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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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27
28 #include <linux/init.h>
29 #include <linux/module.h>
30 #include <linux/kernel.h>
31 #include <linux/delay.h>
32 #include <linux/fs.h>
33 #include <linux/io.h>
34 #include <linux/parport.h>
35 #include <linux/uaccess.h>
36 #include <linux/ks0108.h>
37
38 #define KS0108_NAME "ks0108"
39
40 /*
41 * Module Parameters
42 */
43
44 static unsigned int ks0108_port = CONFIG_KS0108_PORT;
45 module_param(ks0108_port, uint, S_IRUGO);
46 MODULE_PARM_DESC(ks0108_port, "Parallel port where the LCD is connected");
47
48 static unsigned int ks0108_delay = CONFIG_KS0108_DELAY;
49 module_param(ks0108_delay, uint, S_IRUGO);
50 MODULE_PARM_DESC(ks0108_delay, "Delay between each control writing (microseconds)");
51
52 /*
53 * Device
54 */
55
56 static struct parport *ks0108_parport;
57 static struct pardevice *ks0108_pardevice;
58
59 /*
60 * ks0108 Exported Commands (don't lock)
61 *
62 * You _should_ lock in the top driver: This functions _should not_
63 * get race conditions in any way. Locking for each byte here would be
64 * so slow and useless.
65 *
66 * There are not bit definitions because they are not flags,
67 * just arbitrary combinations defined by the documentation for each
68 * function in the ks0108 LCD controller. If you want to know what means
69 * a specific combination, look at the function's name.
70 *
71 * The ks0108_writecontrol bits need to be reverted ^(0,1,3) because
72 * the parallel port also revert them using a "not" logic gate.
73 */
74
75 #define bit(n) (((unsigned char)1)<<(n))
76
77 void ks0108_writedata(unsigned char byte)
78 {
79 parport_write_data(ks0108_parport, byte);
80 }
81
82 void ks0108_writecontrol(unsigned char byte)
83 {
84 udelay(ks0108_delay);
85 parport_write_control(ks0108_parport, byte ^ (bit(0) | bit(1) | bit(3)));
86 }
87
88 void ks0108_displaystate(unsigned char state)
89 {
90 ks0108_writedata((state ? bit(0) : 0) | bit(1) | bit(2) | bit(3) | bit(4) | bit(5));
91 }
92
93 void ks0108_startline(unsigned char startline)
94 {
95 ks0108_writedata(min_t(unsigned char, startline, 63) | bit(6) |
96 bit(7));
97 }
98
99 void ks0108_address(unsigned char address)
100 {
101 ks0108_writedata(min_t(unsigned char, address, 63) | bit(6));
102 }
103
104 void ks0108_page(unsigned char page)
105 {
106 ks0108_writedata(min_t(unsigned char, page, 7) | bit(3) | bit(4) |
107 bit(5) | bit(7));
108 }
109
110 EXPORT_SYMBOL_GPL(ks0108_writedata);
111 EXPORT_SYMBOL_GPL(ks0108_writecontrol);
112 EXPORT_SYMBOL_GPL(ks0108_displaystate);
113 EXPORT_SYMBOL_GPL(ks0108_startline);
114 EXPORT_SYMBOL_GPL(ks0108_address);
115 EXPORT_SYMBOL_GPL(ks0108_page);
116
117 /*
118 * Is the module inited?
119 */
120
121 static unsigned char ks0108_inited;
122 unsigned char ks0108_isinited(void)
123 {
124 return ks0108_inited;
125 }
126 EXPORT_SYMBOL_GPL(ks0108_isinited);
127
128 static void ks0108_parport_attach(struct parport *port)
129 {
130 struct pardev_cb ks0108_cb;
131
132 if (port->base != ks0108_port)
133 return;
134
135 memset(&ks0108_cb, 0, sizeof(ks0108_cb));
136 ks0108_cb.flags = PARPORT_DEV_EXCL;
137 ks0108_pardevice = parport_register_dev_model(port, KS0108_NAME,
138 &ks0108_cb, 0);
139 if (!ks0108_pardevice) {
140 pr_err("ERROR: parport didn't register new device\n");
141 return;
142 }
143 if (parport_claim(ks0108_pardevice)) {
144 pr_err("could not claim access to parport %i. Aborting.\n",
145 ks0108_port);
146 goto err_unreg_device;
147 }
148
149 ks0108_parport = port;
150 ks0108_inited = 1;
151 return;
152
153 err_unreg_device:
154 parport_unregister_device(ks0108_pardevice);
155 ks0108_pardevice = NULL;
156 }
157
158 static void ks0108_parport_detach(struct parport *port)
159 {
160 if (port->base != ks0108_port)
161 return;
162
163 if (!ks0108_pardevice) {
164 pr_err("%s: already unregistered.\n", KS0108_NAME);
165 return;
166 }
167
168 parport_release(ks0108_pardevice);
169 parport_unregister_device(ks0108_pardevice);
170 ks0108_pardevice = NULL;
171 ks0108_parport = NULL;
172 }
173
174 /*
175 * Module Init & Exit
176 */
177
178 static struct parport_driver ks0108_parport_driver = {
179 .name = "ks0108",
180 .match_port = ks0108_parport_attach,
181 .detach = ks0108_parport_detach,
182 .devmodel = true,
183 };
184
185 static int __init ks0108_init(void)
186 {
187 return parport_register_driver(&ks0108_parport_driver);
188 }
189
190 static void __exit ks0108_exit(void)
191 {
192 parport_unregister_driver(&ks0108_parport_driver);
193 }
194
195 module_init(ks0108_init);
196 module_exit(ks0108_exit);
197
198 MODULE_LICENSE("GPL v2");
199 MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>");
200 MODULE_DESCRIPTION("ks0108 LCD Controller driver");
201