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1da177e4 LT |
1 | /* ------------------------------------------------------------------------ * |
2 | * i2c-parport.c I2C bus over parallel port * | |
3 | * ------------------------------------------------------------------------ * | |
35859254 | 4 | Copyright (C) 2003-2010 Jean Delvare <khali@linux-fr.org> |
1da177e4 LT |
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> | |
96de0e25 | 10 | Kyösti Mälkki <kmalkki@cc.hut.fi> |
1da177e4 LT |
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 | ||
1da177e4 LT |
27 | #include <linux/kernel.h> |
28 | #include <linux/module.h> | |
29 | #include <linux/init.h> | |
6d376fcc | 30 | #include <linux/delay.h> |
1da177e4 LT |
31 | #include <linux/parport.h> |
32 | #include <linux/i2c.h> | |
33 | #include <linux/i2c-algo-bit.h> | |
35859254 | 34 | #include <linux/i2c-smbus.h> |
5a0e3ad6 | 35 | #include <linux/slab.h> |
1da177e4 LT |
36 | #include "i2c-parport.h" |
37 | ||
38 | /* ----- Device list ------------------------------------------------------ */ | |
39 | ||
40 | struct i2c_par { | |
41 | struct pardevice *pdev; | |
42 | struct i2c_adapter adapter; | |
43 | struct i2c_algo_bit_data algo_data; | |
35859254 JD |
44 | struct i2c_smbus_alert_setup alert_data; |
45 | struct i2c_client *ara; | |
1da177e4 LT |
46 | struct i2c_par *next; |
47 | }; | |
48 | ||
49 | static struct i2c_par *adapter_list; | |
50 | ||
51 | /* ----- Low-level parallel port access ----------------------------------- */ | |
52 | ||
53 | static void port_write_data(struct parport *p, unsigned char d) | |
54 | { | |
55 | parport_write_data(p, d); | |
56 | } | |
57 | ||
58 | static void port_write_control(struct parport *p, unsigned char d) | |
59 | { | |
60 | parport_write_control(p, d); | |
61 | } | |
62 | ||
63 | static unsigned char port_read_data(struct parport *p) | |
64 | { | |
65 | return parport_read_data(p); | |
66 | } | |
67 | ||
68 | static unsigned char port_read_status(struct parport *p) | |
69 | { | |
70 | return parport_read_status(p); | |
71 | } | |
72 | ||
73 | static unsigned char port_read_control(struct parport *p) | |
74 | { | |
75 | return parport_read_control(p); | |
76 | } | |
77 | ||
78 | static void (*port_write[])(struct parport *, unsigned char) = { | |
79 | port_write_data, | |
80 | NULL, | |
81 | port_write_control, | |
82 | }; | |
83 | ||
84 | static unsigned char (*port_read[])(struct parport *) = { | |
85 | port_read_data, | |
86 | port_read_status, | |
87 | port_read_control, | |
88 | }; | |
89 | ||
90 | /* ----- Unified line operation functions --------------------------------- */ | |
91 | ||
92 | static inline void line_set(struct parport *data, int state, | |
93 | const struct lineop *op) | |
94 | { | |
95 | u8 oldval = port_read[op->port](data); | |
96 | ||
97 | /* Touch only the bit(s) needed */ | |
98 | if ((op->inverted && !state) || (!op->inverted && state)) | |
99 | port_write[op->port](data, oldval | op->val); | |
100 | else | |
101 | port_write[op->port](data, oldval & ~op->val); | |
102 | } | |
103 | ||
104 | static inline int line_get(struct parport *data, | |
105 | const struct lineop *op) | |
106 | { | |
107 | u8 oldval = port_read[op->port](data); | |
108 | ||
109 | return ((op->inverted && (oldval & op->val) != op->val) | |
110 | || (!op->inverted && (oldval & op->val) == op->val)); | |
111 | } | |
112 | ||
113 | /* ----- I2C algorithm call-back functions and structures ----------------- */ | |
114 | ||
115 | static void parport_setscl(void *data, int state) | |
116 | { | |
117 | line_set((struct parport *) data, state, &adapter_parm[type].setscl); | |
