1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Power off through MediaTek PMIC
4 *
5 * Copyright (C) 2018 MediaTek Inc.
6 *
7 * Author: Sean Wang <sean.wang@mediatek.com>
8 *
9 */
10
11#include <linux/err.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/mfd/mt6397/core.h>
16#include <linux/mfd/mt6397/rtc.h>
17#include <linux/reboot.h>
18
19struct mt6323_pwrc {
20	struct device *dev;
21	struct regmap *regmap;
22	u32 base;
23};
24
25static int mt6323_do_pwroff(struct sys_off_data *data)
26{
27	struct mt6323_pwrc *pwrc = data->cb_data;
28	unsigned int val;
29	int ret;
30
31	regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY);
32	regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR_MT6323, 1);
33
34	ret = regmap_read_poll_timeout(pwrc->regmap,
35					pwrc->base + RTC_BBPU, val,
36					!(val & RTC_BBPU_CBUSY),
37					MTK_RTC_POLL_DELAY_US,
38					MTK_RTC_POLL_TIMEOUT);
39	if (ret)
40		dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret);
41
42	/* Wait some time until system down, otherwise, notice with a warn */
43	mdelay(1000);
44
45	WARN_ONCE(1, "Unable to power off system\n");
46
47	return NOTIFY_DONE;
48}
49
50static int mt6323_pwrc_probe(struct platform_device *pdev)
51{
52	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
53	struct mt6323_pwrc *pwrc;
54	struct resource *res;
55	int ret;
56
57	pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
58	if (!pwrc)
59		return -ENOMEM;
60
61	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
62	if (!res)
63		return -EINVAL;
64
65	pwrc->base = res->start;
66	pwrc->regmap = mt6397_chip->regmap;
67	pwrc->dev = &pdev->dev;
68
69	ret = devm_register_sys_off_handler(pwrc->dev,
70					    SYS_OFF_MODE_POWER_OFF,
71					    SYS_OFF_PRIO_DEFAULT,
72					    mt6323_do_pwroff,
73					    pwrc);
74	if (ret)
75		return dev_err_probe(pwrc->dev, ret, "failed to register power-off handler\n");
76
77	return 0;
78}
79
80static const struct of_device_id mt6323_pwrc_dt_match[] = {
81	{ .compatible = "mediatek,mt6323-pwrc" },
82	{},
83};
84MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
85
86static struct platform_driver mt6323_pwrc_driver = {
87	.probe          = mt6323_pwrc_probe,
88	.driver         = {
89		.name   = "mt6323-pwrc",
90		.of_match_table = mt6323_pwrc_dt_match,
91	},
92};
93
94module_platform_driver(mt6323_pwrc_driver);
95
96MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
97MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
98