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a2443fd1 | 1 | // SPDX-License-Identifier: GPL-2.0 |
6cc2ff82 TT |
2 | /* |
3 | * Simple memory-mapped device MDIO MUX driver | |
4 | * | |
5 | * Author: Timur Tabi <timur@freescale.com> | |
6 | * | |
7 | * Copyright 2012 Freescale Semiconductor, Inc. | |
6cc2ff82 TT |
8 | */ |
9 | ||
10 | #include <linux/platform_device.h> | |
11 | #include <linux/device.h> | |
16fa9e1d | 12 | #include <linux/of_address.h> |
6cc2ff82 TT |
13 | #include <linux/of_mdio.h> |
14 | #include <linux/module.h> | |
6cc2ff82 TT |
15 | #include <linux/phy.h> |
16 | #include <linux/mdio-mux.h> | |
17 | ||
18 | struct mdio_mux_mmioreg_state { | |
19 | void *mux_handle; | |
20 | phys_addr_t phys; | |
9a4c8037 NA |
21 | unsigned int iosize; |
22 | unsigned int mask; | |
6cc2ff82 TT |
23 | }; |
24 | ||
25 | /* | |
26 | * MDIO multiplexing switch function | |
27 | * | |
28 | * This function is called by the mdio-mux layer when it thinks the mdio bus | |
29 | * multiplexer needs to switch. | |
30 | * | |
31 | * 'current_child' is the current value of the mux register (masked via | |
32 | * s->mask). | |
33 | * | |
34 | * 'desired_child' is the value of the 'reg' property of the target child MDIO | |
35 | * node. | |
36 | * | |
37 | * The first time this function is called, current_child == -1. | |
38 | * | |
39 | * If current_child == desired_child, then the mux is already set to the | |
40 | * correct bus. | |
41 | */ | |
42 | static int mdio_mux_mmioreg_switch_fn(int current_child, int desired_child, | |
43 | void *data) | |
44 | { | |
45 | struct mdio_mux_mmioreg_state *s = data; | |
46 | ||
47 | if (current_child ^ desired_child) { | |
9a4c8037 | 48 | void __iomem *p = ioremap(s->phys, s->iosize); |
6cc2ff82 TT |
49 | if (!p) |
50 | return -ENOMEM; | |
51 | ||
9a4c8037 NA |
52 | switch (s->iosize) { |
53 | case sizeof(uint8_t): { | |
54 | uint8_t x, y; | |
55 | ||
56 | x = ioread8(p); | |
57 | y = (x & ~s->mask) | desired_child; | |
58 | if (x != y) { | |
59 | iowrite8((x & ~s->mask) | desired_child, p); | |
60 | pr_debug("%s: %02x -> %02x\n", __func__, x, y); | |
61 | } | |
62 | ||
63 | break; | |
64 | } | |
65 | case sizeof(uint16_t): { | |
66 | uint16_t x, y; | |
67 | ||
68 | x = ioread16(p); | |
69 | y = (x & ~s->mask) | desired_child; | |
70 | if (x != y) { | |
71 | iowrite16((x & ~s->mask) | desired_child, p); | |
72 | pr_debug("%s: %04x -> %04x\n", __func__, x, y); | |
73 | } | |
74 | ||
75 | break; | |
76 | } | |
77 | case sizeof(uint32_t): { | |
78 | uint32_t x, y; | |
79 | ||
80 | x = ioread32(p); | |
81 | y = (x & ~s->mask) | desired_child; | |
82 | if (x != y) { | |
83 | iowrite32((x & ~s->mask) | desired_child, p); | |
84 | pr_debug("%s: %08x -> %08x\n", __func__, x, y); | |
85 | } | |
86 | ||
87 | break; | |
88 | } | |
6cc2ff82 TT |
89 | } |
90 | ||
91 | iounmap(p); | |
92 | } | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
633d1594 | 97 | static int mdio_mux_mmioreg_probe(struct platform_device *pdev) |
6cc2ff82 TT |
98 | { |
99 | struct device_node *np2, *np = pdev->dev.of_node; | |
100 | struct mdio_mux_mmioreg_state *s; | |
101 | struct resource res; | |
102 | const __be32 *iprop; | |
103 | int len, ret; | |
104 | ||
f7ce9103 | 105 | dev_dbg(&pdev->dev, "probing node %pOF\n", np); |
6cc2ff82 TT |
106 | |
107 | s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL); | |
108 | if (!s) | |
109 | return -ENOMEM; | |
110 | ||