118 | } | |
119 | ||
120 | static void parport_setsda(void *data, int state) | |
121 | { | |
122 | line_set((struct parport *) data, state, &adapter_parm[type].setsda); | |
123 | } | |
124 | ||
125 | static int parport_getscl(void *data) | |
126 | { | |
127 | return line_get((struct parport *) data, &adapter_parm[type].getscl); | |
128 | } | |
129 | ||
130 | static int parport_getsda(void *data) | |
131 | { | |
132 | return line_get((struct parport *) data, &adapter_parm[type].getsda); | |
133 | } | |
134 | ||
135 | /* Encapsulate the functions above in the correct structure. | |
136 | Note that this is only a template, from which the real structures are | |
137 | copied. The attaching code will set getscl to NULL for adapters that | |
614e24be | 138 | cannot read SCL back, and will also make the data field point to |
1da177e4 LT |
139 | the parallel port structure. */ |
140 | static struct i2c_algo_bit_data parport_algo_data = { | |
141 | .setsda = parport_setsda, | |
142 | .setscl = parport_setscl, | |
143 | .getsda = parport_getsda, | |
144 | .getscl = parport_getscl, | |
3af07bd2 | 145 | .udelay = 10, /* ~50 kbps */ |
1da177e4 LT |
146 | .timeout = HZ, |
147 | }; | |
148 | ||
149 | /* ----- I2c and parallel port call-back functions and structures --------- */ | |
150 | ||
35859254 JD |
151 | void i2c_parport_irq(void *data) |
152 | { | |
153 | struct i2c_par *adapter = data; | |
154 | struct i2c_client *ara = adapter->ara; | |
155 | ||
156 | if (ara) { | |
157 | dev_dbg(&ara->dev, "SMBus alert received\n"); | |
158 | i2c_handle_smbus_alert(ara); | |
159 | } else | |
160 | dev_dbg(&adapter->adapter.dev, | |
161 | "SMBus alert received but no ARA client!\n"); | |
162 | } | |
163 | ||
1da177e4 LT |
164 | static void i2c_parport_attach (struct parport *port) |
165 | { | |
166 | struct i2c_par *adapter; | |
167 | ||
5263ebb5 | 168 | adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL); |
1da177e4 | 169 | if (adapter == NULL) { |
5263ebb5 | 170 | printk(KERN_ERR "i2c-parport: Failed to kzalloc\n"); |
1da177e4 LT |
171 | return; |
172 | } | |
1da177e4 LT |
173 | |
174 | pr_debug("i2c-parport: attaching to %s\n", port->name); | |
35859254 | 175 | parport_disable_irq(port); |
1da177e4 | 176 | adapter->pdev = parport_register_device(port, "i2c-parport", |
35859254 | 177 | NULL, NULL, i2c_parport_irq, PARPORT_FLAG_EXCL, adapter); |
1da177e4 LT |
178 | if (!adapter->pdev) { |
179 | printk(KERN_ERR "i2c-parport: Unable to register with parport\n"); | |
180 | goto ERROR0; | |
181 | } | |
182 | ||
183 | /* Fill the rest of the structure */ | |
cacf2269 JD |
184 | adapter->adapter.owner = THIS_MODULE; |
185 | adapter->adapter.class = I2C_CLASS_HWMON; | |
cacf2269 JD |
186 | strlcpy(adapter->adapter.name, "Parallel port adapter", |
187 | sizeof(adapter->adapter.name)); | |
1da177e4 | 188 | adapter->algo_data = parport_algo_data; |
3af07bd2 JD |
189 | /* Slow down if we can't sense SCL */ |
190 | if (!adapter_parm[type].getscl.val) { | |
1da177e4 | 191 | adapter->algo_data.getscl = NULL; |
3af07bd2 JD |
192 | adapter->algo_data.udelay = 50; /* ~10 kbps */ |
193 | } | |
1da177e4 LT |
194 | adapter->algo_data.data = port; |
195 | adapter->adapter.algo_data = &adapter->algo_data; | |
da675296 | 196 | adapter->adapter.dev.parent = port->physport->dev; |
1da177e4 LT |
197 | |
198 | if (parport_claim_or_block(adapter->pdev) < 0) { | |
199 | printk(KERN_ERR "i2c-parport: Could not claim parallel port\n"); | |
200 | goto ERROR1; | |
201 | } | |
202 | ||
203 | /* Reset hardware to a sane state (SCL and SDA high) */ | |
