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Commit | Line | Data |
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92ed1a76 PK |
1 | /* |
2 | * I2C multiplexer using GPIO API | |
3 | * | |
4 | * Peter Korsgaard <peter.korsgaard@barco.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <linux/i2c.h> | |
12 | #include <linux/i2c-mux.h> | |
e7065e20 | 13 | #include <linux/i2c-mux-gpio.h> |
92ed1a76 | 14 | #include <linux/platform_device.h> |
92ed1a76 PK |
15 | #include <linux/module.h> |
16 | #include <linux/slab.h> | |
17 | #include <linux/gpio.h> | |
9b7a0c40 | 18 | #include <linux/of_gpio.h> |
92ed1a76 PK |
19 | |
20 | struct gpiomux { | |
21 | struct i2c_adapter *parent; | |
22 | struct i2c_adapter **adap; /* child busses */ | |
e7065e20 | 23 | struct i2c_mux_gpio_platform_data data; |
e7ee5140 | 24 | unsigned gpio_base; |
92ed1a76 PK |
25 | }; |
26 | ||
e7065e20 | 27 | static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val) |
92ed1a76 PK |
28 | { |
29 | int i; | |
30 | ||
31 | for (i = 0; i < mux->data.n_gpios; i++) | |
250ad590 IN |
32 | gpio_set_value_cansleep(mux->gpio_base + mux->data.gpios[i], |
33 | val & (1 << i)); | |
92ed1a76 PK |
34 | } |
35 | ||
e7065e20 | 36 | static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan) |
92ed1a76 PK |
37 | { |
38 | struct gpiomux *mux = data; | |
39 | ||
8c0ec250 | 40 | i2c_mux_gpio_set(mux, chan); |
92ed1a76 PK |
41 | |
42 | return 0; | |
43 | } | |
44 | ||
e7065e20 | 45 | static int i2c_mux_gpio_deselect(struct i2c_adapter *adap, void *data, u32 chan) |
92ed1a76 PK |
46 | { |
47 | struct gpiomux *mux = data; | |
48 | ||
e7065e20 | 49 | i2c_mux_gpio_set(mux, mux->data.idle); |
92ed1a76 PK |
50 | |
51 | return 0; | |
52 | } | |
53 | ||
0b255e92 | 54 | static int match_gpio_chip_by_label(struct gpio_chip *chip, |
e7ee5140 JD |
55 | void *data) |
56 | { | |
57 | return !strcmp(chip->label, data); | |
58 | } | |
59 | ||
9b7a0c40 | 60 | #ifdef CONFIG_OF |
0b255e92 | 61 | static int i2c_mux_gpio_probe_dt(struct gpiomux *mux, |
9b7a0c40 MR |
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; | |
492ed77b | 68 | int i = 0, ret; |
9b7a0c40 MR |
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); | |
623e4ecb | 79 | if (!adapter) |
9937b8d8 | 80 | return -EPROBE_DEFER; |
623e4ecb | 81 | |
9b7a0c40 MR |
82 | mux->data.parent = i2c_adapter_id(adapter); |
83 | put_device(&adapter->dev); | |
84 | ||
85 | mux->data.n_values = of_get_child_count(np); | |
86 | ||
87 | values = devm_kzalloc(&pdev->dev, | |
88 | sizeof(*mux->data.values) * mux->data.n_values, | |
89 | GFP_KERNEL); | |
90 | if (!values) { | |
91 | dev_err(&pdev->dev, "Cannot allocate values array"); | |
92 | return -ENOMEM; | |
93 | } | |
94 | ||
95 | for_each_child_of_node(np, child) { | |
96 | of_property_read_u32(child, "reg", values + i); | |
97 | i++; | |
98 | } | |
99 | mux->data.values = values; | |
100 | ||
101 | if (of_property_read_u32(np, "idle-state", &mux->data.idle)) | |
102 | mux->data.idle = I2C_MUX_GPIO_NO_IDLE; | |
103 | ||
104 | mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios"); | |
105 | if (mux->data.n_gpios < 0) { | |
106 | dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n"); | |
107 | return -EINVAL; | |
108 | } | |
109 | ||
110 | gpios = devm_kzalloc(&pdev->dev, | |
