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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> | |
6ef91fcc | 18 | #include "../../gpio/gpiolib.h" |
9b7a0c40 | 19 | #include <linux/of_gpio.h> |
92ed1a76 PK |
20 | |
21 | struct gpiomux { | |
e7065e20 | 22 | struct i2c_mux_gpio_platform_data data; |
e7ee5140 | 23 | unsigned gpio_base; |
feff5c0a PR |
24 | struct gpio_desc **gpios; |
25 | int *values; | |
92ed1a76 PK |
26 | }; |
27 | ||
e7065e20 | 28 | static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val) |
92ed1a76 PK |
29 | { |
30 | int i; | |
31 | ||
32 | for (i = 0; i < mux->data.n_gpios; i++) | |
feff5c0a PR |
33 | mux->values[i] = (val >> i) & 1; |
34 | ||
35 | gpiod_set_array_value_cansleep(mux->data.n_gpios, | |
36 | mux->gpios, mux->values); | |
92ed1a76 PK |
37 | } |
38 | ||
bb448147 | 39 | static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan) |
92ed1a76 | 40 | { |
bb448147 | 41 | struct gpiomux *mux = i2c_mux_priv(muxc); |
92ed1a76 | 42 | |
8c0ec250 | 43 | i2c_mux_gpio_set(mux, chan); |
92ed1a76 PK |
44 | |
45 | return 0; | |
46 | } | |
47 | ||
bb448147 | 48 | static int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan) |
92ed1a76 | 49 | { |
bb448147 | 50 | struct gpiomux *mux = i2c_mux_priv(muxc); |
92ed1a76 | 51 | |
e7065e20 | 52 | i2c_mux_gpio_set(mux, mux->data.idle); |
92ed1a76 PK |
53 | |
54 | return 0; | |
55 | } | |
56 | ||
0b255e92 | 57 | static int match_gpio_chip_by_label(struct gpio_chip *chip, |
e7ee5140 JD |
58 | void *data) |
59 | { | |
60 | return !strcmp(chip->label, data); | |
61 | } | |
62 | ||
9b7a0c40 | 63 | #ifdef CONFIG_OF |
0b255e92 | 64 | static int i2c_mux_gpio_probe_dt(struct gpiomux *mux, |
9b7a0c40 MR |
65 | struct platform_device *pdev) |
66 | { | |
67 | struct device_node *np = pdev->dev.of_node; | |
68 | struct device_node *adapter_np, *child; | |
69 | struct i2c_adapter *adapter; | |
70 | unsigned *values, *gpios; | |
492ed77b | 71 | int i = 0, ret; |
9b7a0c40 MR |
72 | |
73 | if (!np) | |
74 | return -ENODEV; | |
75 | ||
76 | adapter_np = of_parse_phandle(np, "i2c-parent", 0); | |
77 | if (!adapter_np) { | |
78 | dev_err(&pdev->dev, "Cannot parse i2c-parent\n"); | |
79 | return -ENODEV; | |
80 | } | |
81 | adapter = of_find_i2c_adapter_by_node(adapter_np); | |
bdbf4a29 | 82 | of_node_put(adapter_np); |
623e4ecb | 83 | if (!adapter) |
9937b8d8 | 84 | return -EPROBE_DEFER; |
623e4ecb | 85 | |
9b7a0c40 MR |
86 | mux->data.parent = i2c_adapter_id(adapter); |
87 | put_device(&adapter->dev); | |
88 | ||
89 | mux->data.n_values = of_get_child_count(np); | |
90 | ||
91 | values = devm_kzalloc(&pdev->dev, | |
92 | sizeof(*mux->data.values) * mux->data.n_values, | |
93 | GFP_KERNEL); | |
94 | if (!values) { | |
95 | dev_err(&pdev->dev, "Cannot allocate values array"); | |
96 | return -ENOMEM; | |
97 | } | |
98 | ||
99 | for_each_child_of_node(np, child) { | |
100 | of_property_read_u32(child, "reg", values + i); | |
101 | i++; | |
102 | } | |
103 | mux->data.values = values; | |
104 | ||
105 | if (of_property_read_u32(np, "idle-state", &mux->data.idle)) | |
106 | mux->data.idle = I2C_MUX_GPIO_NO_IDLE; | |
107 | ||
108 | mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios"); | |
109 | if (mux->data.n_gpios < 0) { | |
110 | dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n"); | |
111 | return -EINVAL; | |
112 | } | |
113 | ||
114 | gpios = devm_kzalloc(&pdev->dev, | |
