drivers/sysreset/sysreset_syscon.c

   1 /*
   2  * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
   3  *
   4  * Derived from linux/drivers/power/reset/syscon-reboot.c:
   5  *      Copyright (C) 2013, Applied Micro Circuits Corporation
   6  *      Author: Feng Kan <fkan@apm.com>
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12 #include <dm.h>
  13 #include <errno.h>
  14 #include <regmap.h>
  15 #include <sysreset.h>
  16 #include <syscon.h>
  17
  18 DECLARE_GLOBAL_DATA_PTR;
  19
  20 struct syscon_reboot_priv {
  21         struct regmap *regmap;
  22         unsigned int offset;
  23         unsigned int mask;
  24 };
  25
  26 static int syscon_reboot_request(struct udevice *dev, enum sysreset_t type)
  27 {
  28         struct syscon_reboot_priv *priv = dev_get_priv(dev);
  29
  30         regmap_write(priv->regmap, priv->offset, priv->mask);
  31
  32         return -EINPROGRESS;
  33 }
  34
  35 static struct sysreset_ops syscon_reboot_ops = {
  36         .request = syscon_reboot_request,
  37 };
  38
  39 int syscon_reboot_probe(struct udevice *dev)
  40 {
  41         struct udevice *syscon;
  42         struct syscon_reboot_priv *priv = dev_get_priv(dev);
  43         int err;
  44
  45         err = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
  46                                            "regmap", &syscon);
  47         if (err) {
  48                 pr_err("unable to find syscon device\n");
  49                 return err;
  50         }
  51
  52         priv->regmap = syscon_get_regmap(syscon);
  53         if (!priv->regmap) {
  54                 pr_err("unable to find regmap\n");
  55                 return -ENODEV;
  56         }
  57
  58         priv->offset = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev),
  59                                        "offset", 0);
  60         priv->mask = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev),
  61                                        "mask", 0);
  62
  63         return 0;
  64 }
  65
  66 static const struct udevice_id syscon_reboot_ids[] = {
  67         { .compatible = "syscon-reboot" },
  68         { /* sentinel */ }
  69 };
  70
  71 U_BOOT_DRIVER(syscon_reboot) = {
  72         .name = "syscon_reboot",
  73         .id = UCLASS_SYSRESET,
  74         .of_match = syscon_reboot_ids,
  75         .probe = syscon_reboot_probe,
  76         .priv_auto_alloc_size = sizeof(struct syscon_reboot_priv),
  77         .ops = &syscon_reboot_ops,
  78 };