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 return ret;
58 }
59 }
60 }
61
62 return 0;
63 }
64
65 static const struct of_device_id integrator_ap_syscon_match[] = {
66 { .compatible = "arm,integrator-ap-syscon"},
67 { },
68 };
69
integrator_ap_lm_probe(struct platform_device * pdev)70 static 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
113 static const struct of_device_id integrator_ap_lm_match[] = {
114 { .compatible = "arm,integrator-ap-lm"},
115 { },
116 };
117
118 static 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 };
125 module_platform_driver(integrator_ap_lm_driver);
126 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
127 MODULE_DESCRIPTION("Integrator AP Logical Module driver");
128 MODULE_LICENSE("GPL v2");
129
