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kernel/drivers/input/touchscreen/wm9712.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* wm9712.c -- Codec driver for Wolfson WM9712 AC97 Codecs.
*
* 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>
*/
#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 resistor 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\n",
64000 / rpu);
}
/* WM9712 five wire */
if (five_wire) {
dig2 |= WM9712_45W;
dev_dbg(wm->dev, "setting 5-wire touchscreen mode.\n");
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.\n");
} else if (pil)
dev_dbg(wm->dev,
"setting pressure measurement current to 200uA.\n");
if (!pil)
pressure = 0;
/* polling mode sample settling delay */
if (delay < 0 || delay > 15) {
dev_dbg(wm->dev, "supplied delay out of range.\n");
delay = 4;
}
dig1 &= 0xff0f;
dig1 |= WM97XX_DELAY(delay);
dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.\n",
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\n");
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\n",
adcsel & WM97XX_ADCSEL_MASK,
*sample & WM97XX_ADCSEL_MASK);
return RC_AGAIN;
}
if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
/* Sometimes it reads a wrong value the first time. */
*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
if (!(*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\n");
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 <lrg@slimlogic.co.uk>");
MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
MODULE_LICENSE("GPL");
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