115 | sizeof(*mux->data.gpios) * mux->data.n_gpios, GFP_KERNEL); | |
116 | if (!gpios) { | |
117 | dev_err(&pdev->dev, "Cannot allocate gpios array"); | |
118 | return -ENOMEM; | |
119 | } | |
120 | ||
492ed77b IN |
121 | for (i = 0; i < mux->data.n_gpios; i++) { |
122 | ret = of_get_named_gpio(np, "mux-gpios", i); | |
123 | if (ret < 0) | |
124 | return ret; | |
125 | gpios[i] = ret; | |
126 | } | |
9b7a0c40 MR |
127 | |
128 | mux->data.gpios = gpios; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | #else | |
0b255e92 | 133 | static int i2c_mux_gpio_probe_dt(struct gpiomux *mux, |
9b7a0c40 MR |
134 | struct platform_device *pdev) |
135 | { | |
136 | return 0; | |
137 | } | |
138 | #endif | |
139 | ||
0b255e92 | 140 | static int i2c_mux_gpio_probe(struct platform_device *pdev) |
92ed1a76 | 141 | { |
bb448147 | 142 | struct i2c_mux_core *muxc; |
92ed1a76 | 143 | struct gpiomux *mux; |
92ed1a76 | 144 | struct i2c_adapter *parent; |
6ef91fcc | 145 | struct i2c_adapter *root; |
e7ee5140 | 146 | unsigned initial_state, gpio_base; |
92ed1a76 PK |
147 | int i, ret; |
148 | ||
9b7a0c40 | 149 | mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); |
bb448147 | 150 | if (!mux) |
9b7a0c40 | 151 | return -ENOMEM; |
9b7a0c40 | 152 | |
6d4028c6 | 153 | if (!dev_get_platdata(&pdev->dev)) { |
9b7a0c40 MR |
154 | ret = i2c_mux_gpio_probe_dt(mux, pdev); |
155 | if (ret < 0) | |
156 | return ret; | |
6d4028c6 JH |
157 | } else { |
158 | memcpy(&mux->data, dev_get_platdata(&pdev->dev), | |
159 | sizeof(mux->data)); | |
160 | } | |
9b7a0c40 | 161 | |
e7ee5140 JD |
162 | /* |
163 | * If a GPIO chip name is provided, the GPIO pin numbers provided are | |
164 | * relative to its base GPIO number. Otherwise they are absolute. | |
165 | */ | |
9b7a0c40 | 166 | if (mux->data.gpio_chip) { |
e7ee5140 JD |
167 | struct gpio_chip *gpio; |
168 | ||
9b7a0c40 | 169 | gpio = gpiochip_find(mux->data.gpio_chip, |
e7ee5140 JD |
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 | ||
9b7a0c40 | 179 | parent = i2c_get_adapter(mux->data.parent); |
623e4ecb | 180 | if (!parent) |
9937b8d8 | 181 | return -EPROBE_DEFER; |
92ed1a76 | 182 | |
feff5c0a PR |
183 | muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, |
184 | mux->data.n_gpios * sizeof(*mux->gpios) + | |
185 | mux->data.n_gpios * sizeof(*mux->values), 0, | |
bb448147 PR |
186 | i2c_mux_gpio_select, NULL); |
187 | if (!muxc) { | |
92ed1a76 | 188 | ret = -ENOMEM; |
2614a859 | 189 | goto alloc_failed; |
92ed1a76 | 190 | } |
feff5c0a PR |
191 | mux->gpios = muxc->priv; |
192 | mux->values = (int *)(mux->gpios + mux->data.n_gpios); | |
bb448147 PR |
193 | muxc->priv = mux; |
194 | ||
195 | platform_set_drvdata(pdev, muxc); | |
196 | ||
6ef91fcc PR |
197 | root = i2c_root_adapter(&parent->dev); |
198 | ||
199 | muxc->mux_locked = true; | |
bb448147 | 200 | mux->gpio_base = gpio_base; |
92ed1a76 | 201 | |
9b7a0c40 MR |
202 | if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) { |
203 | initial_state = mux->data.idle; | |
bb448147 | 204 | muxc->deselect = i2c_mux_gpio_deselect; |
92ed1a76 | 205 | } else { |
9b7a0c40 | 206 | initial_state = mux->data.values[0]; |
92ed1a76 PK |
207 | } |
208 | ||
9b7a0c40 | 209 | for (i = 0; i < mux->data.n_gpios; i++) { |
6ef91fcc PR |
210 | struct device *gpio_dev; |
211 | struct gpio_desc *gpio_desc; | |
212 | ||
9b7a0c40 | 213 | ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio"); |
7fafae66 JD |
214 | if (ret) { |
