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
18struct mt6323_pwrc {
19	struct device *dev;
20	struct regmap *regmap;
21	u32 base;
22};
23
24static struct mt6323_pwrc *mt_pwrc;
25
26static void mt6323_do_pwroff(void)
27{
28	struct mt6323_pwrc *pwrc = mt_pwrc;
29	unsigned int val;
30	int ret;
31
32	regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY);
33	regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR_MT6323, 1);
34
35	ret = regmap_read_poll_timeout(pwrc->regmap,
36					pwrc->base + RTC_BBPU, val,
37					!(val & RTC_BBPU_CBUSY),
38					MTK_RTC_POLL_DELAY_US,
39					MTK_RTC_POLL_TIMEOUT);
40	if (ret)
41		dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret);
42
43	/* Wait some time until system down, otherwise, notice with a warn */
44	mdelay(1000);
45
46	WARN_ONCE(1, "Unable to power off system\n");
47}
48
49static int mt6323_pwrc_probe(struct platform_device *pdev)
50{
51	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
52	struct mt6323_pwrc *pwrc;
53	struct resource *res;
54
55	pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
56	if (!pwrc)
57		return -ENOMEM;
58
59	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
60	if (!res)
61		return -EINVAL;
62
63	pwrc->base = res->start;
64	pwrc->regmap = mt6397_chip->regmap;
65	pwrc->dev = &pdev->dev;
66	mt_pwrc = pwrc;
67
68	pm_power_off = &mt6323_do_pwroff;
69
70	return 0;
71}
72
73static int mt6323_pwrc_remove(struct platform_device *pdev)
74{
75	if (pm_power_off == &mt6323_do_pwroff)
76		pm_power_off = NULL;
77
78	return 0;
79}
80
81static const struct of_device_id mt6323_pwrc_dt_match[] = {
82	{ .compatible = "mediatek,mt6323-pwrc" },
83	{},
84};
85MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
86
87static struct platform_driver mt6323_pwrc_driver = {
88	.probe          = mt6323_pwrc_probe,
89	.remove         = mt6323_pwrc_remove,
90	.driver         = {
91		.name   = "mt6323-pwrc",
92		.of_match_table = mt6323_pwrc_dt_match,
93	},
94};
95
96module_platform_driver(mt6323_pwrc_driver);
97
98MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
99MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
100MODULE_LICENSE("GPL v2");
101