// SPDX-License-Identifier: GPL-2.0
/*
* Rohm BU21029 touchscreen controller driver
*
* Copyright (C) 2015-2018 Bosch Sicherheitssysteme GmbH
*
* 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/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/touchscreen.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/timer.h>
/*
* HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | HW_IDH |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* HW_ID2 Register (PAGE=0, ADDR=0x0F, Reset value=0x29, Read only)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | HW_IDL |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* HW_IDH: high 8bits of IC's ID
* HW_IDL: low 8bits of IC's ID
*/
#define BU21029_HWID_REG (0x0E << 3)
#define SUPPORTED_HWID 0x0229
/*
* CFR0 Register (PAGE=0, ADDR=0x00, Reset value=0x20)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | 0 | 0 | CALIB | INTRM | 0 | 0 | 0 | 0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* CALIB: 0 = not to use calibration result (*)
* 1 = use calibration result
* INTRM: 0 = INT output depend on "pen down" (*)
* 1 = INT output always "0"
*/
#define BU21029_CFR0_REG (0x00 << 3)
#define CFR0_VALUE 0x00
/*
* CFR1 Register (PAGE=0, ADDR=0x01, Reset value=0xA6)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | MAV | AVE[2:0] | 0 | SMPL[2:0] |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* MAV: 0 = median average filter off
* 1 = median average filter on (*)
* AVE: AVE+1 = number of average samples for MAV,
* if AVE>SMPL, then AVE=SMPL (=3)
* SMPL: SMPL+1 = number of conversion samples for MAV (=7)
*/
#define BU21029_CFR1_REG (0x01 << 3)
#define CFR1_VALUE 0xA6
/*
* CFR2 Register (PAGE=0, ADDR=0x02, Reset value=0x04)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | INTVL_TIME[3:0] | TIME_ST_ADC[3:0] |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* INTVL_TIME: waiting time between completion of conversion
* and start of next conversion, only usable in
* autoscan mode (=20.480ms)
* TIME_ST_ADC: waiting time between application of voltage
* to panel and start of A/D conversion (=100us)
*/
#define BU21029_CFR2_REG (0x02 << 3)
#define CFR2_VALUE 0xC9
/*
* CFR3 Register (PAGE=0, ADDR=0x0B, Reset value=0x72)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | RM8 | STRETCH| PU90K | DUAL | PIDAC_OFS[3:0] |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* RM8: 0 = coordinate resolution is 12bit (*)
* 1 = coordinate resolution is 8bit
* STRETCH: 0 = SCL_STRETCH function off
* 1 = SCL_STRETCH function on (*)
* PU90K: 0 = internal pull-up resistance for touch detection is ~50kohms (*)
* 1 = internal pull-up resistance for touch detection is ~90kohms
* DUAL: 0 = dual touch detection off (*)
* 1 = dual touch detection on
* PIDAC_OFS: dual touch detection circuit adjustment, it is not necessary
* to change this from initial value
*/
#define BU21029_CFR3_REG (0x0B << 3)
#define CFR3_VALUE 0x42
/*
* LDO Register (PAGE=0, ADDR=0x0C, Reset value=0x00)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | 0 | PVDD[2:0] | 0 | AVDD[2:0] |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* PVDD: output voltage of panel output regulator (=2.000V)
* AVDD: output voltage of analog circuit regulator (=2.000V)
*/
#define BU21029_LDO_REG (0x0C << 3)
#define LDO_VALUE 0x77
/*
* Serial Interface Command Byte 1 (CID=1)
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* | 1 | CF | CMSK | PDM | STP |
* +--------+--------+--------+--------+--------+--------+--------+--------+
* CF: conversion function, see table 3 in datasheet p6 (=0000, automatic scan)
* CMSK: 0 = executes convert function (*)
* 1 = reads the convert result
* PDM: 0 = power down after convert function stops (*)
* 1 = keep power on after convert function stops
* STP: 1 = abort current conversion and power down, set to "0" automatically
*/
#define BU21029_AUTOSCAN 0x80
/*
* The timeout value needs to be larger than INTVL_TIME + tConv4 (sample and
* conversion time), where tConv4 is calculated by formula:
* tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2) * 3
* see figure 8 in datasheet p15 for details of each field.
