1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * General Purpose I2C multiplexer |
4 | * |
5 | * Copyright (C) 2017 Axentia Technologies AB |
6 | * |
7 | * Author: Peter Rosin <peda@axentia.se> |
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.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: mux->control, state: 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: 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, phandle_name: "i2c-parent" , index: 0); |
51 | if (!parent_np) { |
52 | dev_err(dev, "Cannot parse i2c-parent\n" ); |
53 | return ERR_PTR(error: -ENODEV); |
54 | } |
55 | parent = of_get_i2c_adapter_by_node(node: parent_np); |
56 | of_node_put(node: parent_np); |
57 | if (!parent) |
58 | return ERR_PTR(error: -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, size: sizeof(*mux), GFP_KERNEL); |
84 | if (!mux) |
85 | return -ENOMEM; |
86 | |
87 | mux->control = devm_mux_control_get(dev, NULL); |
88 | if (IS_ERR(ptr: mux->control)) |
89 | return dev_err_probe(dev, err: PTR_ERR(ptr: mux->control), |
90 | fmt: "failed to get control-mux\n" ); |
91 | |
92 | parent = mux_parent_adapter(dev); |
93 | if (IS_ERR(ptr: parent)) |
94 | return dev_err_probe(dev, err: PTR_ERR(ptr: parent), |
95 | fmt: "failed to get i2c-parent adapter\n" ); |
96 | |
97 | children = of_get_child_count(np); |
98 | |
99 | muxc = i2c_mux_alloc(parent, dev, max_adapters: children, sizeof_priv: 0, flags: 0, |
100 | select: i2c_mux_select, deselect: i2c_mux_deselect); |
101 | if (!muxc) { |
102 | ret = -ENOMEM; |
103 | goto err_parent; |
104 | } |
105 | muxc->priv = mux; |
106 | |
107 | platform_set_drvdata(pdev, data: muxc); |
108 | |
109 | muxc->mux_locked = of_property_read_bool(np, propname: "mux-locked" ); |
110 | |
111 | for_each_child_of_node(np, child) { |
112 | u32 chan; |
113 | |
114 | ret = of_property_read_u32(np: child, propname: "reg" , out_value: &chan); |
115 | if (ret < 0) { |
116 | dev_err(dev, "no reg property for node '%pOFn'\n" , |
117 | child); |
118 | goto err_children; |
119 | } |
120 | |
121 | if (chan >= mux_control_states(mux: mux->control)) { |
122 | dev_err(dev, "invalid reg %u\n" , chan); |
123 | ret = -EINVAL; |
124 | goto err_children; |
125 | } |
126 | |
127 | ret = i2c_mux_add_adapter(muxc, force_nr: 0, chan_id: chan, class: 0); |
128 | if (ret) |
129 | goto err_children; |
130 | } |
131 | |
132 | dev_info(dev, "%d-port mux on %s adapter\n" , children, parent->name); |
133 | |
134 | return 0; |
135 | |
136 | err_children: |
137 | of_node_put(node: child); |
138 | i2c_mux_del_adapters(muxc); |
139 | err_parent: |
140 | i2c_put_adapter(adap: parent); |
141 | |
142 | return ret; |
143 | } |
144 | |
145 | static void i2c_mux_remove(struct platform_device *pdev) |
146 | { |
147 | struct i2c_mux_core *muxc = platform_get_drvdata(pdev); |
148 | |
149 | i2c_mux_del_adapters(muxc); |
150 | i2c_put_adapter(adap: muxc->parent); |
151 | } |
152 | |
153 | static struct platform_driver i2c_mux_driver = { |
154 | .probe = i2c_mux_probe, |
155 | .remove_new = i2c_mux_remove, |
156 | .driver = { |
157 | .name = "i2c-mux-gpmux" , |
158 | .of_match_table = i2c_mux_of_match, |
159 | }, |
160 | }; |
161 | module_platform_driver(i2c_mux_driver); |
162 | |
163 | MODULE_DESCRIPTION("General Purpose I2C multiplexer driver" ); |
164 | MODULE_AUTHOR("Peter Rosin <peda@axentia.se>" ); |
165 | MODULE_LICENSE("GPL v2" ); |
166 | |