diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/i2c/chips/pcf8574.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/i2c/chips/pcf8574.c')
-rw-r--r-- | drivers/i2c/chips/pcf8574.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/i2c/chips/pcf8574.c b/drivers/i2c/chips/pcf8574.c new file mode 100644 index 000000000000..48b4e22eaffe --- /dev/null +++ b/drivers/i2c/chips/pcf8574.c | |||
@@ -0,0 +1,229 @@ | |||
1 | /* | ||
2 | pcf8574.c - Part of lm_sensors, Linux kernel modules for hardware | ||
3 | monitoring | ||
4 | Copyright (c) 2000 Frodo Looijaard <frodol@dds.nl>, | ||
5 | Philip Edelbrock <phil@netroedge.com>, | ||
6 | Dan Eaton <dan.eaton@rocketlogix.com> | ||
7 | Ported to Linux 2.6 by Aurelien Jarno <aurel32@debian.org> with | ||
8 | the help of Jean Delvare <khali@linux-fr.org> | ||
9 | |||
10 | This program is free software; you can redistribute it and/or modify | ||
11 | it under the terms of the GNU General Public License as published by | ||
12 | the Free Software Foundation; either version 2 of the License, or | ||
13 | (at your option) any later version. | ||
14 | |||
15 | This program is distributed in the hope that it will be useful, | ||
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
18 | GNU General Public License for more details. | ||
19 | |||
20 | You should have received a copy of the GNU General Public License | ||
21 | along with this program; if not, write to the Free Software | ||
22 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | ||
23 | */ | ||
24 | |||
25 | /* A few notes about the PCF8574: | ||
26 | |||
27 | * The PCF8574 is an 8-bit I/O expander for the I2C bus produced by | ||
28 | Philips Semiconductors. It is designed to provide a byte I2C | ||
29 | interface to up to 8 separate devices. | ||
30 | |||
31 | * The PCF8574 appears as a very simple SMBus device which can be | ||
32 | read from or written to with SMBUS byte read/write accesses. | ||
33 | |||
34 | --Dan | ||
35 | |||
36 | */ | ||
37 | |||
38 | #include <linux/module.h> | ||
39 | #include <linux/init.h> | ||
40 | #include <linux/slab.h> | ||
41 | #include <linux/i2c.h> | ||
42 | #include <linux/i2c-sensor.h> | ||
43 | |||
44 | /* Addresses to scan */ | ||
45 | static unsigned short normal_i2c[] = { 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, | ||
46 | 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, | ||
47 | I2C_CLIENT_END }; | ||
48 | static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; | ||
49 | |||
50 | /* Insmod parameters */ | ||
51 | SENSORS_INSMOD_2(pcf8574, pcf8574a); | ||
52 | |||
53 | /* Initial values */ | ||
54 | #define PCF8574_INIT 255 /* All outputs on (input mode) */ | ||
55 | |||
56 | /* Each client has this additional data */ | ||
57 | struct pcf8574_data { | ||
58 | struct i2c_client client; | ||
59 | |||
60 | u8 read, write; /* Register values */ | ||
61 | }; | ||
62 | |||
63 | static int pcf8574_attach_adapter(struct i2c_adapter *adapter); | ||
64 | static int pcf8574_detect(struct i2c_adapter *adapter, int address, int kind); | ||
65 | static int pcf8574_detach_client(struct i2c_client *client); | ||
66 | static void pcf8574_init_client(struct i2c_client *client); | ||
67 | |||
68 | /* This is the driver that will be inserted */ | ||
69 | static struct i2c_driver pcf8574_driver = { | ||
70 | .owner = THIS_MODULE, | ||
71 | .name = "pcf8574", | ||
72 | .id = I2C_DRIVERID_PCF8574, | ||
73 | .flags = I2C_DF_NOTIFY, | ||
74 | .attach_adapter = pcf8574_attach_adapter, | ||
75 | .detach_client = pcf8574_detach_client, | ||
76 | }; | ||
77 | |||
78 | /* following are the sysfs callback functions */ | ||
79 | static ssize_t show_read(struct device *dev, char *buf) | ||
80 | { | ||
81 | struct i2c_client *client = to_i2c_client(dev); | ||
82 | struct pcf8574_data *data = i2c_get_clientdata(client); | ||
83 | data->read = i2c_smbus_read_byte(client); | ||
84 | return sprintf(buf, "%u\n", data->read); | ||
85 | } | ||
86 | |||
87 | static DEVICE_ATTR(read, S_IRUGO, show_read, NULL); | ||
88 | |||
89 | static ssize_t show_write(struct device *dev, char *buf) | ||
90 | { | ||
91 | struct pcf8574_data *data = i2c_get_clientdata(to_i2c_client(dev)); | ||
92 | return sprintf(buf, "%u\n", data->write); | ||
93 | } | ||
94 | |||
95 | static ssize_t set_write(struct device *dev, const char *buf, | ||
96 | size_t count) | ||
97 | { | ||
98 | struct i2c_client *client = to_i2c_client(dev); | ||
