11da177e4SLinus Torvalds /* ------------------------------------------------------------------------ * 21da177e4SLinus Torvalds * i2c-parport.c I2C bus over parallel port * 31da177e4SLinus Torvalds * ------------------------------------------------------------------------ * 43af07bd2SJean Delvare Copyright (C) 2003-2007 Jean Delvare <khali@linux-fr.org> 51da177e4SLinus Torvalds 61da177e4SLinus Torvalds Based on older i2c-philips-par.c driver 71da177e4SLinus Torvalds Copyright (C) 1995-2000 Simon G. Vogl 81da177e4SLinus Torvalds With some changes from: 91da177e4SLinus Torvalds Frodo Looijaard <frodol@dds.nl> 1096de0e25SJan Engelhardt Kyösti Mälkki <kmalkki@cc.hut.fi> 111da177e4SLinus Torvalds 121da177e4SLinus Torvalds This program is free software; you can redistribute it and/or modify 131da177e4SLinus Torvalds it under the terms of the GNU General Public License as published by 141da177e4SLinus Torvalds the Free Software Foundation; either version 2 of the License, or 151da177e4SLinus Torvalds (at your option) any later version. 161da177e4SLinus Torvalds 171da177e4SLinus Torvalds This program is distributed in the hope that it will be useful, 181da177e4SLinus Torvalds but WITHOUT ANY WARRANTY; without even the implied warranty of 191da177e4SLinus Torvalds MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 201da177e4SLinus Torvalds GNU General Public License for more details. 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds You should have received a copy of the GNU General Public License 231da177e4SLinus Torvalds along with this program; if not, write to the Free Software 241da177e4SLinus Torvalds Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 251da177e4SLinus Torvalds * ------------------------------------------------------------------------ */ 261da177e4SLinus Torvalds 271da177e4SLinus Torvalds #include <linux/kernel.h> 281da177e4SLinus Torvalds #include <linux/module.h> 291da177e4SLinus Torvalds #include <linux/init.h> 306d376fccSJean Delvare #include <linux/delay.h> 311da177e4SLinus Torvalds #include <linux/parport.h> 321da177e4SLinus Torvalds #include <linux/i2c.h> 331da177e4SLinus Torvalds #include <linux/i2c-algo-bit.h> 341da177e4SLinus Torvalds #include "i2c-parport.h" 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds /* ----- Device list ------------------------------------------------------ */ 371da177e4SLinus Torvalds 381da177e4SLinus Torvalds struct i2c_par { 391da177e4SLinus Torvalds struct pardevice *pdev; 401da177e4SLinus Torvalds struct i2c_adapter adapter; 411da177e4SLinus Torvalds struct i2c_algo_bit_data algo_data; 421da177e4SLinus Torvalds struct i2c_par *next; 431da177e4SLinus Torvalds }; 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds static struct i2c_par *adapter_list; 461da177e4SLinus Torvalds 471da177e4SLinus Torvalds /* ----- Low-level parallel port access ----------------------------------- */ 481da177e4SLinus Torvalds 491da177e4SLinus Torvalds static void port_write_data(struct parport *p, unsigned char d) 501da177e4SLinus Torvalds { 511da177e4SLinus Torvalds parport_write_data(p, d); 521da177e4SLinus Torvalds } 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds static void port_write_control(struct parport *p, unsigned char d) 551da177e4SLinus Torvalds { 561da177e4SLinus Torvalds parport_write_control(p, d); 571da177e4SLinus Torvalds } 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds static unsigned char port_read_data(struct parport *p) 601da177e4SLinus Torvalds { 611da177e4SLinus Torvalds return parport_read_data(p); 621da177e4SLinus Torvalds } 631da177e4SLinus Torvalds 641da177e4SLinus