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