2 * I2C multiplexer using a single register
4 * Copyright 2015 Freescale Semiconductor
5 * York Sun <yorksun@freescale.com>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
13 #include <linux/i2c.h>
14 #include <linux/i2c-mux.h>
15 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/of_address.h>
19 #include <linux/platform_data/i2c-mux-reg.h>
20 #include <linux/platform_device.h>
21 #include <linux/slab.h>
24 struct i2c_adapter *parent;
25 struct i2c_adapter **adap; /* child busses */
26 struct i2c_mux_reg_platform_data data;
29 static int i2c_mux_reg_set(const struct regmux *mux, unsigned int chan_id)
34 switch (mux->data.reg_size) {
36 if (mux->data.little_endian) {
37 iowrite32(chan_id, mux->data.reg);
38 if (!mux->data.write_only)
39 ioread32(mux->data.reg);
41 iowrite32be(chan_id, mux->data.reg);
42 if (!mux->data.write_only)
43 ioread32(mux->data.reg);
47 if (mux->data.little_endian) {
48 iowrite16(chan_id, mux->data.reg);
49 if (!mux->data.write_only)
50 ioread16(mux->data.reg);
52 iowrite16be(chan_id, mux->data.reg);
53 if (!mux->data.write_only)
54 ioread16be(mux->data.reg);
58 iowrite8(chan_id, mux->data.reg);
59 if (!mux->data.write_only)
60 ioread8(mux->data.reg);
63 pr_err("Invalid register size\n");
70 static int i2c_mux_reg_select(struct i2c_adapter *adap, void *data,
73 struct regmux *mux = data;
75 return i2c_mux_reg_set(mux, chan);
78 static int i2c_mux_reg_deselect(struct i2c_adapter *adap, void *data,
81 struct regmux *mux = data;
83 if (mux->data.idle_in_use)
84 return i2c_mux_reg_set(mux, mux->data.idle);
90 static int i2c_mux_reg_probe_dt(struct regmux *mux,
91 struct platform_device *pdev)
93 struct device_node *np = pdev->dev.of_node;
94 struct device_node *adapter_np, *child;
95 struct i2c_adapter *adapter;
103 adapter_np = of_parse_phandle(np, "i2c-parent", 0);
105 dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
108 adapter = of_find_i2c_adapter_by_node(adapter_np);
109 of_node_put(adapter_np);
111 return -EPROBE_DEFER;
113 mux->parent = adapter;
114 mux->data.parent = i2c_adapter_id(adapter);
115 put_device(&adapter->dev);
117 mux->data.n_values = of_get_child_count(np);
118 if (of_find_property(np, "little-endian", NULL)) {
119 mux->data.little_endian = true;
120 } else if (of_find_property(np, "big-endian", NULL)) {
121 mux->data.little_endian = false;
123 #if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : \
124 defined(__LITTLE_ENDIAN)
125 mux->data.little_endian = true;
126 #elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : \
127 defined(__BIG_ENDIAN)
128 mux->data.little_endian = false;
130 #error Endianness not defined?
133 if (of_find_property(np, "write-only", NULL))
134 mux->data.write_only = true;
136 mux->data.write_only = false;
138 values = devm_kzalloc(&pdev->dev,
139 sizeof(*mux->data.values) * mux->data.n_values,
142 dev_err(&pdev->dev, "Cannot allocate values array");
146 for_each_child_of_node(np, child) {
147 of_property_read_u32(child, "reg", values + i);
150 mux->data.values = values;
152 if (!of_property_read_u32(np, "idle-state", &mux->data.idle))
153 mux->data.idle_in_use = true;
155 /* map address from "reg" if exists */
156 if (of_address_to_resource(np, 0, &res)) {
157 mux->data.reg_size = resource_size(&res);
158 if (mux->data.reg_size > 4) {
159 dev_err(&pdev->dev, "Invalid address size\n");
162 mux->data.reg = devm_ioremap_resource(&pdev->dev, &res);
163 if (IS_ERR(mux->data.reg))
164 return PTR_ERR(mux->data.reg);
170 static int i2c_mux_reg_probe_dt(struct gpiomux *mux,
171 struct platform_device *pdev)
177 static int i2c_mux_reg_probe(struct platform_device *pdev)
180 struct i2c_adapter *parent;
181 struct resource *res;
182 int (*deselect)(struct i2c_adapter *, void *, u32);
186 mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
190 platform_set_drvdata(pdev, mux);
192 if (dev_get_platdata(&pdev->dev)) {
193 memcpy(&mux->data, dev_get_platdata(&pdev->dev),
196 parent = i2c_get_adapter(mux->data.parent);
198 return -EPROBE_DEFER;
200 mux->parent = parent;
202 ret = i2c_mux_reg_probe_dt(mux, pdev);
204 dev_err(&pdev->dev, "Error parsing device tree");
209 if (!mux->data.reg) {
211 "Register not set, using platform resource\n");
212 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
213 mux->data.reg_size = resource_size(res);
214 if (mux->data.reg_size > 4) {
215 dev_err(&pdev->dev, "Invalid resource size\n");
218 mux->data.reg = devm_ioremap_resource(&pdev->dev, res);
219 if (IS_ERR(mux->data.reg))
220 return PTR_ERR(mux->data.reg);
223 mux->adap = devm_kzalloc(&pdev->dev,
224 sizeof(*mux->adap) * mux->data.n_values,
227 dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
231 if (mux->data.idle_in_use)
232 deselect = i2c_mux_reg_deselect;
236 for (i = 0; i < mux->data.n_values; i++) {
237 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
238 class = mux->data.classes ? mux->data.classes[i] : 0;
240 mux->adap[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev, mux,
241 nr, mux->data.values[i],
242 class, i2c_mux_reg_select,
246 dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
247 goto add_adapter_failed;
251 dev_dbg(&pdev->dev, "%d port mux on %s adapter\n",
252 mux->data.n_values, mux->parent->name);
258 i2c_del_mux_adapter(mux->adap[i - 1]);
263 static int i2c_mux_reg_remove(struct platform_device *pdev)
265 struct regmux *mux = platform_get_drvdata(pdev);
268 for (i = 0; i < mux->data.n_values; i++)
269 i2c_del_mux_adapter(mux->adap[i]);
271 i2c_put_adapter(mux->parent);
276 static const struct of_device_id i2c_mux_reg_of_match[] = {
277 { .compatible = "i2c-mux-reg", },
280 MODULE_DEVICE_TABLE(of, i2c_mux_reg_of_match);
282 static struct platform_driver i2c_mux_reg_driver = {
283 .probe = i2c_mux_reg_probe,
284 .remove = i2c_mux_reg_remove,
286 .name = "i2c-mux-reg",
290 module_platform_driver(i2c_mux_reg_driver);
292 MODULE_DESCRIPTION("Register-based I2C multiplexer driver");
293 MODULE_AUTHOR("York Sun <yorksun@freescale.com>");
294 MODULE_LICENSE("GPL");
295 MODULE_ALIAS("platform:i2c-mux-reg");