Toggling the INT pin on an STMPE811 in GPIO mode?

[GToyn.778]

I am not using the touchscreen interface, just using the SMPTE811 device as a GPIO expander. I am talking to it over I2C using the STM32F217IGH6. In fact it's wired together exactly the same as the STM3220g-eval board.

I have two STMPE811 chips on my board. One connected to 8 LEDs and one connected to 8 switches. I am able to toggle the LEDs using the switches in an infinite loop. However I would prefer to only update the state of the LEDs when a switch has been pressed using the INT pin connected to pin PI2 on the STM32F217IGH6, but the INT is always high with the Pullup and never de-asserted.

The STMPE811 for the switches is initialised as below:

static void STMPE811_SW_Init(void)
{
 //Issue Software Reset
 buffer[0] = SYS_CTRL1;
 buffer[1] = SOFT_RESET;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10);
 
 //Enable GPIO
 buffer[0] = SYS_CTRL2;
 buffer[1] = TS_OFF|GPIO_ON|TSC_OFF|ADC_OFF;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10); 
 
 //Set GPIO to INPUT
 buffer[0] = GPIO_DIR;
 buffer[1] = 0x00;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10);
 
 //Set GPIO MODE
 buffer[0] = 0x17;
 buffer[1] = GPIO7|GPIO6|GPIO5|GPIO4|GPIO3|GPIO2|GPIO1|GPIO0;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10); 
 
 //INT_CTRL - Interrupt Control Register
 buffer[0] = 0x09;
 buffer[1] = 0x01;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10);
 
 //INT_EN - Interrupt Enable Register
 buffer[0] = 0x0A;
 buffer[1] = 0x80;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10);
 
 //INT_STA - Interrupt Status Register
 buffer[0] = 0x0B;
 buffer[1] = 0xFF;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10);
 
 //GPIO_INT_EN - GPIO Interrupt Enable Register
 buffer[0] = 0x0C;
 buffer[1] = 0xFF;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10);
 
 //GPIO_INT_EN - GPIO Interrupt Status Register
 buffer[0] = 0x0D;
 buffer[1] = 0xFF;
 HAL_I2C_Master_Transmit(&hi2c1, STMPE811_SW_ADDRESS, buffer, 2, 100);
 HAL_Delay(10);
}

I also read back the state of INT_STA and GPIO_INT_STA registers and they are always 0.

Any help would be gratefully appreciated.