drivers/power/reset/qcom-pon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2017-18 Linaro Limited
   3
   4 #include <linux/delay.h>
   5 #include <linux/errno.h>
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/of.h>
   9 #include <linux/of_platform.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/reboot.h>
  12 #include <linux/reboot-mode.h>
  13 #include <linux/regmap.h>
  14
  15 #define PON_SOFT_RB_SPARE               0x8f
  16
  17 struct pm8916_pon {
  18         struct device *dev;
  19         struct regmap *regmap;
  20         u32 baseaddr;
  21         struct reboot_mode_driver reboot_mode;
  22 };
  23
  24 static int pm8916_reboot_mode_write(struct reboot_mode_driver *reboot,
  25                                     unsigned int magic)
  26 {
  27         struct pm8916_pon *pon = container_of
  28                         (reboot, struct pm8916_pon, reboot_mode);
  29         int ret;
  30
  31         ret = regmap_update_bits(pon->regmap,
  32                                  pon->baseaddr + PON_SOFT_RB_SPARE,
  33                                  0xfc, magic << 2);
  34         if (ret < 0)
  35                 dev_err(pon->dev, "update reboot mode bits failed\n");
  36
  37         return ret;
  38 }
  39
  40 static int pm8916_pon_probe(struct platform_device *pdev)
  41 {
  42         struct pm8916_pon *pon;
  43         int error;
  44
  45         pon = devm_kzalloc(&pdev->dev, sizeof(*pon), GFP_KERNEL);
  46         if (!pon)
  47                 return -ENOMEM;
  48
  49         pon->dev = &pdev->dev;
  50
  51         pon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
  52         if (!pon->regmap) {
  53                 dev_err(&pdev->dev, "failed to locate regmap\n");
  54                 return -ENODEV;
  55         }
  56
  57         error = of_property_read_u32(pdev->dev.of_node, "reg",
  58                                      &pon->baseaddr);
  59         if (error)
  60                 return error;
  61
  62         pon->reboot_mode.dev = &pdev->dev;
  63         pon->reboot_mode.write = pm8916_reboot_mode_write;
  64         error = devm_reboot_mode_register(&pdev->dev, &pon->reboot_mode);
  65         if (error) {
  66                 dev_err(&pdev->dev, "can't register reboot mode\n");
  67                 return error;
  68         }
  69
  70         platform_set_drvdata(pdev, pon);
  71
  72         return devm_of_platform_populate(&pdev->dev);
  73 }
  74
  75 static const struct of_device_id pm8916_pon_id_table[] = {
  76         { .compatible = "qcom,pm8916-pon" },
  77         { }
  78 };
  79 MODULE_DEVICE_TABLE(of, pm8916_pon_id_table);
  80
  81 static struct platform_driver pm8916_pon_driver = {
  82         .probe = pm8916_pon_probe,
  83         .driver = {
  84                 .name = "pm8916-pon",
  85                 .of_match_table = of_match_ptr(pm8916_pon_id_table),
  86         },
  87 };
  88 module_platform_driver(pm8916_pon_driver);
  89
  90 MODULE_DESCRIPTION("pm8916 Power On driver");
  91 MODULE_LICENSE("GPL v2");