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
 42static unsigned int ks0108_port = CONFIG_KS0108_PORT;
 43module_param(ks0108_port, uint, S_IRUGO);
 44MODULE_PARM_DESC(ks0108_port, "Parallel port where the LCD is connected");
 45
 46static unsigned int ks0108_delay = CONFIG_KS0108_DELAY;
 47module_param(ks0108_delay, uint, S_IRUGO);
 48MODULE_PARM_DESC(ks0108_delay, "Delay between each control writing (microseconds)");
 49
 50/*
 51 * Device
 52 */
 53
 54static struct parport *ks0108_parport;
 55static 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
 75void ks0108_writedata(unsigned char byte)
 76{
 77	parport_write_data(ks0108_parport, byte);
 78}
 79
 80void 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
 86void 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
 91void ks0108_startline(unsigned char startline)
 92{
 93	ks0108_writedata(min(startline,(unsigned char)63) | bit(6) | bit(7));
 94}
 95
 96void ks0108_address(unsigned char address)
 97{
 98	ks0108_writedata(min(address,(unsigned char)63) | bit(6));
 99}
100
101void ks0108_page(unsigned char page)
102{
103	ks0108_writedata(min(page,(unsigned char)7) | bit(3) | bit(4) | bit(5) | bit(7));
104}
105
106EXPORT_SYMBOL_GPL(ks0108_writedata);
107EXPORT_SYMBOL_GPL(ks0108_writecontrol);
108EXPORT_SYMBOL_GPL(ks0108_displaystate);
109EXPORT_SYMBOL_GPL(ks0108_startline);
110EXPORT_SYMBOL_GPL(ks0108_address);
111EXPORT_SYMBOL_GPL(ks0108_page);
112
113/*
114 * Is the module inited?
115 */
116
117static unsigned char ks0108_inited;
118unsigned char ks0108_isinited(void)
119{
120	return ks0108_inited;
121}
122EXPORT_SYMBOL_GPL(ks0108_isinited);
123
124/*
125 * Module Init & Exit
126 */
127
128static 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
159registered:
160	parport_unregister_device(ks0108_pardevice);
161
162none:
163	return ret;
164}
165
166static void __exit ks0108_exit(void)
167{
168	parport_release(ks0108_pardevice);
169	parport_unregister_device(ks0108_pardevice);
170}
171
172module_init(ks0108_init);
173module_exit(ks0108_exit);
174
175MODULE_LICENSE("GPL v2");
176MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>");
177MODULE_DESCRIPTION("ks0108 LCD Controller driver");
178