Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
92ed1a76 PK |
2 | /* |
3 | * I2C multiplexer using GPIO API | |
4 | * | |
5 | * Peter Korsgaard <peter.korsgaard@barco.com> | |
92ed1a76 PK |
6 | */ |
7 | ||
8 | #include <linux/i2c.h> | |
9 | #include <linux/i2c-mux.h> | |
62ea22c4 | 10 | #include <linux/platform_data/i2c-mux-gpio.h> |
92ed1a76 | 11 | #include <linux/platform_device.h> |
92ed1a76 PK |
12 | #include <linux/module.h> |
13 | #include <linux/slab.h> | |
14 | #include <linux/gpio.h> | |
6ef91fcc | 15 | #include "../../gpio/gpiolib.h" |
9b7a0c40 | 16 | #include <linux/of_gpio.h> |
92ed1a76 PK |
17 | |
18 | struct gpiomux { | |
e7065e20 | 19 | struct i2c_mux_gpio_platform_data data; |
e7ee5140 | 20 | unsigned gpio_base; |
feff5c0a | 21 | struct gpio_desc **gpios; |
92ed1a76 PK |
22 | }; |
23 | ||
e7065e20 | 24 | static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val) |
92ed1a76 | 25 | { |
b9762beb | 26 | DECLARE_BITMAP(values, BITS_PER_TYPE(val)); |
92ed1a76 | 27 | |
b9762beb | 28 | values[0] = val; |
feff5c0a | 29 | |
77588c14 JK |
30 | gpiod_set_array_value_cansleep(mux->data.n_gpios, mux->gpios, NULL, |
31 | values); | |
92ed1a76 PK |
32 | } |
33 | ||
bb448147 | 34 | static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan) |
92ed1a76 | 35 | { |
bb448147 | 36 | struct gpiomux *mux = i2c_mux_priv(muxc); |
92ed1a76 | 37 | |
8c0ec250 | 38 | i2c_mux_gpio_set(mux, chan); |
92ed1a76 PK |
39 | |
40 | return 0; | |
41 | } | |
42 | ||
bb448147 | 43 | static int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan) |
92ed1a76 | 44 | { |
bb448147 | 45 | struct gpiomux *mux = i2c_mux_priv(muxc); |
92ed1a76 | 46 | |
e7065e20 | 47 | i2c_mux_gpio_set(mux, mux->data.idle); |
92ed1a76 PK |
48 | |
49 | return 0; | |
50 | } | |
51 | ||
0b255e92 | 52 | static int match_gpio_chip_by_label(struct gpio_chip *chip, |
e7ee5140 JD |
53 | void *data) |
54 | { | |
55 | return !strcmp(chip->label, data); | |
56 | } | |
57 | ||
9b7a0c40 | 58 | #ifdef CONFIG_OF |
0b255e92 | 59 | static int i2c_mux_gpio_probe_dt(struct gpiomux *mux, |
9b7a0c40 MR |
60 | struct platform_device *pdev) |
61 | { | |
62 | struct device_node *np = pdev->dev.of_node; | |
63 | struct device_node *adapter_np, *child; | |
64 | struct i2c_adapter *adapter; | |
65 | unsigned *values, *gpios; | |
492ed77b | 66 | int i = 0, ret; |
9b7a0c40 MR |
67 | |
68 | if (!np) | |
69 | return -ENODEV; | |
70 | ||
71 | adapter_np = of_parse_phandle(np, "i2c-parent", 0); | |
72 | if (!adapter_np) { | |
73 | dev_err(&pdev->dev, "Cannot parse i2c-parent\n"); | |
74 | return -ENODEV; | |
75 | } | |
76 | adapter = of_find_i2c_adapter_by_node(adapter_np); | |
bdbf4a29 | 77 | of_node_put(adapter_np); |
623e4ecb | 78 | if (!adapter) |
9937b8d8 | 79 | return -EPROBE_DEFER; |
623e4ecb | 80 | |
9b7a0c40 MR |
81 | mux->data.parent = i2c_adapter_id(adapter); |
82 | put_device(&adapter->dev); | |
83 | ||
84 | mux->data.n_values = of_get_child_count(np); | |
85 | ||
a86854d0 KC |
86 | values = devm_kcalloc(&pdev->dev, |
87 | mux->data.n_values, sizeof(*mux->data.values), | |
9b7a0c40 MR |
88 | GFP_KERNEL); |
89 | if (!values) { | |
90 | dev_err(&pdev->dev, "Cannot allocate values array"); | |
91 | return -ENOMEM; | |
92 | } | |
93 | ||
94 | for_each_child_of_node(np, child) { | |
