Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* ------------------------------------------------------------------------ * |
2 | * i2c-parport.c I2C bus over parallel port * | |
3 | * ------------------------------------------------------------------------ * | |
3af07bd2 | 4 | Copyright (C) 2003-2007 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> | |
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 | ||
37 | struct 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 | ||
44 | static struct i2c_par *adapter_list; | |
45 | ||
46 | /* ----- Low-level parallel port access ----------------------------------- */ | |
47 | ||
48 | static void port_write_data(struct parport *p, unsigned char d) | |
49 | { | |
50 | parport_write_data(p, d); | |
51 | } | |
52 | ||
53 | static void port_write_control(struct parport *p, unsigned char d) | |
54 | { | |
55 | parport_write_control(p, d); | |
56 | } | |
57 | ||
58 | static unsigned char port_read_data(struct parport *p) | |
59 | { | |
60 | return parport_read_data(p); | |
61 | } | |
62 | ||
63 | static unsigned char port_read_status(struct parport *p) | |
64 | { | |
65 | return parport_read_status(p); | |
66 | } | |
67 | ||
68 | static unsigned char port_read_control(struct parport *p) | |
69 | { | |
70 | return parport_read_control(p); | |
71 | } | |
72 | ||
73 | static void (*port_write[])(struct parport *, unsigned char) = { | |
74 | port_write_data, | |
75 | NULL, | |
76 | port_write_control, | |
77 | }; | |
78 | ||
79 | static 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 | ||
87 | static 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 | ||
99 | static 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 | ||
110 | static void parport_setscl(void *data, int state) | |
111 | { | |
112 | line_set((struct parport *) data, state, &adapter_parm[type].setscl); | |
113 | } | |
114 | ||
115 | static void parport_setsda(void *data, int state) | |
116 | { | |
117 | line_set((struct parport *) data, state, &adapter_parm[type].setsda); | |
118 | } | |
119 | ||
120 | static int parport_getscl(void *data) | |
121 | { | |
122 | return line_get((struct parport *) data, &adapter_parm[type].getscl); | |
123 | } | |
124 | ||
125 | static 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 | |
614e24be | 133 | cannot read SCL back, and will also make the data field point to |
1da177e4 LT |
134 | the parallel port structure. */ |
135 | static struct i2c_algo_bit_data parport_algo_data = { | |
136 | .setsda = parport_setsda, | |
137 | .setscl = parport_setscl, | |
138 | .getsda = parport_getsda, | |
139 | .getscl = parport_getscl, | |
3af07bd2 | 140 | .udelay = 10, /* ~50 kbps */ |
1da177e4 LT |
141 | .timeout = HZ, |
142 | }; | |
143 | ||
144 | /* ----- I2c and parallel port call-back functions and structures --------- */ | |
145 | ||
1da177e4 LT |
146 | static void i2c_parport_attach (struct parport *port) |
147 | { | |
148 | struct i2c_par *adapter; | |
149 | ||
5263ebb5 | 150 | adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL); |
1da177e4 | 151 | if (adapter == NULL) { |
5263ebb5 | 152 | printk(KERN_ERR "i2c-parport: Failed to kzalloc\n"); |
1da177e4 LT |
153 | return; |
154 | } | |
1da177e4 LT |
155 | |
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 */ | |
cacf2269 JD |
165 | 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)); | |
1da177e4 | 170 | adapter->algo_data = parport_algo_data; |
3af07bd2 JD |
171 | /* Slow down if we can't sense SCL */ |
172 | if (!adapter_parm[type].getscl.val) { | |
1da177e4 | 173 | adapter->algo_data.getscl = NULL; |
3af07bd2 JD |
174 | adapter->algo_data.udelay = 50; /* ~10 kbps */ |
175 | } | |
1da177e4 LT |
176 | adapter->algo_data.data = port; |
177 | adapter->adapter.algo_data = &adapter->algo_data; | |
da675296 | 178 | adapter->adapter.dev.parent = port->physport->dev; |
1da177e4 LT |
179 | |
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 | ||
204 | ERROR1: | |
205 | parport_unregister_device(adapter->pdev); | |
206 | ERROR0: | |
207 | kfree(adapter); | |
208 | } | |
209 | ||
210 | static 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) { | |
3af07bd2 JD |
218 | i2c_del_adapter(&adapter->adapter); |
219 | ||
1da177e4 LT |
220 | /* Un-init if needed (power off...) */ |
221 | if (adapter_parm[type].init.val) | |
222 | line_set(port, 0, &adapter_parm[type].init); | |
223 | ||
1da177e4 LT |
224 | 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 | ||
6c129be8 | 235 | static struct parport_driver i2c_parport_driver = { |
1da177e4 LT |
236 | .name = "i2c-parport", |
237 | .attach = i2c_parport_attach, | |
238 | .detach = i2c_parport_detach, | |
239 | }; | |
240 | ||
241 | /* ----- Module loading, unloading and information ------------------------ */ | |
242 | ||
243 | static int __init i2c_parport_init(void) | |
244 | { | |
e97b81dd MH |
245 | 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)) { | |
1da177e4 | 251 | printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type); |
e97b81dd | 252 | return -ENODEV; |
1da177e4 | 253 | } |
7e3d7db5 | 254 | |
6c129be8 | 255 | return parport_register_driver(&i2c_parport_driver); |
1da177e4 LT |
256 | } |
257 | ||
258 | static void __exit i2c_parport_exit(void) | |
259 | { | |
6c129be8 | 260 | parport_unregister_driver(&i2c_parport_driver); |
1da177e4 LT |
261 | } |
262 | ||
263 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
264 | MODULE_DESCRIPTION("I2C bus over parallel port"); | |
265 | MODULE_LICENSE("GPL"); | |
266 | ||
267 | module_init(i2c_parport_init); | |
268 | module_exit(i2c_parport_exit); |