i2c-ibm_iic.c

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		add_wait_queue(&dev->wq, &wait);
		set_current_state(TASK_INTERRUPTIBLE);
		if (in_8(&iic->sts) & STS_PT)
			schedule_timeout(dev->adap.timeout * HZ);
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&dev->wq, &wait);
		
		if (unlikely(signal_pending(current))){
			DBG("%d: wait interrupted\n", dev->idx);
			ret = -ERESTARTSYS;
		} else if (unlikely(in_8(&iic->sts) & STS_PT)){
			DBG("%d: wait timeout\n", dev->idx);
			ret = -ETIMEDOUT;
		}
	}
	else {
		/* Polling mode */
		unsigned long x = jiffies + dev->adap.timeout * HZ;
		
		while (in_8(&iic->sts) & STS_PT){
			if (unlikely(time_after(jiffies, x))){
				DBG("%d: poll timeout\n", dev->idx);
				ret = -ETIMEDOUT;
				break;
			}
		
			if (unlikely(signal_pending(current))){
				DBG("%d: poll interrupted\n", dev->idx);
				ret = -ERESTARTSYS;
				break;
			}
			schedule();
		}	
	}
	
	if (unlikely(ret < 0))
		iic_abort_xfer(dev);
	else
		ret = iic_xfer_result(dev);
	
	DBG2("%d: iic_wait_for_tc -> %d\n", dev->idx, ret);
	
	return ret;
}

/*
 * Low level master transfer routine
 */
static int iic_xfer_bytes(struct ibm_iic_private* dev, struct i2c_msg* pm, 
			  int combined_xfer)
{
	volatile struct iic_regs *iic = dev->vaddr;
	char* buf = pm->buf;
	int i, j, loops, ret = 0;
	int len = pm->len;

	u8 cntl = (in_8(&iic->cntl) & CNTL_AMD) | CNTL_PT;
	if (pm->flags & I2C_M_RD)
		cntl |= CNTL_RW;
	
	loops = (len + 3) / 4;
	for (i = 0; i < loops; ++i, len -= 4){
		int count = len > 4 ? 4 : len;
		u8 cmd = cntl | ((count - 1) << CNTL_TCT_SHIFT);
		
		if (!(cntl & CNTL_RW))
			for (j = 0; j < count; ++j)
				out_8((volatile u8*)&iic->mdbuf, *buf++);
		
		if (i < loops - 1)
			cmd |= CNTL_CHT;
		else if (combined_xfer)
			cmd |= CNTL_RPST;
		
		DBG2("%d: xfer_bytes, %d, CNTL = 0x%02x\n", dev->idx, count, cmd);
		
		/* Start transfer */
		out_8(&iic->cntl, cmd);
		
		/* Wait for completion */
		ret = iic_wait_for_tc(dev);

		if (unlikely(ret < 0))
			break;
		else if (unlikely(ret != count)){
			DBG("%d: xfer_bytes, requested %d, transfered %d\n", 
				dev->idx, count, ret);
			
			/* If it's not a last part of xfer, abort it */
			if (combined_xfer || (i < loops - 1))
    				iic_abort_xfer(dev);
				
			ret = -EREMOTEIO;
			break;				
		}
		
		if (cntl & CNTL_RW)
			for (j = 0; j < count; ++j)
				*buf++ = in_8((volatile u8*)&iic->mdbuf);
	}
	
	return ret > 0 ? 0 : ret;
}

/*
 * Set target slave address for master transfer
 */
static inline void iic_address(struct ibm_iic_private* dev, struct i2c_msg* msg)
{
	volatile struct iic_regs *iic = dev->vaddr;
	u16 addr = msg->addr;
	
	DBG2("%d: iic_address, 0x%03x (%d-bit)\n", dev->idx, 
		addr, msg->flags & I2C_M_TEN ? 10 : 7);
	
	if (msg->flags & I2C_M_TEN){
	    out_8(&iic->cntl, CNTL_AMD);
	    out_8(&iic->lmadr, addr);
	    out_8(&iic->hmadr, 0xf0 | ((addr >> 7) & 0x06));
	}
	else {
	    out_8(&iic->cntl, 0);
	    out_8(&iic->lmadr, addr << 1);
	}
}

static inline int iic_invalid_address(const struct i2c_msg* p)
{
	return (p->addr > 0x3ff) || (!(p->flags & I2C_M_TEN) && (p->addr > 0x7f));
}

static inline int iic_address_neq(const struct i2c_msg* p1, 
				  const struct i2c_msg* p2)
{
	return (p1->addr != p2->addr) 
		|| ((p1->flags & I2C_M_TEN) != (p2->flags & I2C_M_TEN));
} 

