wm9712.c

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/*
 * wm9712.c  --  Codec driver for Wolfson WM9712 AC97 Codecs.
 *
 * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
 * Author: Liam Girdwood <[email protected]>
 * Parts Copyright : Ian Molton <[email protected]>
 *                   Andrew Zabolotny <[email protected]>
 *                   Russell King <[email protected]>
 *
 *  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;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/wm97xx.h>

#define TS_NAME         "wm97xx"
#define WM9712_VERSION      "1.00"
#define DEFAULT_PRESSURE    0xb0c0

/*
 * Module parameters
 */

/*
 * Set internal pull up for pen detect.
 *
 * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
 * i.e. pull up resistance = 64k Ohms / rpu.
 *
 * Adjust this value if you are having problems with pen detect not
 * detecting any down event.
 */
static int rpu = 8;
module_param(rpu, int, 0);
MODULE_PARM_DESC(rpu, "Set internal pull up resitor for pen detect.");

/*
 * Set current used for pressure measurement.
 *
 * Set pil = 2 to use 400uA
 *     pil = 1 to use 200uA and
 *     pil = 0 to disable pressure measurement.
 *
 * This is used to increase the range of values returned by the adc
 * when measureing touchpanel pressure.
 */
static int pil;
module_param(pil, int, 0);
MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");

/*
 * Set threshold for pressure measurement.
 *
 * Pen down pressure below threshold is ignored.
 */
static int pressure = DEFAULT_PRESSURE & 0xfff;
module_param(pressure, int, 0);
MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");

/*
 * Set adc sample delay.
 *
 * For accurate touchpanel measurements, some settling time may be
 * required between the switch matrix applying a voltage across the
 * touchpanel plate and the ADC sampling the signal.
 *
 * This delay can be set by setting delay = n, where n is the array
 * position of the delay in the array delay_table below.
 * Long delays > 1ms are supported for completeness, but are not
 * recommended.
 */
static int delay = 3;
module_param(delay, int, 0);
MODULE_PARM_DESC(delay, "Set adc sample delay.");

/*
 * Set five_wire = 1 to use a 5 wire touchscreen.
 *
 * NOTE: Five wire mode does not allow for readback of pressure.
 */
static int five_wire;
module_param(five_wire, int, 0);
MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");

/*
 * Set adc mask function.
 *
 * Sources of glitch noise, such as signals driving an LCD display, may feed
 * through to the touch screen plates and affect measurement accuracy. In
 * order to minimise this, a signal may be applied to the MASK pin to delay or
 * synchronise the sampling.
 *
 * 0 = No delay or sync
 * 1 = High on pin stops conversions
 * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
 * 3 = Edge triggered, edge on pin starts conversion after delay param
 */
static int mask;
module_param(mask, int, 0);
MODULE_PARM_DESC(mask, "Set adc mask function.");

/*
 * Coordinate Polling Enable.
 *
 * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
 * for every poll.
 */
static int coord;
module_param(coord, int, 0);
MODULE_PARM_DESC(coord, "Polling coordinate mode");

/*
 * ADC sample delay times in uS
 */
static const int delay_table[] = {
    21,    /* 1 AC97 Link frames */
    42,    /* 2 */
    84,    /* 4 */
    167,   /* 8 */
    333,   /* 16 */
    667,   /* 32 */
    1000,  /* 48 */
    1333,  /* 64 */
    2000,  /* 96 */
    2667,  /* 128 */
    3333,  /* 160 */
    4000,  /* 192 */
    4667,  /* 224 */
    5333,  /* 256 */
    6000,  /* 288 */
    0      /* No delay, switch matrix always on */
};

/*
 * Delay after issuing a POLL command.
 *
 * The delay is 3 AC97 link frames + the touchpanel settling delay
 */
static inline void poll_delay(int d)
{
    udelay(3 * AC97_LINK_FRAME + delay_table[d]);
}

/*
 * set up the physical settings of the WM9712
 */
static void wm9712_phy_init(struct wm97xx *wm)
{
    u16 dig1 = 0;
    u16 dig2 = WM97XX_RPR | WM9712_RPU(1);

    /* WM9712 rpu */
    if (rpu) {
        dig2 &= 0xffc0;
        dig2 |= WM9712_RPU(rpu);
        dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms",
            64000 / rpu);
    }

    /* WM9712 five wire */
    if (five_wire) {
        dig2 |= WM9712_45W;
        dev_dbg(wm->dev, "setting 5-wire touchscreen mode.");

        if (pil) {
            dev_warn(wm->dev, "pressure measurement is not "
                 "supported in 5-wire mode\n");
            pil = 0;
        }
    }

    /* touchpanel pressure current*/
    if (pil == 2) {
        dig2 |= WM9712_PIL;
        dev_dbg(wm->dev,
            "setting pressure measurement current to 400uA.");
    } else if (pil)
        dev_dbg(wm->dev,
            "setting pressure measurement current to 200uA.");
    if (!pil)
        pressure = 0;

    /* polling mode sample settling delay */
    if (delay < 0 || delay > 15) {
        dev_dbg(wm->dev, "supplied delay out of range.");
        delay = 4;
    }
    dig1 &= 0xff0f;
    dig1 |= WM97XX_DELAY(delay);
    dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
        delay_table[delay]);

    /* mask */
    dig2 |= ((mask & 0x3) << 6);
    if (mask) {
        u16 reg;
        /* Set GPIO4 as Mask Pin*/
        reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
        wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
        reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
        wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
    }

    /* wait - coord mode */
    if (coord)
        dig2 |= WM9712_WAIT;

