/*
   * Copyright (C) 2006, 2007 Eugene Konev <ejka@openwrt.org>
   *
   * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * Parts of the VLYNQ specification can be found here:
   * http://www.ti.com/litv/pdf/sprue36a
   */
  
  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/string.h>
  #include <linux/device.h>
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <linux/platform_device.h>
  #include <linux/interrupt.h>
  #include <linux/delay.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  #include <linux/irq.h>
  
  #include <linux/vlynq.h>
  
  #define VLYNQ_CTRL_PM_ENABLE		0x80000000
  #define VLYNQ_CTRL_CLOCK_INT		0x00008000
  #define VLYNQ_CTRL_CLOCK_DIV(x)		(((x) & 7) << 16)
  #define VLYNQ_CTRL_INT_LOCAL		0x00004000
  #define VLYNQ_CTRL_INT_ENABLE		0x00002000
  #define VLYNQ_CTRL_INT_VECTOR(x)	(((x) & 0x1f) << 8)
  #define VLYNQ_CTRL_INT2CFG		0x00000080
  #define VLYNQ_CTRL_RESET		0x00000001
  
  #define VLYNQ_CTRL_CLOCK_MASK          (0x7 << 16)
  
  #define VLYNQ_INT_OFFSET		0x00000014
  #define VLYNQ_REMOTE_OFFSET		0x00000080
  
  #define VLYNQ_STATUS_LINK		0x00000001
  #define VLYNQ_STATUS_LERROR		0x00000080
  #define VLYNQ_STATUS_RERROR		0x00000100
  
  #define VINT_ENABLE			0x00000100
  #define VINT_TYPE_EDGE			0x00000080
  #define VINT_LEVEL_LOW			0x00000040
  #define VINT_VECTOR(x)			((x) & 0x1f)
  #define VINT_OFFSET(irq)		(8 * ((irq) % 4))
  
  #define VLYNQ_AUTONEGO_V2		0x00010000
  
  struct vlynq_regs {
  	u32 revision;
  	u32 control;
  	u32 status;
  	u32 int_prio;
  	u32 int_status;
  	u32 int_pending;
  	u32 int_ptr;
  	u32 tx_offset;
  	struct vlynq_mapping rx_mapping[4];
  	u32 chip;
  	u32 autonego;
  	u32 unused[6];
  	u32 int_device[8];
  };
  
  #ifdef CONFIG_VLYNQ_DEBUG
  static void vlynq_dump_regs(struct vlynq_device *dev)
  {
  	int i;
  
  	printk(KERN_DEBUG "VLYNQ local=%p remote=%p
  ",
  			dev->local, dev->remote);
  	for (i = 0; i < 32; i++) {
  		printk(KERN_DEBUG "VLYNQ: local %d: %08x
  ",
  			i + 1, ((u32 *)dev->local)[i]);
  		printk(KERN_DEBUG "VLYNQ: remote %d: %08x
  ",
  			i + 1, ((u32 *)dev->remote)[i]);
  	}
  }
  
  static void vlynq_dump_mem(u32 *base, int count)
  {
  	int i;
  
  	for (i = 0; i < (count + 3) / 4; i++) {
  		if (i % 4 == 0)
  			printk(KERN_DEBUG "
  MEM[0x%04x]:", i * 4);
  		printk(KERN_DEBUG " 0x%08x", *(base + i));
  	}
  	printk(KERN_DEBUG "
  ");
  }
  #endif
  
  /* Check the VLYNQ link status with a given device */
  static int vlynq_linked(struct vlynq_device *dev)
  {
  	int i;
  
  	for (i = 0; i < 100; i++)
  		if (readl(&dev->local->status) & VLYNQ_STATUS_LINK)
  			return 1;
  		else
  			cpu_relax();
  
  	return 0;
  }
  
  static void vlynq_reset(struct vlynq_device *dev)
  {
  	writel(readl(&dev->local->control) | VLYNQ_CTRL_RESET,
  			&dev->local->control);
  
