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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 <jdelvare@suse.de>.
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
38#include <linux/device.h>
39#include <linux/gpio/consumer.h>
40#include <linux/i2c.h>
41#include <linux/i2c-mux.h>
42#include <linux/i2c/pca954x.h>
43#include <linux/module.h>
44#include <linux/of.h>
45#include <linux/pm.h>
46#include <linux/slab.h>
47
48#define PCA954X_MAX_NCHANS 8
49
50enum 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
61struct 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
68struct 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 */
78static 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
108static 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};
119MODULE_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 */
123static 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 = __i2c_transfer(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
149static 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
172static 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 */
185static int pca954x_probe(struct i2c_client *client,
186 const struct i2c_device_id *id)
187{
188 struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
189 struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
190 struct device_node *of_node = client->dev.of_node;
191 bool idle_disconnect_dt;
192 struct gpio_desc *gpio;
193 int num, force, class;
194 struct pca954x *data;
195 int ret;
196
197 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
198 return -ENODEV;
199
200 data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL);
201 if (!data)
202 return -ENOMEM;
203
204 i2c_set_clientdata(client, data);
205
206 /* Get the mux out of reset if a reset GPIO is specified. */
207 gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
208 if (IS_ERR(gpio))
209 return PTR_ERR(gpio);
210
211 /* Write the mux register at addr to verify
212 * that the mux is in fact present. This also
213 * initializes the mux to disconnected state.
214 */
215 if (i2c_smbus_write_byte(client, 0) < 0) {
216 dev_warn(&client->dev, "probe failed\n");
217 return -ENODEV;
218 }
219
220 data->type = id->driver_data;
221 data->last_chan = 0; /* force the first selection */
222
223 idle_disconnect_dt = of_node &&
224 of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
225
226 /* Now create an adapter for each channel */
227 for (num = 0; num < chips[data->type].nchans; num++) {
228 bool idle_disconnect_pd = false;
229
230 force = 0; /* dynamic adap number */
231 class = 0; /* no class by default */
232 if (pdata) {
233 if (num < pdata->num_modes) {
234 /* force static number */
235 force = pdata->modes[num].adap_id;
236 class = pdata->modes[num].class;
237 } else
238 /* discard unconfigured channels */
239 break;
240 idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
241 }
242
243 data->virt_adaps[num] =
244 i2c_add_mux_adapter(adap, &client->dev, client,
245 force, num, class, pca954x_select_chan,
246 (idle_disconnect_pd || idle_disconnect_dt)
247 ? pca954x_deselect_mux : NULL);
248
249 if (data->virt_adaps[num] == NULL) {
250 ret = -ENODEV;
251 dev_err(&client->dev,
252 "failed to register multiplexed adapter"
253 " %d as bus %d\n", num, force);
254 goto virt_reg_failed;
255 }
256 }
257
258 dev_info(&client->dev,
259 "registered %d multiplexed busses for I2C %s %s\n",
260 num, chips[data->type].muxtype == pca954x_ismux
261 ? "mux" : "switch", client->name);
262
263 return 0;
264
265virt_reg_failed:
266 for (num--; num >= 0; num--)
267 i2c_del_mux_adapter(data->virt_adaps[num]);
268 return ret;
269}
270
271static int pca954x_remove(struct i2c_client *client)
272{
273 struct pca954x *data = i2c_get_clientdata(client);
274 const struct chip_desc *chip = &chips[data->type];
275 int i;
276
277 for (i = 0; i < chip->nchans; ++i)
278 if (data->virt_adaps[i]) {
279 i2c_del_mux_adapter(data->virt_adaps[i]);
280 data->virt_adaps[i] = NULL;
281 }
282
283 return 0;
284}
285
286#ifdef CONFIG_PM_SLEEP
287static int pca954x_resume(struct device *dev)
288{
289 struct i2c_client *client = to_i2c_client(dev);
290 struct pca954x *data = i2c_get_clientdata(client);
291
292 data->last_chan = 0;
293 return i2c_smbus_write_byte(client, 0);
294}
295#endif
296
297static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
298
299static struct i2c_driver pca954x_driver = {
300 .driver = {
301 .name = "pca954x",
302 .pm = &pca954x_pm,
303 },
304 .probe = pca954x_probe,
305 .remove = pca954x_remove,
306 .id_table = pca954x_id,
307};
308
309module_i2c_driver(pca954x_driver);
310
311MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
312MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
313MODULE_LICENSE("GPL v2");
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 <jdelvare@suse.de>.