*/
#define PEN_UP_TIMEOUT_MS 50
#define STOP_DELAY_MIN_US 50
#define STOP_DELAY_MAX_US 1000
#define START_DELAY_MS 2
#define BUF_LEN 8
#define SCALE_12BIT (1 << 12)
#define MAX_12BIT ((1 << 12) - 1)
#define DRIVER_NAME "bu21029"
struct bu21029_ts_data {
struct i2c_client *client;
struct input_dev *in_dev;
struct timer_list timer;
struct regulator *vdd;
struct gpio_desc *reset_gpios;
u32 x_plate_ohms;
struct touchscreen_properties prop;
};
static void bu21029_touch_report(struct bu21029_ts_data *bu21029, const u8 *buf)
{
u16 x, y, z1, z2;
u32 rz;
s32 max_pressure = input_abs_get_max(bu21029->in_dev, ABS_PRESSURE);
/*
* compose upper 8 and lower 4 bits into a 12bit value:
* +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
* | ByteH | ByteL |
* +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
* |b07|b06|b05|b04|b03|b02|b01|b00|b07|b06|b05|b04|b03|b02|b01|b00|
* +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
* |v11|v10|v09|v08|v07|v06|v05|v04|v03|v02|v01|v00| 0 | 0 | 0 | 0 |
* +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
*/
x = (buf[0] << 4) | (buf[1] >> 4);
y = (buf[2] << 4) | (buf[3] >> 4);
z1 = (buf[4] << 4) | (buf[5] >> 4);
z2 = (buf[6] << 4) | (buf[7] >> 4);
if (z1 && z2) {
/*
* calculate Rz (pressure resistance value) by equation:
* Rz = Rx * (x/Q) * ((z2/z1) - 1), where
* Rx is x-plate resistance,
* Q is the touch screen resolution (8bit = 256, 12bit = 4096)
* x, z1, z2 are the measured positions.
*/
rz = z2 - z1;
rz *= x;
rz *= bu21029->x_plate_ohms;
rz /= z1;
rz = DIV_ROUND_CLOSEST(rz, SCALE_12BIT);
if (rz <= max_pressure) {
touchscreen_report_pos(bu21029->in_dev, &bu21029->prop,
x, y, false);
input_report_abs(bu21029->in_dev, ABS_PRESSURE,
max_pressure - rz);
input_report_key(bu21029->in_dev, BTN_TOUCH, 1);
input_sync(bu21029->in_dev);
}
}
}
static void bu21029_touch_release(struct timer_list *t)
{
struct bu21029_ts_data *bu21029 = from_timer(bu21029, t, timer);
input_report_abs(bu21029->in_dev, ABS_PRESSURE, 0);
input_report_key(bu21029->in_dev, BTN_TOUCH, 0);
input_sync(bu21029->in_dev);
}
static irqreturn_t bu21029_touch_soft_irq(int irq, void *data)
{
struct bu21029_ts_data *bu21029 = data;
u8 buf[BUF_LEN];
int error;
/*
* Read touch data and deassert interrupt (will assert again after
* INTVL_TIME + tConv4 for continuous touch)
*/
error = i2c_smbus_read_i2c_block_data(bu21029->client, BU21029_AUTOSCAN,
sizeof(buf), buf);
if (error < 0)
goto out;
bu21029_touch_report(bu21029, buf);
/* reset timer for pen up detection */
mod_timer(&bu21029->timer,
jiffies + msecs_to_jiffies(PEN_UP_TIMEOUT_MS));
out:
return IRQ_HANDLED;
}
static void bu21029_put_chip_in_reset(struct bu21029_ts_data *bu21029)
{
if (bu21029->reset_gpios) {
gpiod_set_value_cansleep(bu21029->reset_gpios, 1);
usleep_range(STOP_DELAY_MIN_US, STOP_DELAY_MAX_US);
}
}
static int bu21029_start_chip(struct input_dev *dev)
{
struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
struct i2c_client *i2c = bu21029->client;
struct {
u8 reg;
u8 value;
} init_table[] = {
{BU21029_CFR0_REG, CFR0_VALUE},
{BU21029_CFR1_REG, CFR1_VALUE},
{BU21029_CFR2_REG, CFR2_VALUE},
{BU21029_CFR3_REG, CFR3_VALUE},
{BU21029_LDO_REG, LDO_VALUE}
};
int error, i;
__be16 hwid;
error = regulator_enable(bu21029->vdd);
if (error) {
dev_err(&i2c->dev, "failed to power up chip: %d", error);
return error;
}
/* take chip out of reset */
if (bu21029->reset_gpios) {
gpiod_set_value_cansleep(bu21029->reset_gpios, 0);
msleep(START_DELAY_MS);
}
error = i2c_smbus_read_i2c_block_data(i2c, BU21029_HWID_REG,
sizeof(hwid), (u8 *)&hwid);
if (error < 0) {
dev_err(&i2c->dev, "failed to read HW ID\n");
goto err_out;
}
if (be16_to_cpu(hwid) != SUPPORTED_HWID) {
dev_err(&i2c->dev,
"unsupported HW ID 0x%x\n", be16_to_cpu(hwid));
error = -ENODEV;
goto err_out;
}
for (i = 0; i < ARRAY_SIZE(init_table); ++i) {
error = i2c_smbus_write_byte_data(i2c,
init_table[i].reg,
init_table[i].value);
if (error < 0) {
dev_err(&i2c->dev,
"failed to write %#02x to register %#02x: %d\n",
init_table[i].value, init_table[i].reg,
error);
goto err_out;
}
}
error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN);
if (error < 0) {
dev_err(&i2c->dev, "failed to start autoscan\n");
goto err_out;
}
