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 
18 struct mt6323_pwrc {
19 	struct device *dev;
20 	struct regmap *regmap;
21 	u32 base;
22 };
23 
24 static struct mt6323_pwrc *mt_pwrc;
25 
mt6323_do_pwroff(void)26 static 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 
mt6323_pwrc_probe(struct platform_device * pdev)49 static 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 
mt6323_pwrc_remove(struct platform_device * pdev)73 static 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 
81 static const struct of_device_id mt6323_pwrc_dt_match[] = {
82 	{ .compatible = "mediatek,mt6323-pwrc" },
83 	{},
84 };
85 MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
86 
87 static 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 
96 module_platform_driver(mt6323_pwrc_driver);
97 
98 MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
99 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
100 MODULE_LICENSE("GPL v2");
101