Torvalds static unsigned char port_read_status(struct parport *p) 651da177e4SLinus Torvalds { 661da177e4SLinus Torvalds return parport_read_status(p); 671da177e4SLinus Torvalds } 681da177e4SLinus Torvalds 691da177e4SLinus Torvalds static unsigned char port_read_control(struct parport *p) 701da177e4SLinus Torvalds { 711da177e4SLinus Torvalds return parport_read_control(p); 721da177e4SLinus Torvalds } 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds static void (*port_write[])(struct parport *, unsigned char) = { 751da177e4SLinus Torvalds port_write_data, 761da177e4SLinus Torvalds NULL, 771da177e4SLinus Torvalds port_write_control, 781da177e4SLinus Torvalds }; 791da177e4SLinus Torvalds 801da177e4SLinus Torvalds static unsigned char (*port_read[])(struct parport *) = { 811da177e4SLinus Torvalds port_read_data, 821da177e4SLinus Torvalds port_read_status, 831da177e4SLinus Torvalds port_read_control, 841da177e4SLinus Torvalds }; 851da177e4SLinus Torvalds 861da177e4SLinus Torvalds /* ----- Unified line operation functions --------------------------------- */ 871da177e4SLinus Torvalds 881da177e4SLinus Torvalds static inline void line_set(struct parport *data, int state, 891da177e4SLinus Torvalds const struct lineop *op) 901da177e4SLinus Torvalds { 911da177e4SLinus Torvalds u8 oldval = port_read[op->port](data); 921da177e4SLinus Torvalds 931da177e4SLinus Torvalds /* Touch only the bit(s) needed */ 941da177e4SLinus Torvalds if ((op->inverted && !state) || (!op->inverted && state)) 951da177e4SLinus Torvalds port_write[op->port](data, oldval | op->val); 961da177e4SLinus Torvalds else 971da177e4SLinus Torvalds port_write[op->port](data, oldval & ~op->val); 981da177e4SLinus Torvalds } 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds static inline int line_get(struct parport *data, 1011da177e4SLinus Torvalds const struct lineop *op) 1021da177e4SLinus Torvalds { 1031da177e4SLinus Torvalds u8 oldval = port_read[op->port](data); 1041da177e4SLinus Torvalds 1051da177e4SLinus Torvalds return ((op->inverted && (oldval & op->val) != op->val) 1061da177e4SLinus Torvalds || (!op->inverted && (oldval & op->val) == op->val)); 1071da177e4SLinus Torvalds } 1081da177e4SLinus Torvalds 1091da177e4SLinus Torvalds /* ----- I2C algorithm call-back functions and structures ----------------- */ 1101da177e4SLinus Torvalds 1111da177e4SLinus Torvalds static void parport_setscl(void *data, int state) 1121da177e4SLinus Torvalds { 1131da177e4SLinus Torvalds line_set((struct parport *) data, state, &adapter_parm[type].setscl); 1141da177e4SLinus Torvalds } 1151da177e4SLinus Torvalds 1161da177e4SLinus Torvalds static void parport_setsda(void *data, int state) 1171da177e4SLinus Torvalds { 1181da177e4SLinus Torvalds line_set((struct parport *) data, state, &adapter_parm[type].setsda); 1191da177e4SLinus Torvalds } 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds static int parport_getscl(void *data) 1221da177e4SLinus Torvalds { 1231da177e4SLinus Torvalds return line_get((struct parport *) data, &adapter_parm[type].getscl); 1241da177e4SLinus Torvalds } 1251da177e4SLinus Torvalds 1261da177e4SLinus Torvalds static int parport_getsda(void *data) 1271da177e4SLinus Torvalds { 1281da177e4SLinus Torvalds return line_get((struct parport *) data, &adapter_parm[type].getsda); 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds 1311da177e4SLinus Torvalds /* Encapsulate the functions above in the correct structure. 