ads7846.c

linux2.6.16版本

	struct ads7846	*ts = (void *)handle;
	int		status = 0;
	unsigned long	flags;

	spin_lock_irqsave(&ts->lock, flags);
	if (!ts->pending) {
		ts->pending = 1;
		if (!ts->irq_disabled) {
			ts->irq_disabled = 1;
			disable_irq(ts->spi->irq);
		}
		status = spi_async(ts->spi, &ts->msg);
		if (status)
			dev_err(&ts->spi->dev, "spi_async --> %d\n",
					status);
	}
	spin_unlock_irqrestore(&ts->lock, flags);
}

static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
{
	ads7846_timer((unsigned long) handle);
	return IRQ_HANDLED;
}

/*--------------------------------------------------------------------------*/

static int
ads7846_suspend(struct spi_device *spi, pm_message_t message)
{
	struct ads7846 *ts = dev_get_drvdata(&spi->dev);
	unsigned long	flags;

	spin_lock_irqsave(&ts->lock, flags);

	spi->dev.power.power_state = message;

	/* are we waiting for IRQ, or polling? */
	if (!ts->pendown) {
		if (!ts->irq_disabled) {
			ts->irq_disabled = 1;
			disable_irq(ts->spi->irq);
		}
	} else {
		/* polling; force a final SPI completion;
		 * that will clean things up neatly
		 */
		if (!ts->pending)
			mod_timer(&ts->timer, jiffies);

		while (ts->pendown || ts->pending) {
			spin_unlock_irqrestore(&ts->lock, flags);
			udelay(10);
			spin_lock_irqsave(&ts->lock, flags);
		}
	}

	/* we know the chip's in lowpower mode since we always
	 * leave it that way after every request
	 */

	spin_unlock_irqrestore(&ts->lock, flags);
	return 0;
}

static int ads7846_resume(struct spi_device *spi)
{
	struct ads7846 *ts = dev_get_drvdata(&spi->dev);

	ts->irq_disabled = 0;
	enable_irq(ts->spi->irq);
	spi->dev.power.power_state = PMSG_ON;
	return 0;
}

static int __devinit ads7846_probe(struct spi_device *spi)
{
	struct ads7846			*ts;
	struct input_dev		*input_dev;
	struct ads7846_platform_data	*pdata = spi->dev.platform_data;
	struct spi_transfer		*x;
	int				err;

	if (!spi->irq) {
		dev_dbg(&spi->dev, "no IRQ?\n");
		return -ENODEV;
	}

	if (!pdata) {
		dev_dbg(&spi->dev, "no platform data?\n");
		return -ENODEV;
	}

	/* don't exceed max specified sample rate */
	if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
		dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
				(spi->max_speed_hz/SAMPLE_BITS)/1000);
		return -EINVAL;
	}

	/* We'd set the wordsize to 12 bits ... except that some controllers
	 * will then treat the 8 bit command words as 12 bits (and drop the
	 * four MSBs of the 12 bit result).  Result: inputs must be shifted
	 * to discard the four garbage LSBs.
	 */

	ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!ts || !input_dev) {
		err = -ENOMEM;
		goto err_free_mem;
	}

	dev_set_drvdata(&spi->dev, ts);
	spi->dev.power.power_state = PMSG_ON;

	ts->spi = spi;
	ts->input = input_dev;

	init_timer(&ts->timer);
	ts->timer.data = (unsigned long) ts;
	ts->timer.function = ads7846_timer;

	ts->model = pdata->model ? : 7846;
	ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;

	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);

	input_dev->name = "ADS784x Touchscreen";
	input_dev->phys = ts->phys;
	input_dev->cdev.dev = &spi->dev;

	input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
	input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
	input_set_abs_params(input_dev, ABS_X,
			pdata->x_min ? : 0,
			pdata->x_max ? : MAX_12BIT,
			0, 0);
	input_set_abs_params(input_dev, ABS_Y,
			pdata->y_min ? : 0,
			pdata->y_max ? : MAX_12BIT,
			0, 0);
	input_set_abs_params(input_dev, ABS_PRESSURE,
			pdata->pressure_min, pdata->pressure_max, 0, 0);

	/* set up the transfers to read touchscreen state; this assumes we
	 * use formula #2 for pressure, not #3.
	 */
	INIT_LIST_HEAD(&ts->msg.transfers);
	x = ts->xfer;

	/* y- still on; turn on only y+ (and ADC) */
	ts->read_y = READ_Y;
	x->tx_buf = &ts->read_y;
	x->len = 1;
	spi_message_add_tail(x, &ts->msg);

	x++;
	x->rx_buf = &ts->tc.y;
	x->len = 2;
	spi_message_add_tail(x, &ts->msg);

