2 i2c-isa.c - an i2c-core-like thing for ISA hardware monitoring chips
3 Copyright (C) 2005 Jean Delvare <khali@linux-fr.org>
5 Based on the i2c-isa pseudo-adapter from the lm_sensors project
6 Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
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.
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.
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.
23 /* This implements an i2c-core-like thing for ISA hardware monitoring
24 chips. Such chips are linked to the i2c subsystem for historical
25 reasons (because the early ISA hardware monitoring chips such as the
26 LM78 had both an I2C and an ISA interface). They used to be
27 registered with the main i2c-core, but as a first step in the
28 direction of a clean separation between I2C and ISA chip drivers,
29 we now have this separate core for ISA ones. It is significantly
30 more simple than the real one, of course, because we don't have to
31 handle multiple busses: there is only one (fake) ISA adapter.
32 It is worth noting that we still rely on i2c-core for some things
33 at the moment - but hopefully this won't last. */
35 #include <linux/init.h>
36 #include <linux/module.h>
37 #include <linux/kernel.h>
38 #include <linux/errno.h>
39 #include <linux/i2c.h>
40 #include <linux/i2c-isa.h>
41 #include <linux/platform_device.h>
43 static u32 isa_func(struct i2c_adapter *adapter);
45 /* This is the actual algorithm we define */
46 static struct i2c_algorithm isa_algorithm = {
47 .functionality = isa_func,
50 /* There can only be one... */
51 static struct i2c_adapter isa_adapter = {
54 .class = I2C_CLASS_HWMON,
55 .algo = &isa_algorithm,
56 .name = "ISA main adapter",
59 /* We can't do a thing... */
60 static u32 isa_func(struct i2c_adapter *adapter)
66 /* Copied from i2c-core */
67 static ssize_t show_adapter_name(struct device *dev,
68 struct device_attribute *attr, char *buf)
70 struct i2c_adapter *adap = dev_to_i2c_adapter(dev);
71 return sprintf(buf, "%s\n", adap->name);
73 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
76 /* We implement an interface which resembles i2c_{add,del}_driver,
77 but for i2c-isa drivers. We don't have to remember and handle lists
78 of drivers and adapters so this is much more simple, of course. */
80 int i2c_isa_add_driver(struct i2c_driver *driver)
84 /* Add the driver to the list of i2c drivers in the driver core */
85 driver->driver.bus = &i2c_bus_type;
86 res = driver_register(&driver->driver);
89 dev_dbg(&isa_adapter.dev, "Driver %s registered\n", driver->driver.name);
91 /* Now look for clients */
92 driver->attach_adapter(&isa_adapter);
97 int i2c_isa_del_driver(struct i2c_driver *driver)
99 struct list_head *item, *_n;
100 struct i2c_client *client;
103 /* Detach all clients belonging to this one driver */
104 list_for_each_safe(item, _n, &isa_adapter.clients) {
105 client = list_entry(item, struct i2c_client, list);
106 if (client->driver != driver)
108 dev_dbg(&isa_adapter.dev, "Detaching client %s at 0x%x\n",
109 client->name, client->addr);
110 if ((res = driver->detach_client(client))) {
111 dev_err(&isa_adapter.dev, "Failed, driver "
112 "%s not unregistered!\n",
113 driver->driver.name);
118 /* Get the driver off the core list */
119 driver_unregister(&driver->driver);
120 dev_dbg(&isa_adapter.dev, "Driver %s unregistered\n", driver->driver.name);
126 static int __init i2c_isa_init(void)
130 mutex_init(&isa_adapter.clist_lock);
131 INIT_LIST_HEAD(&isa_adapter.clients);
133 isa_adapter.nr = ANY_I2C_ISA_BUS;
134 isa_adapter.dev.parent = &platform_bus;
135 sprintf(isa_adapter.dev.bus_id, "i2c-%d", isa_adapter.nr);
136 isa_adapter.dev.driver = &i2c_adapter_driver;
137 isa_adapter.dev.release = &i2c_adapter_dev_release;
138 err = device_register(&isa_adapter.dev);
140 printk(KERN_ERR "i2c-isa: Failed to register device\n");
143 err = device_create_file(&isa_adapter.dev, &dev_attr_name);
145 printk(KERN_ERR "i2c-isa: Failed to create name file\n");
146 goto exit_unregister;
149 /* Add this adapter to the i2c_adapter class */
150 memset(&isa_adapter.class_dev, 0x00, sizeof(struct class_device));
151 isa_adapter.class_dev.dev = &isa_adapter.dev;
152 isa_adapter.class_dev.class = &i2c_adapter_class;
153 strlcpy(isa_adapter.class_dev.class_id, isa_adapter.dev.bus_id,
155 err = class_device_register(&isa_adapter.class_dev);
157 printk(KERN_ERR "i2c-isa: Failed to register class device\n");
158 goto exit_remove_name;
161 dev_dbg(&isa_adapter.dev, "%s registered\n", isa_adapter.name);
166 device_remove_file(&isa_adapter.dev, &dev_attr_name);
168 init_completion(&isa_adapter.dev_released); /* Needed? */
169 device_unregister(&isa_adapter.dev);
170 wait_for_completion(&isa_adapter.dev_released);
175 static void __exit i2c_isa_exit(void)
178 struct list_head *item, *_n;
179 struct i2c_client *client = NULL;
182 /* There should be no more active client */
184 dev_dbg(&isa_adapter.dev, "Looking for clients\n");
185 list_for_each_safe(item, _n, &isa_adapter.clients) {
186 client = list_entry(item, struct i2c_client, list);
187 dev_err(&isa_adapter.dev, "Driver %s still has an active "
188 "ISA client at 0x%x\n", client->driver->driver.name,
195 /* Clean up the sysfs representation */
196 dev_dbg(&isa_adapter.dev, "Unregistering from sysfs\n");
197 init_completion(&isa_adapter.dev_released);
198 init_completion(&isa_adapter.class_dev_released);
199 class_device_unregister(&isa_adapter.class_dev);
200 device_remove_file(&isa_adapter.dev, &dev_attr_name);
201 device_unregister(&isa_adapter.dev);
203 /* Wait for sysfs to drop all references */
204 dev_dbg(&isa_adapter.dev, "Waiting for sysfs completion\n");
205 wait_for_completion(&isa_adapter.dev_released);
206 wait_for_completion(&isa_adapter.class_dev_released);
208 dev_dbg(&isa_adapter.dev, "%s unregistered\n", isa_adapter.name);
211 EXPORT_SYMBOL(i2c_isa_add_driver);
212 EXPORT_SYMBOL(i2c_isa_del_driver);
214 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
215 MODULE_DESCRIPTION("ISA bus access through i2c");
216 MODULE_LICENSE("GPL");
218 module_init(i2c_isa_init);
219 module_exit(i2c_isa_exit);