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1da177e4 | 1 | /* |
400c455e JD |
2 | i2c-isa.c - an i2c-core-like thing for ISA hardware monitoring chips |
3 | Copyright (C) 2005 Jean Delvare <khali@linux-fr.org> | |
4 | ||
5 | Based on the i2c-isa pseudo-adapter from the lm_sensors project | |
1da177e4 LT |
6 | Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl> |
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 | ||
400c455e JD |
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. */ | |
1da177e4 | 34 | |
1da177e4 LT |
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> | |
400c455e | 40 | #include <linux/i2c-isa.h> |
d052d1be | 41 | #include <linux/platform_device.h> |
b8d6f45b | 42 | #include <linux/completion.h> |
1da177e4 LT |
43 | |
44 | static u32 isa_func(struct i2c_adapter *adapter); | |
45 | ||
46 | /* This is the actual algorithm we define */ | |
8f9082c5 | 47 | static const struct i2c_algorithm isa_algorithm = { |
1da177e4 LT |
48 | .functionality = isa_func, |
49 | }; | |
50 | ||
51 | /* There can only be one... */ | |
52 | static struct i2c_adapter isa_adapter = { | |
53 | .owner = THIS_MODULE, | |
c7a46533 | 54 | .id = I2C_HW_ISA, |
1da177e4 LT |
55 | .class = I2C_CLASS_HWMON, |
56 | .algo = &isa_algorithm, | |
57 | .name = "ISA main adapter", | |
58 | }; | |
59 | ||
60 | /* We can't do a thing... */ | |
61 | static u32 isa_func(struct i2c_adapter *adapter) | |
62 | { | |
63 | return 0; | |
64 | } | |
65 | ||
400c455e | 66 | |
400c455e JD |
67 | /* We implement an interface which resembles i2c_{add,del}_driver, |
68 | but for i2c-isa drivers. We don't have to remember and handle lists | |
69 | of drivers and adapters so this is much more simple, of course. */ | |
70 | ||
71 | int i2c_isa_add_driver(struct i2c_driver *driver) | |
72 | { | |
73 | int res; | |
74 | ||
75 | /* Add the driver to the list of i2c drivers in the driver core */ | |
400c455e | 76 | driver->driver.bus = &i2c_bus_type; |
400c455e JD |
77 | res = driver_register(&driver->driver); |
78 | if (res) | |
79 | return res; | |
e1c489b0 | 80 | dev_dbg(&isa_adapter.dev, "Driver %s registered\n", driver->driver.name); |
400c455e JD |
81 | |
82 | /* Now look for clients */ | |
82026326 DH |
83 | res = driver->attach_adapter(&isa_adapter); |
84 | if (res) { | |
e693810c | 85 | dev_dbg(&isa_adapter.dev, |
82026326 DH |
86 | "Driver %s failed to attach adapter, unregistering\n", |
87 | driver->driver.name); | |
88 | driver_unregister(&driver->driver); | |
89 | } | |
90 | return res; | |
400c455e JD |
91 | } |
92 | ||
93 | int i2c_isa_del_driver(struct i2c_driver *driver) | |
94 | { | |
95 | struct list_head *item, *_n; | |
96 | struct i2c_client *client; | |
97 | int res; | |
98 | ||
99 | /* Detach all clients belonging to this one driver */ | |
100 | list_for_each_safe(item, _n, &isa_adapter.clients) { | |
101 | client = list_entry(item, struct i2c_client, list); | |
102 | if (client->driver != driver) | |
103 | continue; | |
104 | dev_dbg(&isa_adapter.dev, "Detaching client %s at 0x%x\n", | |
105 | client->name, client->addr); | |
