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zephyr/drivers/input/input_stmpe811.c

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/**
* Copyright (c) 2023 Antmicro <www.antmicro.com>
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT st_stmpe811
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/input/input.h>
#include <zephyr/sys/byteorder.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(stmpe811, CONFIG_INPUT_LOG_LEVEL);
#define CHIP_ID 0x0811U
/* Touch Screen Pins definition */
#define STMPE811_GPIO_PIN_4 BIT(4)
#define STMPE811_GPIO_PIN_5 BIT(5)
#define STMPE811_GPIO_PIN_6 BIT(6)
#define STMPE811_GPIO_PIN_7 BIT(7)
#define STMPE811_TOUCH_YD STMPE811_GPIO_PIN_7
#define STMPE811_TOUCH_XD STMPE811_GPIO_PIN_6
#define STMPE811_TOUCH_YU STMPE811_GPIO_PIN_5
#define STMPE811_TOUCH_XU STMPE811_GPIO_PIN_4
#define STMPE811_TOUCH_IO_ALL \
(STMPE811_TOUCH_YD | STMPE811_TOUCH_XD | STMPE811_TOUCH_YU | STMPE811_TOUCH_XU)
/* Registers */
#define STMPE811_CHP_ID_LSB_REG 0x00U
#define STMPE811_ADC_CTRL1_REG 0x20U
#define STMPE811_ADC_CTRL2_REG 0x21U
#define STMPE811_SYS_CTRL1_REG 0x03U
#define STMPE811_SYS_CTRL2_REG 0x04U
#define STMPE811_TSC_CFG_REG 0x41U
#define STMPE811_IO_AF_REG 0x17U
#define STMPE811_FIFO_TH_REG 0x4AU
#define STMPE811_FIFO_STA_REG 0x4BU
#define STMPE811_FIFO_SIZE_REG 0x4CU
#define STMPE811_TSC_FRACT_XYZ_REG 0x56U
#define STMPE811_TSC_I_DRIVE_REG 0x58U
#define STMPE811_TSC_CTRL_REG 0x40U
#define STMPE811_INT_STA_REG 0x0BU
#define STMPE811_TSC_DATA_NON_INC_REG 0xD7U
#define STMPE811_INT_CTRL_REG 0x09U
#define STMPE811_INT_EN_REG 0x0AU
/* Touch detected bit */
#define STMPE811_TSC_CTRL_BIT_TOUCH_DET BIT(7)
/* Global interrupt enable bit */
#define STMPE811_INT_CTRL_BIT_GLOBAL_INT BIT(0)
/* IO expander functionalities */
#define STMPE811_SYS_CTRL2_BIT_ADC_FCT BIT(0)
#define STMPE811_SYS_CTRL2_BIT_TS_FCT BIT(1)
#define STMPE811_SYS_CTRL2_BIT_IO_FCT BIT(2)
/* Global Interrupts definitions */
#define STMPE811_INT_BIT_FIFO_THRESHOLD BIT(1) /* FIFO above threshold interrupt */
#define STMPE811_INT_BIT_TOUCH BIT(0) /* Touch/release is detected interrupt */
#define STMPE811_INT_ALL BIT_MASK(8) /* All interrupts */
/* Reset control */
#define STMPE811_SYS_CTRL1_RESET_ON 0
#define STMPE811_SYS_CTRL1_RESET_SOFT BIT(1) /* Soft reset */
/* Delays to ensure registers erasing */
#define STMPE811_RESET_DELAY_MS 10
#define STMPE811_WAIT_DELAY_MS 2
/* Configuration */
#define STMPE811_FIFO_TH_SINGLE_POINT 1
#define STMPE811_FIFO_STA_CLEAR 1
#define STMPE811_FIFO_STA_OPERATIONAL 0
#define STMPE811_TSC_I_DRIVE_LIMIT 1
/**
* Touch Screen Control
*
* - bits [1-3] X, Y only acquisition mode
*/
#define STMPE811_TSC_CTRL_CONF 3U
/**
* Analog-to-digital Converter
*
* - bit [3] selects 12 bit ADC
* - bits [4-6] select ADC conversion time = 80
*/
#define STMPE811_ADC_CTRL1_CONF 0x48U
/**
* ADC clock speed: 3.25 MHz
*
* - 00 : 1.625 MHz
* - 01 : 3.25 MHz
* - 10 : 6.5 MHz
* - 11 : 6.5 MHz
*/
#define STMPE811_ADC_CLOCK_SPEED 1
/**
* Range and accuracy of the pressure measurement (Z)
*
* - Fractional part : 7
* - Whole part : 1
*/
#define STMPE811_TSC_FRACT_XYZ_CONF 1
struct stmpe811_config {
struct i2c_dt_spec bus;
struct gpio_dt_spec int_gpio;
uint8_t panel_driver_settling_time_us;
uint8_t touch_detect_delay_us;
uint8_t touch_average_control;
uint8_t tracking_index;
uint16_t screen_width;
uint16_t screen_height;
int raw_x_min;
int raw_y_min;
uint16_t raw_x_max;
uint16_t raw_y_max;
};
struct stmpe811_data {
const struct device *dev;
struct k_work processing_work;
struct gpio_callback int_gpio_cb;
uint32_t touch_x;
uint32_t touch_y;
};
