Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index e8d7a7b..df90747 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_wakeirq.h>
@@ -105,9 +106,7 @@
 	struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 	u32 usartdiv, baud, cr1, cr3;
 	bool over8;
-	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
 	stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 
 	port->rs485 = *rs485conf;
@@ -147,7 +146,6 @@
 	}
 
 	stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
-	spin_unlock_irqrestore(&port->lock, flags);
 
 	return 0;
 }
@@ -194,8 +192,8 @@
 	return 0;
 }
 
-static unsigned long
-stm32_get_char(struct uart_port *port, u32 *sr, int *last_res)
+static unsigned long stm32_get_char(struct uart_port *port, u32 *sr,
+				    int *last_res)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
@@ -205,10 +203,13 @@
 		c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--];
 		if ((*last_res) == 0)
 			*last_res = RX_BUF_L;
-		return c;
 	} else {
-		return readl_relaxed(port->membase + ofs->rdr);
+		c = readl_relaxed(port->membase + ofs->rdr);
+		/* apply RDR data mask */
+		c &= stm32_port->rdr_mask;
 	}
+
+	return c;
 }
 
 static void stm32_receive_chars(struct uart_port *port, bool threaded)
@@ -225,35 +226,51 @@
 
 	while (stm32_pending_rx(port, &sr, &stm32_port->last_res, threaded)) {
 		sr |= USART_SR_DUMMY_RX;
-		c = stm32_get_char(port, &sr, &stm32_port->last_res);
 		flag = TTY_NORMAL;
-		port->icount.rx++;
 
+		/*
+		 * Status bits has to be cleared before reading the RDR:
+		 * In FIFO mode, reading the RDR will pop the next data
+		 * (if any) along with its status bits into the SR.
+		 * Not doing so leads to misalignement between RDR and SR,
+		 * and clear status bits of the next rx data.
+		 *
+		 * Clear errors flags for stm32f7 and stm32h7 compatible
+		 * devices. On stm32f4 compatible devices, the error bit is
+		 * cleared by the sequence [read SR - read DR].
+		 */
+		if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
+			stm32_clr_bits(port, ofs->icr, USART_ICR_ORECF |
+				       USART_ICR_PECF | USART_ICR_FECF);
+
+		c = stm32_get_char(port, &sr, &stm32_port->last_res);
+		port->icount.rx++;
 		if (sr & USART_SR_ERR_MASK) {
-			if (sr & USART_SR_LBD) {
-				port->icount.brk++;
-				if (uart_handle_break(port))
-					continue;
-			} else if (sr & USART_SR_ORE) {
-				if (ofs->icr != UNDEF_REG)
-					writel_relaxed(USART_ICR_ORECF,
-						       port->membase +
-						       ofs->icr);
+			if (sr & USART_SR_ORE) {
 				port->icount.overrun++;
 			} else if (sr & USART_SR_PE) {
 				port->icount.parity++;
 			} else if (sr & USART_SR_FE) {
-				port->icount.frame++;
+				/* Break detection if character is null */
+				if (!c) {
+					port->icount.brk++;
+					if (uart_handle_break(port))
+						continue;
+				} else {
+					port->icount.frame++;
+				}
 			}
 
 			sr &= port->read_status_mask;
 
-			if (sr & USART_SR_LBD)
-				flag = TTY_BREAK;
-			else if (sr & USART_SR_PE)
+			if (sr & USART_SR_PE) {
 				flag = TTY_PARITY;
-			else if (sr & USART_SR_FE)
-				flag = TTY_FRAME;
+			} else if (sr & USART_SR_FE) {
+				if (!c)
+					flag = TTY_BREAK;
+				else
+					flag = TTY_FRAME;
+			}
 		}
 
 		if (uart_handle_sysrq_char(port, c))
@@ -271,21 +288,6 @@
 	struct uart_port *port = arg;
 	struct stm32_port *stm32port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
-	unsigned int isr;
-	int ret;
-
-	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
-						isr,
-						(isr & USART_SR_TC),
-						10, 100000);
-
-	if (ret)
-		dev_err(port->dev, "terminal count not set\n");
-
-	if (ofs->icr == UNDEF_REG)
-		stm32_clr_bits(port, ofs->isr, USART_SR_TC);
-	else
-		stm32_set_bits(port, ofs->icr, USART_CR_TC);
 
 	stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 	stm32port->tx_dma_busy = false;
@@ -294,32 +296,57 @@
 	stm32_transmit_chars(port);
 }
 
