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(dev: child, index: 0, r: &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(root: child, NULL, parent: dev); |
55 | if (ret) { |
56 | dev_err(dev, "failed to populate module\n" ); |
57 | of_node_put(node: 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, matches: 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(np: syscon); |
88 | if (IS_ERR(ptr: map)) { |
89 | dev_err(dev, |
90 | "could not find Integrator/AP system controller\n" ); |
91 | return PTR_ERR(ptr: map); |
92 | } |
93 | |
94 | ret = regmap_read(map, INTEGRATOR_SC_DEC_OFFSET, val: &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(num: 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 | |