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1da177e4 | 1 | /* |
1da177e4 LT |
2 | Copyright (c) 2000 Frodo Looijaard <frodol@dds.nl>, |
3 | Philip Edelbrock <phil@netroedge.com>, | |
4 | Dan Eaton <dan.eaton@rocketlogix.com> | |
5 | Ported to Linux 2.6 by Aurelien Jarno <aurel32@debian.org> with | |
6 | the help of Jean Delvare <khali@linux-fr.org> | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | */ | |
22 | ||
23 | /* A few notes about the PCF8574: | |
24 | ||
25 | * The PCF8574 is an 8-bit I/O expander for the I2C bus produced by | |
26 | Philips Semiconductors. It is designed to provide a byte I2C | |
27 | interface to up to 8 separate devices. | |
28 | ||
29 | * The PCF8574 appears as a very simple SMBus device which can be | |
30 | read from or written to with SMBUS byte read/write accesses. | |
31 | ||
32 | --Dan | |
33 | ||
34 | */ | |
35 | ||
36 | #include <linux/module.h> | |
37 | #include <linux/init.h> | |
38 | #include <linux/slab.h> | |
39 | #include <linux/i2c.h> | |
1da177e4 | 40 | |
833bedb8 JD |
41 | /* Addresses to scan: none, device can't be detected */ |
42 | static const unsigned short normal_i2c[] = { I2C_CLIENT_END }; | |
1da177e4 LT |
43 | |
44 | /* Insmod parameters */ | |
f4b50261 | 45 | I2C_CLIENT_INSMOD_2(pcf8574, pcf8574a); |
1da177e4 | 46 | |
1da177e4 LT |
47 | /* Each client has this additional data */ |
48 | struct pcf8574_data { | |
553515e5 | 49 | int write; /* Remember last written value */ |
1da177e4 LT |
50 | }; |
51 | ||
1da177e4 LT |
52 | static void pcf8574_init_client(struct i2c_client *client); |
53 | ||
1da177e4 | 54 | /* following are the sysfs callback functions */ |
a5099cfc | 55 | static ssize_t show_read(struct device *dev, struct device_attribute *attr, char *buf) |
1da177e4 LT |
56 | { |
57 | struct i2c_client *client = to_i2c_client(dev); | |
eb071cbb | 58 | return sprintf(buf, "%u\n", i2c_smbus_read_byte(client)); |
1da177e4 LT |
59 | } |
60 | ||
61 | static DEVICE_ATTR(read, S_IRUGO, show_read, NULL); | |
62 | ||
a5099cfc | 63 | static ssize_t show_write(struct device *dev, struct device_attribute *attr, char *buf) |
1da177e4 LT |
64 | { |
65 | struct pcf8574_data *data = i2c_get_clientdata(to_i2c_client(dev)); | |
553515e5 JD |
66 | |
67 | if (data->write < 0) | |
68 | return data->write; | |
69 | ||
70 | return sprintf(buf, "%d\n", data->write); | |
1da177e4 LT |
71 | } |
72 | ||
a5099cfc | 73 | static ssize_t set_write(struct device *dev, struct device_attribute *attr, const char *buf, |
1da177e4 LT |
74 | size_t count) |
75 | { | |
76 | struct i2c_client *client = to_i2c_client(dev); | |
77 | struct pcf8574_data *data = i2c_get_clientdata(client); | |
78 | unsigned long val = simple_strtoul(buf, NULL, 10); | |
79 | ||
80 | if (val > 0xff) | |
81 | return -EINVAL; | |
82 | ||
83 | data->write = val; | |
84 | i2c_smbus_write_byte(client, data->write); | |
85 | return count; | |
86 | } | |
87 | ||
88 | static DEVICE_ATTR(write, S_IWUSR | S_IRUGO, show_write, set_write); | |
89 | ||
7d9db67f JD |
90 | static struct attribute *pcf8574_attributes[] = { |
91 | &dev_attr_read.attr, | |
92 | &dev_attr_write.attr, | |
93 | NULL | |
94 | }; | |
95 | ||
96 | static const struct attribute_group pcf8574_attr_group = { | |
97 | .attrs = pcf8574_attributes, | |
98 | }; | |
99 | ||
1da177e4 LT |
100 | /* |
101 | * Real code | |
102 | */ | |
103 | ||
833bedb8 JD |
104 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
105 | static int pcf8574_detect(struct i2c_client *client, int kind, | |