106 | if ((res = driver->detach_client(client))) { | |
107 | dev_err(&isa_adapter.dev, "Failed, driver " | |
108 | "%s not unregistered!\n", | |
35d8b2e6 | 109 | driver->driver.name); |
400c455e JD |
110 | return res; |
111 | } | |
112 | } | |
113 | ||
114 | /* Get the driver off the core list */ | |
115 | driver_unregister(&driver->driver); | |
e1c489b0 | 116 | dev_dbg(&isa_adapter.dev, "Driver %s unregistered\n", driver->driver.name); |
400c455e JD |
117 | |
118 | return 0; | |
119 | } | |
120 | ||
121 | ||
1da177e4 LT |
122 | static int __init i2c_isa_init(void) |
123 | { | |
b119c6c9 JD |
124 | int err; |
125 | ||
5c085d36 | 126 | mutex_init(&isa_adapter.clist_lock); |
400c455e JD |
127 | INIT_LIST_HEAD(&isa_adapter.clients); |
128 | ||
129 | isa_adapter.nr = ANY_I2C_ISA_BUS; | |
130 | isa_adapter.dev.parent = &platform_bus; | |
131 | sprintf(isa_adapter.dev.bus_id, "i2c-%d", isa_adapter.nr); | |
400c455e | 132 | isa_adapter.dev.release = &i2c_adapter_dev_release; |
fccb56e4 | 133 | isa_adapter.dev.class = &i2c_adapter_class; |
b119c6c9 JD |
134 | err = device_register(&isa_adapter.dev); |
135 | if (err) { | |
136 | printk(KERN_ERR "i2c-isa: Failed to register device\n"); | |
137 | goto exit; | |
138 | } | |
400c455e | 139 | |
400c455e JD |
140 | dev_dbg(&isa_adapter.dev, "%s registered\n", isa_adapter.name); |
141 | ||
142 | return 0; | |
b119c6c9 | 143 | |
b119c6c9 JD |
144 | exit: |
145 | return err; | |
1da177e4 LT |
146 | } |
147 | ||
148 | static void __exit i2c_isa_exit(void) | |
149 | { | |
400c455e JD |
150 | #ifdef DEBUG |
151 | struct list_head *item, *_n; | |
152 | struct i2c_client *client = NULL; | |
153 | #endif | |
154 | ||
155 | /* There should be no more active client */ | |
156 | #ifdef DEBUG | |
157 | dev_dbg(&isa_adapter.dev, "Looking for clients\n"); | |
158 | list_for_each_safe(item, _n, &isa_adapter.clients) { | |
159 | client = list_entry(item, struct i2c_client, list); | |
160 | dev_err(&isa_adapter.dev, "Driver %s still has an active " | |
e1c489b0 | 161 | "ISA client at 0x%x\n", client->driver->driver.name, |
400c455e JD |
162 | client->addr); |
163 | } | |
164 | if (client != NULL) | |
165 | return; | |
166 | #endif | |
167 | ||
168 | /* Clean up the sysfs representation */ | |
169 | dev_dbg(&isa_adapter.dev, "Unregistering from sysfs\n"); | |
170 | init_completion(&isa_adapter.dev_released); | |
400c455e JD |
171 | device_unregister(&isa_adapter.dev); |
172 | ||
173 | /* Wait for sysfs to drop all references */ | |
174 | dev_dbg(&isa_adapter.dev, "Waiting for sysfs completion\n"); | |
175 | wait_for_completion(&isa_adapter.dev_released); | |
400c455e JD |
176 | |
177 | dev_dbg(&isa_adapter.dev, "%s unregistered\n", isa_adapter.name); | |
1da177e4 LT |
178 | } |
179 | ||
400c455e JD |
180 | EXPORT_SYMBOL(i2c_isa_add_driver); |
181 | EXPORT_SYMBOL(i2c_isa_del_driver); | |
182 | ||
183 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
1da177e4 LT |
184 | MODULE_DESCRIPTION("ISA bus access through i2c"); |
185 | MODULE_LICENSE("GPL"); | |
186 | ||
187 | module_init(i2c_isa_init); | |
188 | module_exit(i2c_isa_exit); |