static int stmpe811_reset(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
/* Power down the stmpe811 */
int ret = i2c_reg_write_byte_dt(&config->bus, STMPE811_SYS_CTRL1_REG,
STMPE811_SYS_CTRL1_RESET_SOFT);
if (ret < 0) {
return ret;
}
k_msleep(STMPE811_RESET_DELAY_MS);
/* Power on the stmpe811 after the power off => all registers are reinitialized */
ret = i2c_reg_write_byte_dt(&config->bus, STMPE811_SYS_CTRL1_REG,
STMPE811_SYS_CTRL1_RESET_ON);
if (ret < 0) {
return ret;
}
k_msleep(STMPE811_WAIT_DELAY_MS);
return 0;
}
static int stmpe811_io_enable_af(const struct device *dev, uint32_t io_pin)
{
const struct stmpe811_config *config = dev->config;
/* Apply ~io_pin as a mask to the current register value */
return i2c_reg_update_byte_dt(&config->bus, STMPE811_IO_AF_REG, io_pin, 0);
}
static uint8_t stmpe811_tsc_config_bits(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
/**
* Configuration:
* - bits [0-2] : panel driver settling time
* - bits [3-5] : touch detect delay
* - bits [6-7] : touch average control
*/
return config->panel_driver_settling_time_us | config->touch_detect_delay_us << 3 |
config->touch_average_control << 6;
}
static uint8_t stmpe811_tsc_control_bits(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
/**
* Touch Screen Control
*
* - bit [0] enables TSC
* - bits [1-3] X, Y only acquisition mode
* - bits [4-6] window tracking index (set from config)
* - bit [7] TSC status (writing has no effect)
*/
return STMPE811_TSC_CTRL_CONF | config->tracking_index << 4;
}
static int stmpe811_ts_init(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
int err;
err = stmpe811_reset(dev);
if (err < 0) {
return err;
}
/* Select TSC pins in TSC alternate mode */
err = stmpe811_io_enable_af(dev, STMPE811_TOUCH_IO_ALL);
if (err < 0) {
return err;
}
/**
* Set the functionalities to be enabled
* Bits [0-3] disable functionalities if set to 1 (reset value: 0x0f)
*
* Apply inverted sum of chosen FCT bits as a mask to the currect register value
*/
err = i2c_reg_update_byte_dt(&config->bus, STMPE811_SYS_CTRL2_REG,
STMPE811_SYS_CTRL2_BIT_IO_FCT | STMPE811_SYS_CTRL2_BIT_TS_FCT |
STMPE811_SYS_CTRL2_BIT_ADC_FCT, 0);
if (err < 0) {
return err;
}
/* Select sample time, bit number and ADC reference */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_ADC_CTRL1_REG, STMPE811_ADC_CTRL1_CONF);
if (err < 0) {
return err;
}
/* Select the ADC clock speed */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_ADC_CTRL2_REG, STMPE811_ADC_CLOCK_SPEED);
if (err < 0) {
return err;
}
/* Touch screen configuration */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_TSC_CFG_REG,
stmpe811_tsc_config_bits(dev));
if (err < 0) {
return err;
}
/* Configure the touch FIFO threshold */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_FIFO_TH_REG,
STMPE811_FIFO_TH_SINGLE_POINT);
if (err < 0) {
return err;
}
/* Clear the FIFO memory content */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_FIFO_STA_REG, STMPE811_FIFO_STA_CLEAR);
if (err < 0) {
return err;
}
/* Set the range and accuracy of the pressure measurement (Z) */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_TSC_FRACT_XYZ_REG,
STMPE811_TSC_FRACT_XYZ_CONF);
if (err < 0) {
return err;
}
/* Set the driving capability (limit) of the device for TSC pins */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_TSC_I_DRIVE_REG,
STMPE811_TSC_I_DRIVE_LIMIT);
if (err < 0) {
return err;
}
/* Touch screen control configuration */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_TSC_CTRL_REG,
stmpe811_tsc_control_bits(dev));
if (err < 0) {
return err;
}
/**
* Clear all the status pending bits if any.
