i2c-parport-light.rar_Over

/* ------------------------------------------------------------------------ * * i2c-parport-light.c I2C bus over parallel port * * ------------------------------------------------------------------------ * Copyright (C) 2003-2010 Jean Delvare <jdelvare@suse.de> Based on older i2c-velleman.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. * ------------------------------------------------------------------------ */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/delay.h> #include <linux/platform_device.h> #include <linux/ioport.h> #include <linux/i2c.h> #include <linux/i2c-algo-bit.h> #include <linux/i2c-smbus.h> #include <linux/io.h> #include "i2c-parport.h" #define DEFAULT_BASE 0x378 #define DRVNAME "i2c-parport-light" static struct platform_device *pdev; static u16 base; module_param(base, ushort, 0); MODULE_PARM_DESC(base, "Base I/O address"); static int irq; module_param(irq, int, 0); MODULE_PARM_DESC(irq, "IRQ (optional)"); /* ----- Low-level parallel port access ----------------------------------- */ static inline void port_write(unsigned char p, unsigned char d) { outb(d, base+p); } static inline unsigned char port_read(unsigned char p) { return inb(base+p); } /* ----- Unified line operation functions --------------------------------- */ static inline void line_set(int state, const struct lineop *op) { u8 oldval = port_read(op->port); /* Touch only the bit(s) needed */ if ((op->inverted && !state) || (!op->inverted && state)) port_write(op->port, oldval | op->val); else port_write(op->port, oldval & ~op->val); } static inline int line_get(const struct lineop *op) { u8 oldval = port_read(op->port); 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(state, &adapter_parm[type].setscl); } static void parport_setsda(void *data, int state) { line_set(state, &adapter_parm[type].setsda); } static int parport_getscl(void *data) { return line_get(&adapter_parm[type].getscl); } static int parport_getsda(void *data) { return line_get(&adapter_parm[type].getsda); } /* Encapsulate the functions above in the correct structure Note that getscl will be set to NULL by the attaching code for adapters that cannot read SCL back */ static struct i2c_algo_bit_data parport_algo_data = { .setsda = parport_setsda, .setscl = parport_setscl, .getsda = parport_getsda, .getscl = parport_getscl, .udelay = 50, .timeout = HZ, }; /* ----- Driver registration ---------------------------------------------- */ static struct i2c_adapter parport_adapter = { .owner = THIS_MODULE, .class = I2C_CLASS_HWMON, .algo_data = &parport_algo_data, .name = "Parallel port adapter (light)", }; /* SMBus alert support */ static struct i2c_smbus_alert_setup alert_data = { .alert_edge_triggered = 1, }; static struct i2c_client *ara; static struct lineop parport_ctrl_irq = { .val = (1 << 4), .port = PORT_CTRL, }; static int i2c_parport_probe(struct platform_device *pdev) { int err; /* Reset hardware to a sane state (SCL and SDA high) */ parport_setsda(NULL, 1); parport_setscl(NULL, 1); /* Other init if needed (power on...) */ if (adapter_parm[type].init.val) { line_set(1, &adapter_parm[type].init); /* Give powered devices some time to settle */ msleep(100); } parport_adapter.dev.parent = &pdev->dev; err = i2c_bit_add_bus(&parport_adapter); if (err) { dev_err(&pdev->dev, "Unable to register with I2C\n"); return err; } /* Setup SMBus alert if supported */ if (adapter_parm[type].smbus_alert && irq) { alert_data.irq = irq; ara = i2c_setup_smbus_alert(&parport_adapter, &alert_data); if (ara) line_set(1, &parport_ctrl_irq); else dev_warn(&pdev->dev, "Failed to register ARA client\n"); } return 0; } static int i2c_parport_remove(struct platform_device *pdev) { if (ara) { line_set(0, &parport_ctrl_irq); i2c_unregister_device(ara); ara = NULL; } i2c_del_adapter(&parport_adapter); /* Un-init if needed (power off...) */ if (adapter_parm[type].init.val) line_set(0, &adapter_parm[type].init); return 0; } static struct platform_driver i2c_parport_driver = { .driver = { .name = DRVNAME, }, .probe = i2c_parport_probe, .remove = i2c_parport_remove, }; static int __init i2c_parport_device_add(u16 address) { int err; pdev = platform_device_alloc(DRVNAME, -1); if (!pdev) { err = -ENOMEM; printk(KERN_ERR DRVNAME ": Device allocation failed\n"); goto exit; } err = platform_device_add(pdev); if (err) { printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n", err); goto exit_device_put; } return 0; exit_device_put: platform_device_put(pdev); exit: return err; } static int __init i2c_parport_init(void) { int err; if (type < 0) { printk(KERN_ERR DRVNAME ": adapter type unspecified\n"); return -ENODEV; } if (type >= ARRAY_SIZE(adapter_parm)) { printk(KERN_ERR DRVNAME ": invalid type (%d)\n", type); return -ENODEV; } if (base == 0) { pr_info(DRVNAME ": using default base 0x%x\n", DEFAULT_BASE); base = DEFAULT_BASE; } if (!request_region(base, 3, DRVNAME)) return -EBUSY; if (irq != 0) pr_info(DRVNAME ": using irq %d\n", irq); if (!adapter_parm[type].getscl.val) parport_algo_data.getscl = NULL; /* Sets global pdev as a side effect */ err = i2c_parport_device_add(base); if (err) goto exit_release; err = platform_driver_register(&i2c_parport_driver); if (err) goto exit_device; return 0; exit_device: platform_device_unregister(pdev); exit_release: release_region(base, 3); return err; } static void __exit i2c_parport_exit(void) { platform_driver_unregister(&i2c_parport_driver); platform_device_unregister(pdev); release_region(base, 3); } MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); MODULE_DESCRIPTION("I2C bus over parallel port (light)"); MODULE_LICENSE("GPL"); module_init(i2c_parport_init); module_exit(i2c_parport_exit);