95 | of_property_read_u32(child, "reg", values + i); | |
96 | i++; | |
97 | } | |
98 | mux->data.values = values; | |
99 | ||
100 | if (of_property_read_u32(np, "idle-state", &mux->data.idle)) | |
101 | mux->data.idle = I2C_MUX_GPIO_NO_IDLE; | |
102 | ||
103 | mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios"); | |
104 | if (mux->data.n_gpios < 0) { | |
105 | dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n"); | |
106 | return -EINVAL; | |
107 | } | |
108 | ||
a86854d0 KC |
109 | gpios = devm_kcalloc(&pdev->dev, |
110 | mux->data.n_gpios, sizeof(*mux->data.gpios), | |
111 | GFP_KERNEL); | |
9b7a0c40 MR |
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 | 137 | { |
bb448147 | 138 | struct i2c_mux_core *muxc; |
92ed1a76 | 139 | struct gpiomux *mux; |
92ed1a76 | 140 | struct i2c_adapter *parent; |
6ef91fcc | 141 | struct i2c_adapter *root; |
e7ee5140 | 142 | unsigned initial_state, gpio_base; |
92ed1a76 PK |
143 | int i, ret; |
144 | ||
9b7a0c40 | 145 | mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); |
bb448147 | 146 | if (!mux) |
9b7a0c40 | 147 | return -ENOMEM; |
9b7a0c40 | 148 | |
6d4028c6 | 149 | if (!dev_get_platdata(&pdev->dev)) { |
9b7a0c40 MR |
150 | ret = i2c_mux_gpio_probe_dt(mux, pdev); |
151 | if (ret < 0) | |
152 | return ret; | |
6d4028c6 JH |
153 | } else { |
154 | memcpy(&mux->data, dev_get_platdata(&pdev->dev), | |
155 | sizeof(mux->data)); | |
156 | } | |
9b7a0c40 | 157 | |
e7ee5140 JD |
158 | /* |
159 | * If a GPIO chip name is provided, the GPIO pin numbers provided are | |
160 | * relative to its base GPIO number. Otherwise they are absolute. | |
161 | */ | |
9b7a0c40 | 162 | if (mux->data.gpio_chip) { |
e7ee5140 JD |
163 | struct gpio_chip *gpio; |
164 | ||
9b7a0c40 | 165 | gpio = gpiochip_find(mux->data.gpio_chip, |
e7ee5140 JD |
166 | match_gpio_chip_by_label); |
167 | if (!gpio) | |
168 | return -EPROBE_DEFER; | |
169 | ||
170 | gpio_base = gpio->base; | |
171 | } else { | |
172 | gpio_base = 0; | |
173 | } | |
174 | ||
9b7a0c40 | 175 | parent = i2c_get_adapter(mux->data.parent); |
623e4ecb | 176 | if (!parent) |
9937b8d8 | 177 | return -EPROBE_DEFER; |
92ed1a76 | 178 | |
feff5c0a | 179 | muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, |
b9762beb | 180 | mux->data.n_gpios * sizeof(*mux->gpios), 0, |
bb448147 PR |
181 | i2c_mux_gpio_select, NULL); |
182 | if (!muxc) { | |
92ed1a76 | 183 | ret = -ENOMEM; |
2614a859 | 184 | goto alloc_failed; |
92ed1a76 | 185 | } |
feff5c0a | 186 | mux->gpios = muxc->priv; |
bb448147 PR |
187 | muxc->priv = mux; |
188 | ||
189 | platform_set_drvdata(pdev, muxc); | |
190 | ||
6ef91fcc PR |
191 | root = i2c_root_adapter(&parent->dev); |
192 | ||
193 | muxc->mux_locked = true; | |
bb448147 | 194 | mux->gpio_base = gpio_base; |
92ed1a76 | 195 | |
9b7a0c40 MR |
196 | if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) { |
197 | initial_state = mux->data.idle; | |
bb448147 | 198 | muxc->deselect = i2c_mux_gpio_deselect; |
92ed1a76 | 199 | } else { |
9b7a0c40 | 200 | initial_state = mux->data.values[0]; |
92ed1a76 PK |
201 | } |
202 | ||
9b7a0c40 | 203 | for (i = 0; i < mux->data.n_gpios; i++) { |
6ef91fcc PR |
204 | struct device *gpio_dev; |
205 | struct gpio_desc *gpio_desc; | |
206 | ||
9b7a0c40 | 207 | ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio"); |