* Writing '1' to this register clears the corresponding bits.
* This is an 8-bit register, so writing 0xFF clears all.
*/
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_INT_STA_REG, STMPE811_INT_ALL);
if (err < 0) {
return err;
}
/* Put the FIFO back into operation mode */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_FIFO_STA_REG,
STMPE811_FIFO_STA_OPERATIONAL);
if (err < 0) {
return err;
}
/* Enable FIFO and touch interrupts */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_INT_EN_REG,
STMPE811_INT_BIT_TOUCH | STMPE811_INT_BIT_FIFO_THRESHOLD);
if (err < 0) {
LOG_ERR("Could not enable interrupt types (%d)", err);
return err;
}
return 0;
}
static int stmpe811_ts_get_data(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
struct stmpe811_data *data = dev->data;
uint8_t data_xy[3];
uint32_t uldata_xy;
int ret = i2c_burst_read_dt(&config->bus, STMPE811_TSC_DATA_NON_INC_REG, data_xy,
sizeof(data_xy));
if (ret < 0) {
return ret;
}
/* Calculate positions values */
uldata_xy = (data_xy[0] << 16) | (data_xy[1] << 8) | data_xy[2];
data->touch_x = (uldata_xy >> 12U) & BIT_MASK(12);
data->touch_y = uldata_xy & BIT_MASK(12);
return 0;
}
static void stmpe811_report_touch(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
struct stmpe811_data *data = dev->data;
int x = data->touch_x;
int y = data->touch_y;
if (config->screen_width > 0 && config->screen_height > 0) {
x = (((int)data->touch_x - config->raw_x_min) * config->screen_width) /
(config->raw_x_max - config->raw_x_min);
y = (((int)data->touch_y - config->raw_y_min) * config->screen_height) /
(config->raw_y_max - config->raw_y_min);
x = CLAMP(x, 0, config->screen_width);
y = CLAMP(y, 0, config->screen_height);
}
input_report_abs(dev, INPUT_ABS_X, x, false, K_FOREVER);
input_report_abs(dev, INPUT_ABS_Y, y, false, K_FOREVER);
input_report_key(dev, INPUT_BTN_TOUCH, 1, true, K_FOREVER);
}
static int stmpe811_process(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
int err;
uint8_t int_sta, fifo_size, tsc_ctrl;
err = i2c_reg_read_byte_dt(&config->bus, STMPE811_INT_STA_REG, &int_sta);
if (err < 0) {
return err;
}
/* Clear processed interrupts */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_INT_STA_REG, int_sta);
if (err < 0) {
return err;
}
if (int_sta & STMPE811_INT_BIT_FIFO_THRESHOLD) {
/**
* Report every element in FIFO
*
* This requires a while loop to avoid a race condition
* in which an element is added after reading FIFO_SIZE.
*
* Exiting ISR without handling every element in FIFO
* would prevent FIFO_THRESHOLD interrupt from being triggered again.
*/
while (true) {
err = i2c_reg_read_byte_dt(&config->bus, STMPE811_FIFO_SIZE_REG,
&fifo_size);
if (err < 0) {
return err;
}
if (fifo_size == 0) {
break;
}
for (int i = 0; i < fifo_size; i++) {
err = stmpe811_ts_get_data(dev);
if (err < 0) {
return err;
}
stmpe811_report_touch(dev);
}
}
}
/* TOUCH interrupt also gets triggered at release */
if (int_sta & STMPE811_INT_BIT_TOUCH) {
err = i2c_reg_read_byte_dt(&config->bus, STMPE811_TSC_CTRL_REG, &tsc_ctrl);
if (err < 0) {
return err;
}
/* TOUCH interrupt + no touch detected in TSC_CTRL reg <=> release */
if (!(tsc_ctrl & STMPE811_TSC_CTRL_BIT_TOUCH_DET)) {
input_report_key(dev, INPUT_BTN_TOUCH, 0, true, K_FOREVER);
}
}
return 0;
}
static void stmpe811_work_handler(struct k_work *work)
{
struct stmpe811_data *data = CONTAINER_OF(work, struct stmpe811_data, processing_work);
const struct stmpe811_config *config = data->dev->config;
stmpe811_process(data->dev);
/**
* Reschedule ISR if there was an interrupt triggered during handling (race condition).
* IRQ is edge-triggered, so otherwise it would never be triggered again.
