4 * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
5 * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
7 * This module supports the PCA954x series of I2C multiplexer/switch chips
8 * made by Philips Semiconductors.
10 * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
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.
21 * pca954x.c from Kumar Gala <galak@kernel.crashing.org>
25 * pca954x.c from Ken Harrenstien
26 * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
29 * i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
31 * pca9540.c from Jean Delvare <jdelvare@suse.de>.
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.
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>
46 #include <linux/of_device.h>
48 #include <linux/slab.h>
50 #define PCA954X_MAX_NCHANS 8
65 u8 enable; /* used for muxes only */
73 const struct chip_desc *chip;
75 u8 last_chan; /* last register value */
77 struct i2c_client *client;
80 /* Provide specs for the PCA954x types we know about */
81 static const struct chip_desc chips[] = {
85 .muxtype = pca954x_ismux,
89 .muxtype = pca954x_isswi,
94 .muxtype = pca954x_ismux,
98 .muxtype = pca954x_isswi,
103 .muxtype = pca954x_ismux,
107 .muxtype = pca954x_isswi,
111 static 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 },
122 MODULE_DEVICE_TABLE(i2c, pca954x_id);
125 static 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 },
136 MODULE_DEVICE_TABLE(acpi, pca954x_acpi_ids);
140 static 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] },
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 */
155 static int pca954x_reg_write(struct i2c_adapter *adap,
156 struct i2c_client *client, u8 val)
160 if (adap->algo->master_xfer) {
164 msg.addr = client->addr;
169 ret = __i2c_transfer(adap, &msg, 1);
171 union i2c_smbus_data data;
172 ret = adap->algo->smbus_xfer(adap, client->addr,
175 val, I2C_SMBUS_BYTE, &data);
181 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
183 struct pca954x *data = i2c_mux_priv(muxc);
184 struct i2c_client *client = data->client;
185 const struct chip_desc *chip = data->chip;
189 /* we make switches look like muxes, not sure how to be smarter */
190 if (chip->muxtype == pca954x_ismux)
191 regval = chan | chip->enable;
195 /* Only select the channel if its different from the last channel */
196 if (data->last_chan != regval) {
197 ret = pca954x_reg_write(muxc->parent, client, regval);
198 data->last_chan = ret ? 0 : regval;
204 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
206 struct pca954x *data = i2c_mux_priv(muxc);
207 struct i2c_client *client = data->client;
209 if (!(data->deselect & (1 << chan)))
212 /* Deselect active channel */
214 return pca954x_reg_write(muxc->parent, client, data->last_chan);
218 * I2C init/probing/exit functions
220 static int pca954x_probe(struct i2c_client *client,
221 const struct i2c_device_id *id)
223 struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
224 struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
225 struct device_node *of_node = client->dev.of_node;
226 bool idle_disconnect_dt;
227 struct gpio_desc *gpio;
228 int num, force, class;
229 struct i2c_mux_core *muxc;
230 struct pca954x *data;
231 const struct of_device_id *match;
234 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
237 muxc = i2c_mux_alloc(adap, &client->dev,
238 PCA954X_MAX_NCHANS, sizeof(*data), 0,
239 pca954x_select_chan, pca954x_deselect_mux);
242 data = i2c_mux_priv(muxc);
244 i2c_set_clientdata(client, muxc);
245 data->client = client;
247 /* Get the mux out of reset if a reset GPIO is specified. */
248 gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
250 return PTR_ERR(gpio);
252 /* Write the mux register at addr to verify
253 * that the mux is in fact present. This also
254 * initializes the mux to disconnected state.
256 if (i2c_smbus_write_byte(client, 0) < 0) {
257 dev_warn(&client->dev, "probe failed\n");
261 match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
263 data->chip = of_device_get_match_data(&client->dev);
265 data->chip = &chips[id->driver_data];
267 const struct acpi_device_id *acpi_id;
269 acpi_id = acpi_match_device(ACPI_PTR(pca954x_acpi_ids),
273 data->chip = &chips[acpi_id->driver_data];
276 data->last_chan = 0; /* force the first selection */
278 idle_disconnect_dt = of_node &&
279 of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
281 /* Now create an adapter for each channel */
282 for (num = 0; num < data->chip->nchans; num++) {
283 bool idle_disconnect_pd = false;
285 force = 0; /* dynamic adap number */
286 class = 0; /* no class by default */
288 if (num < pdata->num_modes) {
289 /* force static number */
290 force = pdata->modes[num].adap_id;
291 class = pdata->modes[num].class;
293 /* discard unconfigured channels */
295 idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
297 data->deselect |= (idle_disconnect_pd ||
298 idle_disconnect_dt) << num;
300 ret = i2c_mux_add_adapter(muxc, force, num, class);
303 dev_err(&client->dev,
304 "failed to register multiplexed adapter"
305 " %d as bus %d\n", num, force);
306 goto virt_reg_failed;
310 dev_info(&client->dev,
311 "registered %d multiplexed busses for I2C %s %s\n",
312 num, data->chip->muxtype == pca954x_ismux
313 ? "mux" : "switch", client->name);
318 i2c_mux_del_adapters(muxc);
322 static int pca954x_remove(struct i2c_client *client)
324 struct i2c_mux_core *muxc = i2c_get_clientdata(client);
326 i2c_mux_del_adapters(muxc);
330 #ifdef CONFIG_PM_SLEEP
331 static int pca954x_resume(struct device *dev)
333 struct i2c_client *client = to_i2c_client(dev);
334 struct i2c_mux_core *muxc = i2c_get_clientdata(client);
335 struct pca954x *data = i2c_mux_priv(muxc);
338 return i2c_smbus_write_byte(client, 0);
342 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
344 static struct i2c_driver pca954x_driver = {
348 .of_match_table = of_match_ptr(pca954x_of_match),
349 .acpi_match_table = ACPI_PTR(pca954x_acpi_ids),
351 .probe = pca954x_probe,
352 .remove = pca954x_remove,
353 .id_table = pca954x_id,
356 module_i2c_driver(pca954x_driver);
358 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
359 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
360 MODULE_LICENSE("GPL v2");