enable_irq(bu21029->client->irq);
return 0;
err_out:
bu21029_put_chip_in_reset(bu21029);
regulator_disable(bu21029->vdd);
return error;
}
static void bu21029_stop_chip(struct input_dev *dev)
{
struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
disable_irq(bu21029->client->irq);
del_timer_sync(&bu21029->timer);
bu21029_put_chip_in_reset(bu21029);
regulator_disable(bu21029->vdd);
}
static int bu21029_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct bu21029_ts_data *bu21029;
struct input_dev *in_dev;
int error;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WRITE_BYTE |
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
dev_err(&client->dev,
"i2c functionality support is not sufficient\n");
return -EIO;
}
bu21029 = devm_kzalloc(&client->dev, sizeof(*bu21029), GFP_KERNEL);
if (!bu21029)
return -ENOMEM;
error = device_property_read_u32(&client->dev, "rohm,x-plate-ohms",
&bu21029->x_plate_ohms);
if (error) {
dev_err(&client->dev,
"invalid 'x-plate-ohms' supplied: %d\n", error);
return error;
}
bu21029->vdd = devm_regulator_get(&client->dev, "vdd");
if (IS_ERR(bu21029->vdd)) {
error = PTR_ERR(bu21029->vdd);
if (error != -EPROBE_DEFER)
dev_err(&client->dev,
"failed to acquire 'vdd' supply: %d\n", error);
return error;
}
bu21029->reset_gpios = devm_gpiod_get_optional(&client->dev,
"reset", GPIOD_OUT_HIGH);
if (IS_ERR(bu21029->reset_gpios)) {
error = PTR_ERR(bu21029->reset_gpios);
if (error != -EPROBE_DEFER)
dev_err(&client->dev,
"failed to acquire 'reset' gpio: %d\n", error);
return error;
}
in_dev = devm_input_allocate_device(&client->dev);
if (!in_dev) {
dev_err(&client->dev, "unable to allocate input device\n");
return -ENOMEM;
}
bu21029->client = client;
bu21029->in_dev = in_dev;
timer_setup(&bu21029->timer, bu21029_touch_release, 0);
in_dev->name = DRIVER_NAME;
in_dev->id.bustype = BUS_I2C;
in_dev->open = bu21029_start_chip;
in_dev->close = bu21029_stop_chip;
input_set_capability(in_dev, EV_KEY, BTN_TOUCH);
input_set_abs_params(in_dev, ABS_X, 0, MAX_12BIT, 0, 0);
input_set_abs_params(in_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
input_set_abs_params(in_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
touchscreen_parse_properties(in_dev, false, &bu21029->prop);
input_set_drvdata(in_dev, bu21029);
irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
error = devm_request_threaded_irq(&client->dev, client->irq,
NULL, bu21029_touch_soft_irq,
IRQF_ONESHOT, DRIVER_NAME, bu21029);
if (error) {
dev_err(&client->dev,
"unable to request touch irq: %d\n", error);
return error;
}
error = input_register_device(in_dev);
if (error) {
dev_err(&client->dev,
"unable to register input device: %d\n", error);
return error;
}
i2c_set_clientdata(client, bu21029);
return 0;
}
static int __maybe_unused bu21029_suspend(struct device *dev)
{
struct i2c_client *i2c = to_i2c_client(dev);
struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);
if (!device_may_wakeup(dev)) {
mutex_lock(&bu21029->in_dev->mutex);
if (bu21029->in_dev->users)
bu21029_stop_chip(bu21029->in_dev);
mutex_unlock(&bu21029->in_dev->mutex);
}
return 0;
}
static int __maybe_unused bu21029_resume(struct device *dev)
{
struct i2c_client *i2c = to_i2c_client(dev);
struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c);
if (!device_may_wakeup(dev)) {
mutex_lock(&bu21029->in_dev->mutex);
if (bu21029->in_dev->users)
bu21029_start_chip(bu21029->in_dev);
mutex_unlock(&bu21029->in_dev->mutex);
}
return 0;
}
static SIMPLE_DEV_PM_OPS(bu21029_pm_ops, bu21029_suspend, bu21029_resume);
static const struct i2c_device_id bu21029_ids[] = {
{ DRIVER_NAME, 0 },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, bu21029_ids);
#ifdef [31mCONFIG_OF[0m
static const struct of_device_id bu21029_of_ids[] = {
{ .compatible = "rohm,bu21029" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, bu21029_of_ids);
#endif
static struct i2c_driver bu21029_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = of_match_ptr(bu21029_of_ids),
.pm = &bu21029_pm_ops,
},
.id_table = bu21029_ids,
.probe = bu21029_probe,
};
module_i2c_driver(bu21029_driver);
MODULE_AUTHOR("Zhu Yi <yi.zhu5@cn.bosch.com>");
MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver");
MODULE_LICENSE("GPL v2");