1/*
2 * I2C multiplexer using pinctrl API
3 *
4 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
17 */
18
19#include <linux/i2c.h>
20#include <linux/i2c-mux.h>
21#include <linux/module.h>
22#include <linux/pinctrl/consumer.h>
23#include <linux/i2c-mux-pinctrl.h>
24#include <linux/platform_device.h>
25#include <linux/slab.h>
26#include <linux/of.h>
27
28struct i2c_mux_pinctrl {
29	struct device *dev;
30	struct i2c_mux_pinctrl_platform_data *pdata;
31	struct pinctrl *pinctrl;
32	struct pinctrl_state **states;
33	struct pinctrl_state *state_idle;
34	struct i2c_adapter *parent;
35	struct i2c_adapter **busses;
36};
37
38static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
39				  u32 chan)
40{
41	struct i2c_mux_pinctrl *mux = data;
42
43	return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
44}
45
46static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
47				    u32 chan)
48{
49	struct i2c_mux_pinctrl *mux = data;
50
51	return pinctrl_select_state(mux->pinctrl, mux->state_idle);
52}
53
54#ifdef CONFIG_OF
55static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
56				struct platform_device *pdev)
57{
58	struct device_node *np = pdev->dev.of_node;
59	int num_names, i, ret;
60	struct device_node *adapter_np;
61	struct i2c_adapter *adapter;
62
63	if (!np)
64		return 0;
65
66	mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
67	if (!mux->pdata) {
68		dev_err(mux->dev,
69			"Cannot allocate i2c_mux_pinctrl_platform_data\n");
70		return -ENOMEM;
71	}
72
73	num_names = of_property_count_strings(np, "pinctrl-names");
74	if (num_names < 0) {
75		dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
76			num_names);
77		return num_names;
78	}
79
80	mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
81		sizeof(*mux->pdata->pinctrl_states) * num_names,
82		GFP_KERNEL);
83	if (!mux->pdata->pinctrl_states) {
84		dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
85		return -ENOMEM;
86	}
87
88	for (i = 0; i < num_names; i++) {
89		ret = of_property_read_string_index(np, "pinctrl-names", i,
90			&mux->pdata->pinctrl_states[mux->pdata->bus_count]);
91		if (ret < 0) {
92			dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
93				ret);
94			return ret;
95		}
96		if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
97			    "idle")) {
98			if (i != num_names - 1) {
99				dev_err(mux->dev, "idle state must be last\n");
100				return -EINVAL;
101			}
102			mux->pdata->pinctrl_state_idle = "idle";
103		} else {
104			mux->pdata->bus_count++;
105		}
106	}
107
108	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
109	if (!adapter_np) {
110		dev_err(mux->dev, "Cannot parse i2c-parent\n");
111		return -ENODEV;
112	}
113	adapter = of_find_i2c_adapter_by_node(adapter_np);
114	if (!adapter) {
115		dev_err(mux->dev, "Cannot find parent bus\n");
116		return -EPROBE_DEFER;
117	}
118	mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
119	put_device(&adapter->dev);
120
121	return 0;
122}
123#else
124static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
125					   struct platform_device *pdev)
126{
127	return 0;
128}
129#endif
130
131static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
132{
133	struct i2c_mux_pinctrl *mux;
134	int (*deselect)(struct i2c_adapter *, void *, u32);
135	int i, ret;
136
137	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
138	if (!mux) {
139		dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
140		ret = -ENOMEM;
141		goto err;
142	}
143	platform_set_drvdata(pdev, mux);
144
145	mux->dev = &pdev->dev;
146
147	mux->pdata = dev_get_platdata(&pdev->dev);
148	if (!mux->pdata) {
