fw/drivers/sf32lb52/uart: disable stop mode if RX is enabled

We cannot use stop mode (deepsleep) if UART RX is enabled, otherwise the
system would not react to UART input when in deepsleep. While this
increases power consumption significantly, it is not critical as on
release builds (except on MFG firmware) the dbgserial is turned off.

Fixes #427

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>

Author: gmarull

src/fw/drivers/sf32lb52/uart.c

@@ -17,6 +17,7 @@
 #include "uart_definitions.h"
 
 #include "drivers/uart.h"
+#include "kernel/util/stop.h"
 #include "system/passert.h"
 
 #include "FreeRTOS.h"
@@ -37,12 +38,14 @@ static void prv_init(UARTDevice *dev, uint32_t mode) {
     case UART_MODE_TX_RX:
       HAL_PIN_Set(dev->tx.pad, dev->tx.func, dev->tx.flags, 1);
       HAL_PIN_Set(dev->rx.pad, dev->rx.func, dev->rx.flags, 1);
+      stop_mode_disable(InhibitorDbgSerial);
       break;
     case UART_MODE_TX:
       HAL_PIN_Set(dev->tx.pad, dev->tx.func, dev->tx.flags, 1);
       break;
     case UART_MODE_RX:
       HAL_PIN_Set(dev->rx.pad, dev->rx.func, dev->rx.flags, 1);
+      stop_mode_disable(InhibitorDbgSerial);
       break;
     default:
       WTF;