Logo Search packages:      
Sourcecode: alsa-driver version File versions  Download package

ucb1400_ts.c

/*
 *  Philips UCB1400 touchscreen driver
 *
 *  Author: Nicolas Pitre
 *  Created:      September 25, 2006
 *  Copyright:    MontaVista Software, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This code is heavily based on ucb1x00-*.c copyrighted by Russell King
 * covering the UCB1100, UCB1200 and UCB1300..  Support for the UCB1400 has
 * been made separate from ucb1x00-core/ucb1x00-ts on Russell's request.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/freezer.h>

#include <sound/core.h>
#include <sound/ac97_codec.h>


/*
 * Interesting UCB1400 AC-link registers
 */

#define UCB_IE_RIS            0x5e
#define UCB_IE_FAL            0x60
#define UCB_IE_STATUS         0x62
#define UCB_IE_CLEAR          0x62
#define UCB_IE_ADC            (1 << 11)
#define UCB_IE_TSPX           (1 << 12)

#define UCB_TS_CR       0x64
#define UCB_TS_CR_TSMX_POW    (1 << 0)
#define UCB_TS_CR_TSPX_POW    (1 << 1)
#define UCB_TS_CR_TSMY_POW    (1 << 2)
#define UCB_TS_CR_TSPY_POW    (1 << 3)
#define UCB_TS_CR_TSMX_GND    (1 << 4)
#define UCB_TS_CR_TSPX_GND    (1 << 5)
#define UCB_TS_CR_TSMY_GND    (1 << 6)
#define UCB_TS_CR_TSPY_GND    (1 << 7)
#define UCB_TS_CR_MODE_INT    (0 << 8)
#define UCB_TS_CR_MODE_PRES   (1 << 8)
#define UCB_TS_CR_MODE_POS    (2 << 8)
#define UCB_TS_CR_BIAS_ENA    (1 << 11)
#define UCB_TS_CR_TSPX_LOW    (1 << 12)
#define UCB_TS_CR_TSMX_LOW    (1 << 13)

#define UCB_ADC_CR            0x66
#define UCB_ADC_SYNC_ENA      (1 << 0)
#define UCB_ADC_VREFBYP_CON   (1 << 1)
#define UCB_ADC_INP_TSPX      (0 << 2)
#define UCB_ADC_INP_TSMX      (1 << 2)
#define UCB_ADC_INP_TSPY      (2 << 2)
#define UCB_ADC_INP_TSMY      (3 << 2)
#define UCB_ADC_INP_AD0       (4 << 2)
#define UCB_ADC_INP_AD1       (5 << 2)
#define UCB_ADC_INP_AD2       (6 << 2)
#define UCB_ADC_INP_AD3       (7 << 2)
#define UCB_ADC_EXT_REF       (1 << 5)
#define UCB_ADC_START         (1 << 7)
#define UCB_ADC_ENA           (1 << 15)

#define UCB_ADC_DATA          0x68
#define UCB_ADC_DAT_VALID     (1 << 15)
#define UCB_ADC_DAT_VALUE(x)  ((x) & 0x3ff)

#define UCB_ID                0x7e
#define UCB_ID_1400             0x4304


struct ucb1400 {
      struct snd_ac97         *ac97;
      struct input_dev  *ts_idev;

      int               irq;

      wait_queue_head_t ts_wait;
      struct task_struct      *ts_task;

      unsigned int            irq_pending;      /* not bit field shared */
      unsigned int            ts_restart:1;
      unsigned int            adcsync:1;
};

static int adcsync;
static int ts_delay = 55; /* us */
static int ts_delay_pressure; /* us */

static inline u16 ucb1400_reg_read(struct ucb1400 *ucb, u16 reg)
{
      return ucb->ac97->bus->ops->read(ucb->ac97, reg);
}

static inline void ucb1400_reg_write(struct ucb1400 *ucb, u16 reg, u16 val)
{
      ucb->ac97->bus->ops->write(ucb->ac97, reg, val);
}

static inline void ucb1400_adc_enable(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA);
}

static unsigned int ucb1400_adc_read(struct ucb1400 *ucb, u16 adc_channel)
{
      unsigned int val;

      if (ucb->adcsync)
            adc_channel |= UCB_ADC_SYNC_ENA;

      ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA | adc_channel);
      ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA | adc_channel | UCB_ADC_START);

      for (;;) {
            val = ucb1400_reg_read(ucb, UCB_ADC_DATA);
            if (val & UCB_ADC_DAT_VALID)
                  break;
            /* yield to other processes */
            schedule_timeout_uninterruptible(1);
      }

      return UCB_ADC_DAT_VALUE(val);
}

static inline void ucb1400_adc_disable(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_ADC_CR, 0);
}

