xref: /openbmc/linux/drivers/i2c/muxes/i2c-mux-gpmux.c (revision ac8498f0ce5301c51c32607af5a318a7e05f45c5)
1*ac8498f0SPeter Rosin /*
2*ac8498f0SPeter Rosin  * General Purpose I2C multiplexer
3*ac8498f0SPeter Rosin  *
4*ac8498f0SPeter Rosin  * Copyright (C) 2017 Axentia Technologies AB
5*ac8498f0SPeter Rosin  *
6*ac8498f0SPeter Rosin  * Author: Peter Rosin <peda@axentia.se>
7*ac8498f0SPeter Rosin  *
8*ac8498f0SPeter Rosin  * This program is free software; you can redistribute it and/or modify
9*ac8498f0SPeter Rosin  * it under the terms of the GNU General Public License version 2 as
10*ac8498f0SPeter Rosin  * published by the Free Software Foundation.
11*ac8498f0SPeter Rosin  */
12*ac8498f0SPeter Rosin 
13*ac8498f0SPeter Rosin #include <linux/i2c.h>
14*ac8498f0SPeter Rosin #include <linux/i2c-mux.h>
15*ac8498f0SPeter Rosin #include <linux/module.h>
16*ac8498f0SPeter Rosin #include <linux/mux/consumer.h>
17*ac8498f0SPeter Rosin #include <linux/of_device.h>
18*ac8498f0SPeter Rosin #include <linux/platform_device.h>
19*ac8498f0SPeter Rosin 
20*ac8498f0SPeter Rosin struct mux {
21*ac8498f0SPeter Rosin 	struct mux_control *control;
22*ac8498f0SPeter Rosin 
23*ac8498f0SPeter Rosin 	bool do_not_deselect;
24*ac8498f0SPeter Rosin };
25*ac8498f0SPeter Rosin 
26*ac8498f0SPeter Rosin static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
27*ac8498f0SPeter Rosin {
28*ac8498f0SPeter Rosin 	struct mux *mux = i2c_mux_priv(muxc);
29*ac8498f0SPeter Rosin 	int ret;
30*ac8498f0SPeter Rosin 
31*ac8498f0SPeter Rosin 	ret = mux_control_select(mux->control, chan);
32*ac8498f0SPeter Rosin 	mux->do_not_deselect = ret < 0;
33*ac8498f0SPeter Rosin 
34*ac8498f0SPeter Rosin 	return ret;
35*ac8498f0SPeter Rosin }
36*ac8498f0SPeter Rosin 
37*ac8498f0SPeter Rosin static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
38*ac8498f0SPeter Rosin {
39*ac8498f0SPeter Rosin 	struct mux *mux = i2c_mux_priv(muxc);
40*ac8498f0SPeter Rosin 
41*ac8498f0SPeter Rosin 	if (mux->do_not_deselect)
42*ac8498f0SPeter Rosin 		return 0;
43*ac8498f0SPeter Rosin 
44*ac8498f0SPeter Rosin 	return mux_control_deselect(mux->control);
45*ac8498f0SPeter Rosin }
46*ac8498f0SPeter Rosin 
47*ac8498f0SPeter Rosin static struct i2c_adapter *mux_parent_adapter(struct device *dev)
48*ac8498f0SPeter Rosin {
49*ac8498f0SPeter Rosin 	struct device_node *np = dev->of_node;
50*ac8498f0SPeter Rosin 	struct device_node *parent_np;
51*ac8498f0SPeter Rosin 	struct i2c_adapter *parent;
52*ac8498f0SPeter Rosin 
53*ac8498f0SPeter Rosin 	parent_np = of_parse_phandle(np, "i2c-parent", 0);
54*ac8498f0SPeter Rosin 	if (!parent_np) {
55*ac8498f0SPeter Rosin 		dev_err(dev, "Cannot parse i2c-parent\n");
56*ac8498f0SPeter Rosin 		return ERR_PTR(-ENODEV);
