/*
 * CST826 capacitive touch controller @ I2C 0x15.
 *
 * Note this is CST826, not the CST816 the PRD names. Same family, but the chip
 * ID register reads 0x11 rather than 0xB4, so a CST816 driver's probe rejects
 * it and the board looks broken. Register map below is taken from the
 * Adafruit_CST8XX library bundled with Elecrow's example for this board.
 *
 * Protocol: read register 0x02 for the touch count, then a burst from 0x03 of
 * 6 bytes per touch:
 *
 *   byte 0: [7:6] event, [3:0] X high nibble
 *   byte 1: X low byte
 *   byte 2: [7:4] touch id, [3:0] Y high nibble
 *   byte 3: Y low byte
 *   bytes 4,5: unused
 */
#pragma once

#include <stdbool.h>
#include <stdint.h>

#include "esp_err.h"

#define CST826_I2C_ADDR     0x15
#define CST826_CHIP_ID      0x11

typedef struct {
    uint16_t x;
    uint16_t y;
    bool pressed;
} cst826_touch_t;

/*
 * Initialise and verify the chip ID.
 *
 * Requires i2c_bus_init() and the reset pulse that display.c's power-up
 * sequence performs on expander P0.
 */
esp_err_t cst826_init(void);

bool cst826_is_ready(void);

/* Latest touch state. Never fails hard — an I2C error reports "not pressed"
 * so a flaky touch controller cannot wedge the UI task. */
void cst826_read(cst826_touch_t *out);