/* Switch to interrupt mode. */
static inline void ucb1400_ts_mode_int(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
                  UCB_TS_CR_MODE_INT);
}

/*
 * Switch to pressure mode, and read pressure.  We don't need to wait
 * here, since both plates are being driven.
 */
static inline unsigned int ucb1400_ts_read_pressure(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
      udelay(ts_delay_pressure);
      return ucb1400_adc_read(ucb, UCB_ADC_INP_TSPY);
}

/*
 * Switch to X position mode and measure Y plate.  We switch the plate
 * configuration in pressure mode, then switch to position mode.  This
 * gives a faster response time.  Even so, we need to wait about 55us
 * for things to stabilise.
 */
static inline unsigned int ucb1400_ts_read_xpos(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
                  UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

      udelay(ts_delay);

      return ucb1400_adc_read(ucb, UCB_ADC_INP_TSPY);
}

/*
 * Switch to Y position mode and measure X plate.  We switch the plate
 * configuration in pressure mode, then switch to position mode.  This
 * gives a faster response time.  Even so, we need to wait about 55us
 * for things to stabilise.
 */
static inline unsigned int ucb1400_ts_read_ypos(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
                  UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

      udelay(ts_delay);

      return ucb1400_adc_read(ucb, UCB_ADC_INP_TSPX);
}

/*
 * Switch to X plate resistance mode.  Set MX to ground, PX to
 * supply.  Measure current.
 */
static inline unsigned int ucb1400_ts_read_xres(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
      return ucb1400_adc_read(ucb, 0);
}

/*
 * Switch to Y plate resistance mode.  Set MY to ground, PY to
 * supply.  Measure current.
 */
static inline unsigned int ucb1400_ts_read_yres(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_TS_CR,
                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
      return ucb1400_adc_read(ucb, 0);
}

static inline int ucb1400_ts_pen_down(struct ucb1400 *ucb)
{
      unsigned short val = ucb1400_reg_read(ucb, UCB_TS_CR);
      return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
}

static inline void ucb1400_ts_irq_enable(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, UCB_IE_TSPX);
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);
      ucb1400_reg_write(ucb, UCB_IE_FAL, UCB_IE_TSPX);
}

static inline void ucb1400_ts_irq_disable(struct ucb1400 *ucb)
{
      ucb1400_reg_write(ucb, UCB_IE_FAL, 0);
}

static void ucb1400_ts_evt_add(struct input_dev *idev, u16 pressure, u16 x, u16 y)
{
      input_report_abs(idev, ABS_X, x);
      input_report_abs(idev, ABS_Y, y);
      input_report_abs(idev, ABS_PRESSURE, pressure);
      input_sync(idev);
}

static void ucb1400_ts_event_release(struct input_dev *idev)
{
      input_report_abs(idev, ABS_PRESSURE, 0);
      input_sync(idev);
}

static void ucb1400_handle_pending_irq(struct ucb1400 *ucb)
{
      unsigned int isr;

      isr = ucb1400_reg_read(ucb, UCB_IE_STATUS);
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, isr);
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);

      if (isr & UCB_IE_TSPX)
            ucb1400_ts_irq_disable(ucb);
      else
            printk(KERN_ERR "ucb1400: unexpected IE_STATUS = %#x\n", isr);

      enable_irq(ucb->irq);
}

static int ucb1400_ts_thread(void *_ucb)
{
      struct ucb1400 *ucb = _ucb;
      struct task_struct *tsk = current;
      int valid = 0;
      struct sched_param param = { .sched_priority = 1 };

      sched_setscheduler(tsk, SCHED_FIFO, &param);

      set_freezable();
      while (!kthread_should_stop()) {
            unsigned int x, y, p;
            long timeout;

            ucb->ts_restart = 0;

            if (ucb->irq_pending) {
                  ucb->irq_pending = 0;
                  ucb1400_handle_pending_irq(ucb);
            }

            ucb1400_adc_enable(ucb);
            x = ucb1400_ts_read_xpos(ucb);
            y = ucb1400_ts_read_ypos(ucb);
            p = ucb1400_ts_read_pressure(ucb);
            ucb1400_adc_disable(ucb);

            /* Switch back to interrupt mode. */
            ucb1400_ts_mode_int(ucb);

            msleep(10);

            if (ucb1400_ts_pen_down(ucb)) {
                  ucb1400_ts_irq_enable(ucb);