57*ac8498f0SPeter Rosin 	}
58*ac8498f0SPeter Rosin 	parent = of_find_i2c_adapter_by_node(parent_np);
59*ac8498f0SPeter Rosin 	of_node_put(parent_np);
60*ac8498f0SPeter Rosin 	if (!parent)
61*ac8498f0SPeter Rosin 		return ERR_PTR(-EPROBE_DEFER);
62*ac8498f0SPeter Rosin 
63*ac8498f0SPeter Rosin 	return parent;
64*ac8498f0SPeter Rosin }
65*ac8498f0SPeter Rosin 
66*ac8498f0SPeter Rosin static const struct of_device_id i2c_mux_of_match[] = {
67*ac8498f0SPeter Rosin 	{ .compatible = "i2c-mux", },
68*ac8498f0SPeter Rosin 	{},
69*ac8498f0SPeter Rosin };
70*ac8498f0SPeter Rosin MODULE_DEVICE_TABLE(of, i2c_mux_of_match);
71*ac8498f0SPeter Rosin 
72*ac8498f0SPeter Rosin static int i2c_mux_probe(struct platform_device *pdev)
73*ac8498f0SPeter Rosin {
74*ac8498f0SPeter Rosin 	struct device *dev = &pdev->dev;
75*ac8498f0SPeter Rosin 	struct device_node *np = dev->of_node;
76*ac8498f0SPeter Rosin 	struct device_node *child;
77*ac8498f0SPeter Rosin 	struct i2c_mux_core *muxc;
78*ac8498f0SPeter Rosin 	struct mux *mux;
79*ac8498f0SPeter Rosin 	struct i2c_adapter *parent;
80*ac8498f0SPeter Rosin 	int children;
81*ac8498f0SPeter Rosin 	int ret;
82*ac8498f0SPeter Rosin 
83*ac8498f0SPeter Rosin 	if (!np)
84*ac8498f0SPeter Rosin 		return -ENODEV;
85*ac8498f0SPeter Rosin 
86*ac8498f0SPeter Rosin 	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
87*ac8498f0SPeter Rosin 	if (!mux)
88*ac8498f0SPeter Rosin 		return -ENOMEM;
89*ac8498f0SPeter Rosin 
90*ac8498f0SPeter Rosin 	mux->control = devm_mux_control_get(dev, NULL);
91*ac8498f0SPeter Rosin 	if (IS_ERR(mux->control)) {
92*ac8498f0SPeter Rosin 		if (PTR_ERR(mux->control) != -EPROBE_DEFER)
93*ac8498f0SPeter Rosin 			dev_err(dev, "failed to get control-mux\n");
94*ac8498f0SPeter Rosin 		return PTR_ERR(mux->control);
95*ac8498f0SPeter Rosin 	}
96*ac8498f0SPeter Rosin 
97*ac8498f0SPeter Rosin 	parent = mux_parent_adapter(dev);
98*ac8498f0SPeter Rosin 	if (IS_ERR(parent)) {
99*ac8498f0SPeter Rosin 		if (PTR_ERR(parent) != -EPROBE_DEFER)
100*ac8498f0SPeter Rosin 			dev_err(dev, "failed to get i2c-parent adapter\n");
101*ac8498f0SPeter Rosin 		return PTR_ERR(parent);
102*ac8498f0SPeter Rosin 	}
103*ac8498f0SPeter Rosin 
104*ac8498f0SPeter Rosin 	children = of_get_child_count(np);
105*ac8498f0SPeter Rosin 
106*ac8498f0SPeter Rosin 	muxc = i2c_mux_alloc(parent, dev, children, 0, 0,
107*ac8498f0SPeter Rosin 			     i2c_mux_select, i2c_mux_deselect);
108*ac8498f0SPeter Rosin 	if (!muxc) {
109*ac8498f0SPeter Rosin 		ret = -ENOMEM;
110*ac8498f0SPeter Rosin 		goto err_parent;
111*ac8498f0SPeter Rosin 	}
112*ac8498f0SPeter Rosin 	muxc->priv = mux;
113*ac8498f0SPeter Rosin 
114*ac8498f0SPeter Rosin 	platform_set_drvdata(pdev, muxc);