111 | sizeof(*mux->data.gpios) * mux->data.n_gpios, GFP_KERNEL); | |
112 | if (!gpios) { | |
113 | dev_err(&pdev->dev, "Cannot allocate gpios array"); | |
114 | return -ENOMEM; | |
115 | } | |
116 | ||
492ed77b IN |
117 | for (i = 0; i < mux->data.n_gpios; i++) { |
118 | ret = of_get_named_gpio(np, "mux-gpios", i); | |
119 | if (ret < 0) | |
120 | return ret; | |
121 | gpios[i] = ret; | |
122 | } | |
9b7a0c40 MR |
123 | |
124 | mux->data.gpios = gpios; | |
125 | ||
126 | return 0; | |
127 | } | |
128 | #else | |
0b255e92 | 129 | static int i2c_mux_gpio_probe_dt(struct gpiomux *mux, |
9b7a0c40 MR |
130 | struct platform_device *pdev) |
131 | { | |
132 | return 0; | |
133 | } | |
134 | #endif | |
135 | ||
0b255e92 | 136 | static int i2c_mux_gpio_probe(struct platform_device *pdev) |
92ed1a76 PK |
137 | { |
138 | struct gpiomux *mux; | |
92ed1a76 PK |
139 | struct i2c_adapter *parent; |
140 | int (*deselect) (struct i2c_adapter *, void *, u32); | |
e7ee5140 | 141 | unsigned initial_state, gpio_base; |
92ed1a76 PK |
142 | int i, ret; |
143 | ||
9b7a0c40 MR |
144 | mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); |
145 | if (!mux) { | |
146 | dev_err(&pdev->dev, "Cannot allocate gpiomux structure"); | |
147 | return -ENOMEM; | |
92ed1a76 PK |
148 | } |
149 | ||
9b7a0c40 MR |
150 | platform_set_drvdata(pdev, mux); |
151 | ||
6d4028c6 | 152 | if (!dev_get_platdata(&pdev->dev)) { |
9b7a0c40 MR |
153 | ret = i2c_mux_gpio_probe_dt(mux, pdev); |
154 | if (ret < 0) | |
155 | return ret; | |
6d4028c6 JH |
156 | } else { |
157 | memcpy(&mux->data, dev_get_platdata(&pdev->dev), | |
158 | sizeof(mux->data)); | |
159 | } | |
9b7a0c40 | 160 | |
e7ee5140 JD |
161 | /* |
162 | * If a GPIO chip name is provided, the GPIO pin numbers provided are | |
163 | * relative to its base GPIO number. Otherwise they are absolute. | |
164 | */ | |
9b7a0c40 | 165 | if (mux->data.gpio_chip) { |
e7ee5140 JD |
166 | struct gpio_chip *gpio; |
167 | ||
9b7a0c40 | 168 | gpio = gpiochip_find(mux->data.gpio_chip, |
e7ee5140 JD |
169 | match_gpio_chip_by_label); |
170 | if (!gpio) | |
171 | return -EPROBE_DEFER; | |
172 | ||
173 | gpio_base = gpio->base; | |
174 | } else { | |
175 | gpio_base = 0; | |
176 | } | |
177 | ||
9b7a0c40 | 178 | parent = i2c_get_adapter(mux->data.parent); |
623e4ecb | 179 | if (!parent) |
9937b8d8 | 180 | return -EPROBE_DEFER; |
92ed1a76 | 181 | |
92ed1a76 | 182 | mux->parent = parent; |
e7ee5140 | 183 | mux->gpio_base = gpio_base; |
9b7a0c40 | 184 | |
2614a859 | 185 | mux->adap = devm_kzalloc(&pdev->dev, |
9b7a0c40 | 186 | sizeof(*mux->adap) * mux->data.n_values, |
2614a859 | 187 | GFP_KERNEL); |
92ed1a76 | 188 | if (!mux->adap) { |
9b7a0c40 | 189 | dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure"); |
92ed1a76 | 190 | ret = -ENOMEM; |
2614a859 | 191 | goto alloc_failed; |
92ed1a76 PK |
192 | } |
193 | ||
9b7a0c40 MR |
194 | if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) { |
195 | initial_state = mux->data.idle; | |
e7065e20 | 196 | deselect = i2c_mux_gpio_deselect; |
92ed1a76 | 197 | } else { |
9b7a0c40 | 198 | initial_state = mux->data.values[0]; |
92ed1a76 PK |
199 | deselect = NULL; |
200 | } | |
201 | ||
9b7a0c40 MR |
202 | for (i = 0; i < mux->data.n_gpios; i++) { |
