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/*
* TSC2004/TSC2005 touchscreen driver core
*
* Copyright (C) 2006-2010 Nokia Corporation
* Copyright (C) 2015 QWERTY Embedded Design
* Copyright (C) 2015 EMAC Inc.
*
* Author: Lauri Leukkunen <lauri.leukkunen@nokia.com>
* based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/input/touchscreen.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/pm.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/regmap.h>
#include <linux/gpio/consumer.h>
#include "tsc200x-core.h"
/*
* The touchscreen interface operates as follows:
*
* 1) Pen is pressed against the touchscreen.
* 2) TSC200X performs AD conversion.
* 3) After the conversion is done TSC200X drives DAV line down.
* 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
* 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
* values.
* 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
* tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
* 7) When the penup timer expires, there have not been touch or DAV interrupts
* during the last 40ms which means the pen has been lifted.
*
* ESD recovery via a hardware reset is done if the TSC200X doesn't respond
* after a configurable period (in ms) of activity. If esd_timeout is 0, the
* watchdog is disabled.
*/
static const struct regmap_range tsc200x_writable_ranges[] = {
regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
};
static const struct regmap_access_table tsc200x_writable_table = {
.yes_ranges = tsc200x_writable_ranges,
.n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
};
const struct regmap_config tsc200x_regmap_config = {
.reg_bits = 8,
.val_bits = 16,
.reg_stride = 0x08,
.max_register = 0x78,
.read_flag_mask = TSC200X_REG_READ,
.write_flag_mask = TSC200X_REG_PND0,
.wr_table = &tsc200x_writable_table,
.use_single_rw = true,
};
EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
struct tsc200x_data {
u16 x;
u16 y;
u16 z1;
u16 z2;
} __packed;
#define TSC200X_DATA_REGS 4
struct tsc200x {
struct device *dev;
struct regmap *regmap;
__u16 bustype;
struct input_dev *idev;
char phys[32];
struct mutex mutex;
/* raw copy of previous x,y,z */
int in_x;
int in_y;
int in_z1;
int in_z2;
spinlock_t lock;
struct timer_list penup_timer;
unsigned int esd_timeout;
struct delayed_work esd_work;
unsigned long last_valid_interrupt;
unsigned int x_plate_ohm;
bool opened;
bool suspended;
bool pen_down;
struct regulator *vio;
struct gpio_desc *reset_gpio;
int (*tsc200x_cmd)(struct device *dev, u8 cmd);
int irq;
};
static void tsc200x_update_pen_state(struct tsc200x *ts,
int x, int y, int pressure)
{
if (pressure) {
input_report_abs(ts->idev, ABS_X, x);
input_report_abs(ts->idev, ABS_Y, y);
input_report_abs(ts->idev, ABS_PRESSURE, pressure);
if (!ts->pen_down) {
input_report_key(ts->idev, BTN_TOUCH, !!pressure);
ts->pen_down = true;
}
} else {
input_report_abs(ts->idev, ABS_PRESSURE, 0);
if (ts->pen_down) {
input_report_key(ts->idev, BTN_TOUCH, 0);
ts->pen_down = false;
}
}
input_sync(ts->idev);
dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
pressure);
}
static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
{
struct tsc200x *ts = _ts;
unsigned long flags;
unsigned int pressure;
struct tsc200x_data tsdata;
int error;
/* read the coordinates */
error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
TSC200X_DATA_REGS);
if (unlikely(error))
goto out;
/* validate position */
if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
goto out;
/* Skip reading if the pressure components are out of range */
if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
goto out;
if (unlikely(tsdata.z1 >= tsdata.z2))
goto out;
/*
* Skip point if this is a pen down with the exact same values as
* the value before pen-up - that implies SPI fed us stale data
*/
if (!ts->pen_down &&
ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
goto out;
}
/*
* At this point we are happy we have a valid and useful reading.
* Remember it for later comparisons. We may now begin downsampling.
*/
ts->in_x = tsdata.x;
ts->in_y = tsdata.y;
ts->in_z1 = tsdata.z1;
ts->in_z2 = tsdata.z2;
/* Compute touch pressure resistance using equation #1 */
pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
pressure = pressure * ts->x_plate_ohm / 4096;
if (unlikely(pressure > MAX_12BIT))
goto out;
spin_lock_irqsave(&ts->lock, flags);
tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
mod_timer(&ts->penup_timer,
jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
spin_unlock_irqrestore(&ts->lock, flags);
ts->last_valid_interrupt = jiffies;
out:
return IRQ_HANDLED;
}
static void tsc200x_penup_timer(struct timer_list *t)
{
struct tsc200x *ts = from_timer(ts, t, penup_timer);
unsigned long flags;
spin_lock_irqsave(&ts->lock, flags);
tsc200x_update_pen_state(ts, 0, 0, 0);
spin_unlock_irqrestore(&ts->lock, flags);
}
static void tsc200x_start_scan(struct tsc200x *ts)
{
regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
}
static void tsc200x_stop_scan(struct tsc200x *ts)
{
ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
}
static void tsc200x_reset(struct tsc200x *ts)
{
if (ts->reset_gpio) {
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