    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
}

static void wm9712_dig_enable(struct wm97xx *wm, int enable)
{
    u16 dig2 = wm->dig[2];

    if (enable) {
        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
                 dig2 | WM97XX_PRP_DET_DIG);
        wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
    } else
        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
                 dig2 & ~WM97XX_PRP_DET_DIG);
}

static void wm9712_aux_prepare(struct wm97xx *wm)
{
    memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
}

static void wm9712_dig_restore(struct wm97xx *wm)
{
    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
}

static inline int is_pden(struct wm97xx *wm)
{
    return wm->dig[2] & WM9712_PDEN;
}

/*
 * Read a sample from the WM9712 adc in polling mode.
 */
static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
{
    int timeout = 5 * delay;
    bool wants_pen = adcsel & WM97XX_PEN_DOWN;

    if (wants_pen && !wm->pen_probably_down) {
        u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
        if (!(data & WM97XX_PEN_DOWN))
            return RC_PENUP;
        wm->pen_probably_down = 1;
    }

    /* set up digitiser */
    if (wm->mach_ops && wm->mach_ops->pre_sample)
        wm->mach_ops->pre_sample(adcsel);
    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
                | WM97XX_POLL | WM97XX_DELAY(delay));

    /* wait 3 AC97 time slots + delay for conversion */
    poll_delay(delay);

    /* wait for POLL to go low */
    while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
           && timeout) {
        udelay(AC97_LINK_FRAME);
        timeout--;
    }

    if (timeout <= 0) {
        /* If PDEN is set, we can get a timeout when pen goes up */
        if (is_pden(wm))
            wm->pen_probably_down = 0;
        else
            dev_dbg(wm->dev, "adc sample timeout");
        return RC_PENUP;
    }

    *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
    if (wm->mach_ops && wm->mach_ops->post_sample)
        wm->mach_ops->post_sample(adcsel);

    /* check we have correct sample */
    if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
        dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
            adcsel & WM97XX_ADCSEL_MASK,
            *sample & WM97XX_ADCSEL_MASK);
        return RC_PENUP;
    }

    if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
        wm->pen_probably_down = 0;
        return RC_PENUP;
    }

    return RC_VALID;
}

/*
 * Read a coord from the WM9712 adc in polling mode.
 */
static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
{
    int timeout = 5 * delay;

    if (!wm->pen_probably_down) {
        u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
        if (!(data_rd & WM97XX_PEN_DOWN))
            return RC_PENUP;
        wm->pen_probably_down = 1;
    }

    /* set up digitiser */
    if (wm->mach_ops && wm->mach_ops->pre_sample)
        wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);

    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
        WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));

    /* wait 3 AC97 time slots + delay for conversion and read x */
    poll_delay(delay);
    data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
    /* wait for POLL to go low */
    while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
           && timeout) {
        udelay(AC97_LINK_FRAME);
        timeout--;
    }

    if (timeout <= 0) {
        /* If PDEN is set, we can get a timeout when pen goes up */
        if (is_pden(wm))
            wm->pen_probably_down = 0;
        else
            dev_dbg(wm->dev, "adc sample timeout");
        return RC_PENUP;
    }

    /* read back y data */
    data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
    if (pil)
        data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
    else
        data->p = DEFAULT_PRESSURE;

    if (wm->mach_ops && wm->mach_ops->post_sample)
        wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);

    /* check we have correct sample */
    if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
        goto err;
    if (pil && !(data->p & WM97XX_ADCSEL_PRES))
        goto err;

    if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
        wm->pen_probably_down = 0;
        return RC_PENUP;
    }
    return RC_VALID;
err:
    return 0;
}

/*
 * Sample the WM9712 touchscreen in polling mode
 */
static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
{
    int rc;

    if (coord) {
        rc = wm9712_poll_coord(wm, data);
        if (rc != RC_VALID)
            return rc;
    } else {
        rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN,
                    &data->x);
        if (rc != RC_VALID)
            return rc;

        rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN,
                    &data->y);
        if (rc != RC_VALID)
            return rc;

        if (pil && !five_wire) {
            rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
                        &data->p);
            if (rc != RC_VALID)
                return rc;
        } else
            data->p = DEFAULT_PRESSURE;
    }
    return RC_VALID;
}

/*
 * Enable WM9712 continuous mode, i.e. touch data is streamed across
 * an AC97 slot
 */
static int wm9712_acc_enable(struct wm97xx *wm, int enable)
{
    u16 dig1, dig2;
    int ret = 0;

    dig1 = wm->dig[1];
    dig2 = wm->dig[2];

    if (enable) {
        /* continuous mode */
        if (wm->mach_ops->acc_startup) {
            ret = wm->mach_ops->acc_startup(wm);
            if (ret < 0)
                return ret;
        }
        dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
            WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
        dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
            WM97XX_DELAY(delay) |
            WM97XX_SLT(wm->acc_slot) |
            WM97XX_RATE(wm->acc_rate);
        if (pil)
            dig1 |= WM97XX_ADCSEL_PRES;
        dig2 |= WM9712_PDEN;
    } else {
        dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
        dig2 &= ~WM9712_PDEN;
        if (wm->mach_ops->acc_shutdown)
            wm->mach_ops->acc_shutdown(wm);
    }

    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
    wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);

    return 0;
}

struct wm97xx_codec_drv wm9712_codec = {
    .id = WM9712_ID2,
    .name = "wm9712",
    .poll_sample = wm9712_poll_sample,
    .poll_touch = wm9712_poll_touch,
    .acc_enable = wm9712_acc_enable,
    .phy_init = wm9712_phy_init,
    .dig_enable = wm9712_dig_enable,
    .dig_restore = wm9712_dig_restore,
    .aux_prepare = wm9712_aux_prepare,
};
EXPORT_SYMBOL_GPL(wm9712_codec);

/* Module information */
MODULE_AUTHOR("Liam Girdwood <[email protected]>");
MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
MODULE_LICENSE("GPL");