+static void stm32_tx_interrupt_enable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	/*
+	 * Enables TX FIFO threashold irq when FIFO is enabled,
+	 * or TX empty irq when FIFO is disabled
+	 */
+	if (stm32_port->fifoen)
+		stm32_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
+	else
+		stm32_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
+}
+
+static void stm32_tx_interrupt_disable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	if (stm32_port->fifoen)
+		stm32_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
+	else
+		stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
+}
+
 static void stm32_transmit_chars_pio(struct uart_port *port)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 	struct circ_buf *xmit = &port->state->xmit;
-	unsigned int isr;
-	int ret;
 
 	if (stm32_port->tx_dma_busy) {
 		stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 		stm32_port->tx_dma_busy = false;
 	}
 
-	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
-						isr,
-						(isr & USART_SR_TXE),
-						10, 100000);
+	while (!uart_circ_empty(xmit)) {
+		/* Check that TDR is empty before filling FIFO */
+		if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
+			break;
+		writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+	}
 
-	if (ret)
-		dev_err(port->dev, "tx empty not set\n");
-
-	stm32_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
-
-	writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
-	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
-	port->icount.tx++;
+	/* rely on TXE irq (mask or unmask) for sending remaining data */
+	if (uart_circ_empty(xmit))
+		stm32_tx_interrupt_disable(port);
+	else
+		stm32_tx_interrupt_enable(port);
 }
 
 static void stm32_transmit_chars_dma(struct uart_port *port)
@@ -377,7 +404,6 @@
 	/* Issue pending DMA TX requests */
 	dma_async_issue_pending(stm32port->tx_ch);
 
-	stm32_clr_bits(port, ofs->isr, USART_SR_TC);
 	stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
 
 	xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
@@ -401,15 +427,15 @@
 		return;
 	}
 
-	if (uart_tx_stopped(port)) {
-		stm32_stop_tx(port);
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		stm32_tx_interrupt_disable(port);
 		return;
 	}
 
-	if (uart_circ_empty(xmit)) {
-		stm32_stop_tx(port);
-		return;
-	}
+	if (ofs->icr == UNDEF_REG)
+		stm32_clr_bits(port, ofs->isr, USART_SR_TC);
+	else
+		stm32_set_bits(port, ofs->icr, USART_ICR_TCCF);
 
 	if (stm32_port->tx_ch)
 		stm32_transmit_chars_dma(port);
@@ -420,7 +446,7 @@
 		uart_write_wakeup(port);
 
 	if (uart_circ_empty(xmit))
-		stm32_stop_tx(port);
+		stm32_tx_interrupt_disable(port);
 }
 
 static irqreturn_t stm32_interrupt(int irq, void *ptr)
@@ -434,6 +460,10 @@
 
 	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))
 		writel_relaxed(USART_ICR_WUCF,
 			       port->membase + ofs->icr);
@@ -495,10 +525,7 @@
 /* Transmit stop */
 static void stm32_stop_tx(struct uart_port *port)
 {
-	struct stm32_port *stm32_port = to_stm32_port(port);
-	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
-
-	stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
+	stm32_tx_interrupt_disable(port);
 }
 
 /* There are probably characters waiting to be transmitted. */
@@ -520,7 +547,10 @@
 	unsigned long flags;
 
 	spin_lock_irqsave(&port->lock, flags);
-	stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE);
+	stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
+	if (stm32_port->cr3_irq)
+		stm32_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
+
 	spin_unlock_irqrestore(&port->lock, flags);
 }
 
@@ -532,7 +562,10 @@
 	unsigned long flags;
 
 	spin_lock_irqsave(&port->lock, flags);
-	stm32_set_bits(port, ofs->cr1, USART_CR1_RXNEIE);
+	stm32_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
+	if (stm32_port->cr3_irq)
+		stm32_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
+
 	spin_unlock_irqrestore(&port->lock, flags);
 }
 
