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/*
* AD7879/AD7889 based touchscreen and GPIO driver
*
* Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*
* History:
* Copyright (c) 2005 David Brownell
* Copyright (c) 2006 Nokia Corporation
* Various changes: Imre Deak <imre.deak@nokia.com>
*
* Using code from:
* - corgi_ts.c
* Copyright (C) 2004-2005 Richard Purdie
* - omap_ts.[hc], ads7846.h, ts_osk.c
* Copyright (C) 2002 MontaVista Software
* Copyright (C) 2004 Texas Instruments
* Copyright (C) 2005 Dirk Behme
* - ad7877.c
* Copyright (C) 2006-2008 Analog Devices Inc.
*/
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/input/touchscreen.h>
#include <linux/platform_data/ad7879.h>
#include <linux/module.h>
#include "ad7879.h"
#define AD7879_REG_ZEROS 0
#define AD7879_REG_CTRL1 1
#define AD7879_REG_CTRL2 2
#define AD7879_REG_CTRL3 3
#define AD7879_REG_AUX1HIGH 4
#define AD7879_REG_AUX1LOW 5
#define AD7879_REG_TEMP1HIGH 6
#define AD7879_REG_TEMP1LOW 7
#define AD7879_REG_XPLUS 8
#define AD7879_REG_YPLUS 9
#define AD7879_REG_Z1 10
#define AD7879_REG_Z2 11
#define AD7879_REG_AUXVBAT 12
#define AD7879_REG_TEMP 13
#define AD7879_REG_REVID 14
/* Control REG 1 */
#define AD7879_TMR(x) ((x & 0xFF) << 0)
#define AD7879_ACQ(x) ((x & 0x3) << 8)
#define AD7879_MODE_NOC (0 << 10) /* Do not convert */
#define AD7879_MODE_SCC (1 << 10) /* Single channel conversion */
#define AD7879_MODE_SEQ0 (2 << 10) /* Sequence 0 in Slave Mode */
#define AD7879_MODE_SEQ1 (3 << 10) /* Sequence 1 in Master Mode */
#define AD7879_MODE_INT (1 << 15) /* PENIRQ disabled INT enabled */
/* Control REG 2 */
#define AD7879_FCD(x) ((x & 0x3) << 0)
#define AD7879_RESET (1 << 4)
#define AD7879_MFS(x) ((x & 0x3) << 5)
#define AD7879_AVG(x) ((x & 0x3) << 7)
#define AD7879_SER (1 << 9) /* non-differential */
#define AD7879_DFR (0 << 9) /* differential */
#define AD7879_GPIOPOL (1 << 10)
#define AD7879_GPIODIR (1 << 11)
#define AD7879_GPIO_DATA (1 << 12)
#define AD7879_GPIO_EN (1 << 13)
#define AD7879_PM(x) ((x & 0x3) << 14)
#define AD7879_PM_SHUTDOWN (0)
#define AD7879_PM_DYN (1)
#define AD7879_PM_FULLON (2)
/* Control REG 3 */
#define AD7879_TEMPMASK_BIT (1<<15)
#define AD7879_AUXVBATMASK_BIT (1<<14)
#define AD7879_INTMODE_BIT (1<<13)
#define AD7879_GPIOALERTMASK_BIT (1<<12)
#define AD7879_AUXLOW_BIT (1<<11)
#define AD7879_AUXHIGH_BIT (1<<10)
#define AD7879_TEMPLOW_BIT (1<<9)
#define AD7879_TEMPHIGH_BIT (1<<8)
#define AD7879_YPLUS_BIT (1<<7)
#define AD7879_XPLUS_BIT (1<<6)
#define AD7879_Z1_BIT (1<<5)
#define AD7879_Z2_BIT (1<<4)
#define AD7879_AUX_BIT (1<<3)
#define AD7879_VBAT_BIT (1<<2)
#define AD7879_TEMP_BIT (1<<1)
enum {
AD7879_SEQ_YPOS = 0,
AD7879_SEQ_XPOS = 1,
AD7879_SEQ_Z1 = 2,
AD7879_SEQ_Z2 = 3,
AD7879_NR_SENSE = 4,
};
#define MAX_12BIT ((1<<12)-1)
#define TS_PEN_UP_TIMEOUT msecs_to_jiffies(50)
struct ad7879 {
struct regmap *regmap;
struct device *dev;
struct input_dev *input;
struct timer_list timer;
#ifdef CONFIG_GPIOLIB
struct gpio_chip gc;
struct mutex mutex;
#endif
unsigned int irq;
bool disabled; /* P: input->mutex */
bool suspended; /* P: input->mutex */
bool swap_xy;
u16 conversion_data[AD7879_NR_SENSE];
char phys[32];
u8 first_conversion_delay;
u8 acquisition_time;
