linux/drivers/input/touchscreen/tsc2007.c

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/*
* drivers/input/touchscreen/tsc2007.c
*
* Copyright (c) 2008 MtekVision Co., Ltd.
* Kwangwoo Lee <kwlee@mtekvision.com>
*
* Using code from:
* - ads7846.c
* Copyright (c) 2005 David Brownell
* Copyright (c) 2006 Nokia Corporation
* - 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
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/hrtimer.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/i2c/tsc2007.h>
#define TS_POLL_DELAY (10 * 1000) /* ns delay before the first sample */
#define TS_POLL_PERIOD (5 * 1000) /* ns delay between samples */
#define TSC2007_MEASURE_TEMP0 (0x0 << 4)
#define TSC2007_MEASURE_AUX (0x2 << 4)
#define TSC2007_MEASURE_TEMP1 (0x4 << 4)
#define TSC2007_ACTIVATE_XN (0x8 << 4)
#define TSC2007_ACTIVATE_YN (0x9 << 4)
#define TSC2007_ACTIVATE_YP_XN (0xa << 4)
#define TSC2007_SETUP (0xb << 4)
#define TSC2007_MEASURE_X (0xc << 4)
#define TSC2007_MEASURE_Y (0xd << 4)
#define TSC2007_MEASURE_Z1 (0xe << 4)
#define TSC2007_MEASURE_Z2 (0xf << 4)
#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2)
#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2)
#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2)
#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2)
#define TSC2007_12BIT (0x0 << 1)
#define TSC2007_8BIT (0x1 << 1)
#define MAX_12BIT ((1 << 12) - 1)
#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y)
#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X)
#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
struct ts_event {
u16 x;
u16 y;
u16 z1, z2;
};
struct tsc2007 {
struct input_dev *input;
char phys[32];
struct hrtimer timer;
struct ts_event tc;
struct i2c_client *client;
spinlock_t lock;
u16 model;
u16 x_plate_ohms;
unsigned pendown;
int irq;
int (*get_pendown_state)(void);
void (*clear_penirq)(void);
};
static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
{
s32 data;
u16 val;
data = i2c_smbus_read_word_data(tsc->client, cmd);
if (data < 0) {
dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
return data;
}
/* The protocol and raw data format from i2c interface:
* S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
* Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
*/
val = swab16(data) >> 4;
dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
return val;
}
static void tsc2007_send_event(void *tsc)
{
struct tsc2007 *ts = tsc;
u32 rt;
u16 x, y, z1, z2;
x = ts->tc.x;
y = ts->tc.y;
z1 = ts->tc.z1;
z2 = ts->tc.z2;
/* range filtering */
if (x == MAX_12BIT)
x = 0;
if (likely(x && z1)) {
/* compute touch pressure resistance using equation #1 */
rt = z2;
rt -= z1;
rt *= x;
rt *= ts->x_plate_ohms;
rt /= z1;
rt = (rt + 2047) >> 12;
} else
rt = 0;
/* Sample found inconsistent by debouncing or pressure is beyond
* the maximum. Don't report it to user space, repeat at least
* once more the measurement
*/
if (rt > MAX_12BIT) {
dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
HRTIMER_MODE_REL);
return;
}
/* NOTE: We can't rely on the pressure to determine the pen down
* state, even this controller has a pressure sensor. The pressure
* value can fluctuate for quite a while after lifting the pen and
* in some cases may not even settle at the expected value.
*
* The only safe way to check for the pen up condition is in the
* timer by reading the pen signal state (it's a GPIO _and_ IRQ).
