drivers/power/reset/mt6323-poweroff.c

   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
  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
  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>");