linux/drivers/power/reset/as3722-poweroff.c
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   1/*
   2 * Power off driver for ams AS3722 device.
   3 *
   4 * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
   5 *
   6 * Author: Laxman Dewangan <ldewangan@nvidia.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms and conditions of the GNU General Public License,
  10 * version 2, as published by the Free Software Foundation.
  11 *
  12 * This program is distributed in the hope it will be useful, but WITHOUT
  13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15 * more details.
  16 */
  17
  18#include <linux/mfd/as3722.h>
  19#include <linux/module.h>
  20#include <linux/of.h>
  21#include <linux/of_device.h>
  22#include <linux/platform_device.h>
  23#include <linux/slab.h>
  24
  25struct as3722_poweroff {
  26        struct device *dev;
  27        struct as3722 *as3722;
  28};
  29
  30static struct as3722_poweroff *as3722_pm_poweroff;
  31
  32static void as3722_pm_power_off(void)
  33{
  34        int ret;
  35
  36        if (!as3722_pm_poweroff) {
  37                pr_err("AS3722 poweroff is not initialised\n");
  38                return;
  39        }
  40
  41        ret = as3722_update_bits(as3722_pm_poweroff->as3722,
  42                AS3722_RESET_CONTROL_REG, AS3722_POWER_OFF, AS3722_POWER_OFF);
  43        if (ret < 0)
  44                dev_err(as3722_pm_poweroff->dev,
  45                        "RESET_CONTROL_REG update failed, %d\n", ret);
  46}
  47
  48static int as3722_poweroff_probe(struct platform_device *pdev)
  49{
  50        struct as3722_poweroff *as3722_poweroff;
  51        struct device_node *np = pdev->dev.parent->of_node;
  52
  53        if (!np)
  54                return -EINVAL;
  55
  56        if (!of_property_read_bool(np, "ams,system-power-controller"))
  57                return 0;
  58
  59        as3722_poweroff = devm_kzalloc(&pdev->dev, sizeof(*as3722_poweroff),
  60                                GFP_KERNEL);
  61        if (!as3722_poweroff)
  62                return -ENOMEM;
  63
  64        as3722_poweroff->as3722 = dev_get_drvdata(pdev->dev.parent);
  65        as3722_poweroff->dev = &pdev->dev;
  66        as3722_pm_poweroff = as3722_poweroff;
  67        if (!pm_power_off)
  68                pm_power_off = as3722_pm_power_off;
  69
  70        return 0;
  71}
  72
  73static int as3722_poweroff_remove(struct platform_device *pdev)
  74{
  75        if (pm_power_off == as3722_pm_power_off)
  76                pm_power_off = NULL;
  77        as3722_pm_poweroff = NULL;
  78
  79        return 0;
  80}
  81
  82static struct platform_driver as3722_poweroff_driver = {
  83        .driver = {
  84                .name = "as3722-power-off",
  85        },
  86        .probe = as3722_poweroff_probe,
  87        .remove = as3722_poweroff_remove,
  88};
  89
  90module_platform_driver(as3722_poweroff_driver);
  91
  92MODULE_DESCRIPTION("Power off driver for ams AS3722 PMIC Device");
  93MODULE_ALIAS("platform:as3722-power-off");
  94MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
  95MODULE_LICENSE("GPL v2");
  96
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