  	/* Wait for the devices to finish resetting */
  	msleep(5);
  
  	/* Remove reset bit */
  	writel(readl(&dev->local->control) & ~VLYNQ_CTRL_RESET,
  			&dev->local->control);
  
  	/* Give some time for the devices to settle */
  	msleep(5);
  }
  
  static void vlynq_irq_unmask(struct irq_data *d)
  {
  	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
  	int virq;
  	u32 val;
  
  	BUG_ON(!dev);
  	virq = d->irq - dev->irq_start;
  	val = readl(&dev->remote->int_device[virq >> 2]);
  	val |= (VINT_ENABLE | virq) << VINT_OFFSET(virq);
  	writel(val, &dev->remote->int_device[virq >> 2]);
  }
  
  static void vlynq_irq_mask(struct irq_data *d)
  {
  	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
  	int virq;
  	u32 val;
  
  	BUG_ON(!dev);
  	virq = d->irq - dev->irq_start;
  	val = readl(&dev->remote->int_device[virq >> 2]);
  	val &= ~(VINT_ENABLE << VINT_OFFSET(virq));
  	writel(val, &dev->remote->int_device[virq >> 2]);
  }
  
  static int vlynq_irq_type(struct irq_data *d, unsigned int flow_type)
  {
  	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
  	int virq;
  	u32 val;
  
  	BUG_ON(!dev);
  	virq = d->irq - dev->irq_start;
  	val = readl(&dev->remote->int_device[virq >> 2]);
  	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
  	case IRQ_TYPE_EDGE_RISING:
  	case IRQ_TYPE_EDGE_FALLING:
  	case IRQ_TYPE_EDGE_BOTH:
  		val |= VINT_TYPE_EDGE << VINT_OFFSET(virq);
  		val &= ~(VINT_LEVEL_LOW << VINT_OFFSET(virq));
  		break;
  	case IRQ_TYPE_LEVEL_HIGH:
  		val &= ~(VINT_TYPE_EDGE << VINT_OFFSET(virq));
  		val &= ~(VINT_LEVEL_LOW << VINT_OFFSET(virq));
  		break;
  	case IRQ_TYPE_LEVEL_LOW:
  		val &= ~(VINT_TYPE_EDGE << VINT_OFFSET(virq));
  		val |= VINT_LEVEL_LOW << VINT_OFFSET(virq);
  		break;
  	default:
  		return -EINVAL;
  	}
  	writel(val, &dev->remote->int_device[virq >> 2]);
  	return 0;
  }
  
  static void vlynq_local_ack(struct irq_data *d)
  {
  	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
  	u32 status = readl(&dev->local->status);
  
  	pr_debug("%s: local status: 0x%08x
  ",
  		       dev_name(&dev->dev), status);
  	writel(status, &dev->local->status);
  }
  
  static void vlynq_remote_ack(struct irq_data *d)
  {
  	struct vlynq_device *dev = irq_data_get_irq_chip_data(d);
  	u32 status = readl(&dev->remote->status);
  
  	pr_debug("%s: remote status: 0x%08x
  ",
  		       dev_name(&dev->dev), status);
  	writel(status, &dev->remote->status);
  }
  
  static irqreturn_t vlynq_irq(int irq, void *dev_id)
  {
  	struct vlynq_device *dev = dev_id;
  	u32 status;
  	int virq = 0;
  
  	status = readl(&dev->local->int_status);
  	writel(status, &dev->local->int_status);
  
  	if (unlikely(!status))
  		spurious_interrupt();
  
  	while (status) {
  		if (status & 1)
  			do_IRQ(dev->irq_start + virq);
  		status >>= 1;
  		virq++;
  	}
  
  	return IRQ_HANDLED;
  }
  
  static struct irq_chip vlynq_irq_chip = {
  	.name = "vlynq",
  	.irq_unmask = vlynq_irq_unmask,
  	.irq_mask = vlynq_irq_mask,
  	.irq_set_type = vlynq_irq_type,
  };
  
