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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* ------------------------------------------------------------------------ *
2 * i2c-parport.c I2C bus over parallel port *
3 * ------------------------------------------------------------------------ *
Jean Delvare3af07bd2007-05-01 23:26:30 +02004 Copyright (C) 2003-2007 Jean Delvare <khali@linux-fr.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005
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>
Jan Engelhardt96de0e22007-10-19 23:21:04 +020010 Kyösti Mälkki <kmalkki@cc.hut.fi>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/init.h>
30#include <linux/parport.h>
31#include <linux/i2c.h>
32#include <linux/i2c-algo-bit.h>
33#include "i2c-parport.h"
34
35/* ----- Device list ------------------------------------------------------ */
36
37struct i2c_par {
38 struct pardevice *pdev;
39 struct i2c_adapter adapter;
40 struct i2c_algo_bit_data algo_data;
41 struct i2c_par *next;
42};
43
44static struct i2c_par *adapter_list;
45
46/* ----- Low-level parallel port access ----------------------------------- */
47
48static void port_write_data(struct parport *p, unsigned char d)
49{
50 parport_write_data(p, d);
51}
52
53static void port_write_control(struct parport *p, unsigned char d)
54{
55 parport_write_control(p, d);
56}
57
58static unsigned char port_read_data(struct parport *p)
59{
60 return parport_read_data(p);
61}
62
63static unsigned char port_read_status(struct parport *p)
64{
65 return parport_read_status(p);
66}
67
68static unsigned char port_read_control(struct parport *p)
69{
70 return parport_read_control(p);
71}
72
73static void (*port_write[])(struct parport *, unsigned char) = {
74 port_write_data,
75 NULL,
76 port_write_control,
77};
78
79static unsigned char (*port_read[])(struct parport *) = {
80 port_read_data,
81 port_read_status,
82 port_read_control,
83};
84
85/* ----- Unified line operation functions --------------------------------- */
86
87static inline void line_set(struct parport *data, int state,
88 const struct lineop *op)
89{
90 u8 oldval = port_read[op->port](data);
91
92 /* Touch only the bit(s) needed */
93 if ((op->inverted && !state) || (!op->inverted && state))
94 port_write[op->port](data, oldval | op->val);
95 else
96 port_write[op->port](data, oldval & ~op->val);
97}
98
99static inline int line_get(struct parport *data,
100 const struct lineop *op)
101{
102 u8 oldval = port_read[op->port](data);
103
104 return ((op->inverted && (oldval & op->val) != op->val)
105 || (!op->inverted && (oldval & op->val) == op->val));
106}
107
108/* ----- I2C algorithm call-back functions and structures ----------------- */
109
110static void parport_setscl(void *data, int state)
111{
112 line_set((struct parport *) data, state, &adapter_parm[type].setscl);
113}
114
115static void parport_setsda(void *data, int state)
116{
117 line_set((struct parport *) data, state, &adapter_parm[type].setsda);
118}
119
120static int parport_getscl(void *data)
121{
122 return line_get((struct parport *) data, &adapter_parm[type].getscl);
123}
124
125static int parport_getsda(void *data)
126{
127 return line_get((struct parport *) data, &adapter_parm[type].getsda);
128}
129
130/* Encapsulate the functions above in the correct structure.