149		ret = i2c_mux_pinctrl_parse_dt(mux, pdev);
150		if (ret < 0)
151			goto err;
152	}
153	if (!mux->pdata) {
154		dev_err(&pdev->dev, "Missing platform data\n");
155		ret = -ENODEV;
156		goto err;
157	}
158
159	mux->states = devm_kzalloc(&pdev->dev,
160				   sizeof(*mux->states) * mux->pdata->bus_count,
161				   GFP_KERNEL);
162	if (!mux->states) {
163		dev_err(&pdev->dev, "Cannot allocate states\n");
164		ret = -ENOMEM;
165		goto err;
166	}
167
168	mux->busses = devm_kzalloc(&pdev->dev,
169				   sizeof(*mux->busses) * mux->pdata->bus_count,
170				   GFP_KERNEL);
171	if (!mux->busses) {
172		dev_err(&pdev->dev, "Cannot allocate busses\n");
173		ret = -ENOMEM;
174		goto err;
175	}
176
177	mux->pinctrl = devm_pinctrl_get(&pdev->dev);
178	if (IS_ERR(mux->pinctrl)) {
179		ret = PTR_ERR(mux->pinctrl);
180		dev_err(&pdev->dev, "Cannot get pinctrl: %d\n", ret);
181		goto err;
182	}
183	for (i = 0; i < mux->pdata->bus_count; i++) {
184		mux->states[i] = pinctrl_lookup_state(mux->pinctrl,
185						mux->pdata->pinctrl_states[i]);
186			if (IS_ERR(mux->states[i])) {
187				ret = PTR_ERR(mux->states[i]);
188				dev_err(&pdev->dev,
189					"Cannot look up pinctrl state %s: %d\n",
190					mux->pdata->pinctrl_states[i], ret);
191				goto err;
192			}
193	}
194	if (mux->pdata->pinctrl_state_idle) {
195		mux->state_idle = pinctrl_lookup_state(mux->pinctrl,
196						mux->pdata->pinctrl_state_idle);
197		if (IS_ERR(mux->state_idle)) {
198			ret = PTR_ERR(mux->state_idle);
199			dev_err(&pdev->dev,
200				"Cannot look up pinctrl state %s: %d\n",
201				mux->pdata->pinctrl_state_idle, ret);
202			goto err;
203		}
204
205		deselect = i2c_mux_pinctrl_deselect;
206	} else {
207		deselect = NULL;
208	}
209
210	mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
211	if (!mux->parent) {
212		dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
213			mux->pdata->parent_bus_num);
214		ret = -EPROBE_DEFER;
215		goto err;
216	}
217
218	for (i = 0; i < mux->pdata->bus_count; i++) {
219		u32 bus = mux->pdata->base_bus_num ?
220				(mux->pdata->base_bus_num + i) : 0;
221
222		mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
223						     mux, bus, i, 0,
224						     i2c_mux_pinctrl_select,
225						     deselect);
226		if (!mux->busses[i]) {
227			ret = -ENODEV;
228			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
229			goto err_del_adapter;
230		}
231	}
232
233	return 0;
234
235err_del_adapter:
236	for (; i > 0; i--)
237		i2c_del_mux_adapter(mux->busses[i - 1]);
238	i2c_put_adapter(mux->parent);
239err:
240	return ret;
241}
242
243static int i2c_mux_pinctrl_remove(struct platform_device *pdev)
244{
245	struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
246	int i;
247
248	for (i = 0; i < mux->pdata->bus_count; i++)
249		i2c_del_mux_adapter(mux->busses[i]);
250
251	i2c_put_adapter(mux->parent);
252
253	return 0;
254}
255
256#ifdef CONFIG_OF
257static const struct of_device_id i2c_mux_pinctrl_of_match[] = {
258	{ .compatible = "i2c-mux-pinctrl", },
259	{},
260};
261MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
262#endif
263
264static struct platform_driver i2c_mux_pinctrl_driver = {
265	.driver	= {
266		.name	= "i2c-mux-pinctrl",
267		.owner	= THIS_MODULE,
268		.of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
269	},
270	.probe	= i2c_mux_pinctrl_probe,
271	.remove	= i2c_mux_pinctrl_remove,
272};
273module_platform_driver(i2c_mux_pinctrl_driver);
274
275MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
276MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
277MODULE_LICENSE("GPL v2");
278MODULE_ALIAS("platform:i2c-mux-pinctrl");
279