[PATCH 0/7] usart various fixes for STM32

[PATCH 0/7] usart various fixes for STM32

[Erwan Le Ray]

This series delivers fixes in various uart functions of stm32-usart
driver.

Erwan Le Ray (7):
  serial: stm32: fix word length configuration
  serial: stm32: fix rx error handling
  serial: stm32: fix rx data length when parity enabled
  serial: stm32: fix transmit_chars when tx is stopped
  serial: stm32: Add support of TC bit status check
  serial: stm32: fix wakeup source initialization
  serial: stm32: fix the get_irq error case

 drivers/tty/serial/stm32-usart.c | 221 ++++++++++++++++++++++++++-------------
 drivers/tty/serial/stm32-usart.h |  14 +--
 2 files changed, 152 insertions(+), 83 deletions(-)

-- 
1.9.1

[PATCH 1/7] serial: stm32: fix word length configuration

[Erwan Le Ray]

STM32 supports either:
- 8 and 9 bits word length (including parity bit) for stm32f4 compatible
  devices
- 7, 8 and 9 bits word length (including parity bit) for stm32f7 and
  stm32h7 compatible devices.

As a consequence STM32 supports the following termios configurations:
- CS7 with parity bit, and CS8 (with or without parity bit) for stm32f4
  compatible devices.
- CS6 with parity bit, CS7 and CS8 (with or without parity bit) for
  stm32f7 and stm32h7 compatible devices.

This patch is fixing word length by configuring correctly the SoC with
supported configurations.

Fixes: ada8618ff3bf ("serial: stm32: adding support for stm32f7")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index e8d7a7b..e832185 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -599,6 +599,36 @@ static void stm32_shutdown(struct uart_port *port)
 	free_irq(port->irq, port);
 }
 
+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 +636,7 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 	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;
@@ -632,16 +662,28 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 	if (cflag & CSTOPB)
 		cr2 |= USART_CR2_STOP_2B;
 
+	bits = stm32_get_databits(termios);
+
 	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 (cflag & PARODD)
 		cr1 |= USART_CR1_PS;
 
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index 6f294e2..a70aa50 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -151,8 +151,7 @@ struct stm32_usart_info stm32h7_info = {
 #define USART_CR1_PS		BIT(9)
 #define USART_CR1_PCE		BIT(10)
 #define USART_CR1_WAKE		BIT(11)
-#define USART_CR1_M		BIT(12)
-#define USART_CR1_M0		BIT(12)		/* F7 */
+#define USART_CR1_M0		BIT(12)		/* F7 (CR1_M for F4) */
 #define USART_CR1_MME		BIT(13)		/* F7 */
 #define USART_CR1_CMIE		BIT(14)		/* F7 */
 #define USART_CR1_OVER8		BIT(15)
-- 
1.9.1

[PATCH 2/7] serial: stm32: fix rx error handling

[Erwan Le Ray]

- Fixes parity and framing error bit by clearing parity and framing error
  flag. The current implementation doesn't clear the error bits when an
  error is detected.
- Fixes the incorrect name of framing error clearing flag in header file.
- Fixes misalignement between data frame and errors status. The status
  read for "n" frame was the status of "n+1" frame".
- Fixes break detection was not triggered by the expected register.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index e832185..f6b7393 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -225,35 +225,51 @@ static void stm32_receive_chars(struct uart_port *port, bool threaded)
 
 	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))
@@ -721,14 +737,14 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 	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).
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index a70aa50..8d34802 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -108,7 +108,6 @@ struct stm32_usart_info stm32h7_info = {
 #define USART_SR_RXNE		BIT(5)
 #define USART_SR_TC		BIT(6)
 #define USART_SR_TXE		BIT(7)
-#define USART_SR_LBD		BIT(8)
 #define USART_SR_CTSIF		BIT(9)
 #define USART_SR_CTS		BIT(10)		/* F7 */
 #define USART_SR_RTOF		BIT(11)		/* F7 */
@@ -120,8 +119,7 @@ struct stm32_usart_info stm32h7_info = {
 #define USART_SR_SBKF		BIT(18)		/* F7 */
 #define USART_SR_WUF		BIT(20)		/* H7 */
 #define USART_SR_TEACK		BIT(21)		/* F7 */
-#define USART_SR_ERR_MASK	(USART_SR_LBD | USART_SR_ORE | \
-				 USART_SR_FE | USART_SR_PE)
+#define USART_SR_ERR_MASK	(USART_SR_ORE | USART_SR_FE | USART_SR_PE)
 /* Dummy bits */
 #define USART_SR_DUMMY_RX	BIT(16)
 
