1 files changed, 209 insertions, 101 deletions

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index b3675cf25a69..c2ae7b392b86 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -218,8 +218,7 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded)
 	u32 sr;
 	char flag;
 
-	if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
-		pm_wakeup_event(tport->tty->dev, 0);
+	spin_lock(&port->lock);
 
 	while (stm32_usart_pending_rx(port, &sr, &stm32_port->last_res,
 				      threaded)) {
@@ -271,14 +270,14 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded)
 			}
 		}
 
-		if (uart_handle_sysrq_char(port, c))
+		if (uart_prepare_sysrq_char(port, c))
 			continue;
 		uart_insert_char(port, sr, USART_SR_ORE, c, flag);
 	}
 
-	spin_unlock(&port->lock);
+	uart_unlock_and_check_sysrq(port);
+
 	tty_flip_buffer_push(tport);
-	spin_lock(&port->lock);
 }
 
 static void stm32_usart_tx_dma_complete(void *arg)
@@ -286,12 +285,16 @@ static void stm32_usart_tx_dma_complete(void *arg)
 	struct uart_port *port = arg;
 	struct stm32_port *stm32port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
+	unsigned long flags;
 
+	dmaengine_terminate_async(stm32port->tx_ch);
 	stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 	stm32port->tx_dma_busy = false;
 
 	/* Let's see if we have pending data to send */
+	spin_lock_irqsave(&port->lock, flags);
 	stm32_usart_transmit_chars(port);
+	spin_unlock_irqrestore(&port->lock, flags);
 }
 
 static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
@@ -303,7 +306,7 @@ static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
 	 * Enables TX FIFO threashold irq when FIFO is enabled,
 	 * or TX empty irq when FIFO is disabled
 	 */
-	if (stm32_port->fifoen)
+	if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
 		stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
 	else
 		stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
@@ -314,7 +317,7 @@ static void stm32_usart_tx_interrupt_disable(struct uart_port *port)
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
-	if (stm32_port->fifoen)
+	if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
 		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
 	else
 		stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
@@ -455,29 +458,34 @@ static void stm32_usart_transmit_chars(struct uart_port *port)
 static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 {
 	struct uart_port *port = ptr;
+	struct tty_port *tport = &port->state->port;
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 	u32 sr;
 
-	spin_lock(&port->lock);
-
 	sr = readl_relaxed(port->membase + ofs->isr);
 
 	if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
 		writel_relaxed(USART_ICR_RTOCF,
 			       port->membase + ofs->icr);
 
-	if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG)
+	if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
+		/* Clear wake up flag and disable wake up interrupt */
 		writel_relaxed(USART_ICR_WUCF,
 			       port->membase + ofs->icr);
+		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
+		if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
+			pm_wakeup_event(tport->tty->dev, 0);
+	}
 
 	if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch))
 		stm32_usart_receive_chars(port, false);
 
-	if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch))
+	if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) {
+		spin_lock(&port->lock);
 		stm32_usart_transmit_chars(port);
-
-	spin_unlock(&port->lock);
+		spin_unlock(&port->lock);
+	}
 
 	if (stm32_port->rx_ch)
 		return IRQ_WAKE_THREAD;
@@ -490,13 +498,9 @@ static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr)
 	struct uart_port *port = ptr;
 	struct stm32_port *stm32_port = to_stm32_port(port);
 
-	spin_lock(&port->lock);
-
 	if (stm32_port->rx_ch)
 		stm32_usart_receive_chars(port, true);
 
-	spin_unlock(&port->lock);
-
 	return IRQ_HANDLED;
 }
 
@@ -505,7 +509,10 @@ static unsigned int stm32_usart_tx_empty(struct uart_port *port)
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
-	return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE;
+	if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
+		return TIOCSER_TEMT;
+
+	return 0;
 }
 
 static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -584,6 +591,19 @@ static void stm32_usart_start_tx(struct uart_port *port)
 	stm32_usart_transmit_chars(port);
 }
 