@@ -542,7 +575,10 @@
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
-	stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE);
+	stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
+	if (stm32_port->cr3_irq)
+		stm32_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
+
 }
 
 /* Handle breaks - ignored by us */
@@ -554,7 +590,6 @@
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
-	struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 	const char *name = to_platform_device(port->dev)->name;
 	u32 val;
 	int ret;
@@ -565,16 +600,21 @@
 	if (ret)
 		return ret;
 
-	if (cfg->has_wakeup && stm32_port->wakeirq >= 0) {
-		ret = dev_pm_set_dedicated_wake_irq(port->dev,
-						    stm32_port->wakeirq);
-		if (ret) {
-			free_irq(port->irq, port);
-			return ret;
-		}
+	/* RX FIFO Flush */
+	if (ofs->rqr != UNDEF_REG)
+		stm32_set_bits(port, ofs->rqr, USART_RQR_RXFRQ);
+
+	/* 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);
 	}
 
-	val = USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;
+	/* RX FIFO enabling */
+	val = stm32_port->cr1_irq | USART_CR1_RE;
 	if (stm32_port->fifoen)
 		val |= USART_CR1_FIFOEN;
 	stm32_set_bits(port, ofs->cr1, val);
@@ -587,18 +627,57 @@
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 	struct stm32_usart_config *cfg = &stm32_port->info->cfg;
-	u32 val;
+	u32 val, isr;
+	int ret;
 
-	val = USART_CR1_TXEIE | USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;
+	val = USART_CR1_TXEIE | USART_CR1_TE;
+	val |= stm32_port->cr1_irq | USART_CR1_RE;
 	val |= BIT(cfg->uart_enable_bit);
 	if (stm32_port->fifoen)
 		val |= USART_CR1_FIFOEN;
+
+	ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
+					 isr, (isr & USART_SR_TC),
+					 10, 100000);
+
+	if (ret)
+		dev_err(port->dev, "transmission complete not set\n");
+
 	stm32_clr_bits(port, ofs->cr1, val);
 
-	dev_pm_clear_wake_irq(port->dev);
 	free_irq(port->irq, port);
 }
 
+static unsigned int stm32_get_databits(struct ktermios *termios)
+{
+	unsigned int bits;
+
+	tcflag_t cflag = termios->c_cflag;
+
+	switch (cflag & CSIZE) {
+	/*
+	 * CSIZE settings are not necessarily supported in hardware.
+	 * CSIZE unsupported configurations are handled here to set word length
+	 * to 8 bits word as default configuration and to print debug message.
+	 */
+	case CS5:
+		bits = 5;
+		break;
+	case CS6:
+		bits = 6;
+		break;
+	case CS7:
+		bits = 7;
+		break;
+	/* default including CS8 */
+	default:
+		bits = 8;
+		break;
+	}
+
+	return bits;
+}
+
 static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 			    struct ktermios *old)
 {
@@ -606,7 +685,7 @@
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 	struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 	struct serial_rs485 *rs485conf = &port->rs485;
-	unsigned int baud;
+	unsigned int baud, bits;
 	u32 usartdiv, mantissa, fraction, oversampling;
 	tcflag_t cflag = termios->c_cflag;
 	u32 cr1, cr2, cr3;
@@ -622,26 +701,64 @@
 	/* Stop serial port and reset value */
 	writel_relaxed(0, port->membase + ofs->cr1);
 
-	cr1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE;
+	/* flush RX & TX FIFO */
+	if (ofs->rqr != UNDEF_REG)
+		stm32_set_bits(port, ofs->rqr,
+			       USART_RQR_TXFRQ | USART_RQR_RXFRQ);
 
+	cr1 = USART_CR1_TE | USART_CR1_RE;
 	if (stm32_port->fifoen)
 		cr1 |= USART_CR1_FIFOEN;
 	cr2 = 0;
-	cr3 = 0;
+	cr3 = readl_relaxed(port->membase + ofs->cr3);
+	cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE
+		| USART_CR3_TXFTCFG_MASK;
 
 	if (cflag & CSTOPB)
 		cr2 |= USART_CR2_STOP_2B;
 