215 | dev_err(&pdev->dev, "Failed to request GPIO %d\n", | |
216 | mux->data.gpios[i]); | |
92ed1a76 | 217 | goto err_request_gpio; |
7fafae66 JD |
218 | } |
219 | ||
220 | ret = gpio_direction_output(gpio_base + mux->data.gpios[i], | |
221 | initial_state & (1 << i)); | |
222 | if (ret) { | |
223 | dev_err(&pdev->dev, | |
224 | "Failed to set direction of GPIO %d to output\n", | |
225 | mux->data.gpios[i]); | |
226 | i++; /* gpio_request above succeeded, so must free */ | |
227 | goto err_request_gpio; | |
228 | } | |
6ef91fcc | 229 | |
feff5c0a PR |
230 | gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]); |
231 | mux->gpios[i] = gpio_desc; | |
232 | ||
6ef91fcc PR |
233 | if (!muxc->mux_locked) |
234 | continue; | |
235 | ||
6ef91fcc PR |
236 | gpio_dev = &gpio_desc->gdev->dev; |
237 | muxc->mux_locked = i2c_root_adapter(gpio_dev) == root; | |
92ed1a76 PK |
238 | } |
239 | ||
6ef91fcc PR |
240 | if (muxc->mux_locked) |
241 | dev_info(&pdev->dev, "mux-locked i2c mux\n"); | |
242 | ||
9b7a0c40 MR |
243 | for (i = 0; i < mux->data.n_values; i++) { |
244 | u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0; | |
245 | unsigned int class = mux->data.classes ? mux->data.classes[i] : 0; | |
92ed1a76 | 246 | |
bb448147 | 247 | ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class); |
1b00900f | 248 | if (ret) |
92ed1a76 | 249 | goto add_adapter_failed; |
92ed1a76 PK |
250 | } |
251 | ||
252 | dev_info(&pdev->dev, "%d port mux on %s adapter\n", | |
9b7a0c40 | 253 | mux->data.n_values, parent->name); |
92ed1a76 PK |
254 | |
255 | return 0; | |
256 | ||
257 | add_adapter_failed: | |
bb448147 | 258 | i2c_mux_del_adapters(muxc); |
9b7a0c40 | 259 | i = mux->data.n_gpios; |
92ed1a76 PK |
260 | err_request_gpio: |
261 | for (; i > 0; i--) | |
9b7a0c40 | 262 | gpio_free(gpio_base + mux->data.gpios[i - 1]); |
92ed1a76 PK |
263 | alloc_failed: |
264 | i2c_put_adapter(parent); | |
265 | ||
266 | return ret; | |
267 | } | |
268 | ||
0b255e92 | 269 | static int i2c_mux_gpio_remove(struct platform_device *pdev) |
92ed1a76 | 270 | { |
bb448147 PR |
271 | struct i2c_mux_core *muxc = platform_get_drvdata(pdev); |
272 | struct gpiomux *mux = i2c_mux_priv(muxc); | |
92ed1a76 PK |
273 | int i; |
274 | ||
bb448147 | 275 | i2c_mux_del_adapters(muxc); |
92ed1a76 PK |
276 | |
277 | for (i = 0; i < mux->data.n_gpios; i++) | |
e7ee5140 | 278 | gpio_free(mux->gpio_base + mux->data.gpios[i]); |
92ed1a76 | 279 | |
bb448147 | 280 | i2c_put_adapter(muxc->parent); |
92ed1a76 PK |
281 | |
282 | return 0; | |
283 | } | |
284 | ||
0b255e92 | 285 | static const struct of_device_id i2c_mux_gpio_of_match[] = { |
9b7a0c40 MR |
286 | { .compatible = "i2c-mux-gpio", }, |
287 | {}, | |
288 | }; | |
289 | MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match); | |
290 | ||
e7065e20 JD |
291 | static struct platform_driver i2c_mux_gpio_driver = { |
292 | .probe = i2c_mux_gpio_probe, | |
0b255e92 | 293 | .remove = i2c_mux_gpio_remove, |
92ed1a76 | 294 | .driver = { |
e7065e20 | 295 | .name = "i2c-mux-gpio", |
4e905323 | 296 | .of_match_table = i2c_mux_gpio_of_match, |
92ed1a76 PK |
297 | }, |
298 | }; | |
299 | ||
e7065e20 | 300 | module_platform_driver(i2c_mux_gpio_driver); |
92ed1a76 PK |
301 | |
302 | MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver"); | |
303 | MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>"); | |
304 | MODULE_LICENSE("GPL"); | |
e7065e20 | 305 | MODULE_ALIAS("platform:i2c-mux-gpio"); |