115*ac8498f0SPeter Rosin 
116*ac8498f0SPeter Rosin 	muxc->mux_locked = of_property_read_bool(np, "mux-locked");
117*ac8498f0SPeter Rosin 
118*ac8498f0SPeter Rosin 	for_each_child_of_node(np, child) {
119*ac8498f0SPeter Rosin 		u32 chan;
120*ac8498f0SPeter Rosin 
121*ac8498f0SPeter Rosin 		ret = of_property_read_u32(child, "reg", &chan);
122*ac8498f0SPeter Rosin 		if (ret < 0) {
123*ac8498f0SPeter Rosin 			dev_err(dev, "no reg property for node '%s'\n",
124*ac8498f0SPeter Rosin 				child->name);
125*ac8498f0SPeter Rosin 			goto err_children;
126*ac8498f0SPeter Rosin 		}
127*ac8498f0SPeter Rosin 
128*ac8498f0SPeter Rosin 		if (chan >= mux_control_states(mux->control)) {
129*ac8498f0SPeter Rosin 			dev_err(dev, "invalid reg %u\n", chan);
130*ac8498f0SPeter Rosin 			ret = -EINVAL;
131*ac8498f0SPeter Rosin 			goto err_children;
132*ac8498f0SPeter Rosin 		}
133*ac8498f0SPeter Rosin 
134*ac8498f0SPeter Rosin 		ret = i2c_mux_add_adapter(muxc, 0, chan, 0);
135*ac8498f0SPeter Rosin 		if (ret)
136*ac8498f0SPeter Rosin 			goto err_children;
137*ac8498f0SPeter Rosin 	}
138*ac8498f0SPeter Rosin 
139*ac8498f0SPeter Rosin 	dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name);
140*ac8498f0SPeter Rosin 
141*ac8498f0SPeter Rosin 	return 0;
142*ac8498f0SPeter Rosin 
143*ac8498f0SPeter Rosin err_children:
144*ac8498f0SPeter Rosin 	i2c_mux_del_adapters(muxc);
145*ac8498f0SPeter Rosin err_parent:
146*ac8498f0SPeter Rosin 	i2c_put_adapter(parent);
147*ac8498f0SPeter Rosin 
148*ac8498f0SPeter Rosin 	return ret;
149*ac8498f0SPeter Rosin }
150*ac8498f0SPeter Rosin 
151*ac8498f0SPeter Rosin static int i2c_mux_remove(struct platform_device *pdev)
152*ac8498f0SPeter Rosin {
153*ac8498f0SPeter Rosin 	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
154*ac8498f0SPeter Rosin 
155*ac8498f0SPeter Rosin 	i2c_mux_del_adapters(muxc);
156*ac8498f0SPeter Rosin 	i2c_put_adapter(muxc->parent);
157*ac8498f0SPeter Rosin 
158*ac8498f0SPeter Rosin 	return 0;
159*ac8498f0SPeter Rosin }
160*ac8498f0SPeter Rosin 
161*ac8498f0SPeter Rosin static struct platform_driver i2c_mux_driver = {
162*ac8498f0SPeter Rosin 	.probe	= i2c_mux_probe,
163*ac8498f0SPeter Rosin 	.remove	= i2c_mux_remove,
164*ac8498f0SPeter Rosin 	.driver	= {
165*ac8498f0SPeter Rosin 		.name	= "i2c-mux-gpmux",
166*ac8498f0SPeter Rosin 		.of_match_table = i2c_mux_of_match,
167*ac8498f0SPeter Rosin 	},
168*ac8498f0SPeter Rosin };
169*ac8498f0SPeter Rosin module_platform_driver(i2c_mux_driver);
170*ac8498f0SPeter Rosin 
171*ac8498f0SPeter Rosin MODULE_DESCRIPTION("General Purpose I2C multiplexer driver");
172*ac8498f0SPeter Rosin MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
173*ac8498f0SPeter Rosin MODULE_LICENSE("GPL v2");
174