1321da177e4SLinus Torvalds Note that this is only a template, from which the real structures are 1331da177e4SLinus Torvalds copied. The attaching code will set getscl to NULL for adapters that 134614e24beSTobias Klauser cannot read SCL back, and will also make the data field point to 1351da177e4SLinus Torvalds the parallel port structure. */ 1361da177e4SLinus Torvalds static struct i2c_algo_bit_data parport_algo_data = { 1371da177e4SLinus Torvalds .setsda = parport_setsda, 1381da177e4SLinus Torvalds .setscl = parport_setscl, 1391da177e4SLinus Torvalds .getsda = parport_getsda, 1401da177e4SLinus Torvalds .getscl = parport_getscl, 1413af07bd2SJean Delvare .udelay = 10, /* ~50 kbps */ 1421da177e4SLinus Torvalds .timeout = HZ, 1431da177e4SLinus Torvalds }; 1441da177e4SLinus Torvalds 1451da177e4SLinus Torvalds /* ----- I2c and parallel port call-back functions and structures --------- */ 1461da177e4SLinus Torvalds 1471da177e4SLinus Torvalds static void i2c_parport_attach (struct parport *port) 1481da177e4SLinus Torvalds { 1491da177e4SLinus Torvalds struct i2c_par *adapter; 1501da177e4SLinus Torvalds 1515263ebb5SDeepak Saxena adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL); 1521da177e4SLinus Torvalds if (adapter == NULL) { 1535263ebb5SDeepak Saxena printk(KERN_ERR "i2c-parport: Failed to kzalloc\n"); 1541da177e4SLinus Torvalds return; 1551da177e4SLinus Torvalds } 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds pr_debug("i2c-parport: attaching to %s\n", port->name); 1581da177e4SLinus Torvalds adapter->pdev = parport_register_device(port, "i2c-parport", 1591da177e4SLinus Torvalds NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL); 1601da177e4SLinus Torvalds if (!adapter->pdev) { 1611da177e4SLinus Torvalds printk(KERN_ERR "i2c-parport: Unable to register with parport\n"); 1621da177e4SLinus Torvalds goto ERROR0; 1631da177e4SLinus Torvalds } 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds /* Fill the rest of the structure */ 166cacf2269SJean Delvare adapter->adapter.owner = THIS_MODULE; 167cacf2269SJean Delvare adapter->adapter.class = I2C_CLASS_HWMON; 168cacf2269SJean Delvare strlcpy(adapter->adapter.name, "Parallel port adapter", 169cacf2269SJean Delvare sizeof(adapter->adapter.name)); 1701da177e4SLinus Torvalds adapter->algo_data = parport_algo_data; 1713af07bd2SJean Delvare /* Slow down if we can't sense SCL */ 1723af07bd2SJean Delvare if (!adapter_parm[type].getscl.val) { 1731da177e4SLinus Torvalds adapter->algo_data.getscl = NULL; 1743af07bd2SJean Delvare adapter->algo_data.udelay = 50; /* ~10 kbps */ 1753af07bd2SJean Delvare } 1761da177e4SLinus Torvalds adapter->algo_data.data = port; 1771da177e4SLinus Torvalds adapter->adapter.algo_data = &adapter->algo_data; 178da675296SDavid Brownell adapter->adapter.dev.parent = port->physport->dev; 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds if (parport_claim_or_block(adapter->pdev) < 0) { 1811da177e4SLinus Torvalds printk(KERN_ERR "i2c-parport: Could not claim parallel port\n"); 1821da177e4SLinus Torvalds goto ERROR1; 1831da177e4SLinus Torvalds } 1841da177e4SLinus Torvalds 1851da177e4SLinus Torvalds /* Reset hardware to a sane state (SCL and SDA high) */ 1861da177e4SLinus Torvalds parport_setsda(port, 1); 1871da177e4SLinus Torvalds parport_setscl(port, 1); 1881da177e4SLinus Torvalds /* Other init if needed (power on...) */ 1896d376fccSJean Delvare if (adapter_parm[type].init.val) { 1901da177e4SLinus Torvalds line_set(port, 1, &adapter_parm[type].init); 1916d376fccSJean Delvare /* Give powered devices some time to settle */ 1926d376fccSJean Delvare msleep(100); 1936d376fccSJean Delvare } 1941da177e4SLinus Torvalds 1951da177e4SLinus Torvalds if (i2c_bit_add_bus(&adapter->adapter) < 0) { 1961da177e4SLinus Torvalds printk(KERN_ERR "i2c-parport: