drivers/power/reset/as3722-poweroff.c

   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
  25 struct as3722_poweroff {
  26         struct device *dev;
  27         struct as3722 *as3722;
  28 };
  29
  30 static struct as3722_poweroff *as3722_pm_poweroff;
  31
  32 static 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
  48 static 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
  73 static 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
  82 static 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
  90 module_platform_driver(as3722_poweroff_driver);
  91
  92 MODULE_DESCRIPTION("Power off driver for ams AS3722 PMIC Device");
  93 MODULE_ALIAS("platform:as3722-power-off");
  94 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
  95 MODULE_LICENSE("GPL v2");