1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ARM Integrator Logical Module bus driver
4  * Copyright (C) 2020 Linaro Ltd.
5  * Author: Linus Walleij <linus.walleij@linaro.org>
6  *
7  * See the device tree bindings for this block for more details on the
8  * hardware.
9  */
10 
11 #include <linux/module.h>
12 #include <linux/err.h>
13 #include <linux/io.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16 #include <linux/of_platform.h>
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <linux/platform_device.h>
20 #include <linux/bitops.h>
21 #include <linux/mfd/syscon.h>
22 #include <linux/regmap.h>
23 
24 /* All information about the connected logic modules are in here */
25 #define INTEGRATOR_SC_DEC_OFFSET	0x10
26 
27 /* Base address for the expansion modules */
28 #define INTEGRATOR_AP_EXP_BASE		0xc0000000
29 #define INTEGRATOR_AP_EXP_STRIDE	0x10000000
30 
31 static int integrator_lm_populate(int num, struct device *dev)
32 {
33 	struct device_node *np = dev->of_node;
34 	struct device_node *child;
35 	u32 base;
36 	int ret;
37 
38 	base = INTEGRATOR_AP_EXP_BASE + (num * INTEGRATOR_AP_EXP_STRIDE);
39 
40 	/* Walk over the child nodes and see what chipselects we use */
41 	for_each_available_child_of_node(np, child) {
42 		struct resource res;
43 
44 		ret = of_address_to_resource(child, 0, &res);
45 		if (ret) {
46 			dev_info(dev, "no valid address on child\n");
47 			continue;
48 		}
49 
50 		/* First populate the syscon then any devices */
51 		if (res.start == base) {
52 			dev_info(dev, "populate module @0x%08x from DT\n",
53 				 base);
54 			ret = of_platform_default_populate(child, NULL, dev);
55 			if (ret) {
56 				dev_err(dev, "failed to populate module\n");
57 				of_node_put(child);
58 				return ret;
59 			}
60 		}
61 	}
62 
63 	return 0;
64 }
65 
66 static const struct of_device_id integrator_ap_syscon_match[] = {
67 	{ .compatible = "arm,integrator-ap-syscon"},
68 	{ },
69 };
70 
71 static int integrator_ap_lm_probe(struct platform_device *pdev)
72 {
73 	struct device *dev = &pdev->dev;
74 	struct device_node *syscon;
75 	static struct regmap *map;
76 	u32 val;
77 	int ret;
78 	int i;
79 
80 	/* Look up the system controller */
81 	syscon = of_find_matching_node(NULL, integrator_ap_syscon_match);
82 	if (!syscon) {
83 		dev_err(dev,
84 			"could not find Integrator/AP system controller\n");
85 		return -ENODEV;
86 	}
87 	map = syscon_node_to_regmap(syscon);
88 	of_node_put(syscon);
89 	if (IS_ERR(map)) {
90 		dev_err(dev,
91 			"could not find Integrator/AP system controller\n");
92 		return PTR_ERR(map);
93 	}
94 
95 	ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
96 	if (ret) {
97 		dev_err(dev, "could not read from Integrator/AP syscon\n");
98 		return ret;
99 	}
100 
101 	/* Loop over the connected modules */
102 	for (i = 0; i < 4; i++) {
103 		if (!(val & BIT(4 + i)))
104 			continue;
105 
106 		dev_info(dev, "detected module in slot %d\n", i);
107 		ret = integrator_lm_populate(i, dev);
108 		if (ret)
109 			return ret;
110 	}
111 
112 	return 0;
113 }
114 
115 static const struct of_device_id integrator_ap_lm_match[] = {
116 	{ .compatible = "arm,integrator-ap-lm"},
117 	{ },
118 };
119 
120 static struct platform_driver integrator_ap_lm_driver = {
121 	.probe = integrator_ap_lm_probe,
122 	.driver = {
123 		.name = "integratorap-lm",
124 		.of_match_table = integrator_ap_lm_match,
125 	},
126 };
127 module_platform_driver(integrator_ap_lm_driver);
128 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
129 MODULE_DESCRIPTION("Integrator AP Logical Module driver");
130