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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 | |
7c81c60f | 31 | * pca9540.c from Jean Delvare <jdelvare@suse.de>. |
7f528135 ML |
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> |
642653d1 | 39 | #include <linux/gpio/consumer.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/module.h> |
44 | #include <linux/slab.h> | |
7f528135 ML |
45 | |
46 | #define PCA954X_MAX_NCHANS 8 | |
47 | ||
48 | enum pca_type { | |
49 | pca_9540, | |
50 | pca_9542, | |
51 | pca_9543, | |
52 | pca_9544, | |
53 | pca_9545, | |
54 | pca_9546, | |
55 | pca_9547, | |
56 | pca_9548, | |
57 | }; | |
58 | ||
59 | struct pca954x { | |
60 | enum pca_type type; | |
61 | struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS]; | |
62 | ||
63 | u8 last_chan; /* last register value */ | |
64 | }; | |
65 | ||
66 | struct chip_desc { | |
67 | u8 nchans; | |
68 | u8 enable; /* used for muxes only */ | |
69 | enum muxtype { | |
70 | pca954x_ismux = 0, | |
71 | pca954x_isswi | |
72 | } muxtype; | |
73 | }; | |
74 | ||
75 | /* Provide specs for the PCA954x types we know about */ | |
76 | static const struct chip_desc chips[] = { | |
77 | [pca_9540] = { | |
78 | .nchans = 2, | |
79 | .enable = 0x4, | |
80 | .muxtype = pca954x_ismux, | |
81 | }, | |
82 | [pca_9543] = { | |
83 | .nchans = 2, | |
84 | .muxtype = pca954x_isswi, | |
85 | }, | |
86 | [pca_9544] = { | |
87 | .nchans = 4, | |
88 | .enable = 0x4, | |
89 | .muxtype = pca954x_ismux, | |
90 | }, | |
91 | [pca_9545] = { | |
92 | .nchans = 4, | |
93 | .muxtype = pca954x_isswi, | |
94 | }, | |
95 | [pca_9547] = { | |
96 | .nchans = 8, | |
97 | .enable = 0x8, | |
98 | .muxtype = pca954x_ismux, | |
99 | }, | |
100 | [pca_9548] = { | |
101 | .nchans = 8, | |
102 | .muxtype = pca954x_isswi, | |
103 | }, | |
104 | }; | |
105 | ||
106 | static const struct i2c_device_id pca954x_id[] = { | |
107 | { "pca9540", pca_9540 }, | |
108 | { "pca9542", pca_9540 }, | |
109 | { "pca9543", pca_9543 }, | |
110 | { "pca9544", pca_9544 }, | |
111 | { "pca9545", pca_9545 }, | |
112 | { "pca9546", pca_9545 }, | |
113 | { "pca9547", pca_9547 }, | |
114 | { "pca9548", pca_9548 }, | |
115 | { } | |
116 | }; | |
117 | MODULE_DEVICE_TABLE(i2c, pca954x_id); | |
118 | ||
119 | /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() | |
120 | for this as they will try to lock adapter a second time */ | |
121 | static int pca954x_reg_write(struct i2c_adapter *adap, | |
122 | struct i2c_client *client, u8 val) | |
123 | { | |
124 | int ret = -ENODEV; | |
125 | ||
126 | if (adap->algo->master_xfer) { | |
127 | struct i2c_msg msg; | |
128 | char buf[1]; | |
129 | ||
130 | msg.addr = client->addr; | |
131 | msg.flags = 0; | |
132 | msg.len = 1; | |
133 | buf[0] = val; | |
134 | msg.buf = buf; | |
135 | ret = adap->algo->master_xfer(adap, &msg, 1); | |
136 | } else { | |
137 | union i2c_smbus_data data; | |
138 | ret = adap->algo->smbus_xfer(adap, client->addr, | |
139 | client->flags, | |
140 | I2C_SMBUS_WRITE, | |
141 | val, I2C_SMBUS_BYTE, &data); | |
142 | } | |
143 | ||
144 | return ret; | |
145 | } | |
146 | ||
147 | static int pca954x_select_chan(struct i2c_adapter *adap, | |
148 | void *client, u32 chan) | |
149 | { | |
150 | struct pca954x *data = i2c_get_clientdata(client); | |
151 | const struct chip_desc *chip = &chips[data->type]; | |
152 | u8 regval; | |
153 | int ret = 0; | |
154 | ||
155 | /* we make switches look like muxes, not sure how to be smarter */ | |
156 | if (chip->muxtype == pca954x_ismux) | |
157 | regval = chan | chip->enable; | |
158 | else | |
159 | regval = 1 << chan; | |
160 | ||
161 | /* Only select the channel if its different from the last channel */ | |
162 | if (data->last_chan != regval) { | |
163 | ret = pca954x_reg_write(adap, client, regval); | |
164 | data->last_chan = regval; | |
165 | } | |
166 | ||
167 | return ret; | |
168 | } | |
169 | ||
170 | static int pca954x_deselect_mux(struct i2c_adapter *adap, | |
171 | void *client, u32 chan) | |
172 | { | |
173 | struct pca954x *data = i2c_get_clientdata(client); | |
174 | ||
175 | /* Deselect active channel */ | |
176 | data->last_chan = 0; | |
177 | return pca954x_reg_write(adap, client, data->last_chan); | |
