Commit | Line | Data |
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1da177e4 | 1 | /* ------------------------------------------------------------------------ * |
c6e8bb2c | 2 | * i2c-parport-light.c I2C bus over parallel port * |
1da177e4 | 3 | * ------------------------------------------------------------------------ * |
c6e8bb2c | 4 | Copyright (C) 2003-2007 Jean Delvare <khali@linux-fr.org> |
1da177e4 LT |
5 | |
6 | Based on older i2c-velleman.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> | |
c6e8bb2c | 30 | #include <linux/platform_device.h> |
1da177e4 LT |
31 | #include <linux/ioport.h> |
32 | #include <linux/i2c.h> | |
33 | #include <linux/i2c-algo-bit.h> | |
34 | #include <asm/io.h> | |
35 | #include "i2c-parport.h" | |
36 | ||
37 | #define DEFAULT_BASE 0x378 | |
c6e8bb2c JD |
38 | #define DRVNAME "i2c-parport-light" |
39 | ||
40 | static struct platform_device *pdev; | |
1da177e4 LT |
41 | |
42 | static u16 base; | |
43 | module_param(base, ushort, 0); | |
44 | MODULE_PARM_DESC(base, "Base I/O address"); | |
45 | ||
46 | /* ----- Low-level parallel port access ----------------------------------- */ | |
47 | ||
48 | static inline void port_write(unsigned char p, unsigned char d) | |
49 | { | |
50 | outb(d, base+p); | |
51 | } | |
52 | ||
53 | static inline unsigned char port_read(unsigned char p) | |
54 | { | |
55 | return inb(base+p); | |
56 | } | |
57 | ||
58 | /* ----- Unified line operation functions --------------------------------- */ | |
59 | ||
60 | static inline void line_set(int state, const struct lineop *op) | |
61 | { | |
62 | u8 oldval = port_read(op->port); | |
63 | ||
64 | /* Touch only the bit(s) needed */ | |
65 | if ((op->inverted && !state) || (!op->inverted && state)) | |
66 | port_write(op->port, oldval | op->val); | |
67 | else | |
68 | port_write(op->port, oldval & ~op->val); | |
69 | } | |
70 | ||
71 | static inline int line_get(const struct lineop *op) | |
72 | { | |
73 | u8 oldval = port_read(op->port); | |
74 | ||
75 | return ((op->inverted && (oldval & op->val) != op->val) | |
76 | || (!op->inverted && (oldval & op->val) == op->val)); | |
77 | } | |
78 | ||
79 | /* ----- I2C algorithm call-back functions and structures ----------------- */ | |
80 | ||
81 | static void parport_setscl(void *data, int state) | |
82 | { | |
83 | line_set(state, &adapter_parm[type].setscl); | |
84 | } | |
85 | ||
86 | static void parport_setsda(void *data, int state) | |
87 | { | |
88 | line_set(state, &adapter_parm[type].setsda); | |
89 | } | |
90 | ||
91 | static int parport_getscl(void *data) | |
92 | { | |
93 | return line_get(&adapter_parm[type].getscl); | |
94 | } | |
95 | ||
96 | static int parport_getsda(void *data) | |
97 | { | |
98 | return line_get(&adapter_parm[type].getsda); | |
99 | } | |
100 | ||
101 | /* Encapsulate the functions above in the correct structure | |
102 | Note that getscl will be set to NULL by the attaching code for adapters | |
103 | that cannot read SCL back */ | |
104 | static struct i2c_algo_bit_data parport_algo_data = { | |
105 | .setsda = parport_setsda, | |
106 | .setscl = parport_setscl, | |
107 | .getsda = parport_getsda, | |
108 | .getscl = parport_getscl, | |
109 | .udelay = 50, | |
1da177e4 LT |
110 | .timeout = HZ, |
111 | }; | |
112 | ||
c6e8bb2c | 113 | /* ----- Driver registration ---------------------------------------------- */ |
1da177e4 LT |
114 | |
115 | static struct i2c_adapter parport_adapter = { | |
116 | .owner = THIS_MODULE, | |
117 | .class = I2C_CLASS_HWMON, | |
118 | .id = I2C_HW_B_LP, | |
119 | .algo_data = &parport_algo_data, | |
120 | .name = "Parallel port adapter (light)", | |
121 | }; | |
122 | ||
c6e8bb2c JD |
123 | static int __devinit i2c_parport_probe(struct platform_device *pdev) |
124 | { | |
125 | int err; | |
126 | struct resource *res; | |
127 | ||
128 | res = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
129 | if (!request_region(res->start, res->end - res->start + 1, DRVNAME)) | |
130 | return -EBUSY; | |
131 | ||
132 | /* Reset hardware to a sane state (SCL and SDA high) */ | |
133 | parport_setsda(NULL, 1); | |
134 | parport_setscl(NULL, 1); | |
