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
19 struct mt6323_pwrc {
20 struct device *dev;
21 struct regmap *regmap;
22 u32 base;
23 };
24
mt6323_do_pwroff(struct sys_off_data * data)25 static 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
mt6323_pwrc_probe(struct platform_device * pdev)50 static 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
80 static const struct of_device_id mt6323_pwrc_dt_match[] = {
81 { .compatible = "mediatek,mt6323-pwrc" },
82 {},
83 };
84 MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
85
86 static 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
94 module_platform_driver(mt6323_pwrc_driver);
95
96 MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
97 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
98