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
38#include <linux/device.h>
39#include <linux/gpio.h>
40#include <linux/i2c.h>
41#include <linux/i2c-mux.h>
42#include <linux/i2c/pca954x.h>
43#include <linux/module.h>
44#include <linux/of_gpio.h>
45#include <linux/slab.h>
46
47#define PCA954X_MAX_NCHANS 8
48
49enum pca_type {
50 pca_9540,
51 pca_9542,
52 pca_9543,
53 pca_9544,
54 pca_9545,
55 pca_9546,
56 pca_9547,
57 pca_9548,
58};
59
60struct pca954x {
61 enum pca_type type;
62 struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
63
64 u8 last_chan; /* last register value */
65};
66
67struct chip_desc {
68 u8 nchans;
69 u8 enable; /* used for muxes only */
70 enum muxtype {
71 pca954x_ismux = 0,
72 pca954x_isswi
73 } muxtype;
74};
75
76/* Provide specs for the PCA954x types we know about */
77static const struct chip_desc chips[] = {
78 [pca_9540] = {
79 .nchans = 2,
80 .enable = 0x4,
81 .muxtype = pca954x_ismux,
82 },
83 [pca_9543] = {
84 .nchans = 2,
85 .muxtype = pca954x_isswi,
86 },
87 [pca_9544] = {
88 .nchans = 4,
89 .enable = 0x4,
90 .muxtype = pca954x_ismux,
91 },
92 [pca_9545] = {
93 .nchans = 4,
94 .muxtype = pca954x_isswi,
95 },
96 [pca_9547] = {
97 .nchans = 8,
98 .enable = 0x8,
99 .muxtype = pca954x_ismux,
100 },
101 [pca_9548] = {
102 .nchans = 8,
103 .muxtype = pca954x_isswi,
104 },
105};
106
107static const struct i2c_device_id pca954x_id[] = {
108 { "pca9540", pca_9540 },
109 { "pca9542", pca_9540 },
110 { "pca9543", pca_9543 },
111 { "pca9544", pca_9544 },
112 { "pca9545", pca_9545 },
113 { "pca9546", pca_9545 },
114 { "pca9547", pca_9547 },
115 { "pca9548", pca_9548 },
116 { }
117};
118MODULE_DEVICE_TABLE(i2c, pca954x_id);
119
120/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
121 for this as they will try to lock adapter a second time */
122static int pca954x_reg_write(struct i2c_adapter *adap,
123 struct i2c_client *client, u8 val)
124{
125 int ret = -ENODEV;
126
127 if (adap->algo->master_xfer) {
128 struct i2c_msg msg;
129 char buf[1];
130
131 msg.addr = client->addr;
132 msg.flags = 0;
133 msg.len = 1;
134 buf[0] = val;
135 msg.buf = buf;
136 ret = adap->algo->master_xfer(adap, &msg, 1);
137 } else {
138 union i2c_smbus_data data;
139 ret = adap->algo->smbus_xfer(adap, client->addr,
140 client->flags,
141 I2C_SMBUS_WRITE,
142 val, I2C_SMBUS_BYTE, &data);
143 }
144
145 return ret;
146}
147
148static int pca954x_select_chan(struct i2c_adapter *adap,
149 void *client, u32 chan)
150{
151 struct pca954x *data = i2c_get_clientdata(client);
152 const struct chip_desc *chip = &chips[data->type];
153 u8 regval;
154 int ret = 0;
155
156 /* we make switches look like muxes, not sure how to be smarter */
157 if (chip->muxtype == pca954x_ismux)
158 regval = chan | chip->enable;
159 else
160 regval = 1 << chan;
161
162 /* Only select the channel if its different from the last channel */
163 if (data->last_chan != regval) {
164 ret = pca954x_reg_write(adap, client, regval);
165 data->last_chan = regval;
166 }
167
168 return ret;
169}
170
171static int pca954x_deselect_mux(struct i2c_adapter *adap,
172 void *client, u32 chan)
173{
174 struct pca954x *data = i2c_get_clientdata(client);
175
176 /* Deselect active channel */
177 data->last_chan = 0;
178 return pca954x_reg_write(adap, client, data->last_chan);
179}
180
181/*
182 * I2C init/probing/exit functions
