Configuration and setup

Debug cst816s driver

I made some changes to the cst816s.c driver to see what is happening and ensure the chip works.

Set the debug level of the driver:

//LOG_MODULE_REGISTER(cst816s, CONFIG_INPUT_LOG_LEVEL);
LOG_MODULE_REGISTER(cst816s, LOG_LEVEL_DBG);

Comment out the chip ID and use:

//#define CST816S_CHIP_ID 0xB4
#define CST816S_CHIP_ID 0xB5

I also added to debug statements to the file:

static int cst816s_process(const struct device *dev)
{
	const struct cst816s_config *cfg = dev->config;

	int r;
	uint8_t event;
	uint16_t row, col;
	bool pressed;
	uint16_t x;
	uint16_t y;

	r = i2c_burst_read_dt(&cfg->i2c, CST816S_REG_XPOS_H, (uint8_t *)&x, sizeof(x));
	if (r < 0) {
		LOG_ERR("Could not read x data");
		return r;
	}

	r = i2c_burst_read_dt(&cfg->i2c, CST816S_REG_YPOS_H, (uint8_t *)&y, sizeof(y));
	if (r < 0) {
		LOG_ERR("Could not read y data");
		return r;
	}
	col = sys_be16_to_cpu(x) & 0x0fff;
	row = sys_be16_to_cpu(y) & 0x0fff;

	event = (x & 0xff) >> CST816S_EVENT_BITS_POS;
	pressed = (event == EVENT_PRESS_DOWN) || (event == EVENT_CONTACT);

	if (pressed) {
		LOG_DBG("pressed event: %d, row: %d, col: %d", event, row, col);
		input_report_abs(dev, INPUT_ABS_X, col, false, K_FOREVER);
		input_report_abs(dev, INPUT_ABS_Y, row, false, K_FOREVER);
		input_report_key(dev, INPUT_BTN_TOUCH, 1, true, K_FOREVER);
	} else {
		LOG_DBG("not pressed event: %d, row: %d, col: %d", event, row, col);
		input_report_key(dev, INPUT_BTN_TOUCH, 0, true, K_FOREVER);
	}

	return r;
}

Display

The display is Waveshare - 1.69inch Touch LCD Module

Development kit connections

Display is connected to the nRF5340 DK using the following PIN settings:

Pin No.	Module Pin	nRF5340 Pin
1	VCC	VDD (3.3)
2	GND	GND
3	LCD_DIN	P0.25
4	LCD_CLK	P0.06
5	LCD_CS	P0.11
6	LCD_DC	P1.11
7	LCS_RST	P1.10
8	LCS_BL	VDD (3.3)
9	TP_SDA	P1.02
10	TP_SCL	P1.03
11	TP_RST	P0.20
12	TP_IRQ	P1.01