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"); 201 202