1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2025 Alexey Charkov <alchark@gmail.com>
4 * Based on aspeed-socinfo.c
5 */
6
7 #include <linux/dev_printk.h>
8 #include <linux/device.h>
9 #include <linux/io.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/sys_soc.h>
13
14 static const struct {
15 const char *name;
16 const u32 id;
17 } chip_id_table[] = {
18 /* VIA */
19 { "VT8420", 0x3300 },
20 { "VT8430", 0x3357 },
21 { "VT8500", 0x3400 },
22
23 /* WonderMedia */
24 { "WM8425", 0x3429 },
25 { "WM8435", 0x3437 },
26 { "WM8440", 0x3451 },
27 { "WM8505", 0x3426 },
28 { "WM8650", 0x3465 },
29 { "WM8750", 0x3445 },
30 { "WM8850", 0x3481 },
31 { "WM8880", 0x3498 },
32 };
33
sccid_to_name(u32 sccid)34 static const char *sccid_to_name(u32 sccid)
35 {
36 u32 id = sccid >> 16;
37 unsigned int i;
38
39 for (i = 0 ; i < ARRAY_SIZE(chip_id_table) ; ++i) {
40 if (chip_id_table[i].id == id)
41 return chip_id_table[i].name;
42 }
43
44 return "Unknown";
45 }
46
wmt_socinfo_probe(struct platform_device * pdev)47 static int wmt_socinfo_probe(struct platform_device *pdev)
48 {
49 struct device_node *np = pdev->dev.of_node;
50 struct soc_device_attribute *attrs;
51 struct soc_device *soc_dev;
52 char letter, digit;
53 void __iomem *reg;
54 u32 sccid;
55
56 reg = devm_of_iomap(&pdev->dev, np, 0, NULL);
57 if (IS_ERR(reg))
58 return PTR_ERR(reg);
59
60 sccid = readl(reg);
61
62 attrs = devm_kzalloc(&pdev->dev, sizeof(*attrs), GFP_KERNEL);
63 if (!attrs)
64 return -ENOMEM;
65
66 /*
67 * Machine: VIA APC Rock
68 * Family: WM8850
69 * Revision: A2
70 * SoC ID: raw silicon revision id (34810103 in hexadecimal)
71 */
72
73 attrs->family = sccid_to_name(sccid);
74
75 letter = (sccid >> 8) & 0xf;
76 letter = (letter - 1) + 'A';
77 digit = sccid & 0xff;
78 digit = (digit - 1) + '0';
79 attrs->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL,
80 "%c%c", letter, digit);
81
82 attrs->soc_id = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%08x", sccid);
83
84 if (!attrs->revision || !attrs->soc_id)
85 return -ENOMEM;
86
87 soc_dev = soc_device_register(attrs);
88 if (IS_ERR(soc_dev))
89 return PTR_ERR(soc_dev);
90
91 dev_info(&pdev->dev,
92 "VIA/WonderMedia %s rev %s (%s)\n",
93 attrs->family,
94 attrs->revision,
95 attrs->soc_id);
96
97 platform_set_drvdata(pdev, soc_dev);
98 return 0;
99 }
100
wmt_socinfo_remove(struct platform_device * pdev)101 static void wmt_socinfo_remove(struct platform_device *pdev)
102 {
103 struct soc_device *soc_dev = platform_get_drvdata(pdev);
104
105 soc_device_unregister(soc_dev);
106 }
107
108 static const struct of_device_id wmt_socinfo_ids[] = {
109 { .compatible = "via,vt8500-scc-id" },
110 { /* Sentinel */ },
111 };
112
113 static struct platform_driver wmt_socinfo = {
114 .probe = wmt_socinfo_probe,
115 .remove = wmt_socinfo_remove,
116 .driver = {
117 .name = "wmt-socinfo",
118 .of_match_table = wmt_socinfo_ids,
119 },
120 };
121 module_platform_driver(wmt_socinfo);
122
123 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
124 MODULE_DESCRIPTION("VIA/WonderMedia socinfo driver");
125 MODULE_LICENSE("GPL");
126