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linux/drivers/input/touchscreen/wm9705.c
Mark Brown 9448cefc66 Input: WM97xx - add chip driver for WM9705 touchscreen 
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>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2008-04-02 00:51:21 -04:00

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/*
* 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");
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