*/
if (rt) {
struct input_dev *input = ts->input;
if (!ts->pendown) {
dev_dbg(&ts->client->dev, "DOWN\n");
input_report_key(input, BTN_TOUCH, 1);
ts->pendown = 1;
}
input_report_abs(input, ABS_X, x);
input_report_abs(input, ABS_Y, y);
input_report_abs(input, ABS_PRESSURE, rt);
input_sync(input);
dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
x, y, rt);
}
hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
HRTIMER_MODE_REL);
}
static int tsc2007_read_values(struct tsc2007 *tsc)
{
/* y- still on; turn on only y+ (and ADC) */
tsc->tc.y = tsc2007_xfer(tsc, READ_Y);
/* turn y- off, x+ on, then leave in lowpower */
tsc->tc.x = tsc2007_xfer(tsc, READ_X);
/* turn y+ off, x- on; we'll use formula #1 */
tsc->tc.z1 = tsc2007_xfer(tsc, READ_Z1);
tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2);
/* power down */
tsc2007_xfer(tsc, PWRDOWN);
return 0;
}
static enum hrtimer_restart tsc2007_timer(struct hrtimer *handle)
{
struct tsc2007 *ts = container_of(handle, struct tsc2007, timer);
unsigned long flags;
spin_lock_irqsave(&ts->lock, flags);
if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
struct input_dev *input = ts->input;
dev_dbg(&ts->client->dev, "UP\n");
input_report_key(input, BTN_TOUCH, 0);
input_report_abs(input, ABS_PRESSURE, 0);
input_sync(input);
ts->pendown = 0;
enable_irq(ts->irq);
} else {
/* pen is still down, continue with the measurement */
dev_dbg(&ts->client->dev, "pen is still down\n");
tsc2007_read_values(ts);
tsc2007_send_event(ts);
}
spin_unlock_irqrestore(&ts->lock, flags);
return HRTIMER_NORESTART;
}
static irqreturn_t tsc2007_irq(int irq, void *handle)
{
struct tsc2007 *ts = handle;
unsigned long flags;
spin_lock_irqsave(&ts->lock, flags);
if (likely(ts->get_pendown_state())) {
disable_irq_nosync(ts->irq);
hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
HRTIMER_MODE_REL);
}
if (ts->clear_penirq)
ts->clear_penirq();
spin_unlock_irqrestore(&ts->lock, flags);
return IRQ_HANDLED;
}
static int tsc2007_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct tsc2007 *ts;
struct tsc2007_platform_data *pdata = pdata = client->dev.platform_data;
struct input_dev *input_dev;
int err;
if (!pdata || !pdata->get_pendown_state) {
dev_err(&client->dev, "platform data is required!\n");
return -EINVAL;
}
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_WORD_DATA))
return -EIO;
ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
input_dev = input_allocate_device();
if (!ts || !input_dev) {
err = -ENOMEM;
goto err_free_mem;
}
ts->client = client;
i2c_set_clientdata(client, ts);
ts->input = input_dev;
hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
ts->timer.function = tsc2007_timer;
spin_lock_init(&ts->lock);
ts->model = pdata->model;
ts->x_plate_ohms = pdata->x_plate_ohms;
ts->get_pendown_state = pdata->get_pendown_state;
ts->clear_penirq = pdata->clear_penirq;
pdata->init_platform_hw();
snprintf(ts->phys, sizeof(ts->phys),
"%s/input0", dev_name(&client->dev));
input_dev->name = "TSC2007 Touchscreen";
input_dev->phys = ts->phys;
input_dev->id.bustype = BUS_I2C;
input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
tsc2007_read_values(ts);
ts->irq = client->irq;
err = request_irq(ts->irq, tsc2007_irq, 0,
client->dev.driver->name, ts);
if (err < 0) {
dev_err(&client->dev, "irq %d busy?\n", ts->irq);
goto err_free_mem;
}
err = input_register_device(input_dev);
if (err)
goto err_free_irq;
dev_info(&client->dev, "registered with irq (%d)\n", ts->irq);
return 0;
err_free_irq:
free_irq(ts->irq, ts);
hrtimer_cancel(&ts->timer);
err_free_mem:
input_free_device(input_dev);
kfree(ts);
return err;
}
static int tsc2007_remove(struct i2c_client *client)
{
struct tsc2007 *ts = i2c_get_clientdata(client);
struct tsc2007_platform_data *pdata;
pdata = client->dev.platform_data;
pdata->exit_platform_hw();
free_irq(ts->irq, ts);
hrtimer_cancel(&ts->timer);
input_unregister_device(ts->input);
kfree(ts);
return 0;
}
static struct i2c_device_id tsc2007_idtable[] = {
{ "tsc2007", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
static struct i2c_driver tsc2007_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "tsc2007"
},
.id_table = tsc2007_idtable,
.probe = tsc2007_probe,
.remove = tsc2007_remove,
};
static int __init tsc2007_init(void)
{
return i2c_add_driver(&tsc2007_driver);
}
static void __exit tsc2007_exit(void)
{
i2c_del_driver(&tsc2007_driver);
}
module_init(tsc2007_init);
module_exit(tsc2007_exit);
MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
MODULE_LICENSE("GPL");