locomo.c

底层驱动开发

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem)
		return -EINVAL;
	irq = platform_get_irq(pdev, 0);

	return __locomo_probe(dev, mem, irq);
}

static int locomo_remove(struct device *dev)
{
	struct locomo *lchip = dev_get_drvdata(dev);

	if (lchip) {
		__locomo_remove(lchip);
		dev_set_drvdata(dev, NULL);
	}

	return 0;
}

/*
 *	Not sure if this should be on the system bus or not yet.
 *	We really want some way to register a system device at
 *	the per-machine level, and then have this driver pick
 *	up the registered devices.
 */
static struct device_driver locomo_device_driver = {
	.name		= "locomo",
	.bus		= &platform_bus_type,
	.probe		= locomo_probe,
	.remove		= locomo_remove,
#ifdef CONFIG_PM
	.suspend	= locomo_suspend,
	.resume		= locomo_resume,
#endif
};

/*
 *	Get the parent device driver (us) structure
 *	from a child function device
 */
static inline struct locomo *locomo_chip_driver(struct locomo_dev *ldev)
{
	return (struct locomo *)dev_get_drvdata(ldev->dev.parent);
}

void locomo_gpio_set_dir(struct locomo_dev *ldev, unsigned int bits, unsigned int dir)
{
	struct locomo *lchip = locomo_chip_driver(ldev);
	unsigned long flags;
	unsigned int r;

	spin_lock_irqsave(&lchip->lock, flags);

	r = locomo_readl(lchip->base + LOCOMO_GPD);
	r &= ~bits;
	locomo_writel(r, lchip->base + LOCOMO_GPD);

	r = locomo_readl(lchip->base + LOCOMO_GPE);
	if (dir)
		r |= bits;
	else
		r &= ~bits;
	locomo_writel(r, lchip->base + LOCOMO_GPE);

	spin_unlock_irqrestore(&lchip->lock, flags);
}

unsigned int locomo_gpio_read_level(struct locomo_dev *ldev, unsigned int bits)
{
	struct locomo *lchip = locomo_chip_driver(ldev);
	unsigned long flags;
	unsigned int ret;

	spin_lock_irqsave(&lchip->lock, flags);
	ret = locomo_readl(lchip->base + LOCOMO_GPL);
	spin_unlock_irqrestore(&lchip->lock, flags);

	ret &= bits;
	return ret;
}

unsigned int locomo_gpio_read_output(struct locomo_dev *ldev, unsigned int bits)
{
	struct locomo *lchip = locomo_chip_driver(ldev);
	unsigned long flags;
	unsigned int ret;

	spin_lock_irqsave(&lchip->lock, flags);
	ret = locomo_readl(lchip->base + LOCOMO_GPO);
	spin_unlock_irqrestore(&lchip->lock, flags);

	ret &= bits;
	return ret;
}

void locomo_gpio_write(struct locomo_dev *ldev, unsigned int bits, unsigned int set)
{
	struct locomo *lchip = locomo_chip_driver(ldev);
	unsigned long flags;
	unsigned int r;

	spin_lock_irqsave(&lchip->lock, flags);

	r = locomo_readl(lchip->base + LOCOMO_GPO);
	if (set)
		r |= bits;
	else
		r &= ~bits;
	locomo_writel(r, lchip->base + LOCOMO_GPO);

	spin_unlock_irqrestore(&lchip->lock, flags);
}

static void locomo_m62332_sendbit(void *mapbase, int bit)
{
	unsigned int r;

	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SCLOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	udelay(DAC_DATA_HOLD_TIME);	/* 300 nsec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SCLOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	udelay(DAC_SCL_LOW_HOLD_TIME);	/* 4.7 usec */

	if (bit & 1) {
		r = locomo_readl(mapbase + LOCOMO_DAC);
		r |=  LOCOMO_DAC_SDAOEB;
		locomo_writel(r, mapbase + LOCOMO_DAC);
		udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	} else {
		r = locomo_readl(mapbase + LOCOMO_DAC);
		r &=  ~(LOCOMO_DAC_SDAOEB);
		locomo_writel(r, mapbase + LOCOMO_DAC);
		udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	}

	udelay(DAC_DATA_SETUP_TIME);	/* 250 nsec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SCLOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_HIGH_HOLD_TIME);	/*  4.0 usec */
}

void locomo_m62332_senddata(struct locomo_dev *ldev, unsigned int dac_data, int channel)
{
	struct locomo *lchip = locomo_chip_driver(ldev);
	int i;
	unsigned char data;
	unsigned int r;
	void *mapbase = lchip->base;
	unsigned long flags;

	spin_lock_irqsave(&lchip->lock, flags);

	/* Start */
	udelay(DAC_BUS_FREE_TIME);	/* 5.0 usec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SCLOEB | LOCOMO_DAC_SDAOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_HIGH_HOLD_TIME);	/* 4.0 usec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SDAOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_START_HOLD_TIME);	/* 5.0 usec */
	udelay(DAC_DATA_HOLD_TIME);	/* 300 nsec */

	/* Send slave address and W bit (LSB is W bit) */
	data = (M62332_SLAVE_ADDR << 1) | M62332_W_BIT;
	for (i = 1; i <= 8; i++) {
		locomo_m62332_sendbit(mapbase, data >> (8 - i));
	}

	/* Check A bit */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SCLOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	udelay(DAC_SCL_LOW_HOLD_TIME);	/* 4.7 usec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SDAOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SCLOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_HIGH_HOLD_TIME);	/* 4.7 usec */
	if (locomo_readl(mapbase + LOCOMO_DAC) & LOCOMO_DAC_SDAOEB) {	/* High is error */
		printk(KERN_WARNING "locomo: m62332_senddata Error 1\n");
		return;
	}