7fafae66 JD |
208 | if (ret) { |
209 | dev_err(&pdev->dev, "Failed to request GPIO %d\n", | |
210 | mux->data.gpios[i]); | |
92ed1a76 | 211 | goto err_request_gpio; |
7fafae66 JD |
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++; /* gpio_request above succeeded, so must free */ | |
221 | goto err_request_gpio; | |
222 | } | |
6ef91fcc | 223 | |
feff5c0a PR |
224 | gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]); |
225 | mux->gpios[i] = gpio_desc; | |
226 | ||
6ef91fcc PR |
227 | if (!muxc->mux_locked) |
228 | continue; | |
229 | ||
6ef91fcc PR |
230 | gpio_dev = &gpio_desc->gdev->dev; |
231 | muxc->mux_locked = i2c_root_adapter(gpio_dev) == root; | |
92ed1a76 PK |
232 | } |
233 | ||
6ef91fcc PR |
234 | if (muxc->mux_locked) |
235 | dev_info(&pdev->dev, "mux-locked i2c mux\n"); | |
236 | ||
9b7a0c40 MR |
237 | for (i = 0; i < mux->data.n_values; i++) { |
238 | u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0; | |
239 | unsigned int class = mux->data.classes ? mux->data.classes[i] : 0; | |
92ed1a76 | 240 | |
bb448147 | 241 | ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class); |
1b00900f | 242 | if (ret) |
92ed1a76 | 243 | goto add_adapter_failed; |
92ed1a76 PK |
244 | } |
245 | ||
246 | dev_info(&pdev->dev, "%d port mux on %s adapter\n", | |
9b7a0c40 | 247 | mux->data.n_values, parent->name); |
92ed1a76 PK |
248 | |
249 | return 0; | |
250 | ||
251 | add_adapter_failed: | |
bb448147 | 252 | i2c_mux_del_adapters(muxc); |
9b7a0c40 | 253 | i = mux->data.n_gpios; |
92ed1a76 PK |
254 | err_request_gpio: |
255 | for (; i > 0; i--) | |
9b7a0c40 | 256 | gpio_free(gpio_base + mux->data.gpios[i - 1]); |
92ed1a76 PK |
257 | alloc_failed: |
258 | i2c_put_adapter(parent); | |
259 | ||
260 | return ret; | |
261 | } | |
262 | ||
0b255e92 | 263 | static int i2c_mux_gpio_remove(struct platform_device *pdev) |
92ed1a76 | 264 | { |
bb448147 PR |
265 | struct i2c_mux_core *muxc = platform_get_drvdata(pdev); |
266 | struct gpiomux *mux = i2c_mux_priv(muxc); | |
92ed1a76 PK |
267 | int i; |
268 | ||
bb448147 | 269 | i2c_mux_del_adapters(muxc); |
92ed1a76 PK |
270 | |
271 | for (i = 0; i < mux->data.n_gpios; i++) | |
e7ee5140 | 272 | gpio_free(mux->gpio_base + mux->data.gpios[i]); |
92ed1a76 | 273 | |
bb448147 | 274 | i2c_put_adapter(muxc->parent); |
92ed1a76 PK |
275 | |
276 | return 0; | |
277 | } | |
278 | ||
0b255e92 | 279 | static const struct of_device_id i2c_mux_gpio_of_match[] = { |
9b7a0c40 MR |
280 | { .compatible = "i2c-mux-gpio", }, |
281 | {}, | |
282 | }; | |
283 | MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match); | |
284 | ||
e7065e20 JD |
285 | static struct platform_driver i2c_mux_gpio_driver = { |
286 | .probe = i2c_mux_gpio_probe, | |
0b255e92 | 287 | .remove = i2c_mux_gpio_remove, |
92ed1a76 | 288 | .driver = { |
e7065e20 | 289 | .name = "i2c-mux-gpio", |
4e905323 | 290 | .of_match_table = i2c_mux_gpio_of_match, |
92ed1a76 PK |
291 | }, |
292 | }; | |
293 | ||
e7065e20 | 294 | module_platform_driver(i2c_mux_gpio_driver); |
92ed1a76 PK |
295 | |
296 | MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver"); | |
297 | MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>"); | |
298 | MODULE_LICENSE("GPL"); | |
e7065e20 | 299 | MODULE_ALIAS("platform:i2c-mux-gpio"); |