/* ------------------------------------------------------------------------- i2c-adap-ite.c i2c-hw access for the IIC peripheral on the ITE MIPS system ------------------------------------------------------------------------- Hai-Pao Fan, MontaVista Software, Inc. hpfan@mvista.com or source@mvista.com Copyright 2001 MontaVista Software Inc. ---------------------------------------------------------------------------- This file was highly leveraged from i2c-elektor.c, which was created by Simon G. Vogl and Hans Berglund: Copyright (C) 1995-97 Simon G. Vogl 1998-99 Hans Berglund 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. */ /* ------------------------------------------------------------------------- */ /* With some changes from Kyösti Mälkki and even Frodo Looijaard */ #include #include #include #include #include #include #include #include #include #include #include #include #include "../i2c-ite.h" #define DEFAULT_BASE 0x14014030 #define ITE_IIC_IO_SIZE 0x40 #define DEFAULT_IRQ 0 #define DEFAULT_CLOCK 0x1b0e /* default 16MHz/(27+14) = 400KHz */ #define DEFAULT_OWN 0x55 static int base; static int irq; static int clock; static int own; static struct iic_ite gpi; static wait_queue_head_t iic_wait; static int iic_pending; static spinlock_t lock; /* ----- local functions ---------------------------------------------- */ static void iic_ite_setiic(void *data, int ctl, short val) { unsigned long j = jiffies + 10; pr_debug(" Write 0x%02x to 0x%x\n",(unsigned short)val, ctl&0xff); #ifdef DEBUG while (time_before(jiffies, j)) schedule(); #endif outw(val,ctl); } static short iic_ite_getiic(void *data, int ctl) { short val; val = inw(ctl); pr_debug("Read 0x%02x from 0x%x\n",(unsigned short)val, ctl&0xff); return (val); } /* Return our slave address. This is the address * put on the I2C bus when another master on the bus wants to address us * as a slave */ static int iic_ite_getown(void *data) { return (gpi.iic_own); } static int iic_ite_getclock(void *data) { return (gpi.iic_clock); } /* Put this process to sleep. We will wake up when the * IIC controller interrupts. */ static void iic_ite_waitforpin(void) { DEFINE_WAIT(wait); int timeout = 2; long flags; /* If interrupts are enabled (which they are), then put the process to * sleep. This process will be awakened by two events -- either the * the IIC peripheral interrupts or the timeout expires. * If interrupts are not enabled then delay for a reasonable amount * of time and return. */ if (gpi.iic_irq > 0) { spin_lock_irqsave(&lock, flags); if (iic_pending == 0) { spin_unlock_irqrestore(&lock, flags); prepare_to_wait(&iic_wait, &wait, TASK_INTERRUPTIBLE); if (schedule_timeout(timeout*HZ)) { spin_lock_irqsave(&lock, flags); if (iic_pending == 1) { iic_pending = 0; } spin_unlock_irqrestore(&lock, flags); } finish_wait(&iic_wait, &wait); } else { iic_pending = 0; spin_unlock_irqrestore(&lock, flags); } } else { udelay(100); } } static irqreturn_t iic_ite_handler(int this_irq, void *dev_id, struct pt_regs *regs) { spin_lock(&lock); iic_pending = 1; spin_unlock(&lock); wake_up_interruptible(&iic_wait); return IRQ_HANDLED; } /* Lock the region of memory where I/O registers exist. Request our * interrupt line and register its associated handler. */ static int iic_hw_resrc_init(void) { if (!request_region(gpi.iic_base, ITE_IIC_IO_SIZE, "i2c")) return -ENODEV; if (gpi.iic_irq <= 0) return 0; if (request_irq(gpi.iic_irq, iic_ite_handler, 0, "ITE IIC", 0) < 0) gpi.iic_irq = 0; else enable_irq(gpi.iic_irq); return 0; } static void iic_ite_release(void) { if (gpi.iic_irq > 0) { disable_irq(gpi.iic_irq); free_irq(gpi.iic_irq, 0); } release_region(gpi.iic_base , 2); } /* ------------------------------------------------------------------------ * Encapsulate the above functions in the correct operations structure. * This is only done when more than one hardware adapter is supported. */ static struct i2c_algo_iic_data iic_ite_data = { NULL, iic_ite_setiic, iic_ite_getiic, iic_ite_getown, iic_ite_getclock, iic_ite_waitforpin, 80, 80, 100, /* waits, timeout */ }; static struct i2c_adapter iic_ite_ops = { .owner = THIS_MODULE, .id = I2C_HW_I_IIC, .algo_data = &iic_ite_data, .name = "ITE IIC adapter", }; /* Called when the module is loaded. This function starts the * cascade of calls up through the hierarchy of i2c modules (i.e. up to the * algorithm layer and into to the core layer) */ static int __init iic_ite_init(void) { struct iic_ite *piic = &gpi; printk(KERN_INFO "Initialize ITE IIC adapter module\n"); if (base == 0) piic->iic_base = DEFAULT_BASE; else piic->iic_base = base; if (irq == 0) piic->iic_irq = DEFAULT_IRQ; else piic->iic_irq = irq; if (clock == 0) piic->iic_clock = DEFAULT_CLOCK; else piic->iic_clock = clock; if (own == 0) piic->iic_own = DEFAULT_OWN; else piic->iic_own = own; iic_ite_data.data = (void *)piic; init_waitqueue_head(&iic_wait); spin_lock_init(&lock); if (iic_hw_resrc_init() == 0) { if (i2c_iic_add_bus(&iic_ite_ops) < 0) return -ENODEV; } else { return -ENODEV; } printk(KERN_INFO " found device at %#x irq %d.\n", piic->iic_base, piic->iic_irq); return 0; } static void iic_ite_exit(void) { i2c_iic_del_bus(&iic_ite_ops); iic_ite_release(); } /* If modules is NOT defined when this file is compiled, then the MODULE_* * macros will resolve to nothing */ MODULE_AUTHOR("MontaVista Software "); MODULE_DESCRIPTION("I2C-Bus adapter routines for ITE IIC bus adapter"); MODULE_LICENSE("GPL"); module_param(base, int, 0); module_param(irq, int, 0); module_param(clock, int, 0); module_param(own, int, 0); /* Called when module is loaded or when kernel is initialized. * If MODULES is defined when this file is compiled, then this function will * resolve to init_module (the function called when insmod is invoked for a * module). Otherwise, this function is called early in the boot, when the * kernel is intialized. Check out /include/init.h to see how this works. */ module_init(iic_ite_init); /* Resolves to module_cleanup when MODULES is defined. */ module_exit(iic_ite_exit);