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[hh.org.git] / drivers / misc / ucb1x00-ts.c

/*
 *  linux/drivers/misc/ucb1x00-ts.c
 *
 *  Copyright (C) 2001 Russell King, All Rights Reserved.
 *
 * 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.
 *
 * 21-Jan-2002 <jco@ict.es> :
 *
 * Added support for synchronous A/D mode. This mode is useful to
 * avoid noise induced in the touchpanel by the LCD, provided that
 * the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
 * It is important to note that the signal connected to the ADCSYNC
 * pin should provide pulses even when the LCD is blanked, otherwise
 * a pen touch needed to unblank the LCD will never be read.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/slab.h>

#include <asm/dma.h>
#include <asm/semaphore.h>

#include "ucb1x00.h"


struct ucb1x00_ts {
        struct input_dev        idev;
        struct ucb1x00          *ucb;

        wait_queue_head_t       irq_wait;
        struct semaphore        sem;
        struct completion       init_exit;
        struct task_struct      *rtask;
        int                     use_count;
        u16                     x_res;
        u16                     y_res;

        int                     restart:1;
        int                     adcsync:1;
};

static int adcsync = UCB_NOSYNC;

static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
{
        input_report_abs(&ts->idev, ABS_X, x);
        input_report_abs(&ts->idev, ABS_Y, y);
        input_report_abs(&ts->idev, ABS_PRESSURE, pressure);
        input_sync(&ts->idev);
}

static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
{
        input_report_abs(&ts->idev, ABS_PRESSURE, 0);
        input_sync(&ts->idev);
}

/*
 * Switch to interrupt mode.
 */
static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
{
        ucb1x00_reg_write(ts->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 ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
{
        ucb1x00_reg_write(ts->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);

        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
}

/*
 * 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 ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
{
        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
                        UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
        ucb1x00_reg_write(ts->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(55);

        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
}

/*
 * 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 ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
{
        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
                        UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
                        UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
        ucb1x00_reg_write(ts->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(55);

        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
}

/*
 * Switch to X plate resistance mode.  Set MX to ground, PX to
 * supply.  Measure current.
 */
static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
{
        ucb1x00_reg_write(ts->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 ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
}

/*
 * Switch to Y plate resistance mode.  Set MY to ground, PY to
 * supply.  Measure current.
 */
static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
{
        ucb1x00_reg_write(ts->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 ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
}

/*
 * This is a RT kernel thread that handles the ADC accesses
 * (mainly so we can use semaphores in the UCB1200 core code
 * to serialise accesses to the ADC).
 */
static int ucb1x00_thread(void *_ts)
{
        struct ucb1x00_ts *ts = _ts;
        struct task_struct *tsk = current;
        DECLARE_WAITQUEUE(wait, tsk);
        int valid;

        ts->rtask = tsk;

        daemonize("ktsd");
        /* only want to receive SIGKILL */
        allow_signal(SIGKILL);

        /*
         * We could run as a real-time thread.  However, thus far
         * this doesn't seem to be necessary.
         */
//      tsk->policy = SCHED_FIFO;
//      tsk->rt_priority = 1;

        complete(&ts->init_exit);

        valid = 0;

        add_wait_queue(&ts->irq_wait, &wait);
        for (;;) {
                unsigned int x, y, p, val;
                signed long timeout;

                ts->restart = 0;

                ucb1x00_adc_enable(ts->ucb);

                x = ucb1x00_ts_read_xpos(ts);
                y = ucb1x00_ts_read_ypos(ts);
                p = ucb1x00_ts_read_pressure(ts);

                /*
                 * Switch back to interrupt mode.
                 */
                ucb1x00_ts_mode_int(ts);
                ucb1x00_adc_disable(ts->ucb);

                set_task_state(tsk, TASK_UNINTERRUPTIBLE);
                schedule_timeout(HZ / 100);
                if (signal_pending(tsk))
                        break;

                ucb1x00_enable(ts->ucb);
                val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);

                if (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW)) {
                        set_task_state(tsk, TASK_INTERRUPTIBLE);

                        ucb1x00_enable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
                        ucb1x00_disable(ts->ucb);

                        /*
                         * If we spat out a valid sample set last time,
                         * spit out a "pen off" sample here.
                         */
                        if (valid) {
                                ucb1x00_ts_event_release(ts);
                                valid = 0;
                        }

                        timeout = MAX_SCHEDULE_TIMEOUT;
                } else {
                        ucb1x00_disable(ts->ucb);

                        /*
                         * Filtering is policy.  Policy belongs in user
                         * space.  We therefore leave it to user space
                         * to do any filtering they please.
                         */
                        if (!ts->restart) {
                                ucb1x00_ts_evt_add(ts, p, x, y);
                                valid = 1;
                        }