*/
if (gpio_pin_get_dt(&config->int_gpio)) {
k_work_submit(&data->processing_work);
}
}
static void stmpe811_interrupt_handler(const struct device *dev, struct gpio_callback *cb,
uint32_t pins)
{
struct stmpe811_data *data = CONTAINER_OF(cb, struct stmpe811_data, int_gpio_cb);
k_work_submit(&data->processing_work);
}
static int stmpe811_verify_chip_id(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
uint8_t buf[2];
i2c_burst_read_dt(&config->bus, STMPE811_CHP_ID_LSB_REG, buf, 2);
if (sys_get_be16(buf) != CHIP_ID) {
return -EINVAL;
}
return 0;
}
static int stmpe811_init(const struct device *dev)
{
const struct stmpe811_config *config = dev->config;
struct stmpe811_data *data = dev->data;
int err;
if (!i2c_is_ready_dt(&config->bus)) {
LOG_ERR("I2C controller device not ready");
return -ENODEV;
}
data->dev = dev;
k_work_init(&data->processing_work, stmpe811_work_handler);
/* Verify CHIP_ID */
err = stmpe811_verify_chip_id(dev);
if (err) {
LOG_ERR("CHIP ID verification failed (%d)", err);
return err;
}
/* Initialize */
err = stmpe811_ts_init(dev);
if (err) {
LOG_ERR("Touch screen controller initialization failed (%d)", err);
return err;
}
/* Initialize GPIO interrupt */
if (!gpio_is_ready_dt(&config->int_gpio)) {
LOG_ERR("Interrupt GPIO controller device not ready");
return -ENODEV;
}
err = gpio_pin_configure_dt(&config->int_gpio, GPIO_INPUT);
if (err < 0) {
LOG_ERR("Could not configure interrupt GPIO pin (%d)", err);
return err;
}
err = gpio_pin_interrupt_configure_dt(&config->int_gpio, GPIO_INT_EDGE_TO_ACTIVE);
if (err < 0) {
LOG_ERR("Could not configure GPIO interrupt (%d)", err);
return err;
}
gpio_init_callback(&data->int_gpio_cb, stmpe811_interrupt_handler,
BIT(config->int_gpio.pin));
err = gpio_add_callback_dt(&config->int_gpio, &data->int_gpio_cb);
if (err < 0) {
LOG_ERR("Could not set GPIO callback (%d)", err);
return err;
}
/* Enable global interrupts */
err = i2c_reg_write_byte_dt(&config->bus, STMPE811_INT_CTRL_REG,
STMPE811_INT_CTRL_BIT_GLOBAL_INT);
if (err < 0) {
LOG_ERR("Could not enable global interrupts (%d)", err);
return err;
}
return 0;
}
#define STMPE811_DEFINE(index) \
BUILD_ASSERT(DT_INST_PROP_OR(index, raw_x_max, 4096) > \
DT_INST_PROP_OR(index, raw_x_min, 0), \
"raw-x-max should be larger than raw-x-min"); \
BUILD_ASSERT(DT_INST_PROP_OR(index, raw_y_max, 4096) > \
DT_INST_PROP_OR(index, raw_y_min, 0), \
"raw-y-max should be larger than raw-y-min"); \
static const struct stmpe811_config stmpe811_config_##index = { \
.bus = I2C_DT_SPEC_INST_GET(index), \
.int_gpio = GPIO_DT_SPEC_INST_GET(index, int_gpios), \
.panel_driver_settling_time_us = \
DT_INST_ENUM_IDX(index, panel_driver_settling_time_us), \
.screen_width = DT_INST_PROP(index, screen_width), \
.screen_height = DT_INST_PROP(index, screen_height), \
.raw_x_min = DT_INST_PROP_OR(index, raw_x_min, 0), \
.raw_y_min = DT_INST_PROP_OR(index, raw_y_min, 0), \
.raw_x_max = DT_INST_PROP_OR(index, raw_x_max, 4096), \
.raw_y_max = DT_INST_PROP_OR(index, raw_y_max, 4096), \
.touch_detect_delay_us = DT_INST_ENUM_IDX(index, touch_detect_delay_us), \
.touch_average_control = DT_INST_ENUM_IDX(index, touch_average_control), \
.tracking_index = DT_INST_ENUM_IDX(index, tracking_index)}; \
static struct stmpe811_data stmpe811_data_##index; \
DEVICE_DT_INST_DEFINE(index, stmpe811_init, NULL, &stmpe811_data_##index, \
&stmpe811_config_##index, POST_KERNEL, CONFIG_INPUT_INIT_PRIORITY, \
NULL);
DT_INST_FOREACH_STATUS_OKAY(STMPE811_DEFINE)
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