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11#include <linux/i2c.h>
12#include <linux/i2c-mux.h>
13#include <linux/i2c-mux-gpio.h>
14#include <linux/platform_device.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/gpio.h>
18#include <linux/of_gpio.h>
19
20struct gpiomux {
21 struct i2c_adapter *parent;
22 struct i2c_adapter **adap;
23 struct i2c_mux_gpio_platform_data data;
24 unsigned gpio_base;
25};
26
27static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
28{
29 int i;
30
31 for (i = 0; i < mux->data.n_gpios; i++)
32 gpio_set_value_cansleep(mux->gpio_base + mux->data.gpios[i],
33 val & (1 << i));
34}
35
36static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan)
37{
38 struct gpiomux *mux = data;
39
40 i2c_mux_gpio_set(mux, chan);
41
42 return 0;
43}
44
45static int i2c_mux_gpio_deselect(struct i2c_adapter *adap, void *data, u32 chan)
46{
47 struct gpiomux *mux = data;
48
49 i2c_mux_gpio_set(mux, mux->data.idle);
50
51 return 0;
52}
53
54static int match_gpio_chip_by_label(struct gpio_chip *chip,
55 void *data)
56{
57 return !strcmp(chip->label, data);
58}
59
60#ifdef CONFIG_OF
61static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
62 struct platform_device *pdev)
63{
64 struct device_node *np = pdev->dev.of_node;
65 struct device_node *adapter_np, *child;
66 struct i2c_adapter *adapter;
67 unsigned *values, *gpios;
68 int i = 0, ret;
69
70 if (!np)
71 return -ENODEV;
72
73 adapter_np = of_parse_phandle(np, "i2c-parent", 0);
74 if (!adapter_np) {
75 dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
76 return -ENODEV;
77 }
78 adapter = of_find_i2c_adapter_by_node(adapter_np);
79 if (!adapter) {
80 dev_err(&pdev->dev, "Cannot find parent bus\n");
81 return -EPROBE_DEFER;
82 }
83 mux->data.parent = i2c_adapter_id(adapter);
84 put_device(&adapter->dev);
85
86 mux->data.n_values = of_get_child_count(np);
87
88 values = devm_kzalloc(&pdev->dev,
89 sizeof(*mux->data.values) * mux->data.n_values,
90 GFP_KERNEL);
91 if (!values) {
92 dev_err(&pdev->dev, "Cannot allocate values array");
93 return -ENOMEM;
94 }
95
96 for_each_child_of_node(np, child) {
97 of_property_read_u32(child, "reg", values + i);
98 i++;
99 }
100 mux->data.values = values;
101
102 if (of_property_read_u32(np, "idle-state", &mux->data.idle))
103 mux->data.idle = I2C_MUX_GPIO_NO_IDLE;
104
105 mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios");
106 if (mux->data.n_gpios < 0) {
107 dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n");
108 return -EINVAL;
109 }
110
111 gpios = devm_kzalloc(&pdev->dev,
112 sizeof(*mux->data.gpios) * mux->data.n_gpios, GFP_KERNEL);
113 if (!gpios) {
114 dev_err(&pdev->dev, "Cannot allocate gpios array");
115 return -ENOMEM;
116 }
117
118 for (i = 0; i < mux->data.n_gpios; i++) {
119 ret = of_get_named_gpio(np, "mux-gpios", i);
120 if (ret < 0)
121 return ret;
122 gpios[i] = ret;
123 }
124
125 mux->data.gpios = gpios;
126
127 return 0;
128}
129#else
130static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
131 struct platform_device *pdev)
132{
133 return 0;
134}
135#endif
136
137static int i2c_mux_gpio_probe(struct platform_device *pdev)
138{
139 struct gpiomux *mux;
140 struct i2c_adapter *parent;
141 int (*deselect) (struct i2c_adapter *, void *, u32);
142 unsigned initial_state, gpio_base;
143 int i, ret;
144
145 mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
146 if (!mux) {
147 dev_err(&pdev->dev, "Cannot allocate gpiomux structure");
148 return -ENOMEM;
149 }
150
151 platform_set_drvdata(pdev, mux);
152
153 if (!dev_get_platdata(&pdev->dev)) {
