1 /* ------------------------------------------------------------------------ * 2 * i2c-parport.c I2C bus over parallel port * 3 * ------------------------------------------------------------------------ * 4 Copyright (C) 2003-2004 Jean Delvare <khali@linux-fr.org> 5 6 Based on older i2c-philips-par.c driver 7 Copyright (C) 1995-2000 Simon G. Vogl 8 With some changes from: 9 Frodo Looijaard <frodol@dds.nl> 10 Ky�sti M�lkki <kmalkki@cc.hut.fi> 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 27 #include <linux/config.h> 28 #include <linux/kernel.h> 29 #include <linux/module.h> 30 #include <linux/init.h> 31 #include <linux/parport.h> 32 #include <linux/i2c.h> 33 #include <linux/i2c-algo-bit.h> 34 #include "i2c-parport.h" 35 36 /* ----- Device list ------------------------------------------------------ */ 37 38 struct i2c_par { 39 struct pardevice *pdev; 40 struct i2c_adapter adapter; 41 struct i2c_algo_bit_data algo_data; 42 struct i2c_par *next; 43 }; 44 45 static struct i2c_par *adapter_list; 46 47 /* ----- Low-level parallel port access ----------------------------------- */ 48 49 static void port_write_data(struct parport *p, unsigned char d) 50 { 51 parport_write_data(p, d); 52 } 53 54 static void port_write_control(struct parport *p, unsigned char d) 55 { 56 parport_write_control(p, d); 57 } 58 59 static unsigned char port_read_data(struct parport *p) 60 { 61 return parport_read_data(p); 62 } 63 64 static unsigned char port_read_status(struct parport *p) 65 { 66 return parport_read_status(p); 67 } 68 69 static unsigned char port_read_control(struct parport *p) 70 { 71 return parport_read_control(p); 72 } 73 74 static void (*port_write[])(struct parport *, unsigned char) = { 75 port_write_data, 76 NULL, 77 port_write_control, 78 }; 79 80 static unsigned char (*port_read[])(struct parport *) = { 81 port_read_data, 82 port_read_status, 83 port_read_control, 84 }; 85 86 /* ----- Unified line operation functions --------------------------------- */ 87 88 static inline void line_set(struct parport *data, int state, 89 const struct lineop *op) 90 { 91 u8 oldval = port_read[op->port](data); 92 93 /* Touch only the bit(s) needed */ 94 if ((op->inverted && !state) || (!op->inverted && state)) 95 port_write[op->port](data, oldval | op->val); 96 else 97 port_write[op->port](data, oldval & ~op->val); 98 } 99 100 static inline int line_get(struct parport *data, 101 const struct lineop *op) 102 { 103 u8 oldval = port_read[op->port](data); 104 105 return ((op->inverted && (oldval & op->val) != op->val) 106 || (!op->inverted && (oldval & op->val) == op->val)); 107 } 108 109 /* ----- I2C algorithm call-back functions and structures ----------------- */ 110 111 static void parport_setscl(void *data, int state) 112 { 113 line_set((struct parport *) data, state, &adapter_parm[type].setscl); 114 } 115 116 static void parport_setsda(void *data, int state) 117 { 118 line_set((struct parport *) data, state, &adapter_parm[type].setsda); 119 } 120 121 static int parport_getscl(void *data) 122 { 123 return line_get((struct parport *) data, &adapter_parm[type].getscl); 124 } 125 126 static int parport_getsda(void *data) 127 { 128 return line_get((struct parport *) data, &adapter_parm[type].getsda); 129 } 130 131 /* Encapsulate the functions above in the correct structure. 