1 // SPDX-License-Identifier: GPL-2.0-only
3 * I2C multiplexer using pinctrl API
5 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
9 #include <linux/i2c-mux.h>
10 #include <linux/module.h>
11 #include <linux/pinctrl/consumer.h>
12 #include <linux/platform_device.h>
13 #include <linux/slab.h>
15 #include "../../pinctrl/core.h"
17 struct i2c_mux_pinctrl {
18 struct pinctrl *pinctrl;
19 struct pinctrl_state **states;
22 static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan)
24 struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);
26 return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
29 static int i2c_mux_pinctrl_deselect(struct i2c_mux_core *muxc, u32 chan)
31 return i2c_mux_pinctrl_select(muxc, muxc->num_adapters);
34 static struct i2c_adapter *i2c_mux_pinctrl_root_adapter(
35 struct pinctrl_state *state)
37 struct i2c_adapter *root = NULL;
38 struct pinctrl_setting *setting;
39 struct i2c_adapter *pin_root;
41 list_for_each_entry(setting, &state->settings, node) {
42 pin_root = i2c_root_adapter(setting->pctldev->dev);
47 else if (root != pin_root)
54 static struct i2c_adapter *i2c_mux_pinctrl_parent_adapter(struct device *dev)
56 struct device_node *np = dev->of_node;
57 struct device_node *parent_np;
58 struct i2c_adapter *parent;
60 parent_np = of_parse_phandle(np, "i2c-parent", 0);
62 dev_err(dev, "Cannot parse i2c-parent\n");
63 return ERR_PTR(-ENODEV);
65 parent = of_find_i2c_adapter_by_node(parent_np);
66 of_node_put(parent_np);
68 return ERR_PTR(-EPROBE_DEFER);
73 static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
75 struct device *dev = &pdev->dev;
76 struct device_node *np = dev->of_node;
77 struct i2c_mux_core *muxc;
78 struct i2c_mux_pinctrl *mux;
79 struct i2c_adapter *parent;
80 struct i2c_adapter *root;
81 int num_names, i, ret;
84 num_names = of_property_count_strings(np, "pinctrl-names");
86 dev_err(dev, "Cannot parse pinctrl-names: %d\n",
91 parent = i2c_mux_pinctrl_parent_adapter(dev);
93 return PTR_ERR(parent);
95 muxc = i2c_mux_alloc(parent, dev, num_names,
96 sizeof(*mux) + num_names * sizeof(*mux->states),
97 0, i2c_mux_pinctrl_select, NULL);
102 mux = i2c_mux_priv(muxc);
103 mux->states = (struct pinctrl_state **)(mux + 1);
105 platform_set_drvdata(pdev, muxc);
107 mux->pinctrl = devm_pinctrl_get(dev);
108 if (IS_ERR(mux->pinctrl)) {
109 ret = PTR_ERR(mux->pinctrl);
110 dev_err(dev, "Cannot get pinctrl: %d\n", ret);
114 for (i = 0; i < num_names; i++) {
115 ret = of_property_read_string_index(np, "pinctrl-names", i,
118 dev_err(dev, "Cannot parse pinctrl-names: %d\n", ret);
122 mux->states[i] = pinctrl_lookup_state(mux->pinctrl, name);
123 if (IS_ERR(mux->states[i])) {
124 ret = PTR_ERR(mux->states[i]);
125 dev_err(dev, "Cannot look up pinctrl state %s: %d\n",
130 if (strcmp(name, "idle"))
133 if (i != num_names - 1) {
134 dev_err(dev, "idle state must be last\n");
138 muxc->deselect = i2c_mux_pinctrl_deselect;
141 root = i2c_root_adapter(&muxc->parent->dev);
143 muxc->mux_locked = true;
144 for (i = 0; i < num_names; i++) {
145 if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) {
146 muxc->mux_locked = false;
150 if (muxc->mux_locked)
151 dev_info(dev, "mux-locked i2c mux\n");
153 /* Do not add any adapter for the idle state (if it's there at all). */
154 for (i = 0; i < num_names - !!muxc->deselect; i++) {
155 ret = i2c_mux_add_adapter(muxc, 0, i, 0);
157 goto err_del_adapter;
163 i2c_mux_del_adapters(muxc);
165 i2c_put_adapter(parent);
170 static int i2c_mux_pinctrl_remove(struct platform_device *pdev)
172 struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
174 i2c_mux_del_adapters(muxc);
175 i2c_put_adapter(muxc->parent);
180 static const struct of_device_id i2c_mux_pinctrl_of_match[] = {
181 { .compatible = "i2c-mux-pinctrl", },
184 MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
186 static struct platform_driver i2c_mux_pinctrl_driver = {
188 .name = "i2c-mux-pinctrl",
189 .of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
191 .probe = i2c_mux_pinctrl_probe,
192 .remove = i2c_mux_pinctrl_remove,
194 module_platform_driver(i2c_mux_pinctrl_driver);
196 MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
197 MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
198 MODULE_LICENSE("GPL v2");
199 MODULE_ALIAS("platform:i2c-mux-pinctrl");