                        set_task_state(tsk, TASK_INTERRUPTIBLE);
                        timeout = HZ / 100;
                }

                schedule_timeout(timeout);
                if (signal_pending(tsk))
                        break;
        }

        remove_wait_queue(&ts->irq_wait, &wait);

        ts->rtask = NULL;
        complete_and_exit(&ts->init_exit, 0);
}

/*
 * We only detect touch screen _touches_ with this interrupt
 * handler, and even then we just schedule our task.
 */
static void ucb1x00_ts_irq(int idx, void *id)
{
        struct ucb1x00_ts *ts = id;
        ucb1x00_disable_irq(ts->ucb, UCB_IRQ_TSPX, UCB_FALLING);
        wake_up(&ts->irq_wait);
}

static int ucb1x00_ts_open(struct input_dev *idev)
{
        struct ucb1x00_ts *ts = (struct ucb1x00_ts *)idev;
        int ret = 0;

        if (down_interruptible(&ts->sem))
                return -EINTR;

        if (ts->use_count++ != 0)
                goto out;

        if (ts->rtask)
                panic("ucb1x00: rtask running?");

        init_waitqueue_head(&ts->irq_wait);
        ret = ucb1x00_hook_irq(ts->ucb, UCB_IRQ_TSPX, ucb1x00_ts_irq, ts);
        if (ret < 0)
                goto out;

        /*
         * If we do this at all, we should allow the user to
         * measure and read the X and Y resistance at any time.
         */
        ucb1x00_adc_enable(ts->ucb);
        ts->x_res = ucb1x00_ts_read_xres(ts);
        ts->y_res = ucb1x00_ts_read_yres(ts);
        ucb1x00_adc_disable(ts->ucb);

        init_completion(&ts->init_exit);
        ret = kernel_thread(ucb1x00_thread, ts, 0);
        if (ret >= 0) {
                wait_for_completion(&ts->init_exit);
                ret = 0;
        } else {
                ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
        }

 out:
        if (ret)
                ts->use_count--;
        up(&ts->sem);
        return ret;
}

/*
 * Release touchscreen resources.  Disable IRQs.
 */
static void ucb1x00_ts_close(struct input_dev *idev)
{
        struct ucb1x00_ts *ts = (struct ucb1x00_ts *)idev;

        down(&ts->sem);
        if (--ts->use_count == 0) {
                if (ts->rtask) {
                        send_sig(SIGKILL, ts->rtask, 1);
                        wait_for_completion(&ts->init_exit);
                }

                ucb1x00_enable(ts->ucb);
                ucb1x00_free_irq(ts->ucb, UCB_IRQ_TSPX, ts);
                ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
                ucb1x00_disable(ts->ucb);
        }
        up(&ts->sem);
}

static int ucb1x00_ts_resume(struct ucb1x00 *ucb)
{
        struct ucb1x00_ts *ts = (struct ucb1x00_ts*)ucb->ts_data;

        if (ts->rtask != NULL) {
                /*
                 * Restart the TS thread to ensure the
                 * TS interrupt mode is set up again
                 * after sleep.
                 */
                ts->restart = 1;
                wake_up(&ts->irq_wait);
        }

        return 0;
}


/*
 * Initialisation.
 */
static int ucb1x00_ts_add(struct class_device *dev)
{
        struct ucb1x00 *ucb = classdev_to_ucb1x00(dev);
        struct ucb1x00_ts *ts;

        ts = kmalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
        if (!ts)
                return -ENOMEM;

        memset(ts, 0, sizeof(struct ucb1x00_ts));

        ts->ucb = ucb;
        ts->adcsync = adcsync;
        init_MUTEX(&ts->sem);

        ts->idev.name       = "Touchscreen panel";
        ts->idev.id.product = ts->ucb->id;
        ts->idev.open       = ucb1x00_ts_open;
        ts->idev.close      = ucb1x00_ts_close;

        __set_bit(EV_ABS, ts->idev.evbit);
        __set_bit(ABS_X, ts->idev.absbit);
        __set_bit(ABS_Y, ts->idev.absbit);
        __set_bit(ABS_PRESSURE, ts->idev.absbit);

        input_register_device(&ts->idev);

        ucb->ts_data = ts;

        return 0;
}

static void ucb1x00_ts_remove(struct class_device *dev)
{
        struct ucb1x00 *ucb = classdev_to_ucb1x00(dev);
        struct ucb1x00_ts *ts = ucb->ts_data;

        input_unregister_device(&ts->idev);
        kfree(ts);
}

static struct ucb1x00_class_interface ucb1x00_ts_interface = {
        .interface      = {
                .add            = ucb1x00_ts_add,
                .remove         = ucb1x00_ts_remove,
        },
        .resume         = ucb1x00_ts_resume,
};

static int __init ucb1x00_ts_init(void)
{
        return ucb1x00_register_interface(&ucb1x00_ts_interface);
}

static void __exit ucb1x00_ts_exit(void)
{
        ucb1x00_unregister_interface(&ucb1x00_ts_interface);
}

#ifndef MODULE

/*
 * Parse kernel command-line options.
 *
 * syntax : ucbts=[sync|nosync],...
 */
static int __init ucb1x00_ts_setup(char *str)
{
        char *p;

        while ((p = strsep(&str, ",")) != NULL) {
                if (strcmp(p, "sync") == 0)
                        adcsync = UCB_SYNC;
        }

        return 1;
}

__setup("ucbts=", ucb1x00_ts_setup);

#else

MODULE_PARM(adcsync, "i");
MODULE_PARM_DESC(adcsync, "Enable use of ADCSYNC signal");

#endif

module_init(ucb1x00_ts_init);
module_exit(ucb1x00_ts_exit);

MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
MODULE_LICENSE("GPL");