+/* Flush the transmit buffer. */
+static void stm32_usart_flush_buffer(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	if (stm32_port->tx_ch) {
+		dmaengine_terminate_async(stm32_port->tx_ch);
+		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
+		stm32_port->tx_dma_busy = false;
+	}
+}
+
 /* Throttle the remote when input buffer is about to overflow. */
 static void stm32_usart_throttle(struct uart_port *port)
 {
@@ -634,33 +654,30 @@ static int stm32_usart_startup(struct uart_port *port)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+	const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 	const char *name = to_platform_device(port->dev)->name;
 	u32 val;
 	int ret;
 
 	ret = request_threaded_irq(port->irq, stm32_usart_interrupt,
 				   stm32_usart_threaded_interrupt,
-				   IRQF_NO_SUSPEND, name, port);
+				   IRQF_ONESHOT | IRQF_NO_SUSPEND,
+				   name, port);
 	if (ret)
 		return ret;
 
+	if (stm32_port->swap) {
+		val = readl_relaxed(port->membase + ofs->cr2);
+		val |= USART_CR2_SWAP;
+		writel_relaxed(val, port->membase + ofs->cr2);
+	}
+
 	/* RX FIFO Flush */
 	if (ofs->rqr != UNDEF_REG)
-		stm32_usart_set_bits(port, ofs->rqr, USART_RQR_RXFRQ);
+		writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
 
-	/* Tx and RX FIFO configuration */
-	if (stm32_port->fifoen) {
-		val = readl_relaxed(port->membase + ofs->cr3);
-		val &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK);
-		val |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT;
-		val |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT;
-		writel_relaxed(val, port->membase + ofs->cr3);
-	}
-
-	/* RX FIFO enabling */
-	val = stm32_port->cr1_irq | USART_CR1_RE;
-	if (stm32_port->fifoen)
-		val |= USART_CR1_FIFOEN;
+	/* RX enabling */
+	val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
 	stm32_usart_set_bits(port, ofs->cr1, val);
 
 	return 0;
@@ -691,6 +708,11 @@ static void stm32_usart_shutdown(struct uart_port *port)
 	if (ret)
 		dev_err(port->dev, "Transmission is not complete\n");
 
+	/* flush RX & TX FIFO */
+	if (ofs->rqr != UNDEF_REG)
+		writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
+			       port->membase + ofs->rqr);
+
 	stm32_usart_clr_bits(port, ofs->cr1, val);
 
 	free_irq(port->irq, port);
@@ -737,8 +759,9 @@ static void stm32_usart_set_termios(struct uart_port *port,
 	unsigned int baud, bits;
 	u32 usartdiv, mantissa, fraction, oversampling;
 	tcflag_t cflag = termios->c_cflag;
-	u32 cr1, cr2, cr3;
+	u32 cr1, cr2, cr3, isr;
 	unsigned long flags;
+	int ret;
 
 	if (!stm32_port->hw_flow_control)
 		cflag &= ~CRTSCTS;
@@ -747,21 +770,37 @@ static void stm32_usart_set_termios(struct uart_port *port,
 
 	spin_lock_irqsave(&port->lock, flags);
 
+	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
+						isr,
+						(isr & USART_SR_TC),
+						10, 100000);
+
+	/* Send the TC error message only when ISR_TC is not set. */
+	if (ret)
+		dev_err(port->dev, "Transmission is not complete\n");
+
 	/* Stop serial port and reset value */
 	writel_relaxed(0, port->membase + ofs->cr1);
 
 	/* flush RX & TX FIFO */
 	if (ofs->rqr != UNDEF_REG)
-		stm32_usart_set_bits(port, ofs->rqr,
-				     USART_RQR_TXFRQ | USART_RQR_RXFRQ);
+		writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
+			       port->membase + ofs->rqr);
 
 	cr1 = USART_CR1_TE | USART_CR1_RE;
 	if (stm32_port->fifoen)
 		cr1 |= USART_CR1_FIFOEN;
-	cr2 = 0;
+	cr2 = stm32_port->swap ? USART_CR2_SWAP : 0;
+
+	/* Tx and RX FIFO configuration */
 	cr3 = readl_relaxed(port->membase + ofs->cr3);
-	cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE
-		| USART_CR3_TXFTCFG_MASK;
+	cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
+	if (stm32_port->fifoen) {
+		if (stm32_port->txftcfg >= 0)
+			cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT;
+		if (stm32_port->rxftcfg >= 0)
+			cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT;
+	}
 
 	if (cflag & CSTOPB)
 		cr2 |= USART_CR2_STOP_2B;
@@ -790,7 +829,8 @@ static void stm32_usart_set_termios(struct uart_port *port,
 			, bits);
 
 	if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
-				       stm32_port->fifoen)) {
+				       (stm32_port->fifoen &&
+					stm32_port->rxftcfg >= 0))) {
 		if (cflag & CSTOPB)
 			bits = bits + 3; /* 1 start bit + 2 stop bits */
 		else
@@ -817,12 +857,6 @@ static void stm32_usart_set_termios(struct uart_port *port,
 		cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
 	}
 