                  /*
                   * If we spat out a valid sample set last time,
                   * spit out a "pen off" sample here.
                   */
                  if (valid) {
                        ucb1400_ts_event_release(ucb->ts_idev);
                        valid = 0;
                  }

                  timeout = MAX_SCHEDULE_TIMEOUT;
            } else {
                  valid = 1;
                  ucb1400_ts_evt_add(ucb->ts_idev, p, x, y);
                  timeout = msecs_to_jiffies(10);
            }

            wait_event_freezable_timeout(ucb->ts_wait,
                  ucb->irq_pending || ucb->ts_restart || kthread_should_stop(),
                  timeout);
      }

      /* Send the "pen off" if we are stopping with the pen still active */
      if (valid)
            ucb1400_ts_event_release(ucb->ts_idev);

      ucb->ts_task = NULL;
      return 0;
}

/*
 * A restriction with interrupts exists when using the ucb1400, as
 * the codec read/write routines may sleep while waiting for codec
 * access completion and uses semaphores for access control to the
 * AC97 bus.  A complete codec read cycle could take  anywhere from
 * 60 to 100uSec so we *definitely* don't want to spin inside the
 * interrupt handler waiting for codec access.  So, we handle the
 * interrupt by scheduling a RT kernel thread to run in process
 * context instead of interrupt context.
 */
static irqreturn_t ucb1400_hard_irq(int irqnr, void *devid)
{
      struct ucb1400 *ucb = devid;

      if (irqnr == ucb->irq) {
            disable_irq(ucb->irq);
            ucb->irq_pending = 1;
            wake_up(&ucb->ts_wait);
            return IRQ_HANDLED;
      }
      return IRQ_NONE;
}

static int ucb1400_ts_open(struct input_dev *idev)
{
      struct ucb1400 *ucb = input_get_drvdata(idev);
      int ret = 0;

      BUG_ON(ucb->ts_task);

      ucb->ts_task = kthread_run(ucb1400_ts_thread, ucb, "UCB1400_ts");
      if (IS_ERR(ucb->ts_task)) {
            ret = PTR_ERR(ucb->ts_task);
            ucb->ts_task = NULL;
      }

      return ret;
}

static void ucb1400_ts_close(struct input_dev *idev)
{
      struct ucb1400 *ucb = input_get_drvdata(idev);

      if (ucb->ts_task)
            kthread_stop(ucb->ts_task);

      ucb1400_ts_irq_disable(ucb);
      ucb1400_reg_write(ucb, UCB_TS_CR, 0);
}

#ifdef CONFIG_PM
static int ucb1400_ts_resume(struct device *dev)
{
      struct ucb1400 *ucb = dev_get_drvdata(dev);

      if (ucb->ts_task) {
            /*
             * Restart the TS thread to ensure the
             * TS interrupt mode is set up again
             * after sleep.
             */
            ucb->ts_restart = 1;
            wake_up(&ucb->ts_wait);
      }
      return 0;
}
#else
#define ucb1400_ts_resume NULL
#endif

#ifndef NO_IRQ
#define NO_IRQ    0
#endif

/*
 * Try to probe our interrupt, rather than relying on lots of
 * hard-coded machine dependencies.
 */
static int ucb1400_detect_irq(struct ucb1400 *ucb)
{
      unsigned long mask, timeout;

      mask = probe_irq_on();
      if (!mask) {
            probe_irq_off(mask);
            return -EBUSY;
      }

      /* Enable the ADC interrupt. */
      ucb1400_reg_write(ucb, UCB_IE_RIS, UCB_IE_ADC);
      ucb1400_reg_write(ucb, UCB_IE_FAL, UCB_IE_ADC);
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0xffff);
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);

      /* Cause an ADC interrupt. */
      ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA);
      ucb1400_reg_write(ucb, UCB_ADC_CR, UCB_ADC_ENA | UCB_ADC_START);

      /* Wait for the conversion to complete. */
      timeout = jiffies + HZ/2;
      while (!(ucb1400_reg_read(ucb, UCB_ADC_DATA) & UCB_ADC_DAT_VALID)) {
            cpu_relax();
            if (time_after(jiffies, timeout)) {
                  printk(KERN_ERR "ucb1400: timed out in IRQ probe\n");
                  probe_irq_off(mask);
                  return -ENODEV;
            }
      }
      ucb1400_reg_write(ucb, UCB_ADC_CR, 0);

