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7f528135 ML |
1 | /* |
2 | * I2C multiplexer | |
3 | * | |
4 | * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> | |
5 | * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> | |
6 | * | |
7 | * This module supports the PCA954x series of I2C multiplexer/switch chips | |
8 | * made by Philips Semiconductors. | |
9 | * This includes the: | |
10 | * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547 | |
11 | * and PCA9548. | |
12 | * | |
13 | * These chips are all controlled via the I2C bus itself, and all have a | |
14 | * single 8-bit register. The upstream "parent" bus fans out to two, | |
15 | * four, or eight downstream busses or channels; which of these | |
16 | * are selected is determined by the chip type and register contents. A | |
17 | * mux can select only one sub-bus at a time; a switch can select any | |
18 | * combination simultaneously. | |
19 | * | |
20 | * Based on: | |
21 | * pca954x.c from Kumar Gala <galak@kernel.crashing.org> | |
22 | * Copyright (C) 2006 | |
23 | * | |
24 | * Based on: | |
25 | * pca954x.c from Ken Harrenstien | |
26 | * Copyright (C) 2004 Google, Inc. (Ken Harrenstien) | |
27 | * | |
28 | * Based on: | |
29 | * i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com> | |
30 | * and | |
31 | * pca9540.c from Jean Delvare <khali@linux-fr.org>. | |
32 | * | |
33 | * This file is licensed under the terms of the GNU General Public | |
34 | * License version 2. This program is licensed "as is" without any | |
35 | * warranty of any kind, whether express or implied. | |
36 | */ | |
37 | ||
7f528135 | 38 | #include <linux/device.h> |
12097957 | 39 | #include <linux/gpio.h> |
7f528135 ML |
40 | #include <linux/i2c.h> |
41 | #include <linux/i2c-mux.h> | |
7f528135 | 42 | #include <linux/i2c/pca954x.h> |
4b9b0073 LP |
43 | #include <linux/init.h> |
44 | #include <linux/module.h> | |
12097957 | 45 | #include <linux/of_gpio.h> |
4b9b0073 | 46 | #include <linux/slab.h> |
7f528135 ML |
47 | |
48 | #define PCA954X_MAX_NCHANS 8 | |
49 | ||
50 | enum pca_type { | |
51 | pca_9540, | |
52 | pca_9542, | |
53 | pca_9543, | |
54 | pca_9544, | |
55 | pca_9545, | |
56 | pca_9546, | |
57 | pca_9547, | |
58 | pca_9548, | |
59 | }; | |
60 | ||
61 | struct pca954x { | |
62 | enum pca_type type; | |
63 | struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS]; | |
64 | ||
65 | u8 last_chan; /* last register value */ | |
66 | }; | |
67 | ||
68 | struct chip_desc { | |
69 | u8 nchans; | |
70 | u8 enable; /* used for muxes only */ | |
71 | enum muxtype { | |
72 | pca954x_ismux = 0, | |
73 | pca954x_isswi | |
74 | } muxtype; | |
75 | }; | |
76 | ||
77 | /* Provide specs for the PCA954x types we know about */ | |
78 | static const struct chip_desc chips[] = { | |
79 | [pca_9540] = { | |
80 | .nchans = 2, | |
81 | .enable = 0x4, | |
82 | .muxtype = pca954x_ismux, | |
83 | }, | |
84 | [pca_9543] = { | |
85 | .nchans = 2, | |
86 | .muxtype = pca954x_isswi, | |
87 | }, | |
88 | [pca_9544] = { | |
89 | .nchans = 4, | |
90 | .enable = 0x4, | |
91 | .muxtype = pca954x_ismux, | |
92 | }, | |
93 | [pca_9545] = { | |
94 | .nchans = 4, | |
95 | .muxtype = pca954x_isswi, | |
96 | }, | |
97 | [pca_9547] = { | |
98 | .nchans = 8, | |
99 | .enable = 0x8, | |
100 | .muxtype = pca954x_ismux, | |
101 | }, | |
102 | [pca_9548] = { | |
103 | .nchans = 8, | |
104 | .muxtype = pca954x_isswi, | |
105 | }, | |
106 | }; | |
107 | ||