106 | struct i2c_board_info *info) | |
1da177e4 | 107 | { |
833bedb8 JD |
108 | struct i2c_adapter *adapter = client->adapter; |
109 | const char *client_name; | |
1da177e4 LT |
110 | |
111 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) | |
833bedb8 | 112 | return -ENODEV; |
1da177e4 LT |
113 | |
114 | /* Now, we would do the remaining detection. But the PCF8574 is plainly | |
115 | impossible to detect! Stupid chip. */ | |
116 | ||
117 | /* Determine the chip type */ | |
118 | if (kind <= 0) { | |
833bedb8 | 119 | if (client->addr >= 0x38 && client->addr <= 0x3f) |
1da177e4 LT |
120 | kind = pcf8574a; |
121 | else | |
122 | kind = pcf8574; | |
123 | } | |
124 | ||
125 | if (kind == pcf8574a) | |
126 | client_name = "pcf8574a"; | |
127 | else | |
128 | client_name = "pcf8574"; | |
833bedb8 | 129 | strlcpy(info->type, client_name, I2C_NAME_SIZE); |
1da177e4 | 130 | |
833bedb8 JD |
131 | return 0; |
132 | } | |
133 | ||
134 | static int pcf8574_probe(struct i2c_client *client, | |
135 | const struct i2c_device_id *id) | |
136 | { | |
137 | struct pcf8574_data *data; | |
138 | int err; | |
139 | ||
140 | data = kzalloc(sizeof(struct pcf8574_data), GFP_KERNEL); | |
141 | if (!data) { | |
142 | err = -ENOMEM; | |
143 | goto exit; | |
144 | } | |
145 | ||
146 | i2c_set_clientdata(client, data); | |
1da177e4 | 147 | |
1da177e4 | 148 | /* Initialize the PCF8574 chip */ |
f741f673 | 149 | pcf8574_init_client(client); |
1da177e4 LT |
150 | |
151 | /* Register sysfs hooks */ | |
f741f673 | 152 | err = sysfs_create_group(&client->dev.kobj, &pcf8574_attr_group); |
7d9db67f | 153 | if (err) |
833bedb8 | 154 | goto exit_free; |
1da177e4 LT |
155 | return 0; |
156 | ||
1da177e4 LT |
157 | exit_free: |
158 | kfree(data); | |
159 | exit: | |
160 | return err; | |
161 | } | |
162 | ||
833bedb8 | 163 | static int pcf8574_remove(struct i2c_client *client) |
1da177e4 | 164 | { |
7d9db67f | 165 | sysfs_remove_group(&client->dev.kobj, &pcf8574_attr_group); |
1da177e4 LT |
166 | kfree(i2c_get_clientdata(client)); |
167 | return 0; | |
168 | } | |
169 | ||
170 | /* Called when we have found a new PCF8574. */ | |
171 | static void pcf8574_init_client(struct i2c_client *client) | |
172 | { | |
173 | struct pcf8574_data *data = i2c_get_clientdata(client); | |
553515e5 | 174 | data->write = -EAGAIN; |
1da177e4 LT |
175 | } |
176 | ||
833bedb8 JD |
177 | static const struct i2c_device_id pcf8574_id[] = { |
178 | { "pcf8574", 0 }, | |
179 | { "pcf8574a", 0 }, | |
180 | { } | |
181 | }; | |
182 | ||
183 | static struct i2c_driver pcf8574_driver = { | |
184 | .driver = { | |
185 | .name = "pcf8574", | |
186 | }, | |
187 | .probe = pcf8574_probe, | |
188 | .remove = pcf8574_remove, | |
189 | .id_table = pcf8574_id, | |
190 | ||
191 | .detect = pcf8574_detect, | |
192 | .address_data = &addr_data, | |
193 | }; | |
194 | ||
1da177e4 LT |
195 | static int __init pcf8574_init(void) |
196 | { | |
197 | return i2c_add_driver(&pcf8574_driver); | |
198 | } | |
199 | ||
200 | static void __exit pcf8574_exit(void) | |
201 | { | |
202 | i2c_del_driver(&pcf8574_driver); | |
203 | } | |
204 | ||
205 | ||
206 | MODULE_AUTHOR | |
207 | ("Frodo Looijaard <frodol@dds.nl>, " | |
208 | "Philip Edelbrock <phil@netroedge.com>, " | |
209 | "Dan Eaton <dan.eaton@rocketlogix.com> " | |
210 | "and Aurelien Jarno <aurelien@aurel32.net>"); | |
211 | MODULE_DESCRIPTION("PCF8574 driver"); | |
212 | MODULE_LICENSE("GPL"); | |
213 | ||
214 | module_init(pcf8574_init); | |
215 | module_exit(pcf8574_exit); |