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    Subject[PATCH 2/6] Add chip driver for WM9705 touchscreen
    Date
    Signed-off-by: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
    Signed-off-by: Graeme Gregory <gg@opensource.wolfsonmicro.com>
    Signed-off-by: Mike Arthur <mike.arthur@wolfsonmicro.com>
    Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
    Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
    Cc: Stanley Cai <stanley.cai@intel.com>
    Cc: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
    Cc: Rodolfo Giometti <giometti@enneenne.com>
    Cc: Russell King <rmk@arm.linux.org.uk>
    Cc: Marc Kleine-Budde <mkl@pengutronix.de>
    Cc: Pete MacKay <linux01@architechnical.net>
    Cc: Ian Molton <spyro@f2s.com>
    Cc: Vince Sanders <vince@kyllikki.org>
    Cc: Andrew Zabolotny <zap@homelink.ru>
    ---
    drivers/input/touchscreen/wm9705.c | 352 ++++++++++++++++++++++++++++++++++++
    1 files changed, 352 insertions(+), 0 deletions(-)
    create mode 100644 drivers/input/touchscreen/wm9705.c

    diff --git a/drivers/input/touchscreen/wm9705.c b/drivers/input/touchscreen/wm9705.c
    new file mode 100644
    index 0000000..d4008f9
    --- /dev/null
    +++ b/drivers/input/touchscreen/wm9705.c
    @@ -0,0 +1,352 @@
    +/*
    + * wm9705.c -- Codec driver for Wolfson WM9705 AC97 Codec.
    + *
    + * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
    + * Author: Liam Girdwood
    + * liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com
    + * Parts Copyright : Ian Molton <spyro@f2s.com>
    + * Andrew Zabolotny <zap@homelink.ru>
    + * Russell King <rmk@arm.linux.org.uk>
    + *
    + * 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/version.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 WM9705_VERSION "1.00"
    +#define DEFAULT_PRESSURE 0xb0c0
    +
    +/*
    + * Module parameters
    + */
    +
    +/*
    + * 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 = 4;
    +module_param(delay, int, 0);
    +MODULE_PARM_DESC(delay, "Set adc sample delay.");
    +
    +/*
    + * Pen detect comparator threshold.
    + *
    + * 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold
    + * i.e. 1 = Vmid/15 threshold
    + * 15 = Vmid/1 threshold
    + *
    + * Adjust this value if you are having problems with pen detect not
    + * detecting any down events.
    + */
    +static int pdd = 8;
    +module_param(pdd, int, 0);
    +MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold");
    +
    +/*
    + * 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.");
    +
    +/*
    + * 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 WM9705
    + */
    +static void wm9705_phy_init(struct wm97xx *wm)
    +{
    + u16 dig1 = 0, dig2 = WM97XX_RPR;
    +
    + /*
    + * mute VIDEO and AUX as they share X and Y touchscreen
    + * inputs on the WM9705
    + */
    + wm97xx_reg_write(wm, AC97_AUX, 0x8000);
    + wm97xx_reg_write(wm, AC97_VIDEO, 0x8000);
    +
    + /* touchpanel pressure current*/
    + if (pil == 2) {
    + dig2 |= WM9705_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 != 4) {
    + 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]);
    +
    + /* WM9705 pdd */
    + dig2 |= (pdd & 0x000f);
    + dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f));
    +
    + /* mask */
    + dig2 |= ((mask & 0x3) << 4);
    +
    + wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
    + wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
    +}
    +
    +static void wm9705_dig_enable(struct wm97xx *wm, int enable)
    +{
    + if (enable) {
    + wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
    + wm->dig[2] | WM97XX_PRP_DET_DIG);
    + wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
    + } else
    + wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
    + wm->dig[2] & ~WM97XX_PRP_DET_DIG);
    +}
    +
    +static void wm9705_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 wm9705_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] & WM9705_PDEN;
    +}
    +
    +/*
    + * Read a sample from the WM9705 adc in polling mode.
    + */
    +static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
    +{
    + int timeout = 5 * delay;
    +
    + if (!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 (adcsel & 0x8000)
    + adcsel = ((adcsel & 0x7fff) + 3) << 12;
    +
    + if (wm->mach_ops && wm->mach_ops->pre_sample)
    + wm->mach_ops->pre_sample(adcsel);
    + wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
    + adcsel | 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 & WM97XX_ADCSEL_MASK) != adcsel) {
    + dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
    + *sample & WM97XX_ADCSEL_MASK);
    + return RC_PENUP;
    + }
    +
    + if (!(*sample & WM97XX_PEN_DOWN)) {
    + wm->pen_probably_down = 0;
    + return RC_PENUP;
    + }
    +
    + return RC_VALID;
    +}
    +
    +/*
    + * Sample the WM9705 touchscreen in polling mode
    + */
    +static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
    +{
    + int rc;
    +
    + rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X, &data->x);
    + if (rc != RC_VALID)
    + return rc;
    + rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y, &data->y);
    + if (rc != RC_VALID)
    + return rc;
    + if (pil) {
    + rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES, &data->p);
    + if (rc != RC_VALID)
    + return rc;
    + } else
    + data->p = DEFAULT_PRESSURE;
    +
    + return RC_VALID;
    +}
    +
    +/*
    + * Enable WM9705 continuous mode, i.e. touch data is streamed across
    + * an AC97 slot
    + */
    +static int wm9705_acc_enable(struct wm97xx *wm, int enable)
    +{
    + u16 dig1, dig2;
    + int ret = 0;
    +
    + dig1 = wm->dig[1];
    + dig2 = wm->dig[2];
    +
    + if (enable) {
    + /* continous mode */
    + if (wm->mach_ops->acc_startup &&
    + (ret = wm->mach_ops->acc_startup(wm)) < 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 |= WM9705_PDEN;
    + } else {
    + dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
    + dig2 &= ~WM9705_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 ret;
    +}
    +
    +struct wm97xx_codec_drv wm9705_codec = {
    + .id = WM9705_ID2,
    + .name = "wm9705",
    + .poll_sample = wm9705_poll_sample,
    + .poll_touch = wm9705_poll_touch,
    + .acc_enable = wm9705_acc_enable,
    + .phy_init = wm9705_phy_init,
    + .dig_enable = wm9705_dig_enable,
    + .dig_restore = wm9705_dig_restore,
    + .aux_prepare = wm9705_aux_prepare,
    +};
    +EXPORT_SYMBOL_GPL(wm9705_codec);
    +
    +/* Module information */
    +MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
    +MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
    +MODULE_LICENSE("GPL");
    --
    1.5.4.5


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