+static inline int oxygen_uart_input_ready(struct oxygen *chip)
+{
+ return !(oxygen_read8(chip, OXYGEN_MPU401 + 1) & MPU401_RX_EMPTY);
+}
+
+static void oxygen_read_uart(struct oxygen *chip)
+{
+ if (unlikely(!oxygen_uart_input_ready(chip))) {
+ /* no data, but read it anyway to clear the interrupt */
+ oxygen_read8(chip, OXYGEN_MPU401);
+ return;
+ }
+ do {
+ u8 data = oxygen_read8(chip, OXYGEN_MPU401);
+ if (data == MPU401_ACK)
+ continue;
+ if (chip->uart_input_count >= ARRAY_SIZE(chip->uart_input))
+ chip->uart_input_count = 0;
+ chip->uart_input[chip->uart_input_count++] = data;
+ } while (oxygen_uart_input_ready(chip));
+ if (chip->model.uart_input)
+ chip->model.uart_input(chip);
+}
+