204 | parport_setsda(port, 1); | |
205 | parport_setscl(port, 1); | |
206 | /* Other init if needed (power on...) */ | |
6d376fcc | 207 | if (adapter_parm[type].init.val) { |
1da177e4 | 208 | line_set(port, 1, &adapter_parm[type].init); |
6d376fcc JD |
209 | /* Give powered devices some time to settle */ |
210 | msleep(100); | |
211 | } | |
1da177e4 | 212 | |
1da177e4 LT |
213 | if (i2c_bit_add_bus(&adapter->adapter) < 0) { |
214 | printk(KERN_ERR "i2c-parport: Unable to register with I2C\n"); | |
215 | goto ERROR1; | |
216 | } | |
217 | ||
35859254 JD |
218 | /* Setup SMBus alert if supported */ |
219 | if (adapter_parm[type].smbus_alert) { | |
220 | adapter->alert_data.alert_edge_triggered = 1; | |
221 | adapter->ara = i2c_setup_smbus_alert(&adapter->adapter, | |
222 | &adapter->alert_data); | |
223 | if (adapter->ara) | |
224 | parport_enable_irq(port); | |
225 | else | |
226 | printk(KERN_WARNING "i2c-parport: Failed to register " | |
227 | "ARA client\n"); | |
228 | } | |
229 | ||
1da177e4 LT |
230 | /* Add the new adapter to the list */ |
231 | adapter->next = adapter_list; | |
232 | adapter_list = adapter; | |
233 | return; | |
234 | ||
235 | ERROR1: | |
7b964f73 | 236 | parport_release(adapter->pdev); |
1da177e4 LT |
237 | parport_unregister_device(adapter->pdev); |
238 | ERROR0: | |
239 | kfree(adapter); | |
240 | } | |
241 | ||
242 | static void i2c_parport_detach (struct parport *port) | |
243 | { | |
244 | struct i2c_par *adapter, *prev; | |
245 | ||
246 | /* Walk the list */ | |
247 | for (prev = NULL, adapter = adapter_list; adapter; | |
248 | prev = adapter, adapter = adapter->next) { | |
249 | if (adapter->pdev->port == port) { | |
35859254 JD |
250 | if (adapter->ara) { |
251 | parport_disable_irq(port); | |
252 | i2c_unregister_device(adapter->ara); | |
253 | } | |
3af07bd2 JD |
254 | i2c_del_adapter(&adapter->adapter); |
255 | ||
1da177e4 LT |
256 | /* Un-init if needed (power off...) */ |
257 | if (adapter_parm[type].init.val) | |
258 | line_set(port, 0, &adapter_parm[type].init); | |
259 | ||
7b964f73 | 260 | parport_release(adapter->pdev); |
1da177e4 LT |
261 | parport_unregister_device(adapter->pdev); |
262 | if (prev) | |
263 | prev->next = adapter->next; | |
264 | else | |
265 | adapter_list = adapter->next; | |
266 | kfree(adapter); | |
267 | return; | |
268 | } | |
269 | } | |
270 | } | |
271 | ||
6c129be8 | 272 | static struct parport_driver i2c_parport_driver = { |
1da177e4 LT |
273 | .name = "i2c-parport", |
274 | .attach = i2c_parport_attach, | |
275 | .detach = i2c_parport_detach, | |
276 | }; | |
277 | ||
278 | /* ----- Module loading, unloading and information ------------------------ */ | |
279 | ||
280 | static int __init i2c_parport_init(void) | |
281 | { | |
e97b81dd MH |
282 | if (type < 0) { |
283 | printk(KERN_WARNING "i2c-parport: adapter type unspecified\n"); | |
284 | return -ENODEV; | |
285 | } | |
286 | ||
287 | if (type >= ARRAY_SIZE(adapter_parm)) { | |
1da177e4 | 288 | printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type); |
e97b81dd | 289 | return -ENODEV; |
1da177e4 | 290 | } |
7e3d7db5 | 291 | |
6c129be8 | 292 | return parport_register_driver(&i2c_parport_driver); |
1da177e4 LT |
293 | } |
294 | ||
295 | static void __exit i2c_parport_exit(void) | |
296 | { | |
6c129be8 | 297 | parport_unregister_driver(&i2c_parport_driver); |
1da177e4 LT |
298 | } |
299 | ||
300 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
301 | MODULE_DESCRIPTION("I2C bus over parallel port"); | |
302 | MODULE_LICENSE("GPL"); | |
303 | ||
304 | module_init(i2c_parport_init); | |
305 | module_exit(i2c_parport_exit); |