      /* Disable and clear interrupt. */
      ucb1400_reg_write(ucb, UCB_IE_RIS, 0);
      ucb1400_reg_write(ucb, UCB_IE_FAL, 0);
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0xffff);
      ucb1400_reg_write(ucb, UCB_IE_CLEAR, 0);

      /* Read triggered interrupt. */
      ucb->irq = probe_irq_off(mask);
      if (ucb->irq < 0 || ucb->irq == NO_IRQ)
            return -ENODEV;

      return 0;
}

static int ucb1400_ts_probe(struct device *dev)
{
      struct ucb1400 *ucb;
      struct input_dev *idev;
      int error, id, x_res, y_res;

      ucb = kzalloc(sizeof(struct ucb1400), GFP_KERNEL);
      idev = input_allocate_device();
      if (!ucb || !idev) {
            error = -ENOMEM;
            goto err_free_devs;
      }

      ucb->ts_idev = idev;
      ucb->adcsync = adcsync;
      ucb->ac97 = to_ac97_t(dev);
      init_waitqueue_head(&ucb->ts_wait);

      id = ucb1400_reg_read(ucb, UCB_ID);
      if (id != UCB_ID_1400) {
            error = -ENODEV;
            goto err_free_devs;
      }

      error = ucb1400_detect_irq(ucb);
      if (error) {
            printk(KERN_ERR "UCB1400: IRQ probe failed\n");
            goto err_free_devs;
      }

      error = request_irq(ucb->irq, ucb1400_hard_irq, IRQF_TRIGGER_RISING,
                        "UCB1400", ucb);
      if (error) {
            printk(KERN_ERR "ucb1400: unable to grab irq%d: %d\n",
                        ucb->irq, error);
            goto err_free_devs;
      }
      printk(KERN_DEBUG "UCB1400: found IRQ %d\n", ucb->irq);

      input_set_drvdata(idev, ucb);

      idev->dev.parent  = dev;
      idev->name        = "UCB1400 touchscreen interface";
      idev->id.vendor         = ucb1400_reg_read(ucb, AC97_VENDOR_ID1);
      idev->id.product  = id;
      idev->open        = ucb1400_ts_open;
      idev->close       = ucb1400_ts_close;
      idev->evbit[0]          = BIT_MASK(EV_ABS);

      ucb1400_adc_enable(ucb);
      x_res = ucb1400_ts_read_xres(ucb);
      y_res = ucb1400_ts_read_yres(ucb);
      ucb1400_adc_disable(ucb);
      printk(KERN_DEBUG "UCB1400: x/y = %d/%d\n", x_res, y_res);

      input_set_abs_params(idev, ABS_X, 0, x_res, 0, 0);
      input_set_abs_params(idev, ABS_Y, 0, y_res, 0, 0);
      input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);

      error = input_register_device(idev);
      if (error)
            goto err_free_irq;

      dev_set_drvdata(dev, ucb);
      return 0;

 err_free_irq:
      free_irq(ucb->irq, ucb);
 err_free_devs:
      input_free_device(idev);
      kfree(ucb);
      return error;
}

static int ucb1400_ts_remove(struct device *dev)
{
      struct ucb1400 *ucb = dev_get_drvdata(dev);

      free_irq(ucb->irq, ucb);
      input_unregister_device(ucb->ts_idev);
      dev_set_drvdata(dev, NULL);
      kfree(ucb);
      return 0;
}

static struct device_driver ucb1400_ts_driver = {
      .name       = "ucb1400_ts",
      .owner            = THIS_MODULE,
      .bus        = &ac97_bus_type,
      .probe            = ucb1400_ts_probe,
      .remove           = ucb1400_ts_remove,
      .resume           = ucb1400_ts_resume,
};

static int __init ucb1400_ts_init(void)
{
      return driver_register(&ucb1400_ts_driver);
}

static void __exit ucb1400_ts_exit(void)
{
      driver_unregister(&ucb1400_ts_driver);
}

module_param(adcsync, bool, 0444);
MODULE_PARM_DESC(adcsync, "Synchronize touch readings with ADCSYNC pin.");

module_param(ts_delay, int, 0444);
MODULE_PARM_DESC(ts_delay, "Delay between panel setup and position read. Default = 55us.");

module_param(ts_delay_pressure, int, 0444);
MODULE_PARM_DESC(ts_delay_pressure,
              "delay between panel setup and pressure read.  Default = 0us.");

module_init(ucb1400_ts_init);
module_exit(ucb1400_ts_exit);

MODULE_DESCRIPTION("Philips UCB1400 touchscreen driver");
MODULE_LICENSE("GPL");

Generated by  Doxygen 1.6.0   Back to index