111 | ret = of_address_to_resource(np, 0, &res); | |
112 | if (ret) { | |
f7ce9103 RH |
113 | dev_err(&pdev->dev, "could not obtain memory map for node %pOF\n", |
114 | np); | |
6cc2ff82 TT |
115 | return ret; |
116 | } | |
117 | s->phys = res.start; | |
118 | ||
9a4c8037 NA |
119 | s->iosize = resource_size(&res); |
120 | if (s->iosize != sizeof(uint8_t) && | |
121 | s->iosize != sizeof(uint16_t) && | |
122 | s->iosize != sizeof(uint32_t)) { | |
123 | dev_err(&pdev->dev, "only 8/16/32-bit registers are supported\n"); | |
6cc2ff82 TT |
124 | return -EINVAL; |
125 | } | |
126 | ||
127 | iprop = of_get_property(np, "mux-mask", &len); | |
128 | if (!iprop || len != sizeof(uint32_t)) { | |
129 | dev_err(&pdev->dev, "missing or invalid mux-mask property\n"); | |
130 | return -ENODEV; | |
131 | } | |
9a4c8037 NA |
132 | if (be32_to_cpup(iprop) >= BIT(s->iosize * 8)) { |
133 | dev_err(&pdev->dev, "only 8/16/32-bit registers are supported\n"); | |
6cc2ff82 TT |
134 | return -EINVAL; |
135 | } | |
136 | s->mask = be32_to_cpup(iprop); | |
137 | ||
138 | /* | |
139 | * Verify that the 'reg' property of each child MDIO bus does not | |
140 | * set any bits outside of the 'mask'. | |
141 | */ | |
142 | for_each_available_child_of_node(np, np2) { | |
143 | iprop = of_get_property(np2, "reg", &len); | |
144 | if (!iprop || len != sizeof(uint32_t)) { | |
f7ce9103 RH |
145 | dev_err(&pdev->dev, "mdio-mux child node %pOF is " |
146 | "missing a 'reg' property\n", np2); | |
02862341 | 147 | of_node_put(np2); |
6cc2ff82 TT |
148 | return -ENODEV; |
149 | } | |
150 | if (be32_to_cpup(iprop) & ~s->mask) { | |
f7ce9103 | 151 | dev_err(&pdev->dev, "mdio-mux child node %pOF has " |
6cc2ff82 | 152 | "a 'reg' value with unmasked bits\n", |
f7ce9103 | 153 | np2); |
02862341 | 154 | of_node_put(np2); |
6cc2ff82 TT |
155 | return -ENODEV; |
156 | } | |
157 | } | |
158 | ||
5482a978 CL |
159 | ret = mdio_mux_init(&pdev->dev, pdev->dev.of_node, |
160 | mdio_mux_mmioreg_switch_fn, | |
f20e6657 | 161 | &s->mux_handle, s, NULL); |
6cc2ff82 | 162 | if (ret) { |
630b21a2 JB |
163 | if (ret != -EPROBE_DEFER) |
164 | dev_err(&pdev->dev, | |
165 | "failed to register mdio-mux bus %pOF\n", np); | |
6cc2ff82 TT |
166 | return ret; |
167 | } | |
168 | ||
169 | pdev->dev.platform_data = s; | |
170 | ||
171 | return 0; | |
172 | } | |
173 | ||
633d1594 | 174 | static int mdio_mux_mmioreg_remove(struct platform_device *pdev) |
6cc2ff82 TT |
175 | { |
176 | struct mdio_mux_mmioreg_state *s = dev_get_platdata(&pdev->dev); | |
177 | ||
178 | mdio_mux_uninit(s->mux_handle); | |
179 | ||
180 | return 0; | |
181 | } | |
182 | ||
d8a7dadb | 183 | static const struct of_device_id mdio_mux_mmioreg_match[] = { |
6cc2ff82 TT |
184 | { |
185 | .compatible = "mdio-mux-mmioreg", | |
186 | }, | |
187 | {}, | |
188 | }; | |
189 | MODULE_DEVICE_TABLE(of, mdio_mux_mmioreg_match); | |
190 | ||
191 | static struct platform_driver mdio_mux_mmioreg_driver = { | |
192 | .driver = { | |
193 | .name = "mdio-mux-mmioreg", | |
6cc2ff82 TT |
194 | .of_match_table = mdio_mux_mmioreg_match, |
195 | }, | |
196 | .probe = mdio_mux_mmioreg_probe, | |
633d1594 | 197 | .remove = mdio_mux_mmioreg_remove, |
6cc2ff82 TT |
198 | }; |
199 | ||
200 | module_platform_driver(mdio_mux_mmioreg_driver); | |
201 | ||
202 | MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); | |
203 | MODULE_DESCRIPTION("Memory-mapped device MDIO MUX driver"); | |
204 | MODULE_LICENSE("GPL v2"); |