1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2014 Linaro Ltd.
4  *
5  * Author: Linus Walleij <linus.walleij@linaro.org>
6  */
7 #include <linux/device.h>
8 #include <linux/init.h>
9 #include <linux/io.h>
10 #include <linux/slab.h>
11 #include <linux/sys_soc.h>
12 #include <linux/platform_device.h>
13 #include <linux/mfd/syscon.h>
14 #include <linux/regmap.h>
15 #include <linux/of.h>
16 
17 /* System ID in syscon */
18 #define REALVIEW_SYS_ID_OFFSET 0x00
19 
20 static const struct of_device_id realview_soc_of_match[] = {
21 	{ .compatible = "arm,realview-eb-soc",	},
22 	{ .compatible = "arm,realview-pb1176-soc", },
23 	{ .compatible = "arm,realview-pb11mp-soc", },
24 	{ .compatible = "arm,realview-pba8-soc", },
25 	{ .compatible = "arm,realview-pbx-soc", },
26 	{ }
27 };
28 
29 static u32 realview_coreid;
30 
31 static const char *realview_arch_str(u32 id)
32 {
33 	switch ((id >> 8) & 0xf) {
34 	case 0x04:
35 		return "AHB";
36 	case 0x05:
37 		return "Multi-layer AXI";
38 	default:
39 		return "Unknown";
40 	}
41 }
42 
43 static ssize_t
44 manufacturer_show(struct device *dev, struct device_attribute *attr, char *buf)
45 {
46 	return sprintf(buf, "%02x\n", realview_coreid >> 24);
47 }
48 
49 static DEVICE_ATTR_RO(manufacturer);
50 
51 static ssize_t
52 board_show(struct device *dev, struct device_attribute *attr, char *buf)
53 {
54 	return sprintf(buf, "HBI-%03x\n", ((realview_coreid >> 16) & 0xfff));
55 }
56 
57 static DEVICE_ATTR_RO(board);
58 
59 static ssize_t
60 fpga_show(struct device *dev, struct device_attribute *attr, char *buf)
61 {
62 	return sprintf(buf, "%s\n", realview_arch_str(realview_coreid));
63 }
64 
65 static DEVICE_ATTR_RO(fpga);
66 
67 static ssize_t
68 build_show(struct device *dev, struct device_attribute *attr, char *buf)
69 {
70 	return sprintf(buf, "%02x\n", (realview_coreid & 0xFF));
71 }
72 
73 static DEVICE_ATTR_RO(build);
74 
75 static struct attribute *realview_attrs[] = {
76 	&dev_attr_manufacturer.attr,
77 	&dev_attr_board.attr,
78 	&dev_attr_fpga.attr,
79 	&dev_attr_build.attr,
80 	NULL
81 };
82 
83 ATTRIBUTE_GROUPS(realview);
84 
85 static void realview_soc_socdev_release(void *data)
86 {
87 	struct soc_device *soc_dev = data;
88 
89 	soc_device_unregister(soc_dev);
90 }
91 
92 static int realview_soc_probe(struct platform_device *pdev)
93 {
94 	struct regmap *syscon_regmap;
95 	struct soc_device *soc_dev;
96 	struct soc_device_attribute *soc_dev_attr;
97 	struct device_node *np = pdev->dev.of_node;
98 	int ret;
99 
100 	syscon_regmap = syscon_regmap_lookup_by_phandle(np, "regmap");
101 	if (IS_ERR(syscon_regmap))
102 		return PTR_ERR(syscon_regmap);
103 
104 	soc_dev_attr = devm_kzalloc(&pdev->dev, sizeof(*soc_dev_attr), GFP_KERNEL);
105 	if (!soc_dev_attr)
106 		return -ENOMEM;
107 
108 	ret = of_property_read_string(np, "compatible",
109 				      &soc_dev_attr->soc_id);
110 	if (ret)
111 		return -EINVAL;
112 
113 	soc_dev_attr->machine = "RealView";
114 	soc_dev_attr->family = "Versatile";
115 	soc_dev_attr->custom_attr_group = realview_groups[0];
116 	soc_dev = soc_device_register(soc_dev_attr);
117 	if (IS_ERR(soc_dev))
118 		return -ENODEV;
119 
120 	ret = devm_add_action_or_reset(&pdev->dev, realview_soc_socdev_release,
121 				       soc_dev);
122 	if (ret)
123 		return ret;
124 
125 	ret = regmap_read(syscon_regmap, REALVIEW_SYS_ID_OFFSET,
126 			  &realview_coreid);
127 	if (ret)
128 		return -ENODEV;
129 
130 	dev_info(&pdev->dev, "RealView Syscon Core ID: 0x%08x, HBI-%03x\n",
131 		 realview_coreid,
132 		 ((realview_coreid >> 16) & 0xfff));
133 	/* FIXME: add attributes for SoC to sysfs */
134 	return 0;
135 }
136 
137 static struct platform_driver realview_soc_driver = {
138 	.probe = realview_soc_probe,
139 	.driver = {
140 		.name = "realview-soc",
141 		.of_match_table = realview_soc_of_match,
142 	},
143 };
144 builtin_platform_driver(realview_soc_driver);
145