183 */
184static int pca954x_probe(struct i2c_client *client,
185 const struct i2c_device_id *id)
186{
187 struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
188 struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
189 struct device_node *np = client->dev.of_node;
190 int num, force, class;
191 struct pca954x *data;
192 int ret;
193
194 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
195 return -ENODEV;
196
197 data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL);
198 if (!data)
199 return -ENOMEM;
200
201 i2c_set_clientdata(client, data);
202
203 if (IS_ENABLED(CONFIG_OF) && np) {
204 enum of_gpio_flags flags;
205 int gpio;
206
207 /* Get the mux out of reset if a reset GPIO is specified. */
208 gpio = of_get_named_gpio_flags(np, "reset-gpio", 0, &flags);
209 if (gpio_is_valid(gpio)) {
210 ret = devm_gpio_request_one(&client->dev, gpio,
211 flags & OF_GPIO_ACTIVE_LOW ?
212 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
213 "pca954x reset");
214 if (ret < 0)
215 return ret;
216 }
217 }
218
219 /* Write the mux register at addr to verify
220 * that the mux is in fact present. This also
221 * initializes the mux to disconnected state.
222 */
223 if (i2c_smbus_write_byte(client, 0) < 0) {
224 dev_warn(&client->dev, "probe failed\n");
225 return -ENODEV;
226 }
227
228 data->type = id->driver_data;
229 data->last_chan = 0; /* force the first selection */
230
231 /* Now create an adapter for each channel */
232 for (num = 0; num < chips[data->type].nchans; num++) {
233 force = 0; /* dynamic adap number */
234 class = 0; /* no class by default */
235 if (pdata) {
236 if (num < pdata->num_modes) {
237 /* force static number */
238 force = pdata->modes[num].adap_id;
239 class = pdata->modes[num].class;
240 } else
241 /* discard unconfigured channels */
242 break;
243 }
244
245 data->virt_adaps[num] =
246 i2c_add_mux_adapter(adap, &client->dev, client,
247 force, num, class, pca954x_select_chan,
248 (pdata && pdata->modes[num].deselect_on_exit)
249 ? pca954x_deselect_mux : NULL);
250
251 if (data->virt_adaps[num] == NULL) {
252 ret = -ENODEV;
253 dev_err(&client->dev,
254 "failed to register multiplexed adapter"
255 " %d as bus %d\n", num, force);
256 goto virt_reg_failed;
257 }
258 }
259
260 dev_info(&client->dev,
261 "registered %d multiplexed busses for I2C %s %s\n",
262 num, chips[data->type].muxtype == pca954x_ismux
263 ? "mux" : "switch", client->name);
264
265 return 0;
266
267virt_reg_failed:
268 for (num--; num >= 0; num--)
269 i2c_del_mux_adapter(data->virt_adaps[num]);
270 return ret;
271}
272
273static int pca954x_remove(struct i2c_client *client)
274{
275 struct pca954x *data = i2c_get_clientdata(client);
276 const struct chip_desc *chip = &chips[data->type];
277 int i;
278
279 for (i = 0; i < chip->nchans; ++i)
280 if (data->virt_adaps[i]) {
281 i2c_del_mux_adapter(data->virt_adaps[i]);
282 data->virt_adaps[i] = NULL;
283 }
284
285 return 0;
286}
287
288static struct i2c_driver pca954x_driver = {
289 .driver = {
290 .name = "pca954x",
291 .owner = THIS_MODULE,
292 },
293 .probe = pca954x_probe,
294 .remove = pca954x_remove,
295 .id_table = pca954x_id,
296};
297
298module_i2c_driver(pca954x_driver);
299
300MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
301MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
302MODULE_LICENSE("GPL v2");