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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/acpi.h>
39#include <linux/device.h>
40#include <linux/gpio/consumer.h>
41#include <linux/i2c.h>
42#include <linux/i2c-mux.h>
43#include <linux/i2c/pca954x.h>
44#include <linux/module.h>
45#include <linux/of.h>
46#include <linux/of_device.h>
47#include <linux/pm.h>
48#include <linux/slab.h>
49
50#define PCA954X_MAX_NCHANS 8
51
52enum pca_type {
53 pca_9540,
54 pca_9542,
55 pca_9543,
56 pca_9544,
57 pca_9545,
58 pca_9546,
59 pca_9547,
60 pca_9548,
61};
62
63struct chip_desc {
64 u8 nchans;
65 u8 enable; /* used for muxes only */
66 enum muxtype {
67 pca954x_ismux = 0,
68 pca954x_isswi
69 } muxtype;
70};
71
72struct pca954x {
73 const struct chip_desc *chip;
74
75 u8 last_chan; /* last register value */
76 u8 deselect;
77 struct i2c_client *client;
78};
79
80/* Provide specs for the PCA954x types we know about */
81static const struct chip_desc chips[] = {
82 [pca_9540] = {
83 .nchans = 2,
84 .enable = 0x4,
85 .muxtype = pca954x_ismux,
86 },
87 [pca_9543] = {
88 .nchans = 2,
89 .muxtype = pca954x_isswi,
90 },
91 [pca_9544] = {
92 .nchans = 4,
93 .enable = 0x4,
94 .muxtype = pca954x_ismux,
95 },
96 [pca_9545] = {
97 .nchans = 4,
98 .muxtype = pca954x_isswi,
99 },
100 [pca_9547] = {
101 .nchans = 8,
102 .enable = 0x8,
103 .muxtype = pca954x_ismux,
104 },
105 [pca_9548] = {
106 .nchans = 8,
107 .muxtype = pca954x_isswi,
108 },
109};
110
111static const struct i2c_device_id pca954x_id[] = {
112 { "pca9540", pca_9540 },
113 { "pca9542", pca_9540 },
114 { "pca9543", pca_9543 },
115 { "pca9544", pca_9544 },
116 { "pca9545", pca_9545 },
117 { "pca9546", pca_9545 },
118 { "pca9547", pca_9547 },
119 { "pca9548", pca_9548 },
120 { }
121};
122MODULE_DEVICE_TABLE(i2c, pca954x_id);
123
124#ifdef CONFIG_ACPI
125static const struct acpi_device_id pca954x_acpi_ids[] = {
126 { .id = "PCA9540", .driver_data = pca_9540 },
127 { .id = "PCA9542", .driver_data = pca_9540 },
128 { .id = "PCA9543", .driver_data = pca_9543 },
129 { .id = "PCA9544", .driver_data = pca_9544 },
130 { .id = "PCA9545", .driver_data = pca_9545 },
131 { .id = "PCA9546", .driver_data = pca_9545 },
132 { .id = "PCA9547", .driver_data = pca_9547 },
133 { .id = "PCA9548", .driver_data = pca_9548 },
134 { }
135};
136MODULE_DEVICE_TABLE(acpi, pca954x_acpi_ids);
137#endif
138
139#ifdef CONFIG_OF
140static const struct of_device_id pca954x_of_match[] = {
141 { .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
142 { .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
143 { .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
144 { .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
145 { .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
146 { .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
147 { .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
148 { .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
149 {}
150};
151#endif
152
153/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
154 for this as they will try to lock adapter a second time */
155static int pca954x_reg_write(struct i2c_adapter *adap,
156 struct i2c_client *client, u8 val)
157{
158 int ret = -ENODEV;
159
160 if (adap->algo->master_xfer) {
161 struct i2c_msg msg;
162 char buf[1];
163
164 msg.addr = client->addr;
165 msg.flags = 0;
166 msg.len = 1;
167 buf[0] = val;
168 msg.buf = buf;
169 ret = __i2c_transfer(adap, &msg, 1);
170
171 if (ret >= 0 && ret != 1)
172 ret = -EREMOTEIO;
173 } else {
174 union i2c_smbus_data data;
175 ret = adap->algo->smbus_xfer(adap, client->addr,
176 client->flags,
177 I2C_SMBUS_WRITE,
178 val, I2C_SMBUS_BYTE, &data);
179 }
180
181 return ret;
182}
183
184static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
185{
186 struct pca954x *data = i2c_mux_priv(muxc);
187 struct i2c_client *client = data->client;
188 const struct chip_desc *chip = data->chip;
189 u8 regval;
190 int ret = 0;
191
192 /* we make switches look like muxes, not sure how to be smarter */
193 if (chip->muxtype == pca954x_ismux)
194 regval = chan | chip->enable;
195 else
196 regval = 1 << chan;
197
198 /* Only select the channel if its different from the last channel */
199 if (data->last_chan != regval) {
200 ret = pca954x_reg_write(muxc->parent, client, regval);
201 data->last_chan = ret < 0 ? 0 : regval;
202 }
203
204 return ret;
205}
206
207static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
