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/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>
46 #include <linux/slab.h>
48 #define PCA954X_MAX_NCHANS 8
64 u8 last_chan
; /* last register value */
66 struct i2c_client
*client
;
71 u8 enable
; /* used for muxes only */
78 /* Provide specs for the PCA954x types we know about */
79 static const struct chip_desc chips
[] = {
83 .muxtype
= pca954x_ismux
,
87 .muxtype
= pca954x_isswi
,
92 .muxtype
= pca954x_ismux
,
96 .muxtype
= pca954x_isswi
,
101 .muxtype
= pca954x_ismux
,
105 .muxtype
= pca954x_isswi
,
109 static const struct i2c_device_id pca954x_id
[] = {
110 { "pca9540", pca_9540
},
111 { "pca9542", pca_9540
},
112 { "pca9543", pca_9543
},
113 { "pca9544", pca_9544
},
114 { "pca9545", pca_9545
},
115 { "pca9546", pca_9545
},
116 { "pca9547", pca_9547
},
117 { "pca9548", pca_9548
},
120 MODULE_DEVICE_TABLE(i2c
, pca954x_id
);
122 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
123 for this as they will try to lock adapter a second time */
124 static int pca954x_reg_write(struct i2c_adapter
*adap
,
125 struct i2c_client
*client
, u8 val
)
129 if (adap
->algo
->master_xfer
) {
133 msg
.addr
= client
->addr
;
138 ret
= __i2c_transfer(adap
, &msg
, 1);
140 union i2c_smbus_data data
;
141 ret
= adap
->algo
->smbus_xfer(adap
, client
->addr
,
144 val
, I2C_SMBUS_BYTE
, &data
);
150 static int pca954x_select_chan(struct i2c_mux_core
*muxc
, u32 chan
)
152 struct pca954x
*data
= i2c_mux_priv(muxc
);
153 struct i2c_client
*client
= data
->client
;
154 const struct chip_desc
*chip
= &chips
[data
->type
];
158 /* we make switches look like muxes, not sure how to be smarter */
159 if (chip
->muxtype
== pca954x_ismux
)
160 regval
= chan
| chip
->enable
;
164 /* Only select the channel if its different from the last channel */
165 if (data
->last_chan
!= regval
) {
166 ret
= pca954x_reg_write(muxc
->parent
, client
, regval
);
167 data
->last_chan
= regval
;
173 static int pca954x_deselect_mux(struct i2c_mux_core
*muxc
, u32 chan
)
175 struct pca954x
*data
= i2c_mux_priv(muxc
);
176 struct i2c_client
*client
= data
->client
;
178 if (!(data
->deselect
& (1 << chan
)))
181 /* Deselect active channel */
183 return pca954x_reg_write(muxc
->parent
, client
, data
->last_chan
);
187 * I2C init/probing/exit functions
189 static int pca954x_probe(struct i2c_client
*client
,
190 const struct i2c_device_id
*id
)
192 struct i2c_adapter
*adap
= to_i2c_adapter(client
->dev
.parent
);
193 struct pca954x_platform_data
*pdata
= dev_get_platdata(&client
->dev
);
194 struct device_node
*of_node
= client
->dev
.of_node
;
195 bool idle_disconnect_dt
;
196 struct gpio_desc
*gpio
;
197 int num
, force
, class;
198 struct i2c_mux_core
*muxc
;
199 struct pca954x
*data
;
202 if (!i2c_check_functionality(adap
, I2C_FUNC_SMBUS_BYTE
))
205 muxc
= i2c_mux_alloc(adap
, &client
->dev
,
206 PCA954X_MAX_NCHANS
, sizeof(*data
), 0,
207 pca954x_select_chan
, pca954x_deselect_mux
);
210 data
= i2c_mux_priv(muxc
);
212 i2c_set_clientdata(client
, muxc
);
213 data
->client
= client
;
215 /* Get the mux out of reset if a reset GPIO is specified. */
216 gpio
= devm_gpiod_get_optional(&client
->dev
, "reset", GPIOD_OUT_LOW
);
218 return PTR_ERR(gpio
);
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.
224 if (i2c_smbus_write_byte(client
, 0) < 0) {
225 dev_warn(&client
->dev
, "probe failed\n");
229 data
->type
= id
->driver_data
;
230 data
->last_chan
= 0; /* force the first selection */
232 idle_disconnect_dt
= of_node
&&
233 of_property_read_bool(of_node
, "i2c-mux-idle-disconnect");
235 /* Now create an adapter for each channel */
236 for (num
= 0; num
< chips
[data
->type
].nchans
; num
++) {
237 bool idle_disconnect_pd
= false;
239 force
= 0; /* dynamic adap number */
240 class = 0; /* no class by default */
242 if (num
< pdata
->num_modes
) {
243 /* force static number */
244 force
= pdata
->modes
[num
].adap_id
;
245 class = pdata
->modes
[num
].class;
247 /* discard unconfigured channels */
249 idle_disconnect_pd
= pdata
->modes
[num
].deselect_on_exit
;
250 data
->deselect
|= (idle_disconnect_pd
251 || idle_disconnect_dt
) << num
;
254 ret
= i2c_mux_add_adapter(muxc
, force
, num
, class);
257 dev_err(&client
->dev
,
258 "failed to register multiplexed adapter"
259 " %d as bus %d\n", num
, force
);
260 goto virt_reg_failed
;
264 dev_info(&client
->dev
,
265 "registered %d multiplexed busses for I2C %s %s\n",
266 num
, chips
[data
->type
].muxtype
== pca954x_ismux
267 ? "mux" : "switch", client
->name
);
272 i2c_mux_del_adapters(muxc
);
276 static int pca954x_remove(struct i2c_client
*client
)
278 struct i2c_mux_core
*muxc
= i2c_get_clientdata(client
);
280 i2c_mux_del_adapters(muxc
);
284 #ifdef CONFIG_PM_SLEEP
285 static int pca954x_resume(struct device
*dev
)
287 struct i2c_client
*client
= to_i2c_client(dev
);
288 struct i2c_mux_core
*muxc
= i2c_get_clientdata(client
);
289 struct pca954x
*data
= i2c_mux_priv(muxc
);
292 return i2c_smbus_write_byte(client
, 0);
296 static SIMPLE_DEV_PM_OPS(pca954x_pm
, NULL
, pca954x_resume
);
298 static struct i2c_driver pca954x_driver
= {
303 .probe
= pca954x_probe
,
304 .remove
= pca954x_remove
,
305 .id_table
= pca954x_id
,
308 module_i2c_driver(pca954x_driver
);
310 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
311 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
312 MODULE_LICENSE("GPL v2");