/*
 * Generic master transfer entrypoint. 
 * Returns the number of processed messages or error (<0)
 */
static int iic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
    	struct ibm_iic_private* dev = (struct ibm_iic_private*)(i2c_get_adapdata(adap));
	volatile struct iic_regs *iic = dev->vaddr;
	int i, ret = 0;
	
	DBG2("%d: iic_xfer, %d msg(s)\n", dev->idx, num);
	
	if (!num)
		return 0;
	
	/* Check the sanity of the passed messages.
	 * Uhh, generic i2c layer is more suitable place for such code...
	 */
	if (unlikely(iic_invalid_address(&msgs[0]))){
		DBG("%d: invalid address 0x%03x (%d-bit)\n", dev->idx, 
			msgs[0].addr, msgs[0].flags & I2C_M_TEN ? 10 : 7);
		return -EINVAL;
	}		
	for (i = 0; i < num; ++i){
		if (unlikely(msgs[i].len <= 0)){
			if (num == 1 && !msgs[0].len){
				/* Special case for I2C_SMBUS_QUICK emulation.
				 * IBM IIC doesn't support 0-length transactions
				 * so we have to emulate them using bit-banging.
				 */
				return iic_smbus_quick(dev, &msgs[0]);
			}
			DBG("%d: invalid len %d in msg[%d]\n", dev->idx, 
				msgs[i].len, i);
			return -EINVAL;
		}
		if (unlikely(iic_address_neq(&msgs[0], &msgs[i]))){
			DBG("%d: invalid addr in msg[%d]\n", dev->idx, i);
			return -EINVAL;
		}
	}
	
	/* Check bus state */
	if (unlikely((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE)){
		DBG("%d: iic_xfer, bus is not free\n", dev->idx);
		
		/* Usually it means something serious has happend.
		 * We *cannot* have unfinished previous transfer
		 * so it doesn't make any sense to try to stop it.
		 * Probably we were not able to recover from the 
		 * previous error.
		 * The only *reasonable* thing I can think of here
		 * is soft reset.  --ebs
		 */
		iic_dev_reset(dev);
		
		if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
			DBG("%d: iic_xfer, bus is still not free\n", dev->idx);
			return -EREMOTEIO;
		}
	} 
	else {
		/* Flush master data buffer (just in case) */
		out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
	}
	
	/* Load slave address */
	iic_address(dev, &msgs[0]);
	
	/* Do real transfer */
    	for (i = 0; i < num && !ret; ++i)
		ret = iic_xfer_bytes(dev, &msgs[i], i < num - 1);

	return ret < 0 ? ret : num;
}

static u32 iic_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
}

static struct i2c_algorithm iic_algo = {
	.name 		= "IBM IIC algorithm",
	.id   		= I2C_ALGO_OCP,
	.master_xfer 	= iic_xfer,
	.smbus_xfer	= NULL,
	.slave_send	= NULL,
	.slave_recv	= NULL,
	.algo_control	= NULL,
	.functionality	= iic_func
};

/*
 * Calculates IICx_CLCKDIV value for a specific OPB clock frequency
 */
static inline u8 iic_clckdiv(unsigned int opb)
{
	/* Compatibility kludge, should go away after all cards
	 * are fixed to fill correct value for opbfreq.
	 * Previous driver version used hardcoded divider value 4,
	 * it corresponds to OPB frequency from the range (40, 50] MHz
	 */
	if (!opb){
		printk(KERN_WARNING "ibm-iic: using compatibility value for OPB freq,"
			" fix your board specific setup\n");
		opb = 50000000;
	}

	/* Convert to MHz */
	opb /= 1000000;
	
	if (opb < 20 || opb > 150){
		printk(KERN_CRIT "ibm-iic: invalid OPB clock frequency %u MHz\n",
			opb);
		opb = opb < 20 ? 20 : 150;
	}
	return (u8)((opb + 9) / 10 - 1);
}