208{
209 struct pca954x *data = i2c_mux_priv(muxc);
210 struct i2c_client *client = data->client;
211
212 if (!(data->deselect & (1 << chan)))
213 return 0;
214
215 /* Deselect active channel */
216 data->last_chan = 0;
217 return pca954x_reg_write(muxc->parent, client, data->last_chan);
218}
219
220/*
221 * I2C init/probing/exit functions
222 */
223static int pca954x_probe(struct i2c_client *client,
224 const struct i2c_device_id *id)
225{
226 struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
227 struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
228 struct device_node *of_node = client->dev.of_node;
229 bool idle_disconnect_dt;
230 struct gpio_desc *gpio;
231 int num, force, class;
232 struct i2c_mux_core *muxc;
233 struct pca954x *data;
234 const struct of_device_id *match;
235 int ret;
236
237 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
238 return -ENODEV;
239
240 muxc = i2c_mux_alloc(adap, &client->dev,
241 PCA954X_MAX_NCHANS, sizeof(*data), 0,
242 pca954x_select_chan, pca954x_deselect_mux);
243 if (!muxc)
244 return -ENOMEM;
245 data = i2c_mux_priv(muxc);
246
247 i2c_set_clientdata(client, muxc);
248 data->client = client;
249
250 /* Get the mux out of reset if a reset GPIO is specified. */
251 gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
252 if (IS_ERR(gpio))
253 return PTR_ERR(gpio);
254
255 /* Write the mux register at addr to verify
256 * that the mux is in fact present. This also
257 * initializes the mux to disconnected state.
258 */
259 if (i2c_smbus_write_byte(client, 0) < 0) {
260 dev_warn(&client->dev, "probe failed\n");
261 return -ENODEV;
262 }
263
264 match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
265 if (match)
266 data->chip = of_device_get_match_data(&client->dev);
267 else if (id)
268 data->chip = &chips[id->driver_data];
269 else {
270 const struct acpi_device_id *acpi_id;
271
272 acpi_id = acpi_match_device(ACPI_PTR(pca954x_acpi_ids),
273 &client->dev);
274 if (!acpi_id)
275 return -ENODEV;
276 data->chip = &chips[acpi_id->driver_data];
277 }
278
279 data->last_chan = 0; /* force the first selection */
280
281 idle_disconnect_dt = of_node &&
282 of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
283
284 /* Now create an adapter for each channel */
285 for (num = 0; num < data->chip->nchans; num++) {
286 bool idle_disconnect_pd = false;
287
288 force = 0; /* dynamic adap number */
289 class = 0; /* no class by default */
290 if (pdata) {
291 if (num < pdata->num_modes) {
292 /* force static number */
293 force = pdata->modes[num].adap_id;
294 class = pdata->modes[num].class;
295 } else
296 /* discard unconfigured channels */
297 break;
298 idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
299 }
300 data->deselect |= (idle_disconnect_pd ||
301 idle_disconnect_dt) << num;
302
303 ret = i2c_mux_add_adapter(muxc, force, num, class);
304
305 if (ret) {
306 dev_err(&client->dev,
307 "failed to register multiplexed adapter"
308 " %d as bus %d\n", num, force);
309 goto virt_reg_failed;
310 }
311 }
312
313 dev_info(&client->dev,
314 "registered %d multiplexed busses for I2C %s %s\n",
315 num, data->chip->muxtype == pca954x_ismux
316 ? "mux" : "switch", client->name);
317
318 return 0;
319
320virt_reg_failed:
321 i2c_mux_del_adapters(muxc);
322 return ret;
323}
324
325static int pca954x_remove(struct i2c_client *client)
326{
327 struct i2c_mux_core *muxc = i2c_get_clientdata(client);
328
329 i2c_mux_del_adapters(muxc);
330 return 0;
331}
332
333#ifdef CONFIG_PM_SLEEP
334static int pca954x_resume(struct device *dev)
335{
336 struct i2c_client *client = to_i2c_client(dev);
337 struct i2c_mux_core *muxc = i2c_get_clientdata(client);
338 struct pca954x *data = i2c_mux_priv(muxc);
339
340 data->last_chan = 0;
341 return i2c_smbus_write_byte(client, 0);
342}
343#endif
344
345static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
346
347static struct i2c_driver pca954x_driver = {
348 .driver = {
349 .name = "pca954x",
350 .pm = &pca954x_pm,
351 .of_match_table = of_match_ptr(pca954x_of_match),
352 .acpi_match_table = ACPI_PTR(pca954x_acpi_ids),
353 },
354 .probe = pca954x_probe,
355 .remove = pca954x_remove,
356 .id_table = pca954x_id,
357};
358
359module_i2c_driver(pca954x_driver);
360
361MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
362MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
363MODULE_LICENSE("GPL v2");