+	bits = stm32_get_databits(termios);
+	stm32_port->rdr_mask = (BIT(bits) - 1);
+
 	if (cflag & PARENB) {
+		bits++;
 		cr1 |= USART_CR1_PCE;
-		if ((cflag & CSIZE) == CS8) {
-			if (cfg->has_7bits_data)
-				cr1 |= USART_CR1_M0;
-			else
-				cr1 |= USART_CR1_M;
-		}
 	}
 
+	/*
+	 * Word length configuration:
+	 * CS8 + parity, 9 bits word aka [M1:M0] = 0b01
+	 * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
+	 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
+	 * M0 and M1 already cleared by cr1 initialization.
+	 */
+	if (bits == 9)
+		cr1 |= USART_CR1_M0;
+	else if ((bits == 7) && cfg->has_7bits_data)
+		cr1 |= USART_CR1_M1;
+	else if (bits != 8)
+		dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
+			, bits);
+
+	if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
+				       stm32_port->fifoen)) {
+		if (cflag & CSTOPB)
+			bits = bits + 3; /* 1 start bit + 2 stop bits */
+		else
+			bits = bits + 2; /* 1 start bit + 1 stop bit */
+
+		/* RX timeout irq to occur after last stop bit + bits */
+		stm32_port->cr1_irq = USART_CR1_RTOIE;
+		writel_relaxed(bits, port->membase + ofs->rtor);
+		cr2 |= USART_CR2_RTOEN;
+		/* Not using dma, enable fifo threshold irq */
+		if (!stm32_port->rx_ch)
+			stm32_port->cr3_irq =  USART_CR3_RXFTIE;
+	}
+
+	cr1 |= stm32_port->cr1_irq;
+	cr3 |= stm32_port->cr3_irq;
+
 	if (cflag & PARODD)
 		cr1 |= USART_CR1_PS;
 
@@ -679,14 +796,14 @@
 	if (termios->c_iflag & INPCK)
 		port->read_status_mask |= USART_SR_PE | USART_SR_FE;
 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
-		port->read_status_mask |= USART_SR_LBD;
+		port->read_status_mask |= USART_SR_FE;
 
 	/* Characters to ignore */
 	port->ignore_status_mask = 0;
 	if (termios->c_iflag & IGNPAR)
 		port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
 	if (termios->c_iflag & IGNBRK) {
-		port->ignore_status_mask |= USART_SR_LBD;
+		port->ignore_status_mask |= USART_SR_FE;
 		/*
 		 * If we're ignoring parity and break indicators,
 		 * ignore overruns too (for real raw support).
@@ -765,13 +882,13 @@
 
 	switch (state) {
 	case UART_PM_STATE_ON:
-		clk_prepare_enable(stm32port->clk);
+		pm_runtime_get_sync(port->dev);
 		break;
 	case UART_PM_STATE_OFF:
 		spin_lock_irqsave(&port->lock, flags);
 		stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 		spin_unlock_irqrestore(&port->lock, flags);
-		clk_disable_unprepare(stm32port->clk);
+		pm_runtime_put_sync(port->dev);
 		break;
 	}
 }
@@ -808,12 +925,23 @@
 	port->flags	= UPF_BOOT_AUTOCONF;
 	port->ops	= &stm32_uart_ops;
 	port->dev	= &pdev->dev;
-	port->irq	= platform_get_irq(pdev, 0);
+	port->fifosize	= stm32port->info->cfg.fifosize;
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret <= 0)
+		return ret ? : -ENODEV;
+	port->irq = ret;
+
 	port->rs485_config = stm32_config_rs485;
 
 	stm32_init_rs485(port, pdev);
 
-	stm32port->wakeirq = platform_get_irq(pdev, 1);
+	if (stm32port->info->cfg.has_wakeup) {
+		stm32port->wakeirq = platform_get_irq(pdev, 1);
+		if (stm32port->wakeirq <= 0 && stm32port->wakeirq != -ENXIO)
+			return stm32port->wakeirq ? : -ENODEV;
+	}
+
 	stm32port->fifoen = stm32port->info->cfg.has_fifo;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -862,6 +990,8 @@
 	stm32_ports[id].hw_flow_control = of_property_read_bool(np,
 							"st,hw-flow-ctrl");
 	stm32_ports[id].port.line = id;
+	stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
+	stm32_ports[id].cr3_irq = 0;
 	stm32_ports[id].last_res = RX_BUF_L;
 	return &stm32_ports[id];
 }
@@ -1020,15 +1150,22 @@
 	if (ret)
 		return ret;
 