	/* Send Sub address (LSB is channel select) */
	/*    channel = 0 : ch1 select              */
	/*            = 1 : ch2 select              */
	data = M62332_SUB_ADDR + channel;
	for (i = 1; i <= 8; i++) {
		locomo_m62332_sendbit(mapbase, data >> (8 - i));
	}

	/* Check A bit */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SCLOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	udelay(DAC_SCL_LOW_HOLD_TIME);	/* 4.7 usec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SDAOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SCLOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_HIGH_HOLD_TIME);	/* 4.7 usec */
	if (locomo_readl(mapbase + LOCOMO_DAC) & LOCOMO_DAC_SDAOEB) {	/* High is error */
		printk(KERN_WARNING "locomo: m62332_senddata Error 2\n");
		return;
	}

	/* Send DAC data */
	for (i = 1; i <= 8; i++) {
		locomo_m62332_sendbit(mapbase, dac_data >> (8 - i));
	}

	/* Check A bit */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SCLOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	udelay(DAC_SCL_LOW_HOLD_TIME);	/* 4.7 usec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SDAOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SCLOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_HIGH_HOLD_TIME);	/* 4.7 usec */
	if (locomo_readl(mapbase + LOCOMO_DAC) & LOCOMO_DAC_SDAOEB) {	/* High is error */
		printk(KERN_WARNING "locomo: m62332_senddata Error 3\n");
		return;
	}

	/* stop */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r &=  ~(LOCOMO_DAC_SCLOEB);
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 300 nsec */
	udelay(DAC_SCL_LOW_HOLD_TIME);	/* 4.7 usec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SCLOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_HIGH_HOLD_TIME);	/* 4 usec */
	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SDAOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_HIGH_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_HIGH_HOLD_TIME);	/* 4 usec */

	r = locomo_readl(mapbase + LOCOMO_DAC);
	r |=  LOCOMO_DAC_SCLOEB | LOCOMO_DAC_SDAOEB;
	locomo_writel(r, mapbase + LOCOMO_DAC);
	udelay(DAC_LOW_SETUP_TIME);	/* 1000 nsec */
	udelay(DAC_SCL_LOW_HOLD_TIME);	/* 4.7 usec */

	spin_unlock_irqrestore(&lchip->lock, flags);
}

/*
 *	LoCoMo "Register Access Bus."
 *
 *	We model this as a regular bus type, and hang devices directly
 *	off this.
 */
static int locomo_match(struct device *_dev, struct device_driver *_drv)
{
	struct locomo_dev *dev = LOCOMO_DEV(_dev);
	struct locomo_driver *drv = LOCOMO_DRV(_drv);

	return dev->devid == drv->devid;
}

static int locomo_bus_suspend(struct device *dev, pm_message_t state)
{
	struct locomo_dev *ldev = LOCOMO_DEV(dev);
	struct locomo_driver *drv = LOCOMO_DRV(dev->driver);
	int ret = 0;

	if (drv && drv->suspend)
		ret = drv->suspend(ldev, state);
	return ret;
}

static int locomo_bus_resume(struct device *dev)
{
	struct locomo_dev *ldev = LOCOMO_DEV(dev);
	struct locomo_driver *drv = LOCOMO_DRV(dev->driver);
	int ret = 0;

	if (drv && drv->resume)
		ret = drv->resume(ldev);
	return ret;
}

static int locomo_bus_probe(struct device *dev)
{
	struct locomo_dev *ldev = LOCOMO_DEV(dev);
	struct locomo_driver *drv = LOCOMO_DRV(dev->driver);
	int ret = -ENODEV;

	if (drv->probe)
		ret = drv->probe(ldev);
	return ret;
}

static int locomo_bus_remove(struct device *dev)
{
	struct locomo_dev *ldev = LOCOMO_DEV(dev);
	struct locomo_driver *drv = LOCOMO_DRV(dev->driver);
	int ret = 0;

	if (drv->remove)
		ret = drv->remove(ldev);
	return ret;
}

struct bus_type locomo_bus_type = {
	.name		= "locomo-bus",
	.match		= locomo_match,
	.suspend	= locomo_bus_suspend,
	.resume		= locomo_bus_resume,
};

int locomo_driver_register(struct locomo_driver *driver)
{
	driver->drv.probe = locomo_bus_probe;
	driver->drv.remove = locomo_bus_remove;
	driver->drv.bus = &locomo_bus_type;
	return driver_register(&driver->drv);
}

void locomo_driver_unregister(struct locomo_driver *driver)
{
	driver_unregister(&driver->drv);
}

static int __init locomo_init(void)
{
	int ret = bus_register(&locomo_bus_type);
	if (ret == 0)
		driver_register(&locomo_device_driver);
	return ret;
}

static void __exit locomo_exit(void)
{
	driver_unregister(&locomo_device_driver);
	bus_unregister(&locomo_bus_type);
}

module_init(locomo_init);
module_exit(locomo_exit);

MODULE_DESCRIPTION("Sharp LoCoMo core driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Lenz <[e-mail]>");

EXPORT_SYMBOL(locomo_driver_register);
EXPORT_SYMBOL(locomo_driver_unregister);
EXPORT_SYMBOL(locomo_gpio_set_dir);
EXPORT_SYMBOL(locomo_gpio_read_level);
EXPORT_SYMBOL(locomo_gpio_read_output);
EXPORT_SYMBOL(locomo_gpio_write);
EXPORT_SYMBOL(locomo_m62332_senddata);