1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
/*
* drivers/i2c/muxes/i2c-mux-mlxcpld.c
* Copyright (c) 2016 Mellanox Technologies. All rights reserved.
* Copyright (c) 2016 Michael Shych <michaels@mellanox.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/version.h>
#include <linux/i2c/mlxcpld.h>
#define CPLD_MUX_MAX_NCHANS 8
/* mlxcpld_mux - mux control structure:
* @last_chan - last register value
* @client - I2C device client
*/
struct mlxcpld_mux {
u8 last_chan;
struct i2c_client *client;
};
/* MUX logic description.
* Driver can support different mux control logic, according to CPLD
* implementation.
*
* Connectivity schema.
*
* i2c-mlxcpld Digital Analog
* driver
* *--------* * -> mux1 (virt bus2) -> mux -> |
* | I2CLPC | i2c physical * -> mux2 (virt bus3) -> mux -> |
* | bridge | bus 1 *---------* |
* | logic |---------------------> * mux reg * |
* | in CPLD| *---------* |
* *--------* i2c-mux-mlxpcld ^ * -> muxn (virt busn) -> mux -> |
* | driver | |
* | *---------------* | Devices
* | * CPLD (i2c bus)* select |
* | * registers for *--------*
* | * mux selection * deselect
* | *---------------*
* | |
* <--------> <----------->
* i2c cntrl Board cntrl reg
* reg space space (mux select,
* IO, LED, WD, info)
*
*/
static const struct i2c_device_id mlxcpld_mux_id[] = {
{ "mlxcpld_mux_module", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mlxcpld_mux_id);
/* Write to mux register. Don't use i2c_transfer() and i2c_smbus_xfer()
* for this as they will try to lock adapter a second time.
*/
static int mlxcpld_mux_reg_write(struct i2c_adapter *adap,
struct i2c_client *client, u8 val)
{
struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&client->dev);
if (adap->algo->master_xfer) {
struct i2c_msg msg;
u8 msgbuf[] = {pdata->sel_reg_addr, val};
msg.addr = client->addr;
msg.flags = 0;
msg.len = 2;
msg.buf = msgbuf;
return __i2c_transfer(adap, &msg, 1);
} else if (adap->algo->smbus_xfer) {
union i2c_smbus_data data;
data.byte = val;
return adap->algo->smbus_xfer(adap, client->addr,
client->flags, I2C_SMBUS_WRITE,
pdata->sel_reg_addr,
I2C_SMBUS_BYTE_DATA, &data);
} else
return -ENODEV;
}
static int mlxcpld_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
{
struct mlxcpld_mux *data = i2c_mux_priv(muxc);
struct i2c_client *client = data->client;
u8 regval = chan + 1;
int err = 0;
/* Only select the channel if its different from the last channel */
if (data->last_chan != regval) {
err = mlxcpld_mux_reg_write(muxc->parent, client, regval);
if (err)
data->last_chan = 0;
else
data->last_chan = regval;
}
return err;
}
static int mlxcpld_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
{
struct mlxcpld_mux *data = i2c_mux_priv(muxc);
struct i2c_client *client = data->client;
/* Deselect active channel */
data->last_chan = 0;
return mlxcpld_mux_reg_write(muxc->parent, client, data->last_chan);
}
/* Probe/reomove functions */
static int mlxcpld_mux_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&client->dev);
struct i2c_mux_core *muxc;
int num, force;
struct mlxcpld_mux *data;
int err;
if (!pdata)
return -EINVAL;
if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
return -ENODEV;
muxc = i2c_mux_alloc(adap, &client->dev, CPLD_MUX_MAX_NCHANS,
sizeof(*data), 0, mlxcpld_mux_select_chan,
mlxcpld_mux_deselect);
if (!muxc)
return -ENOMEM;
data = i2c_mux_priv(muxc);
i2c_set_clientdata(client, muxc);
data->client = client;
data->last_chan = 0; /* force the first selection */
/* Create an adapter for each channel. */
for (num = 0; num < CPLD_MUX_MAX_NCHANS; num++) {
if (num >= pdata->num_adaps)
/* discard unconfigured channels */
break;
force = pdata->adap_ids[num];
err = i2c_mux_add_adapter(muxc, force, num, 0);
if (err)
goto virt_reg_failed;
}
return 0;
virt_reg_failed:
i2c_mux_del_adapters(muxc);
return err;
}
static int mlxcpld_mux_remove(struct i2c_client *client)
{
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
i2c_mux_del_adapters(muxc);
return 0;
}
static struct i2c_driver mlxcpld_mux_driver = {
.driver = {
.name = "mlxcpld-mux",
},
.probe = mlxcpld_mux_probe,
.remove = mlxcpld_mux_remove,
.id_table = mlxcpld_mux_id,
};
module_i2c_driver(mlxcpld_mux_driver);
MODULE_AUTHOR("Michael Shych (michaels@mellanox.com)");
MODULE_DESCRIPTION("Mellanox I2C-CPLD-MUX driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS("platform:i2c-mux-mlxcpld");
|