135 | /* Other init if needed (power on...) */ | |
136 | if (adapter_parm[type].init.val) | |
137 | line_set(1, &adapter_parm[type].init); | |
138 | ||
139 | parport_adapter.dev.parent = &pdev->dev; | |
140 | err = i2c_bit_add_bus(&parport_adapter); | |
141 | if (err) { | |
142 | dev_err(&pdev->dev, "Unable to register with I2C\n"); | |
143 | goto exit_region; | |
144 | } | |
145 | return 0; | |
146 | ||
147 | exit_region: | |
148 | release_region(res->start, res->end - res->start + 1); | |
149 | return err; | |
150 | } | |
151 | ||
152 | static int __devexit i2c_parport_remove(struct platform_device *pdev) | |
153 | { | |
154 | struct resource *res; | |
155 | ||
156 | i2c_del_adapter(&parport_adapter); | |
157 | ||
158 | /* Un-init if needed (power off...) */ | |
159 | if (adapter_parm[type].init.val) | |
160 | line_set(0, &adapter_parm[type].init); | |
161 | ||
162 | res = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
163 | release_region(res->start, res->end - res->start + 1); | |
164 | return 0; | |
165 | } | |
166 | ||
167 | static struct platform_driver i2c_parport_driver = { | |
168 | .driver = { | |
169 | .owner = THIS_MODULE, | |
170 | .name = DRVNAME, | |
171 | }, | |
172 | .probe = i2c_parport_probe, | |
173 | .remove = __devexit_p(i2c_parport_remove), | |
174 | }; | |
175 | ||
176 | static int __init i2c_parport_device_add(u16 address) | |
177 | { | |
178 | struct resource res = { | |
179 | .start = address, | |
180 | .end = address + 2, | |
181 | .name = DRVNAME, | |
182 | .flags = IORESOURCE_IO, | |
183 | }; | |
184 | int err; | |
185 | ||
186 | pdev = platform_device_alloc(DRVNAME, -1); | |
187 | if (!pdev) { | |
188 | err = -ENOMEM; | |
189 | printk(KERN_ERR DRVNAME ": Device allocation failed\n"); | |
190 | goto exit; | |
191 | } | |
192 | ||
193 | err = platform_device_add_resources(pdev, &res, 1); | |
194 | if (err) { | |
195 | printk(KERN_ERR DRVNAME ": Device resource addition failed " | |
196 | "(%d)\n", err); | |
197 | goto exit_device_put; | |
198 | } | |
199 | ||
200 | err = platform_device_add(pdev); | |
201 | if (err) { | |
202 | printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n", | |
203 | err); | |
204 | goto exit_device_put; | |
205 | } | |
206 | ||
207 | return 0; | |
208 | ||
209 | exit_device_put: | |
210 | platform_device_put(pdev); | |
211 | exit: | |
212 | return err; | |
213 | } | |
1da177e4 LT |
214 | |
215 | static int __init i2c_parport_init(void) | |
216 | { | |
c6e8bb2c JD |
217 | int err; |
218 | ||
e97b81dd | 219 | if (type < 0) { |
c6e8bb2c | 220 | printk(KERN_ERR DRVNAME ": adapter type unspecified\n"); |
e97b81dd MH |
221 | return -ENODEV; |
222 | } | |
223 | ||
224 | if (type >= ARRAY_SIZE(adapter_parm)) { | |
c6e8bb2c | 225 | printk(KERN_ERR DRVNAME ": invalid type (%d)\n", type); |
e97b81dd | 226 | return -ENODEV; |
1da177e4 | 227 | } |
7e3d7db5 | 228 | |
1da177e4 | 229 | if (base == 0) { |
c6e8bb2c | 230 | pr_info(DRVNAME ": using default base 0x%x\n", DEFAULT_BASE); |
1da177e4 LT |
231 | base = DEFAULT_BASE; |
232 | } | |
233 | ||
1da177e4 LT |
234 | if (!adapter_parm[type].getscl.val) |
235 | parport_algo_data.getscl = NULL; | |
236 | ||
c6e8bb2c JD |
237 | /* Sets global pdev as a side effect */ |
238 | err = i2c_parport_device_add(base); | |
239 | if (err) | |
240 | goto exit; | |
1da177e4 | 241 | |
c6e8bb2c JD |
242 | err = platform_driver_register(&i2c_parport_driver); |
243 | if (err) | |
244 | goto exit_device; | |
7e3d7db5 | 245 | |
1da177e4 | 246 | return 0; |
c6e8bb2c JD |
247 | |
248 | exit_device: | |
249 | platform_device_unregister(pdev); | |
250 | exit: | |
251 | return err; | |
1da177e4 LT |
252 | } |
253 | ||
254 | static void __exit i2c_parport_exit(void) | |
255 | { | |
c6e8bb2c JD |
256 | platform_driver_unregister(&i2c_parport_driver); |
257 | platform_device_unregister(pdev); | |
1da177e4 LT |
258 | } |
259 | ||
260 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
261 | MODULE_DESCRIPTION("I2C bus over parallel port (light)"); | |
262 | MODULE_LICENSE("GPL"); | |
263 | ||
264 | module_init(i2c_parport_init); | |
265 | module_exit(i2c_parport_exit); |