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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* ------------------------------------------------------------------------ *
2 * i2c-parport.c I2C bus over parallel port *
3 * ------------------------------------------------------------------------ *
Jean Delvare7c81c60f2014-01-29 20:40:08 +01004 Copyright (C) 2003-2011 Jean Delvare <jdelvare@suse.de>
Jean Delvare07da0372011-05-24 20:58:49 +02005
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 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>
Jean Delvare07da0372011-05-24 20:58:49 +020011
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 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>
Jean Delvare6d376fc2010-03-02 12:23:41 +010030#include <linux/delay.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/parport.h>
32#include <linux/i2c.h>
33#include <linux/i2c-algo-bit.h>
Jean Delvare35859252010-03-02 12:23:44 +010034#include <linux/i2c-smbus.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090035#include <linux/slab.h>
Jean Delvare56acc7a2011-05-01 18:18:49 +020036#include <linux/list.h>
37#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038#include "i2c-parport.h"
39
40/* ----- Device list ------------------------------------------------------ */
41
42struct i2c_par {
43 struct pardevice *pdev;
44 struct i2c_adapter adapter;
45 struct i2c_algo_bit_data algo_data;
Jean Delvare35859252010-03-02 12:23:44 +010046 struct i2c_smbus_alert_setup alert_data;
47 struct i2c_client *ara;
Jean Delvare56acc7a2011-05-01 18:18:49 +020048 struct list_head node;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049};
50
Jean Delvare56acc7a2011-05-01 18:18:49 +020051static LIST_HEAD(adapter_list);
52static DEFINE_MUTEX(adapter_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54/* ----- Low-level parallel port access ----------------------------------- */
55
56static void port_write_data(struct parport *p, unsigned char d)
57{
58 parport_write_data(p, d);
59}
60
61static void port_write_control(struct parport *p, unsigned char d)
62{
63 parport_write_control(p, d);
64}
65
66static unsigned char port_read_data(struct parport *p)
67{
68 return parport_read_data(p);
69}
70
71static unsigned char port_read_status(struct parport *p)
72{
73 return parport_read_status(p);
74}
75
76static unsigned char port_read_control(struct parport *p)
77{
78 return parport_read_control(p);
79}
80
Jean Delvare07da0372011-05-24 20:58:49 +020081static void (* const port_write[])(struct parport *, unsigned char) = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 port_write_data,
83 NULL,
84 port_write_control,
85};
86
Jean Delvare07da0372011-05-24 20:58:49 +020087static unsigned char (* const port_read[])(struct parport *) = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 port_read_data,
89 port_read_status,
90 port_read_control,
91};
92
93/* ----- Unified line operation functions --------------------------------- */
94
95static inline void line_set(struct parport *data, int state,
96 const struct lineop *op)
97{
98 u8 oldval = port_read[op->port](data);
99
100 /* Touch only the bit(s) needed */
101 if ((op->inverted && !state) || (!op->inverted && state))
102 port_write[op->port](data, oldval | op->val);
103 else
104 port_write[op->port](data, oldval & ~op->val);
105}
106
107static inline int line_get(struct parport *data,
108 const struct lineop *op)
109{
110 u8 oldval = port_read[op->port](data);
111
112 return ((op->inverted && (oldval & op->val) != op->val)
113 || (!op->inverted && (oldval & op->val) == op->val));
114}
115
116/* ----- I2C algorithm call-back functions and structures ----------------- */
117
118static void parport_setscl(void *data, int state)
119{
120 line_set((struct parport *) data, state, &adapter_parm[type].setscl);
121}
122
123static void parport_setsda(void *data, int state)
124{
125 line_set((struct parport *) data, state, &adapter_parm[type].setsda);
126}
127
128static int parport_getscl(void *data)
129{
130 return line_get((struct parport *) data, &adapter_parm[type].getscl);
131}
132
133static int parport_getsda(void *data)
134{
135 return line_get((struct parport *) data, &adapter_parm[type].getsda);
136}
137
138/* Encapsulate the functions above in the correct structure.