/*
 * Register single IIC interface
 */
static int __devinit iic_probe(struct ocp_device *ocp){

	struct ibm_iic_private* dev;
	struct i2c_adapter* adap;
	struct ocp_func_iic_data* iic_data = ocp->def->additions;
	int ret;
	
	if (!iic_data)
		printk(KERN_WARNING"ibm-iic%d: missing additional data!\n",
			ocp->def->index);

	if (!(dev = kmalloc(sizeof(*dev), GFP_KERNEL))){
		printk(KERN_CRIT "ibm-iic%d: failed to allocate device data\n",
			ocp->def->index);
		return -ENOMEM;
	}

	memset(dev, 0, sizeof(*dev));
	dev->idx = ocp->def->index;
	ocp_set_drvdata(ocp, dev);
	
	if (!(dev->vaddr = ioremap(ocp->def->paddr, sizeof(struct iic_regs)))){
		printk(KERN_CRIT "ibm-iic%d: failed to ioremap device registers\n",
			dev->idx);
		ret = -ENXIO;
		goto fail2;
	}
	
	init_waitqueue_head(&dev->wq);

	dev->irq = iic_force_poll ? -1 : ocp->def->irq;
	if (dev->irq >= 0){
		/* Disable interrupts until we finish intialization,
		   assumes level-sensitive IRQ setup...
		 */
		iic_interrupt_mode(dev, 0);
		if (request_irq(dev->irq, iic_handler, 0, "IBM IIC", dev)){
			printk(KERN_ERR "ibm-iic%d: request_irq %d failed\n", 
				dev->idx, dev->irq);
			/* Fallback to the polling mode */	
			dev->irq = -1;
		}
	}
	
	if (dev->irq < 0)
		printk(KERN_WARNING "ibm-iic%d: using polling mode\n", 
			dev->idx);
		
	/* Board specific settings */
	dev->fast_mode = iic_force_fast ? 1 : (iic_data ? iic_data->fast_mode : 0);
	
	/* clckdiv is the same for *all* IIC interfaces, 
	 * but I'd rather make a copy than introduce another global. --ebs
	 */
	dev->clckdiv = iic_clckdiv(ocp_sys_info.opb_bus_freq);
	DBG("%d: clckdiv = %d\n", dev->idx, dev->clckdiv);
	
	/* Initialize IIC interface */
	iic_dev_init(dev);
	
	/* Register it with i2c layer */
	adap = &dev->adap;
	strcpy(adap->name, "IBM IIC");
	i2c_set_adapdata(adap, dev);
	adap->id = I2C_HW_OCP | iic_algo.id;
	adap->algo = &iic_algo;
	adap->client_register = NULL;
	adap->client_unregister = NULL;
	adap->timeout = 1;
	adap->retries = 1;

	if ((ret = i2c_add_adapter(adap)) != 0){
		printk(KERN_CRIT "ibm-iic%d: failed to register i2c adapter\n",
			dev->idx);
		goto fail;
	}
	
	printk(KERN_INFO "ibm-iic%d: using %s mode\n", dev->idx,
		dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");

	return 0;

fail:	
	if (dev->irq >= 0){
		iic_interrupt_mode(dev, 0);
		free_irq(dev->irq, dev);
	}	

	iounmap((void*)dev->vaddr);
fail2:	
	ocp_set_drvdata(ocp, 0);
	kfree(dev);	
	return ret;
}

/*
 * Cleanup initialized IIC interface
 */
static void __devexit iic_remove(struct ocp_device *ocp)
{
	struct ibm_iic_private* dev = (struct ibm_iic_private*)ocp_get_drvdata(ocp);
	BUG_ON(dev == NULL);
	if (i2c_del_adapter(&dev->adap)){
		printk(KERN_CRIT "ibm-iic%d: failed to delete i2c adapter :(\n",
			dev->idx);
		/* That's *very* bad, just shutdown IRQ ... */
		if (dev->irq >= 0){
		    iic_interrupt_mode(dev, 0);	
		    free_irq(dev->irq, dev);
		    dev->irq = -1;
		}
	} else {
		if (dev->irq >= 0){
		    iic_interrupt_mode(dev, 0);	
		    free_irq(dev->irq, dev);
		}
		iounmap((void*)dev->vaddr);
		kfree(dev);
	}
}

static struct ocp_device_id ibm_iic_ids[] __devinitdata = 
{
	{ .vendor = OCP_VENDOR_IBM, .function = OCP_FUNC_IIC },
	{ .vendor = OCP_VENDOR_INVALID }
};

MODULE_DEVICE_TABLE(ocp, ibm_iic_ids);

static struct ocp_driver ibm_iic_driver =
{
	.name 		= "iic",
	.id_table	= ibm_iic_ids,
	.probe		= iic_probe,
	.remove		= __devexit_p(iic_remove),
#if defined(CONFIG_PM)
	.suspend	= NULL,
	.resume		= NULL,
#endif
};

static int __init iic_init(void)
{
	printk(KERN_INFO "IBM IIC driver v" DRIVER_VERSION "\n");
	return ocp_register_driver(&ibm_iic_driver);
}

static void __exit iic_exit(void)
{
	ocp_unregister_driver(&ibm_iic_driver);
}

module_init(iic_init);
module_exit(iic_exit);