132 Note that this is only a template, from which the real structures are 133 copied. The attaching code will set getscl to NULL for adapters that 134 cannot read SCL back, and will also make the the data field point to 135 the parallel port structure. */ 136 static struct i2c_algo_bit_data parport_algo_data = { 137 .setsda = parport_setsda, 138 .setscl = parport_setscl, 139 .getsda = parport_getsda, 140 .getscl = parport_getscl, 141 .udelay = 60, 142 .mdelay = 60, 143 .timeout = HZ, 144 }; 145 146 /* ----- I2c and parallel port call-back functions and structures --------- */ 147 148 static struct i2c_adapter parport_adapter = { 149 .owner = THIS_MODULE, 150 .class = I2C_CLASS_HWMON, 151 .id = I2C_HW_B_LP, 152 .name = "Parallel port adapter", 153 }; 154 155 static void i2c_parport_attach (struct parport *port) 156 { 157 struct i2c_par *adapter; 158 159 adapter = kmalloc(sizeof(struct i2c_par), GFP_KERNEL); 160 if (adapter == NULL) { 161 printk(KERN_ERR "i2c-parport: Failed to kmalloc\n"); 162 return; 163 } 164 memset(adapter, 0x00, sizeof(struct i2c_par)); 165 166 pr_debug("i2c-parport: attaching to %s\n", port->name); 167 adapter->pdev = parport_register_device(port, "i2c-parport", 168 NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL); 169 if (!adapter->pdev) { 170 printk(KERN_ERR "i2c-parport: Unable to register with parport\n"); 171 goto ERROR0; 172 } 173 174 /* Fill the rest of the structure */ 175 adapter->adapter = parport_adapter; 176 adapter->algo_data = parport_algo_data; 177 if (!adapter_parm[type].getscl.val) 178 adapter->algo_data.getscl = NULL; 179 adapter->algo_data.data = port; 180 adapter->adapter.algo_data = &adapter->algo_data; 181 182 if (parport_claim_or_block(adapter->pdev) < 0) { 183 printk(KERN_ERR "i2c-parport: Could not claim parallel port\n"); 184 goto ERROR1; 185 } 186 187 /* Reset hardware to a sane state (SCL and SDA high) */ 188 parport_setsda(port, 1); 189 parport_setscl(port, 1); 190 /* Other init if needed (power on...) */ 191 if (adapter_parm[type].init.val) 192 line_set(port, 1, &adapter_parm[type].init); 193 194 parport_release(adapter->pdev); 195 196 if (i2c_bit_add_bus(&adapter->adapter) < 0) { 197 printk(KERN_ERR "i2c-parport: Unable to register with I2C\n"); 198 goto ERROR1; 199 } 200 201 /* Add the new adapter to the list */ 202 adapter->next = adapter_list; 203 adapter_list = adapter; 204 return; 205 206 ERROR1: 207 parport_unregister_device(adapter->pdev); 208 ERROR0: 209 kfree(adapter); 210 } 211 212 static void i2c_parport_detach (struct parport *port) 213 { 214 struct i2c_par *adapter, *prev; 215 216 /* Walk the list */ 217 for (prev = NULL, adapter = adapter_list; adapter; 218 prev = adapter, adapter = adapter->next) { 219 if (adapter->pdev->port == port) { 220 /* Un-init if needed (power off...) */ 221 if (adapter_parm[type].init.val) 222 line_set(port, 0, &adapter_parm[type].init); 223 224 i2c_bit_del_bus(&adapter->adapter); 225 parport_unregister_device(adapter->pdev); 226 if (prev) 227 prev->next = adapter->next; 228 else 229 adapter_list = adapter->next; 230 kfree(adapter); 231 return; 232 } 233 } 234 } 235 236 static struct parport_driver i2c_driver = { 237 .name = "i2c-parport", 238 .attach = i2c_parport_attach, 239 .detach = i2c_parport_detach, 240 }; 241 242 /* ----- Module loading, unloading and information ------------------------ */ 243 244 static int __init i2c_parport_init(void) 245 { 246 int type_count; 247 248 type_count = sizeof(adapter_parm)/sizeof(struct adapter_parm); 249 if (type < 0 || type >= type_count) { 250 printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type); 251 type = 0; 252 } 253 254 return parport_register_driver(&i2c_driver); 255 } 256 257 static void __exit i2c_parport_exit(void) 258 { 259 parport_unregister_driver(&i2c_driver); 260 } 261 262 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 263 MODULE_DESCRIPTION("I2C bus over parallel port"); 264 MODULE_LICENSE("GPL"); 265 266 module_init(i2c_parport_init); 267 module_exit(i2c_parport_exit); 268