tnetv107x-ts.c

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/*
 * Texas Instruments TNETV107X Touchscreen Driver
 *
 * Copyright (C) 2010 Texas Instruments
 *
 * 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 version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/input.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/ctype.h>
#include <linux/io.h>
#include <linux/clk.h>

#include <mach/tnetv107x.h>

#define TSC_PENUP_POLL      (HZ / 5)
#define IDLE_TIMEOUT        100 /* msec */

/*
 * The first and last samples of a touch interval are usually garbage and need
 * to be filtered out with these devices.  The following definitions control
 * the number of samples skipped.
 */
#define TSC_HEAD_SKIP       1
#define TSC_TAIL_SKIP       1
#define TSC_SKIP        (TSC_HEAD_SKIP + TSC_TAIL_SKIP + 1)
#define TSC_SAMPLES     (TSC_SKIP + 1)

/* Register Offsets */
struct tsc_regs {
    u32 rev;
    u32 tscm;
    u32 bwcm;
    u32 swc;
    u32 adcchnl;
    u32 adcdata;
    u32 chval[4];
};

/* TSC Mode Configuration Register (tscm) bits */
#define WMODE       BIT(0)
#define TSKIND      BIT(1)
#define ZMEASURE_EN BIT(2)
#define IDLE        BIT(3)
#define TSC_EN      BIT(4)
#define STOP        BIT(5)
#define ONE_SHOT    BIT(6)
#define SINGLE      BIT(7)
#define AVG     BIT(8)
#define AVGNUM(x)   (((x) & 0x03) <<  9)
#define PVSTC(x)    (((x) & 0x07) << 11)
#define PON     BIT(14)
#define PONBG       BIT(15)
#define AFERST      BIT(16)

/* ADC DATA Capture Register bits */
#define DATA_VALID  BIT(16)

/* Register Access Macros */
#define tsc_read(ts, reg)       __raw_readl(&(ts)->regs->reg)
#define tsc_write(ts, reg, val)     __raw_writel(val, &(ts)->regs->reg);
#define tsc_set_bits(ts, reg, val)  \
    tsc_write(ts, reg, tsc_read(ts, reg) | (val))
#define tsc_clr_bits(ts, reg, val)  \
    tsc_write(ts, reg, tsc_read(ts, reg) & ~(val))

struct sample {
    int x, y, p;
};

struct tsc_data {
    struct input_dev        *input_dev;
    struct resource         *res;
    struct tsc_regs __iomem     *regs;
    struct timer_list       timer;
    spinlock_t          lock;
    struct clk          *clk;
    struct device           *dev;
    int             sample_count;
    struct sample           samples[TSC_SAMPLES];
    int             tsc_irq;
};

static int tsc_read_sample(struct tsc_data *ts, struct sample* sample)
{
    int x, y, z1, z2, t, p = 0;
    u32 val;

    val = tsc_read(ts, chval[0]);
    if (val & DATA_VALID)
        x = val & 0xffff;
    else
        return -EINVAL;

    y  = tsc_read(ts, chval[1]) & 0xffff;
    z1 = tsc_read(ts, chval[2]) & 0xffff;
    z2 = tsc_read(ts, chval[3]) & 0xffff;

    if (z1) {
        t = ((600 * x) * (z2 - z1));
        p = t / (u32) (z1 << 12);
        if (p < 0)
            p = 0;
    }

    sample->x  = x;
    sample->y  = y;
    sample->p  = p;

    return 0;
}

static void tsc_poll(unsigned long data)
{
    struct tsc_data *ts = (struct tsc_data *)data;
    unsigned long flags;
    int i, val, x, y, p;

    spin_lock_irqsave(&ts->lock, flags);

    if (ts->sample_count >= TSC_SKIP) {
        input_report_abs(ts->input_dev, ABS_PRESSURE, 0);
        input_report_key(ts->input_dev, BTN_TOUCH, 0);
        input_sync(ts->input_dev);
    } else if (ts->sample_count > 0) {
        /*
         * A touch event lasted less than our skip count.  Salvage and
         * report anyway.
         */
        for (i = 0, val = 0; i < ts->sample_count; i++)
            val += ts->samples[i].x;
        x = val / ts->sample_count;