-	/* Handle modem control interrupts */
-	if (UART_ENABLE_MS(port, termios->c_cflag))
-		stm32_usart_enable_ms(port);
-	else
-		stm32_usart_disable_ms(port);
-
 	usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
 
 	/*
@@ -892,12 +926,24 @@ static void stm32_usart_set_termios(struct uart_port *port,
 		cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
 	}
 
+	/* Configure wake up from low power on start bit detection */
+	if (stm32_port->wakeup_src) {
+		cr3 &= ~USART_CR3_WUS_MASK;
+		cr3 |= USART_CR3_WUS_START_BIT;
+	}
+
 	writel_relaxed(cr3, port->membase + ofs->cr3);
 	writel_relaxed(cr2, port->membase + ofs->cr2);
 	writel_relaxed(cr1, port->membase + ofs->cr1);
 
 	stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 	spin_unlock_irqrestore(&port->lock, flags);
+
+	/* Handle modem control interrupts */
+	if (UART_ENABLE_MS(port, termios->c_cflag))
+		stm32_usart_enable_ms(port);
+	else
+		stm32_usart_disable_ms(port);
 }
 
 static const char *stm32_usart_type(struct uart_port *port)
@@ -962,6 +1008,7 @@ static const struct uart_ops stm32_uart_ops = {
 	.break_ctl	= stm32_usart_break_ctl,
 	.startup	= stm32_usart_startup,
 	.shutdown	= stm32_usart_shutdown,
+	.flush_buffer	= stm32_usart_flush_buffer,
 	.set_termios	= stm32_usart_set_termios,
 	.pm		= stm32_usart_pm,
 	.type		= stm32_usart_type,
@@ -971,6 +1018,39 @@ static const struct uart_ops stm32_uart_ops = {
 	.verify_port	= stm32_usart_verify_port,
 };
 
+/*
+ * STM32H7 RX & TX FIFO threshold configuration (CR3 RXFTCFG / TXFTCFG)
+ * Note: 1 isn't a valid value in RXFTCFG / TXFTCFG. In this case,
+ * RXNEIE / TXEIE can be used instead of threshold irqs: RXFTIE / TXFTIE.
+ * So, RXFTCFG / TXFTCFG bitfields values are encoded as array index + 1.
+ */
+static const u32 stm32h7_usart_fifo_thresh_cfg[] = { 1, 2, 4, 8, 12, 14, 16 };
+
+static void stm32_usart_get_ftcfg(struct platform_device *pdev, const char *p,
+				  int *ftcfg)
+{
+	u32 bytes, i;
+
+	/* DT option to get RX & TX FIFO threshold (default to 8 bytes) */
+	if (of_property_read_u32(pdev->dev.of_node, p, &bytes))
+		bytes = 8;
+
+	for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++)
+		if (stm32h7_usart_fifo_thresh_cfg[i] >= bytes)
+			break;
+	if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg))
+		i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1;
+
+	dev_dbg(&pdev->dev, "%s set to %d bytes\n", p,
+		stm32h7_usart_fifo_thresh_cfg[i]);
+
+	/* Provide FIFO threshold ftcfg (1 is invalid: threshold irq unused) */
+	if (i)
+		*ftcfg = i - 1;
+	else
+		*ftcfg = -EINVAL;
+}
+
 static void stm32_usart_deinit_port(struct stm32_port *stm32port)
 {
 	clk_disable_unprepare(stm32port->clk);
@@ -1000,13 +1080,19 @@ static int stm32_usart_init_port(struct stm32_port *stm32port,
 	if (ret)
 		return ret;
 
