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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
ac8498f0 PR |
2 | /* |
3 | * General Purpose I2C multiplexer | |
4 | * | |
5 | * Copyright (C) 2017 Axentia Technologies AB | |
6 | * | |
7 | * Author: Peter Rosin <peda@axentia.se> | |
ac8498f0 PR |
8 | */ |
9 | ||
10 | #include <linux/i2c.h> | |
11 | #include <linux/i2c-mux.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/mux/consumer.h> | |
14 | #include <linux/of_device.h> | |
15 | #include <linux/platform_device.h> | |
16 | ||
17 | struct mux { | |
18 | struct mux_control *control; | |
19 | ||
20 | bool do_not_deselect; | |
21 | }; | |
22 | ||
23 | static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan) | |
24 | { | |
25 | struct mux *mux = i2c_mux_priv(muxc); | |
26 | int ret; | |
27 | ||
28 | ret = mux_control_select(mux->control, chan); | |
29 | mux->do_not_deselect = ret < 0; | |
30 | ||
31 | return ret; | |
32 | } | |
33 | ||
34 | static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan) | |
35 | { | |
36 | struct mux *mux = i2c_mux_priv(muxc); | |
37 | ||
38 | if (mux->do_not_deselect) | |
39 | return 0; | |
40 | ||
41 | return mux_control_deselect(mux->control); | |
42 | } | |
43 | ||
44 | static struct i2c_adapter *mux_parent_adapter(struct device *dev) | |
45 | { | |
46 | struct device_node *np = dev->of_node; | |
47 | struct device_node *parent_np; | |
48 | struct i2c_adapter *parent; | |
49 | ||
50 | parent_np = of_parse_phandle(np, "i2c-parent", 0); | |
51 | if (!parent_np) { | |
52 | dev_err(dev, "Cannot parse i2c-parent\n"); | |
53 | return ERR_PTR(-ENODEV); | |
54 | } | |
55 | parent = of_find_i2c_adapter_by_node(parent_np); | |
56 | of_node_put(parent_np); | |
57 | if (!parent) | |
58 | return ERR_PTR(-EPROBE_DEFER); | |
59 | ||
60 | return parent; | |
61 | } | |
62 | ||
63 | static const struct of_device_id i2c_mux_of_match[] = { | |
64 | { .compatible = "i2c-mux", }, | |
65 | {}, | |
66 | }; | |
67 | MODULE_DEVICE_TABLE(of, i2c_mux_of_match); | |
68 | ||
69 | static int i2c_mux_probe(struct platform_device *pdev) | |
70 | { | |
71 | struct device *dev = &pdev->dev; | |
72 | struct device_node *np = dev->of_node; | |
73 | struct device_node *child; | |
74 | struct i2c_mux_core *muxc; | |
75 | struct mux *mux; | |
76 | struct i2c_adapter *parent; | |
77 | int children; | |
78 | int ret; | |
79 | ||
80 | if (!np) | |
81 | return -ENODEV; | |
82 | ||
83 | mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL); | |
84 | if (!mux) | |
85 | return -ENOMEM; | |
86 | ||
87 | mux->control = devm_mux_control_get(dev, NULL); | |
88 | if (IS_ERR(mux->control)) { | |
89 | if (PTR_ERR(mux->control) != -EPROBE_DEFER) | |
90 | dev_err(dev, "failed to get control-mux\n"); | |
91 | return PTR_ERR(mux->control); | |
92 | } | |
93 | ||
94 | parent = mux_parent_adapter(dev); | |
95 | if (IS_ERR(parent)) { | |
96 | if (PTR_ERR(parent) != -EPROBE_DEFER) | |
97 | dev_err(dev, "failed to get i2c-parent adapter\n"); | |
98 | return PTR_ERR(parent); | |
99 | } | |
100 | ||
101 | children = of_get_child_count(np); | |
102 | ||
103 | muxc = i2c_mux_alloc(parent, dev, children, 0, 0, | |
104 | i2c_mux_select, i2c_mux_deselect); | |
105 | if (!muxc) { | |
106 | ret = -ENOMEM; | |
107 | goto err_parent; | |
108 | } | |
109 | muxc->priv = mux; | |
110 | ||
111 | platform_set_drvdata(pdev, muxc); | |
112 | ||
113 | muxc->mux_locked = of_property_read_bool(np, "mux-locked"); | |
114 | ||
115 | for_each_child_of_node(np, child) { | |
116 | u32 chan; | |
117 | ||
118 | ret = of_property_read_u32(child, "reg", &chan); | |
119 | if (ret < 0) { | |
49d54abe RH |
120 | dev_err(dev, "no reg property for node '%pOFn'\n", |
121 | child); | |
ac8498f0 PR |
122 | goto err_children; |
123 | } | |
124 | ||
125 | if (chan >= mux_control_states(mux->control)) { | |
126 | dev_err(dev, "invalid reg %u\n", chan); | |
127 | ret = -EINVAL; | |
128 | goto err_children; | |
129 | } | |
130 | ||
131 | ret = i2c_mux_add_adapter(muxc, 0, chan, 0); | |
132 | if (ret) | |
133 | goto err_children; | |
134 | } | |
135 | ||
136 | dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name); | |
137 | ||
138 | return 0; | |
139 | ||
140 | err_children: | |
141 | i2c_mux_del_adapters(muxc); | |
142 | err_parent: | |
143 | i2c_put_adapter(parent); | |
144 | ||
145 | return ret; | |
146 | } | |
147 | ||
148 | static int i2c_mux_remove(struct platform_device *pdev) | |
149 | { | |
150 | struct i2c_mux_core *muxc = platform_get_drvdata(pdev); | |
151 | ||
152 | i2c_mux_del_adapters(muxc); | |
153 | i2c_put_adapter(muxc->parent); | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | static struct platform_driver i2c_mux_driver = { | |
159 | .probe = i2c_mux_probe, | |
160 | .remove = i2c_mux_remove, | |
161 | .driver = { | |
162 | .name = "i2c-mux-gpmux", | |
163 | .of_match_table = i2c_mux_of_match, | |
164 | }, | |
165 | }; | |
166 | module_platform_driver(i2c_mux_driver); | |
167 | ||
168 | MODULE_DESCRIPTION("General Purpose I2C multiplexer driver"); | |
169 | MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); | |
170 | MODULE_LICENSE("GPL v2"); |