        for (i = 0, val = 0; i < ts->sample_count; i++)
            val += ts->samples[i].y;
        y = val / ts->sample_count;

        for (i = 0, val = 0; i < ts->sample_count; i++)
            val += ts->samples[i].p;
        p = val / ts->sample_count;

        input_report_abs(ts->input_dev, ABS_X, x);
        input_report_abs(ts->input_dev, ABS_Y, y);
        input_report_abs(ts->input_dev, ABS_PRESSURE, p);
        input_report_key(ts->input_dev, BTN_TOUCH, 1);
        input_sync(ts->input_dev);
    }

    ts->sample_count = 0;

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

static irqreturn_t tsc_irq(int irq, void *dev_id)
{
    struct tsc_data *ts = (struct tsc_data *)dev_id;
    struct sample *sample;
    int index;

    spin_lock(&ts->lock);

    index = ts->sample_count % TSC_SAMPLES;
    sample = &ts->samples[index];
    if (tsc_read_sample(ts, sample) < 0)
        goto out;

    if (++ts->sample_count >= TSC_SKIP) {
        index = (ts->sample_count - TSC_TAIL_SKIP - 1) % TSC_SAMPLES;
        sample = &ts->samples[index];

        input_report_abs(ts->input_dev, ABS_X, sample->x);
        input_report_abs(ts->input_dev, ABS_Y, sample->y);
        input_report_abs(ts->input_dev, ABS_PRESSURE, sample->p);
        if (ts->sample_count == TSC_SKIP)
            input_report_key(ts->input_dev, BTN_TOUCH, 1);
        input_sync(ts->input_dev);
    }
    mod_timer(&ts->timer, jiffies + TSC_PENUP_POLL);
out:
    spin_unlock(&ts->lock);
    return IRQ_HANDLED;
}

static int tsc_start(struct input_dev *dev)
{
    struct tsc_data *ts = input_get_drvdata(dev);
    unsigned long timeout = jiffies + msecs_to_jiffies(IDLE_TIMEOUT);
    u32 val;

    clk_enable(ts->clk);

    /* Go to idle mode, before any initialization */
    while (time_after(timeout, jiffies)) {
        if (tsc_read(ts, tscm) & IDLE)
            break;
    }

    if (time_before(timeout, jiffies)) {
        dev_warn(ts->dev, "timeout waiting for idle\n");
        clk_disable(ts->clk);
        return -EIO;
    }

    /* Configure TSC Control register*/
    val = (PONBG | PON | PVSTC(4) | ONE_SHOT | ZMEASURE_EN);
    tsc_write(ts, tscm, val);

    /* Bring TSC out of reset: Clear AFE reset bit */
    val &= ~(AFERST);
    tsc_write(ts, tscm, val);

    /* Configure all pins for hardware control*/
    tsc_write(ts, bwcm, 0);

    /* Finally enable the TSC */
    tsc_set_bits(ts, tscm, TSC_EN);

    return 0;
}

static void tsc_stop(struct input_dev *dev)
{
    struct tsc_data *ts = input_get_drvdata(dev);

    tsc_clr_bits(ts, tscm, TSC_EN);
    synchronize_irq(ts->tsc_irq);
    del_timer_sync(&ts->timer);
    clk_disable(ts->clk);
}

static int __devinit tsc_probe(struct platform_device *pdev)
{
    struct device *dev = &pdev->dev;
    struct tsc_data *ts;
    int error = 0;
    u32 rev = 0;

    ts = kzalloc(sizeof(struct tsc_data), GFP_KERNEL);
    if (!ts) {
        dev_err(dev, "cannot allocate device info\n");
        return -ENOMEM;
    }

    ts->dev = dev;
    spin_lock_init(&ts->lock);
    setup_timer(&ts->timer, tsc_poll, (unsigned long)ts);
    platform_set_drvdata(pdev, ts);