Unable to register with I2C\n"); 1971da177e4SLinus Torvalds goto ERROR1; 1981da177e4SLinus Torvalds } 1991da177e4SLinus Torvalds 2001da177e4SLinus Torvalds /* Add the new adapter to the list */ 2011da177e4SLinus Torvalds adapter->next = adapter_list; 2021da177e4SLinus Torvalds adapter_list = adapter; 2031da177e4SLinus Torvalds return; 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds ERROR1: 2067b964f73SJean Delvare parport_release(adapter->pdev); 2071da177e4SLinus Torvalds parport_unregister_device(adapter->pdev); 2081da177e4SLinus Torvalds ERROR0: 2091da177e4SLinus Torvalds kfree(adapter); 2101da177e4SLinus Torvalds } 2111da177e4SLinus Torvalds 2121da177e4SLinus Torvalds static void i2c_parport_detach (struct parport *port) 2131da177e4SLinus Torvalds { 2141da177e4SLinus Torvalds struct i2c_par *adapter, *prev; 2151da177e4SLinus Torvalds 2161da177e4SLinus Torvalds /* Walk the list */ 2171da177e4SLinus Torvalds for (prev = NULL, adapter = adapter_list; adapter; 2181da177e4SLinus Torvalds prev = adapter, adapter = adapter->next) { 2191da177e4SLinus Torvalds if (adapter->pdev->port == port) { 2203af07bd2SJean Delvare i2c_del_adapter(&adapter->adapter); 2213af07bd2SJean Delvare 2221da177e4SLinus Torvalds /* Un-init if needed (power off...) */ 2231da177e4SLinus Torvalds if (adapter_parm[type].init.val) 2241da177e4SLinus Torvalds line_set(port, 0, &adapter_parm[type].init); 2251da177e4SLinus Torvalds 2267b964f73SJean Delvare parport_release(adapter->pdev); 2271da177e4SLinus Torvalds parport_unregister_device(adapter->pdev); 2281da177e4SLinus Torvalds if (prev) 2291da177e4SLinus Torvalds prev->next = adapter->next; 2301da177e4SLinus Torvalds else 2311da177e4SLinus Torvalds adapter_list = adapter->next; 2321da177e4SLinus Torvalds kfree(adapter); 2331da177e4SLinus Torvalds return; 2341da177e4SLinus Torvalds } 2351da177e4SLinus Torvalds } 2361da177e4SLinus Torvalds } 2371da177e4SLinus Torvalds 2386c129be8SJean Delvare static struct parport_driver i2c_parport_driver = { 2391da177e4SLinus Torvalds .name = "i2c-parport", 2401da177e4SLinus Torvalds .attach = i2c_parport_attach, 2411da177e4SLinus Torvalds .detach = i2c_parport_detach, 2421da177e4SLinus Torvalds }; 2431da177e4SLinus Torvalds 2441da177e4SLinus Torvalds /* ----- Module loading, unloading and information ------------------------ */ 2451da177e4SLinus Torvalds 2461da177e4SLinus Torvalds static int __init i2c_parport_init(void) 2471da177e4SLinus Torvalds { 248e97b81ddSMark M. Hoffman if (type < 0) { 249e97b81ddSMark M. Hoffman printk(KERN_WARNING "i2c-parport: adapter type unspecified\n"); 250e97b81ddSMark M. Hoffman return -ENODEV; 251e97b81ddSMark M. Hoffman } 252e97b81ddSMark M. Hoffman 253e97b81ddSMark M. Hoffman if (type >= ARRAY_SIZE(adapter_parm)) { 2541da177e4SLinus Torvalds printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type); 255e97b81ddSMark M. Hoffman return -ENODEV; 2561da177e4SLinus Torvalds } 2571da177e4SLinus Torvalds 2586c129be8SJean Delvare return parport_register_driver(&i2c_parport_driver); 2591da177e4SLinus Torvalds } 2601da177e4SLinus Torvalds 2611da177e4SLinus Torvalds static void __exit i2c_parport_exit(void) 2621da177e4SLinus Torvalds { 2636c129be8SJean Delvare parport_unregister_driver(&i2c_parport_driver); 2641da177e4SLinus Torvalds } 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 2671da177e4SLinus Torvalds MODULE_DESCRIPTION("I2C bus over parallel port"); 2681da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 2691da177e4SLinus Torvalds 2701da177e4SLinus Torvalds module_init(i2c_parport_init); 2711da177e4SLinus Torvalds module_exit(i2c_parport_exit); 272