178 | } | |
179 | ||
180 | /* | |
181 | * I2C init/probing/exit functions | |
182 | */ | |
db79f2a1 GR |
183 | static int pca954x_probe(struct i2c_client *client, |
184 | const struct i2c_device_id *id) | |
7f528135 ML |
185 | { |
186 | struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent); | |
6d4028c6 | 187 | struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev); |
4807e845 | 188 | struct gpio_desc *gpio; |
eee543e8 | 189 | int num, force, class; |
7f528135 | 190 | struct pca954x *data; |
bc12cfc8 | 191 | int ret; |
7f528135 ML |
192 | |
193 | if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) | |
bc12cfc8 | 194 | return -ENODEV; |
7f528135 | 195 | |
bc12cfc8 LP |
196 | data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL); |
197 | if (!data) | |
198 | return -ENOMEM; | |
7f528135 ML |
199 | |
200 | i2c_set_clientdata(client, data); | |
201 | ||
4807e845 LP |
202 | /* Get the mux out of reset if a reset GPIO is specified. */ |
203 | gpio = devm_gpiod_get(&client->dev, "reset"); | |
204 | if (!IS_ERR(gpio)) | |
205 | gpiod_direction_output(gpio, 0); | |
12097957 | 206 | |
cd823db8 PG |
207 | /* Write the mux register at addr to verify |
208 | * that the mux is in fact present. This also | |
209 | * initializes the mux to disconnected state. | |
7f528135 | 210 | */ |
cd823db8 | 211 | if (i2c_smbus_write_byte(client, 0) < 0) { |
7f528135 | 212 | dev_warn(&client->dev, "probe failed\n"); |
bc12cfc8 | 213 | return -ENODEV; |
7f528135 ML |
214 | } |
215 | ||
216 | data->type = id->driver_data; | |
217 | data->last_chan = 0; /* force the first selection */ | |
218 | ||
219 | /* Now create an adapter for each channel */ | |
220 | for (num = 0; num < chips[data->type].nchans; num++) { | |
221 | force = 0; /* dynamic adap number */ | |
eee543e8 | 222 | class = 0; /* no class by default */ |
7f528135 | 223 | if (pdata) { |
eee543e8 | 224 | if (num < pdata->num_modes) { |
7f528135 ML |
225 | /* force static number */ |
226 | force = pdata->modes[num].adap_id; | |
eee543e8 JD |
227 | class = pdata->modes[num].class; |
228 | } else | |
7f528135 ML |
229 | /* discard unconfigured channels */ |
230 | break; | |
231 | } | |
232 | ||
233 | data->virt_adaps[num] = | |
5a3ecd5f | 234 | i2c_add_mux_adapter(adap, &client->dev, client, |
eee543e8 | 235 | force, num, class, pca954x_select_chan, |
7f528135 ML |
236 | (pdata && pdata->modes[num].deselect_on_exit) |
237 | ? pca954x_deselect_mux : NULL); | |
238 | ||
239 | if (data->virt_adaps[num] == NULL) { | |
240 | ret = -ENODEV; | |
241 | dev_err(&client->dev, | |
242 | "failed to register multiplexed adapter" | |
243 | " %d as bus %d\n", num, force); | |
244 | goto virt_reg_failed; | |
245 | } | |
246 | } | |
247 | ||
248 | dev_info(&client->dev, | |
249 | "registered %d multiplexed busses for I2C %s %s\n", | |
250 | num, chips[data->type].muxtype == pca954x_ismux | |
251 | ? "mux" : "switch", client->name); | |
252 | ||
253 | return 0; | |
254 | ||
255 | virt_reg_failed: | |
256 | for (num--; num >= 0; num--) | |
257 | i2c_del_mux_adapter(data->virt_adaps[num]); | |
7f528135 ML |
258 | return ret; |
259 | } | |
260 | ||
db79f2a1 | 261 | static int pca954x_remove(struct i2c_client *client) |
7f528135 ML |
262 | { |
263 | struct pca954x *data = i2c_get_clientdata(client); | |
264 | const struct chip_desc *chip = &chips[data->type]; | |
a205e63d | 265 | int i; |
7f528135 ML |
266 | |
267 | for (i = 0; i < chip->nchans; ++i) | |
268 | if (data->virt_adaps[i]) { | |
a205e63d | 269 | i2c_del_mux_adapter(data->virt_adaps[i]); |
7f528135 ML |
270 | data->virt_adaps[i] = NULL; |
271 | } | |
272 | ||
7f528135 ML |
273 | return 0; |
274 | } | |
275 | ||
276 | static struct i2c_driver pca954x_driver = { | |
277 | .driver = { | |
278 | .name = "pca954x", | |
279 | .owner = THIS_MODULE, | |
280 | }, | |
281 | .probe = pca954x_probe, | |
db79f2a1 | 282 | .remove = pca954x_remove, |
7f528135 ML |
283 | .id_table = pca954x_id, |
284 | }; | |
285 | ||
de05497a | 286 | module_i2c_driver(pca954x_driver); |
7f528135 ML |
287 | |
288 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); | |
289 | MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); | |
290 | MODULE_LICENSE("GPL v2"); |