    ts->tsc_irq = platform_get_irq(pdev, 0);
    if (ts->tsc_irq < 0) {
        dev_err(dev, "cannot determine device interrupt\n");
        error = -ENODEV;
        goto error_res;
    }

    ts->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!ts->res) {
        dev_err(dev, "cannot determine register area\n");
        error = -ENODEV;
        goto error_res;
    }

    if (!request_mem_region(ts->res->start, resource_size(ts->res),
                pdev->name)) {
        dev_err(dev, "cannot claim register memory\n");
        ts->res = NULL;
        error = -EINVAL;
        goto error_res;
    }

    ts->regs = ioremap(ts->res->start, resource_size(ts->res));
    if (!ts->regs) {
        dev_err(dev, "cannot map register memory\n");
        error = -ENOMEM;
        goto error_map;
    }

    ts->clk = clk_get(dev, NULL);
    if (IS_ERR(ts->clk)) {
        dev_err(dev, "cannot claim device clock\n");
        error = PTR_ERR(ts->clk);
        goto error_clk;
    }

    error = request_threaded_irq(ts->tsc_irq, NULL, tsc_irq, IRQF_ONESHOT,
                     dev_name(dev), ts);
    if (error < 0) {
        dev_err(ts->dev, "Could not allocate ts irq\n");
        goto error_irq;
    }

    ts->input_dev = input_allocate_device();
    if (!ts->input_dev) {
        dev_err(dev, "cannot allocate input device\n");
        error = -ENOMEM;
        goto error_input;
    }
    input_set_drvdata(ts->input_dev, ts);

    ts->input_dev->name       = pdev->name;
    ts->input_dev->id.bustype = BUS_HOST;
    ts->input_dev->dev.parent = &pdev->dev;
    ts->input_dev->open   = tsc_start;
    ts->input_dev->close      = tsc_stop;

    clk_enable(ts->clk);
    rev = tsc_read(ts, rev);
    ts->input_dev->id.product = ((rev >>  8) & 0x07);
    ts->input_dev->id.version = ((rev >> 16) & 0xfff);
    clk_disable(ts->clk);

    __set_bit(EV_KEY,    ts->input_dev->evbit);
    __set_bit(EV_ABS,    ts->input_dev->evbit);
    __set_bit(BTN_TOUCH, ts->input_dev->keybit);

    input_set_abs_params(ts->input_dev, ABS_X, 0, 0xffff, 5, 0);
    input_set_abs_params(ts->input_dev, ABS_Y, 0, 0xffff, 5, 0);
    input_set_abs_params(ts->input_dev, ABS_PRESSURE, 0, 4095, 128, 0);

    error = input_register_device(ts->input_dev);
    if (error < 0) {
        dev_err(dev, "failed input device registration\n");
        goto error_reg;
    }

    return 0;

error_reg:
    input_free_device(ts->input_dev);
error_input:
    free_irq(ts->tsc_irq, ts);
error_irq:
    clk_put(ts->clk);
error_clk:
    iounmap(ts->regs);
error_map:
    release_mem_region(ts->res->start, resource_size(ts->res));
error_res:
    platform_set_drvdata(pdev, NULL);
    kfree(ts);

    return error;
}

static int __devexit tsc_remove(struct platform_device *pdev)
{
    struct tsc_data *ts = platform_get_drvdata(pdev);

    input_unregister_device(ts->input_dev);
    free_irq(ts->tsc_irq, ts);
    clk_put(ts->clk);
    iounmap(ts->regs);
    release_mem_region(ts->res->start, resource_size(ts->res));
    platform_set_drvdata(pdev, NULL);
    kfree(ts);

    return 0;
}

static struct platform_driver tsc_driver = {
    .probe      = tsc_probe,
    .remove     = __devexit_p(tsc_remove),
    .driver.name    = "tnetv107x-ts",
    .driver.owner   = THIS_MODULE,
};
module_platform_driver(tsc_driver);

MODULE_AUTHOR("Cyril Chemparathy");
MODULE_DESCRIPTION("TNETV107X Touchscreen Driver");
MODULE_ALIAS("platform:tnetv107x-ts");
MODULE_LICENSE("GPL");