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
31static 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				return ret;
58			}
59		}
60	}
61
62	return 0;
63}
64
65static const struct of_device_id integrator_ap_syscon_match[] = {
66	{ .compatible = "arm,integrator-ap-syscon"},
67	{ },
68};
69
70static int integrator_ap_lm_probe(struct platform_device *pdev)
71{
72	struct device *dev = &pdev->dev;
73	struct device_node *syscon;
74	static struct regmap *map;
75	u32 val;
76	int ret;
77	int i;
78
79	/* Look up the system controller */
80	syscon = of_find_matching_node(NULL, integrator_ap_syscon_match);
81	if (!syscon) {
82		dev_err(dev,
83			"could not find Integrator/AP system controller\n");
84		return -ENODEV;
85	}
86	map = syscon_node_to_regmap(syscon);
87	if (IS_ERR(map)) {
88		dev_err(dev,
89			"could not find Integrator/AP system controller\n");
90		return PTR_ERR(map);
91	}
92
93	ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
94	if (ret) {
95		dev_err(dev, "could not read from Integrator/AP syscon\n");
96		return ret;
97	}
98
99	/* Loop over the connected modules */
100	for (i = 0; i < 4; i++) {
101		if (!(val & BIT(4 + i)))
102			continue;
103
104		dev_info(dev, "detected module in slot %d\n", i);
105		ret = integrator_lm_populate(i, dev);
106		if (ret)
107			return ret;
108	}
109
110	return 0;
111}
112
113static const struct of_device_id integrator_ap_lm_match[] = {
114	{ .compatible = "arm,integrator-ap-lm"},
115	{ },
116};
117
118static struct platform_driver integrator_ap_lm_driver = {
119	.probe = integrator_ap_lm_probe,
120	.driver = {
121		.name = "integratorap-lm",
122		.of_match_table = integrator_ap_lm_match,
123	},
124};
125module_platform_driver(integrator_ap_lm_driver);
126MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
127MODULE_DESCRIPTION("Integrator AP Logical Module driver");
128MODULE_LICENSE("GPL v2");
129