@@ -168,8 +166,6 @@ struct stm32_usart_info stm32h7_info = {
 /* USART_CR2 */
 #define USART_CR2_ADD_MASK	GENMASK(3, 0)	/* F4 */
 #define USART_CR2_ADDM7		BIT(4)		/* F7 */
-#define USART_CR2_LBDL		BIT(5)
-#define USART_CR2_LBDIE		BIT(6)
 #define USART_CR2_LBCL		BIT(8)
 #define USART_CR2_CPHA		BIT(9)
 #define USART_CR2_CPOL		BIT(10)
@@ -226,12 +222,10 @@ struct stm32_usart_info stm32h7_info = {
 
 /* USART_ICR */
 #define USART_ICR_PECF		BIT(0)		/* F7 */
-#define USART_ICR_FFECF		BIT(1)		/* F7 */
-#define USART_ICR_NCF		BIT(2)		/* F7 */
+#define USART_ICR_FECF		BIT(1)		/* F7 */
 #define USART_ICR_ORECF		BIT(3)		/* F7 */
 #define USART_ICR_IDLECF	BIT(4)		/* F7 */
 #define USART_ICR_TCCF		BIT(6)		/* F7 */
-#define USART_ICR_LBDCF		BIT(8)		/* F7 */
 #define USART_ICR_CTSCF		BIT(9)		/* F7 */
 #define USART_ICR_RTOCF		BIT(11)		/* F7 */
 #define USART_ICR_EOBCF		BIT(12)		/* F7 */
-- 
1.9.1

[PATCH 3/7] serial: stm32: fix rx data length when parity enabled

[Erwan Le Ray]

- Fixes a rx data error when data length < 8 bits and parity is enabled.
RDR register MSB is used for parity bit reception.
- Adds a mask to ignore MSB when data is get from RDR.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index f6b7393..0a7953e 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -194,8 +194,8 @@ static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res,
 	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 +205,13 @@ static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res,
 		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)
@@ -679,6 +682,7 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 		cr2 |= USART_CR2_STOP_2B;
 
 	bits = stm32_get_databits(termios);
+	stm32_port->rdr_mask = (BIT(bits) - 1);
 
 	if (cflag & PARENB) {
 		bits++;
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index 8d34802..30d2433 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -254,6 +254,7 @@ struct stm32_port {
 	bool hw_flow_control;
 	bool fifoen;
 	int wakeirq;
+	int rdr_mask;		/* receive data register mask */
 };
 
 static struct stm32_port stm32_ports[STM32_MAX_PORTS];
-- 
1.9.1

[PATCH 4/7] serial: stm32: fix transmit_chars when tx is stopped

[Erwan Le Ray]

Disables the tx irq  when the transmission is ended and updates stop_tx
conditions for code cleanup.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 0a7953e..2e7757d 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -420,13 +420,8 @@ static void stm32_transmit_chars(struct uart_port *port)
 		return;
 	}
 
-	if (uart_tx_stopped(port)) {
-		stm32_stop_tx(port);
-		return;
-	}
-
-	if (uart_circ_empty(xmit)) {
-		stm32_stop_tx(port);
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
 		return;
 	}
 
@@ -439,7 +434,7 @@ static void stm32_transmit_chars(struct uart_port *port)
 		uart_write_wakeup(port);
 
 	if (uart_circ_empty(xmit))
-		stm32_stop_tx(port);
+		stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
 }
 
 static irqreturn_t stm32_interrupt(int irq, void *ptr)
-- 
1.9.1

[PATCH 5/7] serial: stm32: Add support of TC bit status check

[Erwan Le Ray]