  static struct irq_chip vlynq_local_chip = {
  	.name = "vlynq local error",
  	.irq_unmask = vlynq_irq_unmask,
  	.irq_mask = vlynq_irq_mask,
  	.irq_ack = vlynq_local_ack,
  };
  
  static struct irq_chip vlynq_remote_chip = {
  	.name = "vlynq local error",
  	.irq_unmask = vlynq_irq_unmask,
  	.irq_mask = vlynq_irq_mask,
  	.irq_ack = vlynq_remote_ack,
  };
  
  static int vlynq_setup_irq(struct vlynq_device *dev)
  {
  	u32 val;
  	int i, virq;
  
  	if (dev->local_irq == dev->remote_irq) {
  		printk(KERN_ERR
  		       "%s: local vlynq irq should be different from remote
  ",
  		       dev_name(&dev->dev));
  		return -EINVAL;
  	}
  
  	/* Clear local and remote error bits */
  	writel(readl(&dev->local->status), &dev->local->status);
  	writel(readl(&dev->remote->status), &dev->remote->status);
  
  	/* Now setup interrupts */
  	val = VLYNQ_CTRL_INT_VECTOR(dev->local_irq);
  	val |= VLYNQ_CTRL_INT_ENABLE | VLYNQ_CTRL_INT_LOCAL |
  		VLYNQ_CTRL_INT2CFG;
  	val |= readl(&dev->local->control);
  	writel(VLYNQ_INT_OFFSET, &dev->local->int_ptr);
  	writel(val, &dev->local->control);
  
  	val = VLYNQ_CTRL_INT_VECTOR(dev->remote_irq);
  	val |= VLYNQ_CTRL_INT_ENABLE;
  	val |= readl(&dev->remote->control);
  	writel(VLYNQ_INT_OFFSET, &dev->remote->int_ptr);
  	writel(val, &dev->remote->int_ptr);
  	writel(val, &dev->remote->control);
  
  	for (i = dev->irq_start; i <= dev->irq_end; i++) {
  		virq = i - dev->irq_start;
  		if (virq == dev->local_irq) {
  			irq_set_chip_and_handler(i, &vlynq_local_chip,
  						 handle_level_irq);
  			irq_set_chip_data(i, dev);
  		} else if (virq == dev->remote_irq) {
  			irq_set_chip_and_handler(i, &vlynq_remote_chip,
  						 handle_level_irq);
  			irq_set_chip_data(i, dev);
  		} else {
  			irq_set_chip_and_handler(i, &vlynq_irq_chip,
  						 handle_simple_irq);
  			irq_set_chip_data(i, dev);
  			writel(0, &dev->remote->int_device[virq >> 2]);
  		}
  	}
  
  	if (request_irq(dev->irq, vlynq_irq, IRQF_SHARED, "vlynq", dev)) {
  		printk(KERN_ERR "%s: request_irq failed
  ",
  					dev_name(&dev->dev));
  		return -EAGAIN;
  	}
  
  	return 0;
  }
  
  static void vlynq_device_release(struct device *dev)
  {
  	struct vlynq_device *vdev = to_vlynq_device(dev);
  	kfree(vdev);
  }
  
  static int vlynq_device_match(struct device *dev,
  			      struct device_driver *drv)
  {
  	struct vlynq_device *vdev = to_vlynq_device(dev);
  	struct vlynq_driver *vdrv = to_vlynq_driver(drv);
  	struct vlynq_device_id *ids = vdrv->id_table;
  
  	while (ids->id) {
  		if (ids->id == vdev->dev_id) {
  			vdev->divisor = ids->divisor;
  			vlynq_set_drvdata(vdev, ids);
  			printk(KERN_INFO "Driver found for VLYNQ "
  				"device: %08x
  ", vdev->dev_id);
  			return 1;
  		}
  		printk(KERN_DEBUG "Not using the %08x VLYNQ device's driver"
  			" for VLYNQ device: %08x
  ", ids->id, vdev->dev_id);
  		ids++;
  	}
  	return 0;
  }
  
