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Release 4.11 drivers/input/touchscreen/wm9705.c

/*
 * wm9705.c  --  Codec driver for Wolfson WM9705 AC97 Codec.
 *
 * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
 * Author: Liam Girdwood <lrg@slimlogic.co.uk>
 * 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/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]); }

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/* * 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); }

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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); }

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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); }

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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]); }

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static inline int is_pden(struct wm97xx *wm) { return wm->dig[2] & WM9705_PDEN; }

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/* * 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; 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; }

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/* * 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 | WM97XX_PEN_DOWN, &data->x); if (rc != RC_VALID) return rc; rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y); if (rc != RC_VALID) return rc; if (pil) { rc = wm9705_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; }

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/* * 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) { /* continuous 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; }

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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 <lrg@slimlogic.co.uk>"); MODULE_DESCRIPTION("WM9705 Touch Screen Driver"); MODULE_LICENSE("GPL");

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