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
19 struct revision {
20 u8 number;
21 const char *name;
22 };
23
24 static 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
get_revision(unsigned int rev)34 static 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
44 static struct soc_device_attribute *wpcm450_attr;
45 static struct soc_device *wpcm450_soc;
46
wpcm450_soc_init(void)47 static 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 }
95 module_init(wpcm450_soc_init);
96
wpcm450_soc_exit(void)97 static 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 }
105 module_exit(wpcm450_soc_exit);
106
107 MODULE_LICENSE("GPL");
108 MODULE_AUTHOR("Jonathan Neuschäfer");
109 MODULE_DESCRIPTION("Nuvoton WPCM450 SoC Identification driver");
110