-	if (stm32port->info->cfg.has_wakeup) {
-		stm32port->wakeirq = platform_get_irq_optional(pdev, 1);
-		if (stm32port->wakeirq <= 0 && stm32port->wakeirq != -ENXIO)
-			return stm32port->wakeirq ? : -ENODEV;
-	}
+	stm32port->wakeup_src = stm32port->info->cfg.has_wakeup &&
+		of_property_read_bool(pdev->dev.of_node, "wakeup-source");
+
+	stm32port->swap = stm32port->info->cfg.has_swap &&
+		of_property_read_bool(pdev->dev.of_node, "rx-tx-swap");
 
 	stm32port->fifoen = stm32port->info->cfg.has_fifo;
+	if (stm32port->fifoen) {
+		stm32_usart_get_ftcfg(pdev, "rx-threshold",
+				      &stm32port->rxftcfg);
+		stm32_usart_get_ftcfg(pdev, "tx-threshold",
+				      &stm32port->txftcfg);
+	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	port->membase = devm_ioremap_resource(&pdev->dev, res);
@@ -1106,6 +1192,13 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
 	struct dma_async_tx_descriptor *desc = NULL;
 	int ret;
 
+	/*
+	 * Using DMA and threaded handler for the console could lead to
+	 * deadlocks.
+	 */
+	if (uart_console(port))
+		return -ENODEV;
+
 	/* Request DMA RX channel */
 	stm32port->rx_ch = dma_request_slave_channel(dev, "rx");
 	if (!stm32port->rx_ch) {
@@ -1239,23 +1332,13 @@ static int stm32_usart_serial_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	if (stm32port->wakeirq > 0) {
-		ret = device_init_wakeup(&pdev->dev, true);
-		if (ret)
-			goto err_uninit;
-
-		ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
-						    stm32port->wakeirq);
+	if (stm32port->wakeup_src) {
+		device_set_wakeup_capable(&pdev->dev, true);
+		ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);
 		if (ret)
 			goto err_nowup;
-
-		device_set_wakeup_enable(&pdev->dev, false);
 	}
 
-	ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
-	if (ret)
-		goto err_wirq;
-
 	ret = stm32_usart_of_dma_rx_probe(stm32port, pdev);
 	if (ret)
 		dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n");
@@ -1269,19 +1352,47 @@ static int stm32_usart_serial_probe(struct platform_device *pdev)
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
+
+	ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
+	if (ret)
+		goto err_port;
+
 	pm_runtime_put_sync(&pdev->dev);
 
 	return 0;
 
-err_wirq:
-	if (stm32port->wakeirq > 0)
+err_port:
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+	if (stm32port->rx_ch) {
+		dmaengine_terminate_async(stm32port->rx_ch);
+		dma_release_channel(stm32port->rx_ch);
+	}
+
+	if (stm32port->rx_dma_buf)
+		dma_free_coherent(&pdev->dev,
+				  RX_BUF_L, stm32port->rx_buf,
+				  stm32port->rx_dma_buf);
+
+	if (stm32port->tx_ch) {
+		dmaengine_terminate_async(stm32port->tx_ch);
+		dma_release_channel(stm32port->tx_ch);
+	}
+
+	if (stm32port->tx_dma_buf)
+		dma_free_coherent(&pdev->dev,
+				  TX_BUF_L, stm32port->tx_buf,
+				  stm32port->tx_dma_buf);
+
+	if (stm32port->wakeup_src)
 		dev_pm_clear_wake_irq(&pdev->dev);
 
 err_nowup:
-	if (stm32port->wakeirq > 0)
-		device_init_wakeup(&pdev->dev, false);
+	if (stm32port->wakeup_src)
+		device_set_wakeup_capable(&pdev->dev, false);
 
-err_uninit:
 	stm32_usart_deinit_port(stm32port);
 
 	return ret;
@@ -1295,11 +1406,20 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
 	int err;
 
 	pm_runtime_get_sync(&pdev->dev);
+	err = uart_remove_one_port(&stm32_usart_driver, port);
+	if (err)
+		return(err);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 
 	stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
 
