mask = 0xFFFFFFFF;
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} else if (mask_err) {
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/* support value without mask*/
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mask = 0xFFFFFFFF;
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}
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if (pm_power_off) {
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lookup_symbol_name((ulong)pm_power_off, symname);
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dev_err(&pdev->dev,
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"pm_power_off already claimed %p %s",
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pm_power_off, symname);
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return -EBUSY;
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}
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pm_power_off = syscon_poweroff;
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return 0;
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}
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static int syscon_poweroff_remove(struct platform_device *pdev)
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{
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if (pm_power_off == syscon_poweroff)
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pm_power_off = NULL;
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return 0;
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}
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static const struct of_device_id syscon_poweroff_of_match[] = {
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{ .compatible = "syscon-poweroff" },
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{}
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};
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static struct platform_driver syscon_poweroff_driver = {
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.probe = syscon_poweroff_probe,
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.remove = syscon_poweroff_remove,
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.driver = {
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.name = "syscon-poweroff",
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.of_match_table = syscon_poweroff_of_match,
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},
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};
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static int __init syscon_poweroff_register(void)
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{
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return platform_driver_register(&syscon_poweroff_driver);
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}
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device_initcall(syscon_poweroff_register);
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