Adds a check on the Transmission Complete bit status before closing the
com port. Prevents the port closure before the end of the transmission.
TC poll loop is moved from stm32_tx_dma_complete to stm32_shutdown
routine, in order to check TC before shutdown in both dma and
PIO tx modes.
TC clear is added in stm32_transmit_char routine, in order to be cleared
before transmitting in both dma and PIO tx modes.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 2e7757d..d603be9 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -290,21 +290,6 @@ static void stm32_tx_dma_complete(void *arg)
 	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;
@@ -396,7 +381,6 @@ static void stm32_transmit_chars_dma(struct uart_port *port)
 	/* 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);
@@ -425,6 +409,11 @@ static void stm32_transmit_chars(struct uart_port *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);
 	else
@@ -601,12 +590,21 @@ static void stm32_shutdown(struct uart_port *port)
 	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 |= 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);
-- 
1.9.1

[PATCH 6/7] serial: stm32: fix wakeup source initialization

[Erwan Le Ray]

Fixes dedicated_irq_wakeup issue and deactivated uart as wakeup source by
default.

Fixes: 270e5a74fe4c ("serial: stm32: add wakeup mechanism")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index d603be9..1334e42 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -557,7 +557,6 @@ static int stm32_startup(struct uart_port *port)
 {
 	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;
@@ -568,15 +567,6 @@ static int stm32_startup(struct uart_port *port)
 	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;
-		}
-	}
-
 	val = USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;
 	if (stm32_port->fifoen)
 		val |= USART_CR1_FIFOEN;
@@ -607,7 +597,6 @@ static void stm32_shutdown(struct uart_port *port)
 
 	stm32_clr_bits(port, ofs->cr1, val);
 
-	dev_pm_clear_wake_irq(port->dev);
 	free_irq(port->irq, port);
 }
 
@@ -1079,11 +1068,18 @@ static int stm32_serial_probe(struct platform_device *pdev)
 		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)
@@ -1097,6 +1093,10 @@ static int stm32_serial_probe(struct platform_device *pdev)
 
 	return 0;
 
+err_wirq:
+	if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0)
+		dev_pm_clear_wake_irq(&pdev->dev);
+
 err_nowup:
 	if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0)
 		device_init_wakeup(&pdev->dev, false);
@@ -1134,8 +1134,10 @@ static int stm32_serial_remove(struct platform_device *pdev)
 				  TX_BUF_L, stm32_port->tx_buf,
 				  stm32_port->tx_dma_buf);
 
-	if (cfg->has_wakeup && stm32_port->wakeirq >= 0)
+	if (cfg->has_wakeup && stm32_port->wakeirq >= 0) {
+		dev_pm_clear_wake_irq(&pdev->dev);
 		device_init_wakeup(&pdev->dev, false);
+	}
 
 	clk_disable_unprepare(stm32_port->clk);
 
-- 
1.9.1

[PATCH 7/7] serial: stm32: fix the get_irq error case

[Erwan Le Ray]

Checks the returned values of platform_get_irq() for both required
"event" and optional "wakeup" IRQs during probe. This allows the driver
probe to be deferred if needed.
Removes redundant checks for 'cfg.has_wakeup'.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 1334e42..9c2b04e 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -852,12 +852,31 @@ static int stm32_init_port(struct stm32_port *stm32port,
 	port->flags	= UPF_BOOT_AUTOCONF;
 	port->ops	= &stm32_uart_ops;
 	port->dev	= &pdev->dev;
-	port->irq	= platform_get_irq(pdev, 0);
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret <= 0) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Can't get event IRQ: %d\n", ret);
+		return ret ? 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) {
+			if (stm32port->wakeirq != -EPROBE_DEFER)
+				dev_err(&pdev->dev,
+					"Can't get event wake IRQ: %d\n",
+					stm32port->wakeirq);
+			return stm32port->wakeirq ? stm32port->wakeirq :
+				-ENODEV;
+		}
+	}
+
 	stm32port->fifoen = stm32port->info->cfg.has_fifo;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1064,7 +1083,7 @@ static int stm32_serial_probe(struct platform_device *pdev)
 	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;
@@ -1094,11 +1113,11 @@ static int stm32_serial_probe(struct platform_device *pdev)
 	return 0;
 
 err_wirq:
-	if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0)
+	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:
@@ -1112,7 +1131,6 @@ static int stm32_serial_remove(struct platform_device *pdev)
 	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;
 
 	stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
 
@@ -1134,7 +1152,7 @@ static int stm32_serial_remove(struct platform_device *pdev)
 				  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);
 	}
@@ -1252,7 +1270,7 @@ static void stm32_serial_enable_wakeup(struct uart_port *port, bool enable)
 	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) {
-- 
1.9.1