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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/i2c/busses/i2c-parport.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/busses/i2c-parport.c')
-rw-r--r--drivers/i2c/busses/i2c-parport.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-parport.c b/drivers/i2c/busses/i2c-parport.c
new file mode 100644
index 000000000000..e9560bab51c4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-parport.c
@@ -0,0 +1,267 @@
1/* ------------------------------------------------------------------------ *
2 * i2c-parport.c I2C bus over parallel port *
3 * ------------------------------------------------------------------------ *
4 Copyright (C) 2003-2004 Jean Delvare <khali@linux-fr.org>
5
6 Based on older i2c-philips-par.c driver
7 Copyright (C) 1995-2000 Simon G. Vogl
8 With some changes from:
9 Frodo Looijaard <frodol@dds.nl>
10 Ky�sti M�lkki <kmalkki@cc.hut.fi>
11
12 This program is free software; you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation; either version 2 of the License, or
15 (at your option) any later version.
16
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
21
22 You should have received a copy of the GNU General Public License
23 along with this program; if not, write to the Free Software
24 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 * ------------------------------------------------------------------------ */
26
27#include <linux/config.h>
28#include <linux/kernel.h>
29#include <linux/module.h>
30#include <linux/init.h>
31#include <linux/parport.h>
32#include <linux/i2c.h>
33#include <linux/i2c-algo-bit.h>
34#include "i2c-parport.h"
35
36/* ----- Device list ------------------------------------------------------ */
37
38struct i2c_par {
39 struct pardevice *pdev;
40 struct i2c_adapter adapter;
41 struct i2c_algo_bit_data algo_data;
42 struct i2c_par *next;
43};
44
45static struct i2c_par *adapter_list;
46
47/* ----- Low-level parallel port access ----------------------------------- */
48
49static void port_write_data(struct parport *p, unsigned char d)
50{
51 parport_write_data(p, d);
52}
53
54static void port_write_control(struct parport *p, unsigned char d)
55{
56 parport_write_control(p, d);
57}
58
59static unsigned char port_read_data(struct parport *p)
60{
61 return parport_read_data(p);
62}
63
64static unsigned char port_read_status(struct parport *p)
65{
66 return parport_read_status(p);
67}
68
69static unsigned char port_read_control(struct parport *p)
70{
71 return parport_read_control(p);
72}
73
74static void (*port_write[])(struct parport *, unsigned char) = {
75 port_write_data,
76 NULL,
77 port_write_control,
78};
79
80static unsigned char (*port_read[])(struct parport *) = {
81 port_read_data,
82 port_read_status,
83 port_read_control,
84};
85
86/* ----- Unified line operation functions --------------------------------- */
87
88static inline void line_set(struct parport *data, int state,
89 const struct lineop *op)
90{
91 u8 oldval = port_read[op->port](data);
92
93 /* Touch only the bit(s) needed */
94 if ((op->inverted && !state) || (!op->inverted && state))
95 port_write[op->port](data, oldval | op->val);
96 else
97 port_write[op->port](data, oldval & ~op->val);
98}
99
100static inline int line_get(struct parport *data,
101 const struct lineop *op)
102{
103 u8 oldval = port_read[op->port](data);
104
105 return ((op->inverted && (oldval & op->val) != op->val)
106 || (!op->inverted && (oldval & op->val) == op->val));
107}
108
109/* ----- I2C algorithm call-back functions and structures ----------------- */
110
111static void parport_setscl(void *data, int state)
112{
113 line_set((struct parport *) data, state, &adapter_parm[type].setscl);
114}
115
116static void parport_setsda(void *data, int state)
117{
118 line_set((struct parport *) data, state, &adapter_parm[type].setsda);
119}
120
121static int parport_getscl(void *data)
122{
123 return line_get((struct parport *) data, &adapter_parm[type].getscl);
124}
125
126static int parport_getsda(void *data)
127{
128 return line_get((struct parport *) data, &adapter_parm[type].getsda);
129}
130
131/* Encapsulate the functions above in the correct structure.
