LXR linux/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
  18struct mt6323_pwrc {
  19        struct device *dev;
  20        struct regmap *regmap;
  21        u32 base;
  22};
  23
  24static struct mt6323_pwrc *mt_pwrc;
  25
  26static 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
  49static 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
  70static 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
  78static const struct of_device_id mt6323_pwrc_dt_match[] = {
  79        { .compatible = "mediatek,mt6323-pwrc" },
  80        {},
  81};
  82MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
  83
  84static 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
  93module_platform_driver(mt6323_pwrc_driver);
  94
  95MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
  96MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
  97MODULE_LICENSE("GPL v2");
  98