108 | static const struct i2c_device_id pca954x_id[] = { | |
109 | { "pca9540", pca_9540 }, | |
110 | { "pca9542", pca_9540 }, | |
111 | { "pca9543", pca_9543 }, | |
112 | { "pca9544", pca_9544 }, | |
113 | { "pca9545", pca_9545 }, | |
114 | { "pca9546", pca_9545 }, | |
115 | { "pca9547", pca_9547 }, | |
116 | { "pca9548", pca_9548 }, | |
117 | { } | |
118 | }; | |
119 | MODULE_DEVICE_TABLE(i2c, pca954x_id); | |
120 | ||
121 | /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() | |
122 | for this as they will try to lock adapter a second time */ | |
123 | static int pca954x_reg_write(struct i2c_adapter *adap, | |
124 | struct i2c_client *client, u8 val) | |
125 | { | |
126 | int ret = -ENODEV; | |
127 | ||
128 | if (adap->algo->master_xfer) { | |
129 | struct i2c_msg msg; | |
130 | char buf[1]; | |
131 | ||
132 | msg.addr = client->addr; | |
133 | msg.flags = 0; | |
134 | msg.len = 1; | |
135 | buf[0] = val; | |
136 | msg.buf = buf; | |
137 | ret = adap->algo->master_xfer(adap, &msg, 1); | |
138 | } else { | |
139 | union i2c_smbus_data data; | |
140 | ret = adap->algo->smbus_xfer(adap, client->addr, | |
141 | client->flags, | |
142 | I2C_SMBUS_WRITE, | |
143 | val, I2C_SMBUS_BYTE, &data); | |
144 | } | |
145 | ||
146 | return ret; | |
147 | } | |
148 | ||
149 | static int pca954x_select_chan(struct i2c_adapter *adap, | |
150 | void *client, u32 chan) | |
151 | { | |
152 | struct pca954x *data = i2c_get_clientdata(client); | |
153 | const struct chip_desc *chip = &chips[data->type]; | |
154 | u8 regval; | |
155 | int ret = 0; | |
156 | ||
157 | /* we make switches look like muxes, not sure how to be smarter */ | |
158 | if (chip->muxtype == pca954x_ismux) | |
159 | regval = chan | chip->enable; | |
160 | else | |
161 | regval = 1 << chan; | |
162 | ||
163 | /* Only select the channel if its different from the last channel */ | |
164 | if (data->last_chan != regval) { | |
165 | ret = pca954x_reg_write(adap, client, regval); | |
166 | data->last_chan = regval; | |
167 | } | |
168 | ||
169 | return ret; | |
170 | } | |
171 | ||
172 | static int pca954x_deselect_mux(struct i2c_adapter *adap, | |
173 | void *client, u32 chan) | |
174 | { | |
175 | struct pca954x *data = i2c_get_clientdata(client); | |
176 | ||
177 | /* Deselect active channel */ | |
178 | data->last_chan = 0; | |
179 | return pca954x_reg_write(adap, client, data->last_chan); | |
180 | } | |
181 | ||
182 | /* | |
183 | * I2C init/probing/exit functions | |
184 | */ | |
db79f2a1 GR |
185 | static int pca954x_probe(struct i2c_client *client, |
186 | const struct i2c_device_id *id) | |
7f528135 ML |
187 | { |
188 | struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent); | |
6d4028c6 | 189 | struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev); |
12097957 | 190 | struct device_node *np = client->dev.of_node; |
eee543e8 | 191 | int num, force, class; |
7f528135 | 192 | struct pca954x *data; |
bc12cfc8 | 193 | int ret; |
7f528135 ML |
194 | |
195 | if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) | |
bc12cfc8 | 196 | return -ENODEV; |
7f528135 | 197 | |
bc12cfc8 LP |
198 | data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL); |
199 | if (!data) | |
200 | return -ENOMEM; | |
7f528135 ML |
201 | |
202 | i2c_set_clientdata(client, data); | |
203 | ||
12097957 LP |
204 | if (IS_ENABLED(CONFIG_OF) && np) { |
205 | enum of_gpio_flags flags; | |
206 | int gpio; | |
207 | ||
208 | /* Get the mux out of reset if a reset GPIO is specified. */ | |