203 | ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio"); | |
7fafae66 JD |
204 | if (ret) { |
205 | dev_err(&pdev->dev, "Failed to request GPIO %d\n", | |
206 | mux->data.gpios[i]); | |
92ed1a76 | 207 | goto err_request_gpio; |
7fafae66 JD |
208 | } |
209 | ||
210 | ret = gpio_direction_output(gpio_base + mux->data.gpios[i], | |
211 | initial_state & (1 << i)); | |
212 | if (ret) { | |
213 | dev_err(&pdev->dev, | |
214 | "Failed to set direction of GPIO %d to output\n", | |
215 | mux->data.gpios[i]); | |
216 | i++; /* gpio_request above succeeded, so must free */ | |
217 | goto err_request_gpio; | |
218 | } | |
92ed1a76 PK |
219 | } |
220 | ||
9b7a0c40 MR |
221 | for (i = 0; i < mux->data.n_values; i++) { |
222 | u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0; | |
223 | unsigned int class = mux->data.classes ? mux->data.classes[i] : 0; | |
92ed1a76 | 224 | |
eee543e8 | 225 | mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr, |
8c0ec250 | 226 | mux->data.values[i], class, |
e7065e20 | 227 | i2c_mux_gpio_select, deselect); |
92ed1a76 PK |
228 | if (!mux->adap[i]) { |
229 | ret = -ENODEV; | |
230 | dev_err(&pdev->dev, "Failed to add adapter %d\n", i); | |
231 | goto add_adapter_failed; | |
232 | } | |
233 | } | |
234 | ||
235 | dev_info(&pdev->dev, "%d port mux on %s adapter\n", | |
9b7a0c40 | 236 | mux->data.n_values, parent->name); |
92ed1a76 PK |
237 | |
238 | return 0; | |
239 | ||
240 | add_adapter_failed: | |
241 | for (; i > 0; i--) | |
242 | i2c_del_mux_adapter(mux->adap[i - 1]); | |
9b7a0c40 | 243 | i = mux->data.n_gpios; |
92ed1a76 PK |
244 | err_request_gpio: |
245 | for (; i > 0; i--) | |
9b7a0c40 | 246 | gpio_free(gpio_base + mux->data.gpios[i - 1]); |
92ed1a76 PK |
247 | alloc_failed: |
248 | i2c_put_adapter(parent); | |
249 | ||
250 | return ret; | |
251 | } | |
252 | ||
0b255e92 | 253 | static int i2c_mux_gpio_remove(struct platform_device *pdev) |
92ed1a76 PK |
254 | { |
255 | struct gpiomux *mux = platform_get_drvdata(pdev); | |
256 | int i; | |
257 | ||
258 | for (i = 0; i < mux->data.n_values; i++) | |
259 | i2c_del_mux_adapter(mux->adap[i]); | |
260 | ||
261 | for (i = 0; i < mux->data.n_gpios; i++) | |
e7ee5140 | 262 | gpio_free(mux->gpio_base + mux->data.gpios[i]); |
92ed1a76 | 263 | |
92ed1a76 | 264 | i2c_put_adapter(mux->parent); |
92ed1a76 PK |
265 | |
266 | return 0; | |
267 | } | |
268 | ||
0b255e92 | 269 | static const struct of_device_id i2c_mux_gpio_of_match[] = { |
9b7a0c40 MR |
270 | { .compatible = "i2c-mux-gpio", }, |
271 | {}, | |
272 | }; | |
273 | MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match); | |
274 | ||
e7065e20 JD |
275 | static struct platform_driver i2c_mux_gpio_driver = { |
276 | .probe = i2c_mux_gpio_probe, | |
0b255e92 | 277 | .remove = i2c_mux_gpio_remove, |
92ed1a76 | 278 | .driver = { |
e7065e20 | 279 | .name = "i2c-mux-gpio", |
4e905323 | 280 | .of_match_table = i2c_mux_gpio_of_match, |
92ed1a76 PK |
281 | }, |
282 | }; | |
283 | ||
e7065e20 | 284 | module_platform_driver(i2c_mux_gpio_driver); |
92ed1a76 PK |
285 | |
286 | MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver"); | |
287 | MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>"); | |
288 | MODULE_LICENSE("GPL"); | |
e7065e20 | 289 | MODULE_ALIAS("platform:i2c-mux-gpio"); |