| /* ------------------------------------------------------------------------ * |
| * i2c-parport.c I2C bus over parallel port * |
| * ------------------------------------------------------------------------ * |
| Copyright (C) 2003-2004 Jean Delvare <khali@linux-fr.org> |
| |
| Based on older i2c-philips-par.c driver |
| Copyright (C) 1995-2000 Simon G. Vogl |
| With some changes from: |
| Frodo Looijaard <frodol@dds.nl> |
| Kyösti Mälkki <kmalkki@cc.hut.fi> |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| * ------------------------------------------------------------------------ */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/parport.h> |
| #include <linux/i2c.h> |
| #include <linux/i2c-algo-bit.h> |
| #include "i2c-parport.h" |
| |
| /* ----- Device list ------------------------------------------------------ */ |
| |
| struct i2c_par { |
| struct pardevice *pdev; |
| struct i2c_adapter adapter; |
| struct i2c_algo_bit_data algo_data; |
| struct i2c_par *next; |
| }; |
| |
| static struct i2c_par *adapter_list; |
| |
| /* ----- Low-level parallel port access ----------------------------------- */ |
| |
| static void port_write_data(struct parport *p, unsigned char d) |
| { |
| parport_write_data(p, d); |
| } |
| |
| static void port_write_control(struct parport *p, unsigned char d) |
| { |
| parport_write_control(p, d); |
| } |
| |
| static unsigned char port_read_data(struct parport *p) |
| { |
| return parport_read_data(p); |
| } |
| |
| static unsigned char port_read_status(struct parport *p) |
| { |
| return parport_read_status(p); |
| } |
| |
| static unsigned char port_read_control(struct parport *p) |
| { |
| return parport_read_control(p); |
| } |
| |
| static void (*port_write[])(struct parport *, unsigned char) = { |
| port_write_data, |
| NULL, |
| port_write_control, |
| }; |
| |
| static unsigned char (*port_read[])(struct parport *) = { |
| port_read_data, |
| port_read_status, |
| port_read_control, |
| }; |
| |
| /* ----- Unified line operation functions --------------------------------- */ |
| |
| static inline void line_set(struct parport *data, int state, |
| const struct lineop *op) |
| { |
| u8 oldval = port_read[op->port](data); |
| |
| /* Touch only the bit(s) needed */ |
| if ((op->inverted && !state) || (!op->inverted && state)) |
| port_write[op->port](data, oldval | op->val); |
| else |
| port_write[op->port](data, oldval & ~op->val); |
| } |
| |
| static inline int line_get(struct parport *data, |
| const struct lineop *op) |
| { |
| u8 oldval = port_read[op->port](data); |
| |
| return ((op->inverted && (oldval & op->val) != op->val) |
| || (!op->inverted && (oldval & op->val) == op->val)); |
| } |
| |
| /* ----- I2C algorithm call-back functions and structures ----------------- */ |
| |
| static void parport_setscl(void *data, int state) |
| { |
| line_set((struct parport *) data, state, &adapter_parm[type].setscl); |
| } |
| |
| static void parport_setsda(void *data, int state) |
| { |
| line_set((struct parport *) data, state, &adapter_parm[type].setsda); |
| } |
| |
| static int parport_getscl(void *data) |
| { |
| return line_get((struct parport *) data, &adapter_parm[type].getscl); |
| } |
| |
| static int parport_getsda(void *data) |
| { |
| return line_get((struct parport *) data, &adapter_parm[type].getsda); |
| } |
| |
| /* Encapsulate the functions above in the correct structure. |
| Note that this is only a template, from which the real structures are |
| copied. The attaching code will set getscl to NULL for adapters that |
| cannot read SCL back, and will also make the the data field point to |
| the parallel port structure. */ |
| static struct i2c_algo_bit_data parport_algo_data = { |