  static int vlynq_device_probe(struct device *dev)
  {
  	struct vlynq_device *vdev = to_vlynq_device(dev);
  	struct vlynq_driver *drv = to_vlynq_driver(dev->driver);
  	struct vlynq_device_id *id = vlynq_get_drvdata(vdev);
  	int result = -ENODEV;
  
  	if (drv->probe)
  		result = drv->probe(vdev, id);
  	if (result)
  		put_device(dev);
  	return result;
  }
  
  static int vlynq_device_remove(struct device *dev)
  {
  	struct vlynq_driver *drv = to_vlynq_driver(dev->driver);
  
  	if (drv->remove)
  		drv->remove(to_vlynq_device(dev));
  
  	return 0;
  }
  
  int __vlynq_register_driver(struct vlynq_driver *driver, struct module *owner)
  {
  	driver->driver.name = driver->name;
  	driver->driver.bus = &vlynq_bus_type;
  	return driver_register(&driver->driver);
  }
  EXPORT_SYMBOL(__vlynq_register_driver);
  
  void vlynq_unregister_driver(struct vlynq_driver *driver)
  {
  	driver_unregister(&driver->driver);
  }
  EXPORT_SYMBOL(vlynq_unregister_driver);
  
  /*
   * A VLYNQ remote device can clock the VLYNQ bus master
   * using a dedicated clock line. In that case, both the
   * remove device and the bus master should have the same
   * serial clock dividers configured. Iterate through the
   * 8 possible dividers until we actually link with the
   * device.
   */
  static int __vlynq_try_remote(struct vlynq_device *dev)
  {
  	int i;
  
  	vlynq_reset(dev);
  	for (i = dev->dev_id ? vlynq_rdiv2 : vlynq_rdiv8; dev->dev_id ?
  			i <= vlynq_rdiv8 : i >= vlynq_rdiv2;
  		dev->dev_id ? i++ : i--) {
  
  		if (!vlynq_linked(dev))
  			break;
  
  		writel((readl(&dev->remote->control) &
  				~VLYNQ_CTRL_CLOCK_MASK) |
  				VLYNQ_CTRL_CLOCK_INT |
  				VLYNQ_CTRL_CLOCK_DIV(i - vlynq_rdiv1),
  				&dev->remote->control);
  		writel((readl(&dev->local->control)
  				& ~(VLYNQ_CTRL_CLOCK_INT |
  				VLYNQ_CTRL_CLOCK_MASK)) |
  				VLYNQ_CTRL_CLOCK_DIV(i - vlynq_rdiv1),
  				&dev->local->control);
  
  		if (vlynq_linked(dev)) {
  			printk(KERN_DEBUG
  				"%s: using remote clock divisor %d
  ",
  				dev_name(&dev->dev), i - vlynq_rdiv1 + 1);
  			dev->divisor = i;
  			return 0;
  		} else {
  			vlynq_reset(dev);
  		}
  	}
  
  	return -ENODEV;
  }
  
  /*
   * A VLYNQ remote device can be clocked by the VLYNQ bus
   * master using a dedicated clock line. In that case, only
   * the bus master configures the serial clock divider.
   * Iterate through the 8 possible dividers until we
   * actually get a link with the device.
   */
  static int __vlynq_try_local(struct vlynq_device *dev)
  {
  	int i;
  
  	vlynq_reset(dev);
  
  	for (i = dev->dev_id ? vlynq_ldiv2 : vlynq_ldiv8; dev->dev_id ?
  			i <= vlynq_ldiv8 : i >= vlynq_ldiv2;
  		dev->dev_id ? i++ : i--) {
  
  		writel((readl(&dev->local->control) &
  				~VLYNQ_CTRL_CLOCK_MASK) |
  				VLYNQ_CTRL_CLOCK_INT |
  				VLYNQ_CTRL_CLOCK_DIV(i - vlynq_ldiv1),
  				&dev->local->control);
  