-	if (stm32_port->rx_ch)
+	if (stm32_port->rx_ch) {
+		dmaengine_terminate_async(stm32_port->rx_ch);
 		dma_release_channel(stm32_port->rx_ch);
+	}
 
 	if (stm32_port->rx_dma_buf)
 		dma_free_coherent(&pdev->dev,
@@ -1308,27 +1428,24 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
 
 	stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 
-	if (stm32_port->tx_ch)
+	if (stm32_port->tx_ch) {
+		dmaengine_terminate_async(stm32_port->tx_ch);
 		dma_release_channel(stm32_port->tx_ch);
+	}
 
 	if (stm32_port->tx_dma_buf)
 		dma_free_coherent(&pdev->dev,
 				  TX_BUF_L, stm32_port->tx_buf,
 				  stm32_port->tx_dma_buf);
 
-	if (stm32_port->wakeirq > 0) {
+	if (stm32_port->wakeup_src) {
 		dev_pm_clear_wake_irq(&pdev->dev);
 		device_init_wakeup(&pdev->dev, false);
 	}
 
 	stm32_usart_deinit_port(stm32_port);
 
-	err = uart_remove_one_port(&stm32_usart_driver, port);
-
-	pm_runtime_disable(&pdev->dev);
-	pm_runtime_put_noidle(&pdev->dev);
-
-	return err;
+	return 0;
 }
 
 #ifdef CONFIG_SERIAL_STM32_CONSOLE
@@ -1354,13 +1471,10 @@ static void stm32_usart_console_write(struct console *co, const char *s,
 	u32 old_cr1, new_cr1;
 	int locked = 1;
 
-	local_irq_save(flags);
-	if (port->sysrq)
-		locked = 0;
-	else if (oops_in_progress)
-		locked = spin_trylock(&port->lock);
+	if (oops_in_progress)
+		locked = spin_trylock_irqsave(&port->lock, flags);
 	else
-		spin_lock(&port->lock);
+		spin_lock_irqsave(&port->lock, flags);
 
 	/* Save and disable interrupts, enable the transmitter */
 	old_cr1 = readl_relaxed(port->membase + ofs->cr1);
@@ -1374,8 +1488,7 @@ static void stm32_usart_console_write(struct console *co, const char *s,
 	writel_relaxed(old_cr1, port->membase + ofs->cr1);
 
 	if (locked)
-		spin_unlock(&port->lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&port->lock, flags);
 }
 
 static int stm32_usart_console_setup(struct console *co, char *options)
@@ -1436,23 +1549,20 @@ static void __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port,
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
-	const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
-	u32 val;
 
-	if (stm32_port->wakeirq <= 0)
+	if (!stm32_port->wakeup_src)
 		return;
 
+	/*
+	 * Enable low-power wake-up and wake-up irq if argument is set to
+	 * "enable", disable low-power wake-up and wake-up irq otherwise
+	 */
 	if (enable) {
-		stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 		stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM);
-		val = readl_relaxed(port->membase + ofs->cr3);
-		val &= ~USART_CR3_WUS_MASK;
-		/* Enable Wake up interrupt from low power on start bit */
-		val |= USART_CR3_WUS_START_BIT | USART_CR3_WUFIE;
-		writel_relaxed(val, port->membase + ofs->cr3);
-		stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
+		stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE);
 	} else {
 		stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM);
+		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
 	}
 }
 
@@ -1462,10 +1572,8 @@ static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
 
 	uart_suspend_port(&stm32_usart_driver, port);
 
-	if (device_may_wakeup(dev))
+	if (device_may_wakeup(dev) || device_wakeup_path(dev))
 		stm32_usart_serial_en_wakeup(port, true);
-	else
-		stm32_usart_serial_en_wakeup(port, false);
 
 	/*
 	 * When "no_console_suspend" is enabled, keep the pinctrl default state
@@ -1474,7 +1582,7 @@ static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
 	 * capabilities.
 	 */
 	if (console_suspend_enabled || !uart_console(port)) {
-		if (device_may_wakeup(dev))
+		if (device_may_wakeup(dev) || device_wakeup_path(dev))
 			pinctrl_pm_select_idle_state(dev);
 		else
 			pinctrl_pm_select_sleep_state(dev);
@@ -1489,7 +1597,7 @@ static int __maybe_unused stm32_usart_serial_resume(struct device *dev)
 
 	pinctrl_pm_select_default_state(dev);
 
-	if (device_may_wakeup(dev))
+	if (device_may_wakeup(dev) || device_wakeup_path(dev))
 		stm32_usart_serial_en_wakeup(port, false);
 
 	return uart_resume_port(&stm32_usart_driver, port);