131 Note that this is only a template, from which the real structures are
132 copied. The attaching code will set getscl to NULL for adapters that
Tobias Klauser614e24b2005-05-19 21:39:06 +0200133 cannot read SCL back, and will also make the data field point to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 the parallel port structure. */
135static struct i2c_algo_bit_data parport_algo_data = {
136 .setsda = parport_setsda,
137 .setscl = parport_setscl,
138 .getsda = parport_getsda,
139 .getscl = parport_getscl,
Jean Delvare3af07bd2007-05-01 23:26:30 +0200140 .udelay = 10, /* ~50 kbps */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 .timeout = HZ,
142};
143
144/* ----- I2c and parallel port call-back functions and structures --------- */
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146static void i2c_parport_attach (struct parport *port)
147{
148 struct i2c_par *adapter;
149
Deepak Saxena5263ebb2005-10-17 23:09:43 +0200150 adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 if (adapter == NULL) {
Deepak Saxena5263ebb2005-10-17 23:09:43 +0200152 printk(KERN_ERR "i2c-parport: Failed to kzalloc\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 return;
154 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
156 pr_debug("i2c-parport: attaching to %s\n", port->name);
157 adapter->pdev = parport_register_device(port, "i2c-parport",
158 NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL);
159 if (!adapter->pdev) {
160 printk(KERN_ERR "i2c-parport: Unable to register with parport\n");
161 goto ERROR0;
162 }
163
164 /* Fill the rest of the structure */
Jean Delvarecacf2262007-05-01 23:26:29 +0200165 adapter->adapter.owner = THIS_MODULE;
166 adapter->adapter.class = I2C_CLASS_HWMON;
167 adapter->adapter.id = I2C_HW_B_LP;
168 strlcpy(adapter->adapter.name, "Parallel port adapter",
169 sizeof(adapter->adapter.name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 adapter->algo_data = parport_algo_data;
Jean Delvare3af07bd2007-05-01 23:26:30 +0200171 /* Slow down if we can't sense SCL */
172 if (!adapter_parm[type].getscl.val) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 adapter->algo_data.getscl = NULL;
Jean Delvare3af07bd2007-05-01 23:26:30 +0200174 adapter->algo_data.udelay = 50; /* ~10 kbps */
175 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 adapter->algo_data.data = port;
177 adapter->adapter.algo_data = &adapter->algo_data;
David Brownellda675292007-05-08 00:27:42 -0700178 adapter->adapter.dev.parent = port->physport->dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
180 if (parport_claim_or_block(adapter->pdev) < 0) {
181 printk(KERN_ERR "i2c-parport: Could not claim parallel port\n");
182 goto ERROR1;
183 }
184
185 /* Reset hardware to a sane state (SCL and SDA high) */
186 parport_setsda(port, 1);
187 parport_setscl(port, 1);
188 /* Other init if needed (power on...) */
189 if (adapter_parm[type].init.val)
190 line_set(port, 1, &adapter_parm[type].init);
191
192 parport_release(adapter->pdev);
193
194 if (i2c_bit_add_bus(&adapter->adapter) < 0) {
195 printk(KERN_ERR "i2c-parport: Unable to register with I2C\n");
196 goto ERROR1;
197 }
198
199 /* Add the new adapter to the list */
200 adapter->next = adapter_list;
201 adapter_list = adapter;
202 return;
203
204ERROR1:
205 parport_unregister_device(adapter->pdev);
206ERROR0:
207 kfree(adapter);
208}
209
210static void i2c_parport_detach (struct parport *port)
211{
212 struct i2c_par *adapter, *prev;
213
214 /* Walk the list */
215 for (prev = NULL, adapter = adapter_list; adapter;
216 prev = adapter, adapter = adapter->next) {
217 if (adapter->pdev->port == port) {
Jean Delvare3af07bd2007-05-01 23:26:30 +0200218 i2c_del_adapter(&adapter->adapter);
219
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 /* Un-init if needed (power off...) */
221 if (adapter_parm[type].init.val)
222 line_set(port, 0, &adapter_parm[type].init);
223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 parport_unregister_device(adapter->pdev);
225 if (prev)
226 prev->next = adapter->next;
227 else
228 adapter_list = adapter->next;
229 kfree(adapter);
230 return;
231 }
232 }
233}
234
Jean Delvare6c129be2005-10-08 00:17:35 +0200235static struct parport_driver i2c_parport_driver = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 .name = "i2c-parport",
237 .attach = i2c_parport_attach,
238 .detach = i2c_parport_detach,
239};
240
241/* ----- Module loading, unloading and information ------------------------ */
242
243static int __init i2c_parport_init(void)
244{
Mark M. Hoffmane97b81d2006-03-23 16:50:25 +0100245 if (type < 0) {
246 printk(KERN_WARNING "i2c-parport: adapter type unspecified\n");
247 return -ENODEV;
248 }
249
250 if (type >= ARRAY_SIZE(adapter_parm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type);
Mark M. Hoffmane97b81d2006-03-23 16:50:25 +0100252 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 }
Tobias Klauser7e3d7db2006-01-09 23:19:51 +0100254
Jean Delvare6c129be2005-10-08 00:17:35 +0200255 return parport_register_driver(&i2c_parport_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256}
257
258static void __exit i2c_parport_exit(void)
259{
Jean Delvare6c129be2005-10-08 00:17:35 +0200260 parport_unregister_driver(&i2c_parport_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261}
262
263MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
264MODULE_DESCRIPTION("I2C bus over parallel port");
265MODULE_LICENSE("GPL");
266
267module_init(i2c_parport_init);
268module_exit(i2c_parport_exit);