99 | struct pcf8574_data *data = i2c_get_clientdata(client); | ||
100 | unsigned long val = simple_strtoul(buf, NULL, 10); | ||
101 | |||
102 | if (val > 0xff) | ||
103 | return -EINVAL; | ||
104 | |||
105 | data->write = val; | ||
106 | i2c_smbus_write_byte(client, data->write); | ||
107 | return count; | ||
108 | } | ||
109 | |||
110 | static DEVICE_ATTR(write, S_IWUSR | S_IRUGO, show_write, set_write); | ||
111 | |||
112 | /* | ||
113 | * Real code | ||
114 | */ | ||
115 | |||
116 | static int pcf8574_attach_adapter(struct i2c_adapter *adapter) | ||
117 | { | ||
118 | return i2c_detect(adapter, &addr_data, pcf8574_detect); | ||
119 | } | ||
120 | |||
121 | /* This function is called by i2c_detect */ | ||
122 | int pcf8574_detect(struct i2c_adapter *adapter, int address, int kind) | ||
123 | { | ||
124 | struct i2c_client *new_client; | ||
125 | struct pcf8574_data *data; | ||
126 | int err = 0; | ||
127 | const char *client_name = ""; | ||
128 | |||
129 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) | ||
130 | goto exit; | ||
131 | |||
132 | /* OK. For now, we presume we have a valid client. We now create the | ||
133 | client structure, even though we cannot fill it completely yet. */ | ||
134 | if (!(data = kmalloc(sizeof(struct pcf8574_data), GFP_KERNEL))) { | ||
135 | err = -ENOMEM; | ||
136 | goto exit; | ||
137 | } | ||
138 | memset(data, 0, sizeof(struct pcf8574_data)); | ||
139 | |||
140 | new_client = &data->client; | ||
141 | i2c_set_clientdata(new_client, data); | ||
142 | new_client->addr = address; | ||
143 | new_client->adapter = adapter; | ||
144 | new_client->driver = &pcf8574_driver; | ||
145 | new_client->flags = 0; | ||
146 | |||
147 | /* Now, we would do the remaining detection. But the PCF8574 is plainly | ||
148 | impossible to detect! Stupid chip. */ | ||
149 | |||
150 | /* Determine the chip type */ | ||
151 | if (kind <= 0) { | ||
152 | if (address >= 0x38 && address <= 0x3f) | ||
153 | kind = pcf8574a; | ||
154 | else | ||
155 | kind = pcf8574; | ||
156 | } | ||
157 | |||
158 | if (kind == pcf8574a) | ||
159 | client_name = "pcf8574a"; | ||
160 | else | ||
161 | client_name = "pcf8574"; | ||
162 | |||
163 | /* Fill in the remaining client fields and put it into the global list */ | ||
164 | strlcpy(new_client->name, client_name, I2C_NAME_SIZE); | ||
165 | |||
166 | /* Tell the I2C layer a new client has arrived */ | ||
167 | if ((err = i2c_attach_client(new_client))) | ||
168 | goto exit_free; | ||
169 | |||
170 | /* Initialize the PCF8574 chip */ | ||
171 | pcf8574_init_client(new_client); | ||
172 | |||
173 | /* Register sysfs hooks */ | ||
174 | device_create_file(&new_client->dev, &dev_attr_read); | ||
175 | device_create_file(&new_client->dev, &dev_attr_write); | ||
176 | return 0; | ||
177 | |||
178 | /* OK, this is not exactly good programming practice, usually. But it is | ||
179 | very code-efficient in this case. */ | ||
180 | |||
181 | exit_free: | ||
182 | kfree(data); | ||
183 | exit: | ||
184 | return err; | ||
185 | } | ||
186 | |||
187 | static int pcf8574_detach_client(struct i2c_client *client) | ||
188 | { | ||
189 | int err; | ||
190 | |||
191 | if ((err = i2c_detach_client(client))) { | ||
192 | dev_err(&client->dev, | ||
193 | "Client deregistration failed, client not detached.\n"); | ||
194 | return err; | ||
195 | } | ||
196 | |||
197 | kfree(i2c_get_clientdata(client)); | ||
198 | return 0; | ||
199 | } | ||
200 | |||
201 | /* Called when we have found a new PCF8574. */ | ||
202 | static void pcf8574_init_client(struct i2c_client *client) | ||
203 | { | ||
204 | struct pcf8574_data *data = i2c_get_clientdata(client); | ||
205 | data->write = PCF8574_INIT; | ||
206 | i2c_smbus_write_byte(client, data->write); | ||
207 | } | ||
208 | |||
209 | static int __init pcf8574_init(void) | ||
210 | { | ||
211 | return i2c_add_driver(&pcf8574_driver); | ||
212 | } | ||
213 | |||
214 | static void __exit pcf8574_exit(void) | ||
215 | { | ||
216 | i2c_del_driver(&pcf8574_driver); | ||
217 | } | ||
218 | |||
219 | |||
220 | MODULE_AUTHOR | ||
221 | ("Frodo Looijaard <frodol@dds.nl>, " | ||
222 | "Philip Edelbrock <phil@netroedge.com>, " | ||
223 | "Dan Eaton <dan.eaton@rocketlogix.com> " | ||
224 | "and Aurelien Jarno <aurelien@aurel32.net>"); | ||
225 | MODULE_DESCRIPTION("PCF8574 driver"); | ||
226 | MODULE_LICENSE("GPL"); | ||
227 | |||
228 | module_init(pcf8574_init); | ||
229 | module_exit(pcf8574_exit); | ||