1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
4  *
5  * Derived from linux/drivers/power/reset/syscon-reboot.c:
6  *	Copyright (C) 2013, Applied Micro Circuits Corporation
7  *	Author: Feng Kan <fkan@apm.com>
8  */
9 
10 #include <common.h>
11 #include <dm.h>
12 #include <errno.h>
13 #include <regmap.h>
14 #include <sysreset.h>
15 #include <syscon.h>
16 
17 struct syscon_reboot_priv {
18 	struct regmap *regmap;
19 	unsigned int offset;
20 	unsigned int mask;
21 };
22 
23 static int syscon_reboot_request(struct udevice *dev, enum sysreset_t type)
24 {
25 	struct syscon_reboot_priv *priv = dev_get_priv(dev);
26 
27 	regmap_write(priv->regmap, priv->offset, priv->mask);
28 
29 	return -EINPROGRESS;
30 }
31 
32 static struct sysreset_ops syscon_reboot_ops = {
33 	.request = syscon_reboot_request,
34 };
35 
36 int syscon_reboot_probe(struct udevice *dev)
37 {
38 	struct syscon_reboot_priv *priv = dev_get_priv(dev);
39 	int err;
40 	u32 phandle;
41 	ofnode node;
42 
43 	err = ofnode_read_u32(dev_ofnode(dev), "regmap", &phandle);
44 	if (err)
45 		return err;
46 
47 	node = ofnode_get_by_phandle(phandle);
48 	if (!ofnode_valid(node))
49 		return -EINVAL;
50 
51 	priv->regmap = syscon_node_to_regmap(node);
52 	if (!priv->regmap) {
53 		pr_err("unable to find regmap\n");
54 		return -ENODEV;
55 	}
56 
57 	priv->offset = dev_read_u32_default(dev, "offset", 0);
58 	priv->mask = dev_read_u32_default(dev, "mask", 0);
59 
60 	return 0;
61 }
62 
63 static const struct udevice_id syscon_reboot_ids[] = {
64 	{ .compatible = "syscon-reboot" },
65 	{ /* sentinel */ }
66 };
67 
68 U_BOOT_DRIVER(syscon_reboot) = {
69 	.name = "syscon_reboot",
70 	.id = UCLASS_SYSRESET,
71 	.of_match = syscon_reboot_ids,
72 	.probe = syscon_reboot_probe,
73 	.priv_auto_alloc_size = sizeof(struct syscon_reboot_priv),
74 	.ops = &syscon_reboot_ops,
75 };
76