209 | gpio = of_get_named_gpio_flags(np, "reset-gpio", 0, &flags); | |
210 | if (gpio_is_valid(gpio)) { | |
211 | ret = devm_gpio_request_one(&client->dev, gpio, | |
212 | flags & OF_GPIO_ACTIVE_LOW ? | |
213 | GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW, | |
214 | "pca954x reset"); | |
215 | if (ret < 0) | |
216 | return ret; | |
217 | } | |
218 | } | |
219 | ||
cd823db8 PG |
220 | /* Write the mux register at addr to verify |
221 | * that the mux is in fact present. This also | |
222 | * initializes the mux to disconnected state. | |
7f528135 | 223 | */ |
cd823db8 | 224 | if (i2c_smbus_write_byte(client, 0) < 0) { |
7f528135 | 225 | dev_warn(&client->dev, "probe failed\n"); |
bc12cfc8 | 226 | return -ENODEV; |
7f528135 ML |
227 | } |
228 | ||
229 | data->type = id->driver_data; | |
230 | data->last_chan = 0; /* force the first selection */ | |
231 | ||
232 | /* Now create an adapter for each channel */ | |
233 | for (num = 0; num < chips[data->type].nchans; num++) { | |
234 | force = 0; /* dynamic adap number */ | |
eee543e8 | 235 | class = 0; /* no class by default */ |
7f528135 | 236 | if (pdata) { |
eee543e8 | 237 | if (num < pdata->num_modes) { |
7f528135 ML |
238 | /* force static number */ |
239 | force = pdata->modes[num].adap_id; | |
eee543e8 JD |
240 | class = pdata->modes[num].class; |
241 | } else | |
7f528135 ML |
242 | /* discard unconfigured channels */ |
243 | break; | |
244 | } | |
245 | ||
246 | data->virt_adaps[num] = | |
5a3ecd5f | 247 | i2c_add_mux_adapter(adap, &client->dev, client, |
eee543e8 | 248 | force, num, class, pca954x_select_chan, |
7f528135 ML |
249 | (pdata && pdata->modes[num].deselect_on_exit) |
250 | ? pca954x_deselect_mux : NULL); | |
251 | ||
252 | if (data->virt_adaps[num] == NULL) { | |
253 | ret = -ENODEV; | |
254 | dev_err(&client->dev, | |
255 | "failed to register multiplexed adapter" | |
256 | " %d as bus %d\n", num, force); | |
257 | goto virt_reg_failed; | |
258 | } | |
259 | } | |
260 | ||
261 | dev_info(&client->dev, | |
262 | "registered %d multiplexed busses for I2C %s %s\n", | |
263 | num, chips[data->type].muxtype == pca954x_ismux | |
264 | ? "mux" : "switch", client->name); | |
265 | ||
266 | return 0; | |
267 | ||
268 | virt_reg_failed: | |
269 | for (num--; num >= 0; num--) | |
270 | i2c_del_mux_adapter(data->virt_adaps[num]); | |
7f528135 ML |
271 | return ret; |
272 | } | |
273 | ||
db79f2a1 | 274 | static int pca954x_remove(struct i2c_client *client) |
7f528135 ML |
275 | { |
276 | struct pca954x *data = i2c_get_clientdata(client); | |
277 | const struct chip_desc *chip = &chips[data->type]; | |
a205e63d | 278 | int i; |
7f528135 ML |
279 | |
280 | for (i = 0; i < chip->nchans; ++i) | |
281 | if (data->virt_adaps[i]) { | |
a205e63d | 282 | i2c_del_mux_adapter(data->virt_adaps[i]); |
7f528135 ML |
283 | data->virt_adaps[i] = NULL; |
284 | } | |
285 | ||
7f528135 ML |
286 | return 0; |
287 | } | |
288 | ||
289 | static struct i2c_driver pca954x_driver = { | |
290 | .driver = { | |
291 | .name = "pca954x", | |
292 | .owner = THIS_MODULE, | |
293 | }, | |
294 | .probe = pca954x_probe, | |
db79f2a1 | 295 | .remove = pca954x_remove, |
7f528135 ML |
296 | .id_table = pca954x_id, |
297 | }; | |
298 | ||
de05497a | 299 | module_i2c_driver(pca954x_driver); |
7f528135 ML |
300 | |
301 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); | |
302 | MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); | |
303 | MODULE_LICENSE("GPL v2"); |