-	if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0) {
+	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 (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_nowup;
+		goto err_wirq;
 
 	ret = stm32_of_dma_rx_probe(stm32port, pdev);
 	if (ret)
@@ -1040,10 +1177,19 @@
 
 	platform_set_drvdata(pdev, &stm32port->port);
 
+	pm_runtime_get_noresume(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
+
 	return 0;
 
+err_wirq:
+	if (stm32port->wakeirq > 0)
+		dev_pm_clear_wake_irq(&pdev->dev);
+
 err_nowup:
-	if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0)
+	if (stm32port->wakeirq > 0)
 		device_init_wakeup(&pdev->dev, false);
 
 err_uninit:
@@ -1057,7 +1203,9 @@
 	struct uart_port *port = platform_get_drvdata(pdev);
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
-	struct stm32_usart_config *cfg = &stm32_port->info->cfg;
+	int err;
+
+	pm_runtime_get_sync(&pdev->dev);
 
 	stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
 
@@ -1079,12 +1227,19 @@
 				  TX_BUF_L, stm32_port->tx_buf,
 				  stm32_port->tx_dma_buf);
 
-	if (cfg->has_wakeup && stm32_port->wakeirq >= 0)
+	if (stm32_port->wakeirq > 0) {
+		dev_pm_clear_wake_irq(&pdev->dev);
 		device_init_wakeup(&pdev->dev, false);
+	}
 
 	clk_disable_unprepare(stm32_port->clk);
 
-	return uart_remove_one_port(&stm32_usart_driver, port);
+	err = uart_remove_one_port(&stm32_usart_driver, port);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+	return err;
 }
 
 
@@ -1187,15 +1342,15 @@
 	.cons		= STM32_SERIAL_CONSOLE,
 };
 
-#ifdef CONFIG_PM_SLEEP
-static void stm32_serial_enable_wakeup(struct uart_port *port, bool enable)
+static void __maybe_unused stm32_serial_enable_wakeup(struct uart_port *port,
+						      bool enable)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 	struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 	u32 val;
 
-	if (!cfg->has_wakeup || stm32_port->wakeirq < 0)
+	if (stm32_port->wakeirq <= 0)
 		return;
 
 	if (enable) {
@@ -1212,7 +1367,7 @@
 	}
 }
 
-static int stm32_serial_suspend(struct device *dev)
+static int __maybe_unused stm32_serial_suspend(struct device *dev)
 {
 	struct uart_port *port = dev_get_drvdata(dev);
 
@@ -1223,21 +1378,46 @@
 	else
 		stm32_serial_enable_wakeup(port, false);
 
+	pinctrl_pm_select_sleep_state(dev);
+
 	return 0;
 }
 
-static int stm32_serial_resume(struct device *dev)
+static int __maybe_unused stm32_serial_resume(struct device *dev)
 {
 	struct uart_port *port = dev_get_drvdata(dev);
 
+	pinctrl_pm_select_default_state(dev);
+
 	if (device_may_wakeup(dev))
 		stm32_serial_enable_wakeup(port, false);
 
 	return uart_resume_port(&stm32_usart_driver, port);
 }
-#endif /* CONFIG_PM_SLEEP */
+
+static int __maybe_unused stm32_serial_runtime_suspend(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct stm32_port *stm32port = container_of(port,
+			struct stm32_port, port);
+
+	clk_disable_unprepare(stm32port->clk);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_serial_runtime_resume(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct stm32_port *stm32port = container_of(port,
+			struct stm32_port, port);
+
+	return clk_prepare_enable(stm32port->clk);
+}
 
 static const struct dev_pm_ops stm32_serial_pm_ops = {
+	SET_RUNTIME_PM_OPS(stm32_serial_runtime_suspend,
+			   stm32_serial_runtime_resume, NULL)
 	SET_SYSTEM_SLEEP_PM_OPS(stm32_serial_suspend, stm32_serial_resume)
 };