1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* I2C multiplexer using pinctrl API
*
* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
*/
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/of.h>
#include "../../pinctrl/core.h"
struct i2c_mux_pinctrl {
struct pinctrl *pinctrl;
struct pinctrl_state *states[];
};
static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan)
{
struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);
return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
}
static int i2c_mux_pinctrl_deselect(struct i2c_mux_core *muxc, u32 chan)
{
return i2c_mux_pinctrl_select(muxc, muxc->num_adapters);
}
static struct i2c_adapter *i2c_mux_pinctrl_root_adapter(
struct pinctrl_state *state)
{
struct i2c_adapter *root = NULL;
struct pinctrl_setting *setting;
struct i2c_adapter *pin_root;
list_for_each_entry(setting, &state->settings, node) {
pin_root = i2c_root_adapter(setting->pctldev->dev);
if (!pin_root)
return NULL;
if (!root)
root = pin_root;
else if (root != pin_root)
return NULL;
}
return root;
}
static struct i2c_adapter *i2c_mux_pinctrl_parent_adapter(struct device *dev)
{
struct device_node *np = dev->of_node;
struct device_node *parent_np;
struct i2c_adapter *parent;
parent_np = of_parse_phandle(np, "i2c-parent", 0);
if (!parent_np) {
dev_err(dev, "Cannot parse i2c-parent\n");
return ERR_PTR(-ENODEV);
}
parent = of_find_i2c_adapter_by_node(parent_np);
of_node_put(parent_np);
if (!parent)
return ERR_PTR(-EPROBE_DEFER);
return parent;
}
static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct i2c_mux_core *muxc;
struct i2c_mux_pinctrl *mux;
struct i2c_adapter *parent;
struct i2c_adapter *root;
int num_names, i, ret;
const char *name;
num_names = of_property_count_strings(np, "pinctrl-names");
if (num_names < 0) {
dev_err(dev, "Cannot parse pinctrl-names: %d\n",
num_names);
return num_names;
}
parent = i2c_mux_pinctrl_parent_adapter(dev);
if (IS_ERR(parent))
return PTR_ERR(parent);
muxc = i2c_mux_alloc(parent, dev, num_names,
struct_size(mux, states, num_names),
0, i2c_mux_pinctrl_select, NULL);
if (!muxc) {
ret = -ENOMEM;
goto err_put_parent;
}
mux = i2c_mux_priv(muxc);
platform_set_drvdata(pdev, muxc);
mux->pinctrl = devm_pinctrl_get(dev);
if (IS_ERR(mux->pinctrl)) {
ret = PTR_ERR(mux->pinctrl);
dev_err(dev, "Cannot get pinctrl: %d\n", ret);
goto err_put_parent;
}
for (i = 0; i < num_names; i++) {
ret = of_property_read_string_index(np, "pinctrl-names", i,
&name);
if (ret < 0) {
dev_err(dev, "Cannot parse pinctrl-names: %d\n", ret);
goto err_put_parent;
}
mux->states[i] = pinctrl_lookup_state(mux->pinctrl, name);
if (IS_ERR(mux->states[i])) {
ret = PTR_ERR(mux->states[i]);
dev_err(dev, "Cannot look up pinctrl state %s: %d\n",
name, ret);
goto err_put_parent;
}
if (strcmp(name, "idle"))
continue;
if (i != num_names - 1) {
dev_err(dev, "idle state must be last\n");
ret = -EINVAL;
goto err_put_parent;
}
muxc->deselect = i2c_mux_pinctrl_deselect;
}
root = i2c_root_adapter(&muxc->parent->dev);
muxc->mux_locked = true;
for (i = 0; i < num_names; i++) {
if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) {
muxc->mux_locked = false;
break;
}
}
if (muxc->mux_locked)
dev_info(dev, "mux-locked i2c mux\n");
/* Do not add any adapter for the idle state (if it's there at all). */
for (i = 0; i < num_names - !!muxc->deselect; i++) {
ret = i2c_mux_add_adapter(muxc, 0, i, 0);
if (ret)
goto err_del_adapter;
}
return 0;
err_del_adapter:
i2c_mux_del_adapters(muxc);
err_put_parent:
i2c_put_adapter(parent);
return ret;
}
static int i2c_mux_pinctrl_remove(struct platform_device *pdev)
{
struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
i2c_mux_del_adapters(muxc);
i2c_put_adapter(muxc->parent);
return 0;
}
static const struct of_device_id i2c_mux_pinctrl_of_match[] = {
{ .compatible = "i2c-mux-pinctrl", },
{},
};
MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
static struct platform_driver i2c_mux_pinctrl_driver = {
.driver = {
.name = "i2c-mux-pinctrl",
.of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
},
.probe = i2c_mux_pinctrl_probe,
.remove = i2c_mux_pinctrl_remove,
};
module_platform_driver(i2c_mux_pinctrl_driver);
MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-mux-pinctrl");
|
