tests: drivers: lpuart: Fix TX timeout

Some test cases were using too short TX timeout (1 ms). Transfer setup
(waiting for receiver being ready) can take more than 1ms and if
timeout is too short then TX may expire before it is even started.
Added a fixed timeout in the test. It is used for all test cases.

Signed-off-by: Krzysztof Chruściński <[email protected]>

Author: nordic-krch

tests/drivers/lpuart/src/main.c

@@ -25,6 +25,12 @@ static uint8_t rx_buf[5];
 static bool buf_released;
 static int test_time;
 
+/* Timeout should be more than a millisecond as transfer setup with enabling
+ * of HFXO can take more than a millisecond so if timeout is too short it can
+ * expire before first byte is transferred.
+ */
+#define TX_TIMEOUT_US 10000
+
 static void kill_timer_handler(struct k_timer *timer)
 {
 	ARG_UNUSED(timer);
@@ -85,7 +91,7 @@ static void next_tx(const struct device *dev)
 	}
 
 	tx_req_cnt++;
-	int err = uart_tx(dev, tx_buf, tx_len, 100000);
+	int err = uart_tx(dev, tx_buf, tx_len, TX_TIMEOUT_US);
 
 	if (err != 0) {
 		TC_PRINT("uart_tx returned err:%d\n", err);
@@ -323,7 +329,7 @@ static void validate_lpuart(const struct device *lpuart)
 
 	k_timer_start(&wdt_timer, K_MSEC(200), K_NO_WAIT);
 
-	err = uart_tx(lpuart, tx_buf, sizeof(tx_buf), 10000);
+	err = uart_tx(lpuart, tx_buf, sizeof(tx_buf), TX_TIMEOUT_US);
 	zassert_equal(err, 0, NULL);
 
 	k_msleep(10);
@@ -479,7 +485,7 @@ ZTEST(test_lpuart_resilency, test_tx_abort_rx_not_enabled)
 	zassert_true(device_is_ready(lpuart), NULL);
 	uart_callback_set(lpuart, tx_abort_expected_callback, NULL);
 
-	err = uart_tx(lpuart, tx_buf, sizeof(tx_buf), 1000);
+	err = uart_tx(lpuart, tx_buf, sizeof(tx_buf), TX_TIMEOUT_US);
 	zassert_equal(err, 0, "uart_tx - unexpected err: %d", err);
 	k_msleep(10);
 	zassert_equal(tx_abort_cnt, 1, "tx_abort_cnt != 1: %d", tx_abort_cnt);
@@ -500,7 +506,7 @@ ZTEST(test_lpuart_resilency, test_tx_abort_from_api)
 
 	err = uart_rx_enable(lpuart, rx_buffer, sizeof(rx_buffer), 100);
 	zassert_equal(err, 0, "uart_rx_enable - unexpected err:%d", err);
-	err = uart_tx(lpuart, tx_buffer, sizeof(tx_buffer), 1000);
+	err = uart_tx(lpuart, tx_buffer, sizeof(tx_buffer), TX_TIMEOUT_US);
 	zassert_equal(err, 0, "uart_tx - unexpected err:%d", err);
 	k_msleep(1);
 	err = uart_tx_abort(lpuart);