132 Note that this is only a template, from which the real structures are
133 copied. The attaching code will set getscl to NULL for adapters that
134 cannot read SCL back, and will also make the the data field point to
135 the parallel port structure. */
136static struct i2c_algo_bit_data parport_algo_data = {
137 .setsda = parport_setsda,
138 .setscl = parport_setscl,
139 .getsda = parport_getsda,
140 .getscl = parport_getscl,
141 .udelay = 60,
142 .mdelay = 60,
143 .timeout = HZ,
144};
145
146/* ----- I2c and parallel port call-back functions and structures --------- */
147
148static struct i2c_adapter parport_adapter = {
149 .owner = THIS_MODULE,
150 .class = I2C_CLASS_HWMON,
151 .id = I2C_HW_B_LP,
152 .name = "Parallel port adapter",
153};
154
155static void i2c_parport_attach (struct parport *port)
156{
157 struct i2c_par *adapter;
158
159 adapter = kmalloc(sizeof(struct i2c_par), GFP_KERNEL);
160 if (adapter == NULL) {
161 printk(KERN_ERR "i2c-parport: Failed to kmalloc\n");
162 return;
163 }
164 memset(adapter, 0x00, sizeof(struct i2c_par));
165
166 pr_debug("i2c-parport: attaching to %s\n", port->name);
167 adapter->pdev = parport_register_device(port, "i2c-parport",
168 NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL);
169 if (!adapter->pdev) {
170 printk(KERN_ERR "i2c-parport: Unable to register with parport\n");
171 goto ERROR0;
172 }
173
174 /* Fill the rest of the structure */
175 adapter->adapter = parport_adapter;
176 adapter->algo_data = parport_algo_data;
177 if (!adapter_parm[type].getscl.val)
178 adapter->algo_data.getscl = NULL;
179 adapter->algo_data.data = port;
180 adapter->adapter.algo_data = &adapter->algo_data;
181
182 if (parport_claim_or_block(adapter->pdev) < 0) {
183 printk(KERN_ERR "i2c-parport: Could not claim parallel port\n");
184 goto ERROR1;
185 }
186
187 /* Reset hardware to a sane state (SCL and SDA high) */
188 parport_setsda(port, 1);
189 parport_setscl(port, 1);
190 /* Other init if needed (power on...) */
191 if (adapter_parm[type].init.val)
192 line_set(port, 1, &adapter_parm[type].init);
193
194 parport_release(adapter->pdev);
195
196 if (i2c_bit_add_bus(&adapter->adapter) < 0) {
197 printk(KERN_ERR "i2c-parport: Unable to register with I2C\n");
198 goto ERROR1;
199 }
200
201 /* Add the new adapter to the list */
202 adapter->next = adapter_list;
203 adapter_list = adapter;
204 return;
205
206ERROR1:
207 parport_unregister_device(adapter->pdev);
208ERROR0:
209 kfree(adapter);
210}
211
212static void i2c_parport_detach (struct parport *port)
213{
214 struct i2c_par *adapter, *prev;
215
216 /* Walk the list */
217 for (prev = NULL, adapter = adapter_list; adapter;
218 prev = adapter, adapter = adapter->next) {
219 if (adapter->pdev->port == port) {
220 /* Un-init if needed (power off...) */
221 if (adapter_parm[type].init.val)
222 line_set(port, 0, &adapter_parm[type].init);
223
224 i2c_bit_del_bus(&adapter->adapter);
225 parport_unregister_device(adapter->pdev);
226 if (prev)
227 prev->next = adapter->next;
228 else
229 adapter_list = adapter->next;
230 kfree(adapter);
231 return;
232 }
233 }
234}
235
236static struct parport_driver i2c_driver = {
237 .name = "i2c-parport",
238 .attach = i2c_parport_attach,
239 .detach = i2c_parport_detach,
240};
241
242/* ----- Module loading, unloading and information ------------------------ */
243
244static int __init i2c_parport_init(void)
245{
246 int type_count;
247
248 type_count = sizeof(adapter_parm)/sizeof(struct adapter_parm);
249 if (type < 0 || type >= type_count) {
250 printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type);
251 type = 0;
252 }
253
254 return parport_register_driver(&i2c_driver);
255}
256
257static void __exit i2c_parport_exit(void)
258{
259 parport_unregister_driver(&i2c_driver);
260}
261
262MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
263MODULE_DESCRIPTION("I2C bus over parallel port");
264MODULE_LICENSE("GPL");
265
266module_init(i2c_parport_init);
267module_exit(i2c_parport_exit);