| .setsda = parport_setsda, |
| .setscl = parport_setscl, |
| .getsda = parport_getsda, |
| .getscl = parport_getscl, |
| .udelay = 60, |
| .mdelay = 60, |
| .timeout = HZ, |
| }; |
| |
| /* ----- I2c and parallel port call-back functions and structures --------- */ |
| |
| static struct i2c_adapter parport_adapter = { |
| .owner = THIS_MODULE, |
| .class = I2C_CLASS_HWMON, |
| .id = I2C_HW_B_LP, |
| .name = "Parallel port adapter", |
| }; |
| |
| static void i2c_parport_attach (struct parport *port) |
| { |
| struct i2c_par *adapter; |
| |
| adapter = kmalloc(sizeof(struct i2c_par), GFP_KERNEL); |
| if (adapter == NULL) { |
| printk(KERN_ERR "i2c-parport: Failed to kmalloc\n"); |
| return; |
| } |
| memset(adapter, 0x00, sizeof(struct i2c_par)); |
| |
| pr_debug("i2c-parport: attaching to %s\n", port->name); |
| adapter->pdev = parport_register_device(port, "i2c-parport", |
| NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL); |
| if (!adapter->pdev) { |
| printk(KERN_ERR "i2c-parport: Unable to register with parport\n"); |
| goto ERROR0; |
| } |
| |
| /* Fill the rest of the structure */ |
| adapter->adapter = parport_adapter; |
| adapter->algo_data = parport_algo_data; |
| if (!adapter_parm[type].getscl.val) |
| adapter->algo_data.getscl = NULL; |
| adapter->algo_data.data = port; |
| adapter->adapter.algo_data = &adapter->algo_data; |
| |
| if (parport_claim_or_block(adapter->pdev) < 0) { |
| printk(KERN_ERR "i2c-parport: Could not claim parallel port\n"); |
| goto ERROR1; |
| } |
| |
| /* Reset hardware to a sane state (SCL and SDA high) */ |
| parport_setsda(port, 1); |
| parport_setscl(port, 1); |
| /* Other init if needed (power on...) */ |
| if (adapter_parm[type].init.val) |
| line_set(port, 1, &adapter_parm[type].init); |
| |
| parport_release(adapter->pdev); |
| |
| if (i2c_bit_add_bus(&adapter->adapter) < 0) { |
| printk(KERN_ERR "i2c-parport: Unable to register with I2C\n"); |
| goto ERROR1; |
| } |
| |
| /* Add the new adapter to the list */ |
| adapter->next = adapter_list; |
| adapter_list = adapter; |
| return; |
| |
| ERROR1: |
| parport_unregister_device(adapter->pdev); |
| ERROR0: |
| kfree(adapter); |
| } |
| |
| static void i2c_parport_detach (struct parport *port) |
| { |
| struct i2c_par *adapter, *prev; |
| |
| /* Walk the list */ |
| for (prev = NULL, adapter = adapter_list; adapter; |
| prev = adapter, adapter = adapter->next) { |
| if (adapter->pdev->port == port) { |
| /* Un-init if needed (power off...) */ |
| if (adapter_parm[type].init.val) |
| line_set(port, 0, &adapter_parm[type].init); |
| |
| i2c_bit_del_bus(&adapter->adapter); |
| parport_unregister_device(adapter->pdev); |
| if (prev) |
| prev->next = adapter->next; |
| else |
| adapter_list = adapter->next; |
| kfree(adapter); |
| return; |
| } |
| } |
| } |
| |
| static struct parport_driver i2c_driver = { |
| .name = "i2c-parport", |
| .attach = i2c_parport_attach, |
| .detach = i2c_parport_detach, |
| }; |
| |
| /* ----- Module loading, unloading and information ------------------------ */ |
| |
| static int __init i2c_parport_init(void) |
| { |
| int type_count; |
| |
| type_count = sizeof(adapter_parm)/sizeof(struct adapter_parm); |
| if (type < 0 || type >= type_count) { |
| printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type); |
| type = 0; |
| } |
| |
| return parport_register_driver(&i2c_driver); |
| } |
| |
| static void __exit i2c_parport_exit(void) |
| { |
| parport_unregister_driver(&i2c_driver); |
| } |
| |
| MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); |
| MODULE_DESCRIPTION("I2C bus over parallel port"); |
| MODULE_LICENSE("GPL"); |
| |
| module_init(i2c_parport_init); |
| module_exit(i2c_parport_exit); |