  		if (vlynq_linked(dev)) {
  			printk(KERN_DEBUG
  				"%s: using local clock divisor %d
  ",
  				dev_name(&dev->dev), i - vlynq_ldiv1 + 1);
  			dev->divisor = i;
  			return 0;
  		} else {
  			vlynq_reset(dev);
  		}
  	}
  
  	return -ENODEV;
  }
  
  /*
   * When using external clocking method, serial clock
   * is supplied by an external oscillator, therefore we
   * should mask the local clock bit in the clock control
   * register for both the bus master and the remote device.
   */
  static int __vlynq_try_external(struct vlynq_device *dev)
  {
  	vlynq_reset(dev);
  	if (!vlynq_linked(dev))
  		return -ENODEV;
  
  	writel((readl(&dev->remote->control) &
  			~VLYNQ_CTRL_CLOCK_INT),
  			&dev->remote->control);
  
  	writel((readl(&dev->local->control) &
  			~VLYNQ_CTRL_CLOCK_INT),
  			&dev->local->control);
  
  	if (vlynq_linked(dev)) {
  		printk(KERN_DEBUG "%s: using external clock
  ",
  			dev_name(&dev->dev));
  			dev->divisor = vlynq_div_external;
  		return 0;
  	}
  
  	return -ENODEV;
  }
  
  static int __vlynq_enable_device(struct vlynq_device *dev)
  {
  	int result;
  	struct plat_vlynq_ops *ops = dev->dev.platform_data;
  
  	result = ops->on(dev);
  	if (result)
  		return result;
  
  	switch (dev->divisor) {
  	case vlynq_div_external:
  	case vlynq_div_auto:
  		/* When the device is brought from reset it should have clock
  		 * generation negotiated by hardware.
  		 * Check which device is generating clocks and perform setup
  		 * accordingly */
  		if (vlynq_linked(dev) && readl(&dev->remote->control) &
  		   VLYNQ_CTRL_CLOCK_INT) {
  			if (!__vlynq_try_remote(dev) ||
  				!__vlynq_try_local(dev)  ||
  				!__vlynq_try_external(dev))
  				return 0;
  		} else {
  			if (!__vlynq_try_external(dev) ||
  				!__vlynq_try_local(dev)    ||
  				!__vlynq_try_remote(dev))
  				return 0;
  		}
  		break;
  	case vlynq_ldiv1:
  	case vlynq_ldiv2:
  	case vlynq_ldiv3:
  	case vlynq_ldiv4:
  	case vlynq_ldiv5:
  	case vlynq_ldiv6:
  	case vlynq_ldiv7:
  	case vlynq_ldiv8:
  		writel(VLYNQ_CTRL_CLOCK_INT |
  			VLYNQ_CTRL_CLOCK_DIV(dev->divisor -
  			vlynq_ldiv1), &dev->local->control);
  		writel(0, &dev->remote->control);
  		if (vlynq_linked(dev)) {
  			printk(KERN_DEBUG
  				"%s: using local clock divisor %d
  ",
  				dev_name(&dev->dev),
  				dev->divisor - vlynq_ldiv1 + 1);
  			return 0;
  		}
  		break;
  	case vlynq_rdiv1:
  	case vlynq_rdiv2:
  	case vlynq_rdiv3:
  	case vlynq_rdiv4:
  	case vlynq_rdiv5:
  	case vlynq_rdiv6:
  	case vlynq_rdiv7:
  	case vlynq_rdiv8:
  		writel(0, &dev->local->control);
  		writel(VLYNQ_CTRL_CLOCK_INT |
  			VLYNQ_CTRL_CLOCK_DIV(dev->divisor -
  			vlynq_rdiv1), &dev->remote->control);
  		if (vlynq_linked(dev)) {
  			printk(KERN_DEBUG
  				"%s: using remote clock divisor %d
  ",
  				dev_name(&dev->dev),
  				dev->divisor - vlynq_rdiv1 + 1);
  			return 0;
  		}
  		break;
  	}
  
