1 /*
2 * Filename: ks0108.c
3 * Version: 0.1.0
4 * Description: ks0108 LCD Controller driver
5 * License: GPLv2
6 * Depends: parport
7 *
8 * Author: Copyright (C) Miguel Ojeda Sandonis
9 * Date: 2006-10-31
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 *
24 */
25
26 #include <linux/init.h>
27 #include <linux/module.h>
28 #include <linux/kernel.h>
29 #include <linux/delay.h>
30 #include <linux/fs.h>
31 #include <linux/io.h>
32 #include <linux/parport.h>
33 #include <linux/uaccess.h>
34 #include <linux/ks0108.h>
35
36 #define KS0108_NAME "ks0108"
37
38 /*
39 * Module Parameters
40 */
41
42 static unsigned int ks0108_port = CONFIG_KS0108_PORT;
43 module_param(ks0108_port, uint, S_IRUGO);
44 MODULE_PARM_DESC(ks0108_port, "Parallel port where the LCD is connected");
45
46 static unsigned int ks0108_delay = CONFIG_KS0108_DELAY;
47 module_param(ks0108_delay, uint, S_IRUGO);
48 MODULE_PARM_DESC(ks0108_delay, "Delay between each control writing (microseconds)");
49
50 /*
51 * Device
52 */
53
54 static struct parport *ks0108_parport;
55 static struct pardevice *ks0108_pardevice;
56
57 /*
58 * ks0108 Exported Commands (don't lock)
59 *
60 * You _should_ lock in the top driver: This functions _should not_
61 * get race conditions in any way. Locking for each byte here would be
62 * so slow and useless.
63 *
64 * There are not bit definitions because they are not flags,
65 * just arbitrary combinations defined by the documentation for each
66 * function in the ks0108 LCD controller. If you want to know what means
67 * a specific combination, look at the function's name.
68 *
69 * The ks0108_writecontrol bits need to be reverted ^(0,1,3) because
70 * the parallel port also revert them using a "not" logic gate.
71 */
72
73 #define bit(n) (((unsigned char)1)<<(n))
74
ks0108_writedata(unsigned char byte)75 void ks0108_writedata(unsigned char byte)
76 {
77 parport_write_data(ks0108_parport, byte);
78 }
79
ks0108_writecontrol(unsigned char byte)80 void ks0108_writecontrol(unsigned char byte)
81 {
82 udelay(ks0108_delay);
83 parport_write_control(ks0108_parport, byte ^ (bit(0) | bit(1) | bit(3)));
84 }
85
ks0108_displaystate(unsigned char state)86 void ks0108_displaystate(unsigned char state)
87 {
88 ks0108_writedata((state ? bit(0) : 0) | bit(1) | bit(2) | bit(3) | bit(4) | bit(5));
89 }
90
ks0108_startline(unsigned char startline)91 void ks0108_startline(unsigned char startline)
92 {
93 ks0108_writedata(min(startline,(unsigned char)63) | bit(6) | bit(7));
94 }
95
ks0108_address(unsigned char address)96 void ks0108_address(unsigned char address)
97 {
98 ks0108_writedata(min(address,(unsigned char)63) | bit(6));
99 }
100
ks0108_page(unsigned char page)101 void ks0108_page(unsigned char page)
102 {
103 ks0108_writedata(min(page,(unsigned char)7) | bit(3) | bit(4) | bit(5) | bit(7));
104 }
105
106 EXPORT_SYMBOL_GPL(ks0108_writedata);
107 EXPORT_SYMBOL_GPL(ks0108_writecontrol);
108 EXPORT_SYMBOL_GPL(ks0108_displaystate);
109 EXPORT_SYMBOL_GPL(ks0108_startline);
110 EXPORT_SYMBOL_GPL(ks0108_address);
111 EXPORT_SYMBOL_GPL(ks0108_page);
112
113 /*
114 * Is the module inited?
115 */
116
117 static unsigned char ks0108_inited;
ks0108_isinited(void)118 unsigned char ks0108_isinited(void)
119 {
120 return ks0108_inited;
121 }
122 EXPORT_SYMBOL_GPL(ks0108_isinited);
123
124 /*
125 * Module Init & Exit
126 */
127
ks0108_init(void)128 static int __init ks0108_init(void)
129 {
130 int result;
131 int ret = -EINVAL;
132
133 ks0108_parport = parport_find_base(ks0108_port);
134 if (ks0108_parport == NULL) {
135 printk(KERN_ERR KS0108_NAME ": ERROR: "
136 "parport didn't find %i port\n", ks0108_port);
137 goto none;
138 }
139
140 ks0108_pardevice = parport_register_device(ks0108_parport, KS0108_NAME,
141 NULL, NULL, NULL, PARPORT_DEV_EXCL, NULL);
142 if (ks0108_pardevice == NULL) {
143 printk(KERN_ERR KS0108_NAME ": ERROR: "
144 "parport didn't register new device\n");
145 goto none;
146 }
147
148 result = parport_claim(ks0108_pardevice);
149 if (result != 0) {
150 printk(KERN_ERR KS0108_NAME ": ERROR: "
151 "can't claim %i parport, maybe in use\n", ks0108_port);
152 ret = result;
153 goto registered;
154 }
155
156 ks0108_inited = 1;
157 return 0;
158
159 registered:
160 parport_unregister_device(ks0108_pardevice);
161
162 none:
163 return ret;
164 }
165
ks0108_exit(void)166 static void __exit ks0108_exit(void)
167 {
168 parport_release(ks0108_pardevice);
169 parport_unregister_device(ks0108_pardevice);
170 }
171
172 module_init(ks0108_init);
173 module_exit(ks0108_exit);
174
175 MODULE_LICENSE("GPL v2");
176 MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>");
177 MODULE_DESCRIPTION("ks0108 LCD Controller driver");
178
179