139 Note that this is only a template, from which the real structures are
140 copied. The attaching code will set getscl to NULL for adapters that
Tobias Klauser614e24b2005-05-19 21:39:06 +0200141 cannot read SCL back, and will also make the data field point to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 the parallel port structure. */
Jean Delvarebfdcad92010-05-21 18:40:57 +0200143static const struct i2c_algo_bit_data parport_algo_data = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 .setsda = parport_setsda,
145 .setscl = parport_setscl,
146 .getsda = parport_getsda,
147 .getscl = parport_getscl,
Jean Delvare3af07bd2007-05-01 23:26:30 +0200148 .udelay = 10, /* ~50 kbps */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 .timeout = HZ,
Jean Delvare07da0372011-05-24 20:58:49 +0200150};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152/* ----- I2c and parallel port call-back functions and structures --------- */
153
Jean Delvare7fe442a2012-10-05 22:23:53 +0200154static void i2c_parport_irq(void *data)
Jean Delvare35859252010-03-02 12:23:44 +0100155{
156 struct i2c_par *adapter = data;
157 struct i2c_client *ara = adapter->ara;
158
159 if (ara) {
160 dev_dbg(&ara->dev, "SMBus alert received\n");
161 i2c_handle_smbus_alert(ara);
162 } else
163 dev_dbg(&adapter->adapter.dev,
164 "SMBus alert received but no ARA client!\n");
165}
166
Jean Delvare07da0372011-05-24 20:58:49 +0200167static void i2c_parport_attach(struct parport *port)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168{
169 struct i2c_par *adapter;
Jean Delvare07da0372011-05-24 20:58:49 +0200170
Deepak Saxena5263ebb2005-10-17 23:09:43 +0200171 adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 if (adapter == NULL) {
Deepak Saxena5263ebb2005-10-17 23:09:43 +0200173 printk(KERN_ERR "i2c-parport: Failed to kzalloc\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 return;
175 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
177 pr_debug("i2c-parport: attaching to %s\n", port->name);
Jean Delvare35859252010-03-02 12:23:44 +0100178 parport_disable_irq(port);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 adapter->pdev = parport_register_device(port, "i2c-parport",
Jean Delvare35859252010-03-02 12:23:44 +0100180 NULL, NULL, i2c_parport_irq, PARPORT_FLAG_EXCL, adapter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 if (!adapter->pdev) {
182 printk(KERN_ERR "i2c-parport: Unable to register with parport\n");
Jean Delvare07da0372011-05-24 20:58:49 +0200183 goto err_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 }
185
186 /* Fill the rest of the structure */
Jean Delvarecacf2262007-05-01 23:26:29 +0200187 adapter->adapter.owner = THIS_MODULE;
188 adapter->adapter.class = I2C_CLASS_HWMON;
Jean Delvarecacf2262007-05-01 23:26:29 +0200189 strlcpy(adapter->adapter.name, "Parallel port adapter",
190 sizeof(adapter->adapter.name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 adapter->algo_data = parport_algo_data;
Jean Delvare3af07bd2007-05-01 23:26:30 +0200192 /* Slow down if we can't sense SCL */
193 if (!adapter_parm[type].getscl.val) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 adapter->algo_data.getscl = NULL;
Jean Delvare3af07bd2007-05-01 23:26:30 +0200195 adapter->algo_data.udelay = 50; /* ~10 kbps */
196 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 adapter->algo_data.data = port;
198 adapter->adapter.algo_data = &adapter->algo_data;
David Brownellda675292007-05-08 00:27:42 -0700199 adapter->adapter.dev.parent = port->physport->dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
201 if (parport_claim_or_block(adapter->pdev) < 0) {
202 printk(KERN_ERR "i2c-parport: Could not claim parallel port\n");
Jean Delvare07da0372011-05-24 20:58:49 +0200203 goto err_unregister;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 }
205
206 /* Reset hardware to a sane state (SCL and SDA high) */
207 parport_setsda(port, 1);
208 parport_setscl(port, 1);
209 /* Other init if needed (power on...) */
Jean Delvare6d376fc2010-03-02 12:23:41 +0100210 if (adapter_parm[type].init.val) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 line_set(port, 1, &adapter_parm[type].init);
Jean Delvare6d376fc2010-03-02 12:23:41 +0100212 /* Give powered devices some time to settle */
213 msleep(100);
