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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 | ||
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 | ||
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 | ||
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"); |