	/* turn y+ off, x- on; we'll use formula #2 */
	if (ts->model == 7846) {
		x++;
		ts->read_z1 = READ_Z1;
		x->tx_buf = &ts->read_z1;
		x->len = 1;
		spi_message_add_tail(x, &ts->msg);

		x++;
		x->rx_buf = &ts->tc.z1;
		x->len = 2;
		spi_message_add_tail(x, &ts->msg);

		x++;
		ts->read_z2 = READ_Z2;
		x->tx_buf = &ts->read_z2;
		x->len = 1;
		spi_message_add_tail(x, &ts->msg);

		x++;
		x->rx_buf = &ts->tc.z2;
		x->len = 2;
		spi_message_add_tail(x, &ts->msg);
	}

	/* turn y- off, x+ on, then leave in lowpower */
	x++;
	ts->read_x = READ_X;
	x->tx_buf = &ts->read_x;
	x->len = 1;
	spi_message_add_tail(x, &ts->msg);

	x++;
	x->rx_buf = &ts->tc.x;
	x->len = 2;
	CS_CHANGE(*x);
	spi_message_add_tail(x, &ts->msg);

	ts->msg.complete = ads7846_rx;
	ts->msg.context = ts;

	if (request_irq(spi->irq, ads7846_irq,
			SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
			spi->dev.bus_id, ts)) {
		dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
		err = -EBUSY;
		goto err_free_mem;
	}

	dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);

	/* take a first sample, leaving nPENIRQ active; avoid
	 * the touchscreen, in case it's not connected.
	 */
	(void) ads7846_read12_ser(&spi->dev,
			  READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);

	/* ads7843/7845 don't have temperature sensors, and
	 * use the other sensors a bit differently too
	 */
	if (ts->model == 7846) {
		device_create_file(&spi->dev, &dev_attr_temp0);
		device_create_file(&spi->dev, &dev_attr_temp1);
	}
	if (ts->model != 7845)
		device_create_file(&spi->dev, &dev_attr_vbatt);
	device_create_file(&spi->dev, &dev_attr_vaux);

	err = input_register_device(input_dev);
	if (err)
		goto err_free_irq;

	return 0;

 err_free_irq:
	free_irq(spi->irq, ts);
 err_free_mem:
	input_free_device(input_dev);
	kfree(ts);
	return err;
}

static int __devexit ads7846_remove(struct spi_device *spi)
{
	struct ads7846		*ts = dev_get_drvdata(&spi->dev);

	ads7846_suspend(spi, PMSG_SUSPEND);
	free_irq(ts->spi->irq, ts);
	if (ts->irq_disabled)
		enable_irq(ts->spi->irq);

	if (ts->model == 7846) {
		device_remove_file(&spi->dev, &dev_attr_temp0);
		device_remove_file(&spi->dev, &dev_attr_temp1);
	}
	if (ts->model != 7845)
		device_remove_file(&spi->dev, &dev_attr_vbatt);
	device_remove_file(&spi->dev, &dev_attr_vaux);

	input_unregister_device(ts->input);
	kfree(ts);

	dev_dbg(&spi->dev, "unregistered touchscreen\n");
	return 0;
}

static struct spi_driver ads7846_driver = {
	.driver = {
		.name	= "ads7846",
		.bus	= &spi_bus_type,
		.owner	= THIS_MODULE,
	},
	.probe		= ads7846_probe,
	.remove		= __devexit_p(ads7846_remove),
	.suspend	= ads7846_suspend,
	.resume		= ads7846_resume,
};

static int __init ads7846_init(void)
{
	/* grr, board-specific init should stay out of drivers!! */

#ifdef	CONFIG_ARCH_OMAP
	if (machine_is_omap_osk()) {
		/* GPIO4 = PENIRQ; GPIO6 = BUSY */
		omap_request_gpio(4);
		omap_set_gpio_direction(4, 1);
		omap_request_gpio(6);
		omap_set_gpio_direction(6, 1);
	}
	// also TI 1510 Innovator, bitbanging through FPGA
	// also Nokia 770
	// also Palm Tungsten T2
#endif

	// PXA:
	// also Dell Axim X50
	// also HP iPaq H191x/H192x/H415x/H435x
	// also Intel Lubbock (additional to UCB1400; as temperature sensor)
	// also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)

	// Atmel at91sam9261-EK uses ads7843

	// also various AMD Au1x00 devel boards

	return spi_register_driver(&ads7846_driver);
}
module_init(ads7846_init);

static void __exit ads7846_exit(void)
{
	spi_unregister_driver(&ads7846_driver);

#ifdef	CONFIG_ARCH_OMAP
	if (machine_is_omap_osk()) {
		omap_free_gpio(4);
		omap_free_gpio(6);
	}
#endif

}
module_exit(ads7846_exit);

MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
MODULE_LICENSE("GPL");