214 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 if (i2c_bit_add_bus(&adapter->adapter) < 0) {
217 printk(KERN_ERR "i2c-parport: Unable to register with I2C\n");
Jean Delvare07da0372011-05-24 20:58:49 +0200218 goto err_unregister;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 }
220
Jean Delvare35859252010-03-02 12:23:44 +0100221 /* Setup SMBus alert if supported */
222 if (adapter_parm[type].smbus_alert) {
223 adapter->alert_data.alert_edge_triggered = 1;
224 adapter->ara = i2c_setup_smbus_alert(&adapter->adapter,
225 &adapter->alert_data);
226 if (adapter->ara)
227 parport_enable_irq(port);
228 else
229 printk(KERN_WARNING "i2c-parport: Failed to register "
230 "ARA client\n");
231 }
232
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 /* Add the new adapter to the list */
Jean Delvare56acc7a2011-05-01 18:18:49 +0200234 mutex_lock(&adapter_list_lock);
235 list_add_tail(&adapter->node, &adapter_list);
236 mutex_unlock(&adapter_list_lock);
Jean Delvare07da0372011-05-24 20:58:49 +0200237 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238
Jean Delvare07da0372011-05-24 20:58:49 +0200239 err_unregister:
Jean Delvare7b964f7332008-11-28 15:24:39 +0100240 parport_release(adapter->pdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 parport_unregister_device(adapter->pdev);
Jean Delvare07da0372011-05-24 20:58:49 +0200242 err_free:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 kfree(adapter);
244}
245
Jean Delvare07da0372011-05-24 20:58:49 +0200246static void i2c_parport_detach(struct parport *port)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247{
Jean Delvare56acc7a2011-05-01 18:18:49 +0200248 struct i2c_par *adapter, *_n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
250 /* Walk the list */
Jean Delvare56acc7a2011-05-01 18:18:49 +0200251 mutex_lock(&adapter_list_lock);
252 list_for_each_entry_safe(adapter, _n, &adapter_list, node) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 if (adapter->pdev->port == port) {
Jean Delvare35859252010-03-02 12:23:44 +0100254 if (adapter->ara) {
255 parport_disable_irq(port);
256 i2c_unregister_device(adapter->ara);
257 }
Jean Delvare3af07bd2007-05-01 23:26:30 +0200258 i2c_del_adapter(&adapter->adapter);
259
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 /* Un-init if needed (power off...) */
261 if (adapter_parm[type].init.val)
262 line_set(port, 0, &adapter_parm[type].init);
Jean Delvare07da0372011-05-24 20:58:49 +0200263
Jean Delvare7b964f7332008-11-28 15:24:39 +0100264 parport_release(adapter->pdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 parport_unregister_device(adapter->pdev);
Jean Delvare56acc7a2011-05-01 18:18:49 +0200266 list_del(&adapter->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 kfree(adapter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 }
269 }
Jean Delvare56acc7a2011-05-01 18:18:49 +0200270 mutex_unlock(&adapter_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271}
272
Jean Delvare6c129be2005-10-08 00:17:35 +0200273static struct parport_driver i2c_parport_driver = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 .name = "i2c-parport",
275 .attach = i2c_parport_attach,
276 .detach = i2c_parport_detach,
277};
278
279/* ----- Module loading, unloading and information ------------------------ */
280
281static int __init i2c_parport_init(void)
282{
Mark M. Hoffmane97b81d2006-03-23 16:50:25 +0100283 if (type < 0) {
284 printk(KERN_WARNING "i2c-parport: adapter type unspecified\n");
285 return -ENODEV;
286 }
287
288 if (type >= ARRAY_SIZE(adapter_parm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type);
Mark M. Hoffmane97b81d2006-03-23 16:50:25 +0100290 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 }
Tobias Klauser7e3d7db2006-01-09 23:19:51 +0100292
Jean Delvare6c129be2005-10-08 00:17:35 +0200293 return parport_register_driver(&i2c_parport_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294}
295
296static void __exit i2c_parport_exit(void)
297{
Jean Delvare6c129be2005-10-08 00:17:35 +0200298 parport_unregister_driver(&i2c_parport_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299}
300
Jean Delvare7c81c60f2014-01-29 20:40:08 +0100301MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302MODULE_DESCRIPTION("I2C bus over parallel port");
303MODULE_LICENSE("GPL");
304
305module_init(i2c_parport_init);
306module_exit(i2c_parport_exit);