// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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 <[email protected]>
* based on TSC2301 driver by Klaus K. Pedersen <[email protected]>
*/
#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_read = true,
.use_single_write = 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;
struct touchscreen_properties prop;
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 gpio_desc *reset_gpio;
int (*tsc200x_cmd)(struct device *dev, u8 cmd);
int irq;
bool wake_irq_enabled;
};
static void tsc200x_update_pen_state(struct tsc200x *ts,
int x, int y, int pressure)
{
if (pressure) {
touchscreen_report_pos(ts->idev, &ts->prop, x, y, false);
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 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;
scoped_guard(spinlock_irqsave, &ts->lock) {
tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
mod_timer(&ts->penup_timer,
jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
}
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);
guard(spinlock_irqsave)(&ts->lock);
tsc200x_update_pen_state(ts, 0, 0, 0);
}
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) {
gpiod_set_value_cansleep(ts->reset_gpio, 1);
usleep_range(100, 500); /* only 10us required */
gpiod_set_value_cansleep(ts->reset_gpio, 0);
}
}
/* must be called with ts->mutex held */
static void __tsc200x_disable(struct tsc200x *ts)
{
tsc200x_stop_scan(ts);
guard(disable_irq)(&ts->irq);
del_timer_sync(&ts->penup_timer);
cancel_delayed_work_sync(&ts->esd_work);
}
/* must be called with ts->mutex held */
static void __tsc200x_enable(struct tsc200x *ts)
{
tsc200x_start_scan(ts);
if (ts->esd_timeout && ts->reset_gpio) {
ts->last_valid_interrupt = jiffies;
schedule_delayed_work(&ts->esd_work,
round_jiffies_relative(
msecs_to_jiffies(ts->esd_timeout)));
}
}
/*
* Test TSC200X communications via temp high register.
*/
static int tsc200x_do_selftest(struct tsc200x *ts)
{
unsigned int temp_high_orig;
unsigned int temp_high_test;
unsigned int temp_high;
int error;
error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
if (error) {
dev_warn(ts->dev, "selftest failed: read error %d\n", error);
return error;
}
temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
if (error) {
dev_warn(ts->dev, "selftest failed: write error %d\n", error);
return error;
}
error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
if (error) {
dev_warn(ts->dev,
"selftest failed: read error %d after write\n", error);
return error;
}
/* hardware reset */
tsc200x_reset(ts);
if (temp_high != temp_high_test) {
dev_warn(ts->dev, "selftest failed: %d != %d\n",
temp_high, temp_high_test);
return -EINVAL;
}
/* test that the reset really happened */
error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
if (error) {
dev_warn(ts->dev,
"selftest failed: read error %d after reset\n", error);
return error;
}
if (temp_high != temp_high_orig) {
dev_warn(ts->dev, "selftest failed after reset: %d != %d\n",
temp_high, temp_high_orig);
return -EINVAL;
}
return 0;
}
static ssize_t tsc200x_selftest_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct tsc200x *ts = dev_get_drvdata(dev);
int error;
scoped_guard(mutex, &ts->mutex) {
__tsc200x_disable(ts);
error = tsc200x_do_selftest(ts);
__tsc200x_enable(ts);
}
return sprintf(buf, "%d\n", !error);
}
static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
static struct attribute *tsc200x_attrs[] = {
&dev_attr_selftest.attr,
NULL
};
static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
struct attribute *attr, int n)
{
struct device *dev = kobj_to_dev(kobj);
struct tsc200x *ts = dev_get_drvdata(dev);
umode_t mode = attr->mode;
if (attr == &dev_attr_selftest.attr) {
if (!ts->reset_gpio)
mode = 0;
}
return mode;
}
static const struct attribute_group tsc200x_attr_group = {
.is_visible = tsc200x_attr_is_visible,
.attrs = tsc200x_attrs,
};
const struct attribute_group *tsc200x_groups[] = {
&tsc200x_attr_group,
NULL
};
EXPORT_SYMBOL_GPL(tsc200x_groups);
static void tsc200x_esd_work(struct work_struct *work)
{
struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
int error;
unsigned int r;
/*
* If the mutex is taken, it means that disable or enable is in
* progress. In that case just reschedule the work. If the work
* is not needed, it will be canceled by disable.
*/
scoped_guard(mutex_try, &ts->mutex) {
if (time_is_after_jiffies(ts->last_valid_interrupt +
msecs_to_jiffies(ts->esd_timeout)))
break;
/*
* We should be able to read register without disabling
* interrupts.
*/
error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
if (!error &&
!((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
break;
}
/*
* If we could not read our known value from configuration
* register 0 then we should reset the controller as if from
* power-up and start scanning again.