  	ops->off(dev);
  	return -ENODEV;
  }
  
  int vlynq_enable_device(struct vlynq_device *dev)
  {
  	struct plat_vlynq_ops *ops = dev->dev.platform_data;
  	int result = -ENODEV;
  
  	result = __vlynq_enable_device(dev);
  	if (result)
  		return result;
  
  	result = vlynq_setup_irq(dev);
  	if (result)
  		ops->off(dev);
  
  	dev->enabled = !result;
  	return result;
  }
  EXPORT_SYMBOL(vlynq_enable_device);
  
  
  void vlynq_disable_device(struct vlynq_device *dev)
  {
  	struct plat_vlynq_ops *ops = dev->dev.platform_data;
  
  	dev->enabled = 0;
  	free_irq(dev->irq, dev);
  	ops->off(dev);
  }
  EXPORT_SYMBOL(vlynq_disable_device);
  
  int vlynq_set_local_mapping(struct vlynq_device *dev, u32 tx_offset,
  			    struct vlynq_mapping *mapping)
  {
  	int i;
  
  	if (!dev->enabled)
  		return -ENXIO;
  
  	writel(tx_offset, &dev->local->tx_offset);
  	for (i = 0; i < 4; i++) {
  		writel(mapping[i].offset, &dev->local->rx_mapping[i].offset);
  		writel(mapping[i].size, &dev->local->rx_mapping[i].size);
  	}
  	return 0;
  }
  EXPORT_SYMBOL(vlynq_set_local_mapping);
  
  int vlynq_set_remote_mapping(struct vlynq_device *dev, u32 tx_offset,
  			     struct vlynq_mapping *mapping)
  {
  	int i;
  
  	if (!dev->enabled)
  		return -ENXIO;
  
  	writel(tx_offset, &dev->remote->tx_offset);
  	for (i = 0; i < 4; i++) {
  		writel(mapping[i].offset, &dev->remote->rx_mapping[i].offset);
  		writel(mapping[i].size, &dev->remote->rx_mapping[i].size);
  	}
  	return 0;
  }
  EXPORT_SYMBOL(vlynq_set_remote_mapping);
  
  int vlynq_set_local_irq(struct vlynq_device *dev, int virq)
  {
  	int irq = dev->irq_start + virq;
  	if (dev->enabled)
  		return -EBUSY;
  
  	if ((irq < dev->irq_start) || (irq > dev->irq_end))
  		return -EINVAL;
  
  	if (virq == dev->remote_irq)
  		return -EINVAL;
  
  	dev->local_irq = virq;
  
  	return 0;
  }
  EXPORT_SYMBOL(vlynq_set_local_irq);
  
  int vlynq_set_remote_irq(struct vlynq_device *dev, int virq)
  {
  	int irq = dev->irq_start + virq;
  	if (dev->enabled)
  		return -EBUSY;
  
  	if ((irq < dev->irq_start) || (irq > dev->irq_end))
  		return -EINVAL;
  
  	if (virq == dev->local_irq)
  		return -EINVAL;
  
  	dev->remote_irq = virq;
  
  	return 0;
  }
  EXPORT_SYMBOL(vlynq_set_remote_irq);
  
  static int vlynq_probe(struct platform_device *pdev)
  {
  	struct vlynq_device *dev;
  	struct resource *regs_res, *mem_res, *irq_res;
  	int len, result;
  
  	regs_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
  	if (!regs_res)
  		return -ENODEV;
  
  	mem_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
  	if (!mem_res)
  		return -ENODEV;
  
  	irq_res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "devirq");
  	if (!irq_res)
  		return -ENODEV;
  
