drivers/power/reset/as3722-poweroff.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Power off driver for ams AS3722 device.
   4  *
   5  * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
   6  *
   7  * Author: Laxman Dewangan <ldewangan@nvidia.com>
   8  */
   9
  10 #include <linux/mfd/as3722.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/of_device.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/slab.h>
  16
  17 struct as3722_poweroff {
  18         struct device *dev;
  19         struct as3722 *as3722;
  20 };
  21
  22 static struct as3722_poweroff *as3722_pm_poweroff;
  23
  24 static void as3722_pm_power_off(void)
  25 {
  26         int ret;
  27
  28         if (!as3722_pm_poweroff) {
  29                 pr_err("AS3722 poweroff is not initialised\n");
  30                 return;
  31         }
  32
  33         ret = as3722_update_bits(as3722_pm_poweroff->as3722,
  34                 AS3722_RESET_CONTROL_REG, AS3722_POWER_OFF, AS3722_POWER_OFF);
  35         if (ret < 0)
  36                 dev_err(as3722_pm_poweroff->dev,
  37                         "RESET_CONTROL_REG update failed, %d\n", ret);
  38 }
  39
  40 static int as3722_poweroff_probe(struct platform_device *pdev)
  41 {
  42         struct as3722_poweroff *as3722_poweroff;
  43         struct device_node *np = pdev->dev.parent->of_node;
  44
  45         if (!np)
  46                 return -EINVAL;
  47
  48         if (!of_property_read_bool(np, "ams,system-power-controller"))
  49                 return 0;
  50
  51         as3722_poweroff = devm_kzalloc(&pdev->dev, sizeof(*as3722_poweroff),
  52                                 GFP_KERNEL);
  53         if (!as3722_poweroff)
  54                 return -ENOMEM;
  55
  56         as3722_poweroff->as3722 = dev_get_drvdata(pdev->dev.parent);
  57         as3722_poweroff->dev = &pdev->dev;
  58         as3722_pm_poweroff = as3722_poweroff;
  59         if (!pm_power_off)
  60                 pm_power_off = as3722_pm_power_off;
  61
  62         return 0;
  63 }
  64
  65 static int as3722_poweroff_remove(struct platform_device *pdev)
  66 {
  67         if (pm_power_off == as3722_pm_power_off)
  68                 pm_power_off = NULL;
  69         as3722_pm_poweroff = NULL;
  70
  71         return 0;
  72 }
  73
  74 static struct platform_driver as3722_poweroff_driver = {
  75         .driver = {
  76                 .name = "as3722-power-off",
  77         },
  78         .probe = as3722_poweroff_probe,
  79         .remove = as3722_poweroff_remove,
  80 };
  81
  82 module_platform_driver(as3722_poweroff_driver);
  83
  84 MODULE_DESCRIPTION("Power off driver for ams AS3722 PMIC Device");
  85 MODULE_ALIAS("platform:as3722-power-off");
  86 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
  87 MODULE_LICENSE("GPL v2");