*/
dev_info(ts->dev, "TSC200X not responding - resetting\n");
scoped_guard(disable_irq, &ts->irq) {
del_timer_sync(&ts->penup_timer);
tsc200x_update_pen_state(ts, 0, 0, 0);
tsc200x_reset(ts);
}
tsc200x_start_scan(ts);
}
/* re-arm the watchdog */
schedule_delayed_work(&ts->esd_work,
round_jiffies_relative(
msecs_to_jiffies(ts->esd_timeout)));
}
static int tsc200x_open(struct input_dev *input)
{
struct tsc200x *ts = input_get_drvdata(input);
guard(mutex)(&ts->mutex);
if (!ts->suspended)
__tsc200x_enable(ts);
ts->opened = true;
return 0;
}
static void tsc200x_close(struct input_dev *input)
{
struct tsc200x *ts = input_get_drvdata(input);
guard(mutex)(&ts->mutex);
if (!ts->suspended)
__tsc200x_disable(ts);
ts->opened = false;
}
int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
struct regmap *regmap,
int (*tsc200x_cmd)(struct device *dev, u8 cmd))
{
struct tsc200x *ts;
struct input_dev *input_dev;
u32 x_plate_ohm;
u32 esd_timeout;
int error;
if (irq <= 0) {
dev_err(dev, "no irq\n");
return -ENODEV;
}
if (IS_ERR(regmap))
return PTR_ERR(regmap);
if (!tsc200x_cmd) {
dev_err(dev, "no cmd function\n");
return -ENODEV;
}
ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
if (!ts)
return -ENOMEM;
input_dev = devm_input_allocate_device(dev);
if (!input_dev)
return -ENOMEM;
ts->irq = irq;
ts->dev = dev;
ts->idev = input_dev;
ts->regmap = regmap;
ts->tsc200x_cmd = tsc200x_cmd;
error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
&esd_timeout);
ts->esd_timeout = error ? 0 : esd_timeout;
mutex_init(&ts->mutex);
spin_lock_init(&ts->lock);
timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
snprintf(ts->phys, sizeof(ts->phys),
"%s/input-ts", dev_name(dev));
if (tsc_id->product == 2004) {
input_dev->name = "TSC200X touchscreen";
} else {
input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
"TSC%04d touchscreen",
tsc_id->product);
if (!input_dev->name)
return -ENOMEM;
}
input_dev->phys = ts->phys;
input_dev->id = *tsc_id;
input_dev->open = tsc200x_open;
input_dev->close = tsc200x_close;
input_set_drvdata(input_dev, ts);
__set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
input_set_abs_params(input_dev, ABS_X,
0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
input_set_abs_params(input_dev, ABS_Y,
0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
input_set_abs_params(input_dev, ABS_PRESSURE,
0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
touchscreen_parse_properties(input_dev, false, &ts->prop);
ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
error = PTR_ERR_OR_ZERO(ts->reset_gpio);
if (error) {
dev_err(dev, "error acquiring reset gpio: %d\n", error);
return error;
}
error = devm_regulator_get_enable(dev, "vio");
if (error) {
dev_err(dev, "error acquiring vio regulator: %d\n", error);
return error;
}
tsc200x_reset(ts);
/* Ensure the touchscreen is off */
tsc200x_stop_scan(ts);
error = devm_request_threaded_irq(dev, irq, NULL, tsc200x_irq_thread,
IRQF_ONESHOT, "tsc200x", ts);
if (error) {
dev_err(dev, "Failed to request irq, err: %d\n", error);
return error;
}
dev_set_drvdata(dev, ts);
error = input_register_device(ts->idev);
if (error) {
dev_err(dev,
"Failed to register input device, err: %d\n", error);
return error;
}
device_init_wakeup(dev,
device_property_read_bool(dev, "wakeup-source"));
return 0;
}
EXPORT_SYMBOL_GPL(tsc200x_probe);
static int tsc200x_suspend(struct device *dev)
{
struct tsc200x *ts = dev_get_drvdata(dev);
guard(mutex)(&ts->mutex);
if (!ts->suspended && ts->opened)
__tsc200x_disable(ts);
ts->suspended = true;
if (device_may_wakeup(dev))
ts->wake_irq_enabled = enable_irq_wake(ts->irq) == 0;
return 0;
}
static int tsc200x_resume(struct device *dev)
{
struct tsc200x *ts = dev_get_drvdata(dev);
guard(mutex)(&ts->mutex);
if (ts->wake_irq_enabled) {
disable_irq_wake(ts->irq);
ts->wake_irq_enabled = false;
}
if (ts->suspended && ts->opened)
__tsc200x_enable(ts);
ts->suspended = false;
return 0;
}
EXPORT_GPL_SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
MODULE_AUTHOR("Lauri Leukkunen <[email protected]>");
MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
MODULE_LICENSE("GPL");
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