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
integrator_lm_populate(int num,struct device * dev)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
integrator_ap_lm_probe(struct platform_device * pdev)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 if (IS_ERR(map)) {
89 dev_err(dev,
90 "could not find Integrator/AP system controller\n");
91 return PTR_ERR(map);
92 }
93
94 ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, &val);
95 if (ret) {
96 dev_err(dev, "could not read from Integrator/AP syscon\n");
97 return ret;
98 }
99
100 /* Loop over the connected modules */
101 for (i = 0; i < 4; i++) {
102 if (!(val & BIT(4 + i)))
103 continue;
104
105 dev_info(dev, "detected module in slot %d\n", i);
106 ret = integrator_lm_populate(i, dev);
107 if (ret)
108 return ret;
109 }
110
111 return 0;
112 }
113
114 static const struct of_device_id integrator_ap_lm_match[] = {
115 { .compatible = "arm,integrator-ap-lm"},
116 { },
117 };
118
119 static struct platform_driver integrator_ap_lm_driver = {
120 .probe = integrator_ap_lm_probe,
121 .driver = {
122 .name = "integratorap-lm",
123 .of_match_table = integrator_ap_lm_match,
124 },
125 };
126 module_platform_driver(integrator_ap_lm_driver);
127 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
128 MODULE_DESCRIPTION("Integrator AP Logical Module driver");
129