154 ret = i2c_mux_gpio_probe_dt(mux, pdev);
155 if (ret < 0)
156 return ret;
157 } else {
158 memcpy(&mux->data, dev_get_platdata(&pdev->dev),
159 sizeof(mux->data));
160 }
161
162
163
164
165
166 if (mux->data.gpio_chip) {
167 struct gpio_chip *gpio;
168
169 gpio = gpiochip_find(mux->data.gpio_chip,
170 match_gpio_chip_by_label);
171 if (!gpio)
172 return -EPROBE_DEFER;
173
174 gpio_base = gpio->base;
175 } else {
176 gpio_base = 0;
177 }
178
179 parent = i2c_get_adapter(mux->data.parent);
180 if (!parent) {
181 dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
182 mux->data.parent);
183 return -EPROBE_DEFER;
184 }
185
186 mux->parent = parent;
187 mux->gpio_base = gpio_base;
188
189 mux->adap = devm_kzalloc(&pdev->dev,
190 sizeof(*mux->adap) * mux->data.n_values,
191 GFP_KERNEL);
192 if (!mux->adap) {
193 dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
194 ret = -ENOMEM;
195 goto alloc_failed;
196 }
197
198 if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
199 initial_state = mux->data.idle;
200 deselect = i2c_mux_gpio_deselect;
201 } else {
202 initial_state = mux->data.values[0];
203 deselect = NULL;
204 }
205
206 for (i = 0; i < mux->data.n_gpios; i++) {
207 ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
208 if (ret) {
209 dev_err(&pdev->dev, "Failed to request GPIO %d\n",
210 mux->data.gpios[i]);
211 goto err_request_gpio;
212 }
213
214 ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
215 initial_state & (1 << i));
216 if (ret) {
217 dev_err(&pdev->dev,
218 "Failed to set direction of GPIO %d to output\n",
219 mux->data.gpios[i]);
220 i++;
221 goto err_request_gpio;
222 }
223 }
224
225 for (i = 0; i < mux->data.n_values; i++) {
226 u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
227 unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
228
229 mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
230 mux->data.values[i], class,
231 i2c_mux_gpio_select, deselect);
232 if (!mux->adap[i]) {
233 ret = -ENODEV;
234 dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
235 goto add_adapter_failed;
236 }
237 }
238
239 dev_info(&pdev->dev, "%d port mux on %s adapter\n",
240 mux->data.n_values, parent->name);
241
242 return 0;
243
244add_adapter_failed:
245 for (; i > 0; i--)
246 i2c_del_mux_adapter(mux->adap[i - 1]);
247 i = mux->data.n_gpios;
248err_request_gpio:
249 for (; i > 0; i--)
250 gpio_free(gpio_base + mux->data.gpios[i - 1]);
251alloc_failed:
252 i2c_put_adapter(parent);
253
254 return ret;
255}
256
257static int i2c_mux_gpio_remove(struct platform_device *pdev)
258{
259 struct gpiomux *mux = platform_get_drvdata(pdev);
260 int i;
261
262 for (i = 0; i < mux->data.n_values; i++)
263 i2c_del_mux_adapter(mux->adap[i]);
264
265 for (i = 0; i < mux->data.n_gpios; i++)
266 gpio_free(mux->gpio_base + mux->data.gpios[i]);
267
268 i2c_put_adapter(mux->parent);
269
270 return 0;
271}
272
273static const struct of_device_id i2c_mux_gpio_of_match[] = {
274 { .compatible = "i2c-mux-gpio", },
275 {},
276};
277MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);
278
279static struct platform_driver i2c_mux_gpio_driver = {
280 .probe = i2c_mux_gpio_probe,
281 .remove = i2c_mux_gpio_remove,
282 .driver = {
283 .owner = THIS_MODULE,
284 .name = "i2c-mux-gpio",
285 .of_match_table = i2c_mux_gpio_of_match,
286 },
287};
288
289module_platform_driver(i2c_mux_gpio_driver);
290
291MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
292MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
293MODULE_LICENSE("GPL");
294MODULE_ALIAS("platform:i2c-mux-gpio");
295