u8 averaging;
u8 pen_down_acc_interval;
u8 median;
u16 x_plate_ohms;
u16 cmd_crtl1;
u16 cmd_crtl2;
u16 cmd_crtl3;
int x;
int y;
int Rt;
};
static int ad7879_read(struct ad7879 *ts, u8 reg)
{
unsigned int val;
int error;
error = regmap_read(ts->regmap, reg, &val);
if (error) {
dev_err(ts->dev, "failed to read register %#02x: %d\n",
reg, error);
return error;
}
return val;
}
static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
{
int error;
error = regmap_write(ts->regmap, reg, val);
if (error) {
dev_err(ts->dev,
"failed to write %#04x to register %#02x: %d\n",
val, reg, error);
return error;
}
return 0;
}
static int ad7879_report(struct ad7879 *ts)
{
struct input_dev *input_dev = ts->input;
unsigned Rt;
u16 x, y, z1, z2;
x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
if (ts->swap_xy)
swap(x, y);
/*
* The samples processed here are already preprocessed by the AD7879.
* The preprocessing function consists of a median and an averaging
* filter. The combination of these two techniques provides a robust
* solution, discarding the spurious noise in the signal and keeping
* only the data of interest. The size of both filters is
* programmable. (dev.platform_data, see linux/platform_data/ad7879.h)
* Other user-programmable conversion controls include variable
* acquisition time, and first conversion delay. Up to 16 averages can
* be taken per conversion.
*/
if (likely(x && z1)) {
/* compute touch pressure resistance using equation #1 */
Rt = (z2 - z1) * x * ts->x_plate_ohms;
Rt /= z1;
Rt = (Rt + 2047) >> 12;
/*
* Sample found inconsistent, pressure is beyond
* the maximum. Don't report it to user space.
*/
if (Rt > input_abs_get_max(input_dev, ABS_PRESSURE))
return -EINVAL;
/*
* Note that we delay reporting events by one sample.
* This is done to avoid reporting last sample of the
* touch sequence, which may be incomplete if finger
* leaves the surface before last reading is taken.
*/
if (timer_pending(&ts->timer)) {
/* Touch continues */
input_report_key(input_dev, BTN_TOUCH, 1);
input_report_abs(input_dev, ABS_X, ts->x);
input_report_abs(input_dev, ABS_Y, ts->y);
input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
input_sync(input_dev);
}
ts->x = x;
ts->y = y;
ts->Rt = Rt;
return 0;
}
return -EINVAL;
}
static void ad7879_ts_event_release(struct ad7879 *ts)
{
struct input_dev *input_dev = ts->input;
input_report_abs(input_dev, ABS_PRESSURE, 0);
input_report_key(input_dev, BTN_TOUCH, 0);
input_sync(input_dev);
}
static void ad7879_timer(unsigned long handle)
{
struct ad7879 *ts = (void *)handle;
ad7879_ts_event_release(ts);
}
static irqreturn_t ad7879_irq(int irq, void *handle)
{
struct ad7879 *ts = handle;
regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS,
ts->conversion_data, AD7879_NR_SENSE);
if (!ad7879_report(ts))
mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
return IRQ_HANDLED;
}
static void __ad7879_enable(struct ad7879 *ts)
{
ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
enable_irq(ts->irq);
}
static void __ad7879_disable(struct ad7879 *ts)
{
u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) |
AD7879_PM(AD7879_PM_SHUTDOWN);
disable_irq(ts->irq);
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