1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Nuvoton WPCM450 SoC Identification
4 *
5 * Copyright (C) 2022 Jonathan Neuschäfer
6 */
7
8#include <linux/mfd/syscon.h>
9#include <linux/of.h>
10#include <linux/regmap.h>
11#include <linux/slab.h>
12#include <linux/sys_soc.h>
13
14#define GCR_PDID	0
15#define PDID_CHIP(x)	((x) & 0x00ffffff)
16#define CHIP_WPCM450	0x926450
17#define PDID_REV(x)	((x) >> 24)
18
19struct revision {
20	u8 number;
21	const char *name;
22};
23
24static const struct revision revisions[] __initconst = {
25	{ 0x00, "Z1" },
26	{ 0x03, "Z2" },
27	{ 0x04, "Z21" },
28	{ 0x08, "A1" },
29	{ 0x09, "A2" },
30	{ 0x0a, "A3" },
31	{}
32};
33
34static const char * __init get_revision(unsigned int rev)
35{
36	int i;
37
38	for (i = 0; revisions[i].name; i++)
39		if (revisions[i].number == rev)
40			return revisions[i].name;
41	return NULL;
42}
43
44static struct soc_device_attribute *wpcm450_attr;
45static struct soc_device *wpcm450_soc;
46
47static int __init wpcm450_soc_init(void)
48{
49	struct soc_device_attribute *attr;
50	struct soc_device *soc;
51	const char *revision;
52	struct regmap *gcr;
53	u32 pdid;
54	int ret;
55
56	if (!of_machine_is_compatible("nuvoton,wpcm450"))
57		return 0;
58
59	gcr = syscon_regmap_lookup_by_compatible("nuvoton,wpcm450-gcr");
60	if (IS_ERR(gcr))
61		return PTR_ERR(gcr);
62	ret = regmap_read(gcr, GCR_PDID, &pdid);
63	if (ret)
64		return ret;
65
66	if (PDID_CHIP(pdid) != CHIP_WPCM450) {
67		pr_warn("Unknown chip ID in GCR.PDID: 0x%06x\n", PDID_CHIP(pdid));
68		return -ENODEV;
69	}
70
71	revision = get_revision(PDID_REV(pdid));
72	if (!revision) {
73		pr_warn("Unknown chip revision in GCR.PDID: 0x%02x\n", PDID_REV(pdid));
74		return -ENODEV;
75	}
76
77	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
78	if (!attr)
79		return -ENOMEM;
80
81	attr->family = "Nuvoton NPCM";
82	attr->soc_id = "WPCM450";
83	attr->revision = revision;
84	soc = soc_device_register(attr);
85	if (IS_ERR(soc)) {
86		kfree(attr);
87		pr_warn("Could not register SoC device\n");
88		return PTR_ERR(soc);
89	}
90
91	wpcm450_soc = soc;
92	wpcm450_attr = attr;
93	return 0;
94}
95module_init(wpcm450_soc_init);
96
97static void __exit wpcm450_soc_exit(void)
98{
99	if (wpcm450_soc) {
100		soc_device_unregister(wpcm450_soc);
101		wpcm450_soc = NULL;
102		kfree(wpcm450_attr);
103	}
104}
105module_exit(wpcm450_soc_exit);
106
107MODULE_LICENSE("GPL");
108MODULE_AUTHOR("Jonathan Neuschäfer");
109MODULE_DESCRIPTION("Nuvoton WPCM450 SoC Identification driver");
110