  	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  	if (!dev) {
  		printk(KERN_ERR
  		       "vlynq: failed to allocate device structure
  ");
  		return -ENOMEM;
  	}
  
  	dev->id = pdev->id;
  	dev->dev.bus = &vlynq_bus_type;
  	dev->dev.parent = &pdev->dev;
  	dev_set_name(&dev->dev, "vlynq%d", dev->id);
  	dev->dev.platform_data = pdev->dev.platform_data;
  	dev->dev.release = vlynq_device_release;
  
  	dev->regs_start = regs_res->start;
  	dev->regs_end = regs_res->end;
  	dev->mem_start = mem_res->start;
  	dev->mem_end = mem_res->end;
  
  	len = resource_size(regs_res);
  	if (!request_mem_region(regs_res->start, len, dev_name(&dev->dev))) {
  		printk(KERN_ERR "%s: Can't request vlynq registers
  ",
  		       dev_name(&dev->dev));
  		result = -ENXIO;
  		goto fail_request;
  	}
  
  	dev->local = ioremap(regs_res->start, len);
  	if (!dev->local) {
  		printk(KERN_ERR "%s: Can't remap vlynq registers
  ",
  		       dev_name(&dev->dev));
  		result = -ENXIO;
  		goto fail_remap;
  	}
  
  	dev->remote = (struct vlynq_regs *)((void *)dev->local +
  					    VLYNQ_REMOTE_OFFSET);
  
  	dev->irq = platform_get_irq_byname(pdev, "irq");
  	dev->irq_start = irq_res->start;
  	dev->irq_end = irq_res->end;
  	dev->local_irq = dev->irq_end - dev->irq_start;
  	dev->remote_irq = dev->local_irq - 1;
  
  	if (device_register(&dev->dev))
  		goto fail_register;
  	platform_set_drvdata(pdev, dev);
  
  	printk(KERN_INFO "%s: regs 0x%p, irq %d, mem 0x%p
  ",
  	       dev_name(&dev->dev), (void *)dev->regs_start, dev->irq,
  	       (void *)dev->mem_start);
  
  	dev->dev_id = 0;
  	dev->divisor = vlynq_div_auto;
  	result = __vlynq_enable_device(dev);
  	if (result == 0) {
  		dev->dev_id = readl(&dev->remote->chip);
  		((struct plat_vlynq_ops *)(dev->dev.platform_data))->off(dev);
  	}
  	if (dev->dev_id)
  		printk(KERN_INFO "Found a VLYNQ device: %08x
  ", dev->dev_id);
  
  	return 0;
  
  fail_register:
  	iounmap(dev->local);
  fail_remap:
  fail_request:
  	release_mem_region(regs_res->start, len);
  	kfree(dev);
  	return result;
  }
  
  static int vlynq_remove(struct platform_device *pdev)
  {
  	struct vlynq_device *dev = platform_get_drvdata(pdev);
  
  	device_unregister(&dev->dev);
  	iounmap(dev->local);
  	release_mem_region(dev->regs_start,
  			   dev->regs_end - dev->regs_start + 1);
  
  	kfree(dev);
  
  	return 0;
  }
  
  static struct platform_driver vlynq_platform_driver = {
  	.driver.name = "vlynq",
  	.probe = vlynq_probe,
  	.remove = vlynq_remove,
  };
  
  struct bus_type vlynq_bus_type = {
  	.name = "vlynq",
  	.match = vlynq_device_match,
  	.probe = vlynq_device_probe,
  	.remove = vlynq_device_remove,
  };
  EXPORT_SYMBOL(vlynq_bus_type);
  
  static int vlynq_init(void)
  {
  	int res = 0;
  
  	res = bus_register(&vlynq_bus_type);
  	if (res)
  		goto fail_bus;
  
  	res = platform_driver_register(&vlynq_platform_driver);
  	if (res)
  		goto fail_platform;
  
  	return 0;
  
  fail_platform:
  	bus_unregister(&vlynq_bus_type);
  fail_bus:
  	return res;
  }
  
  static void vlynq_exit(void)
  {
  	platform_driver_unregister(&vlynq_platform_driver);
  	bus_unregister(&vlynq_bus_type);
  }
  
  module_init(vlynq_init);
  module_exit(vlynq_exit);