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
  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
  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, 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
  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         pwrc->base = res->start;
  61         pwrc->regmap = mt6397_chip->regmap;
  62         pwrc->dev = &pdev->dev;
  63         mt_pwrc = pwrc;
  64
  65         pm_power_off = &mt6323_do_pwroff;
  66
  67         return 0;
  68 }
  69
  70 static int mt6323_pwrc_remove(struct platform_device *pdev)
  71 {
  72         if (pm_power_off == &mt6323_do_pwroff)
  73                 pm_power_off = NULL;
  74
  75         return 0;
  76 }
  77
  78 static const struct of_device_id mt6323_pwrc_dt_match[] = {
  79         { .compatible = "mediatek,mt6323-pwrc" },
  80         {},
  81 };
  82 MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
  83
  84 static struct platform_driver mt6323_pwrc_driver = {
  85         .probe          = mt6323_pwrc_probe,
  86         .remove         = mt6323_pwrc_remove,
  87         .driver         = {
  88                 .name   = "mt6323-pwrc",
  89                 .of_match_table = mt6323_pwrc_dt_match,
  90         },
  91 };
  92
  93 module_platform_driver(mt6323_pwrc_driver);
  94
  95 MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
  96 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
  97 MODULE_LICENSE("GPL v2");