[PATCH 0/2] tty: serial: 8250: Adjustments of MOXA PCIe boards serial interface

[PATCH 0/2] tty: serial: 8250: Adjustments of MOXA PCIe boards serial interface

[Crescent CY Hsieh]

This patch series do some adjustments about serial interface of MOXA
PCIe boards including:

- Fix MOXA RS422/RS485 PCIe boards not function by default
- Add support for MOXA PCIe boards to switch serial interface

The second patch depends on the first patch because the first patch
introduces a function called pci_moxa_set_interface() to set serial
interface and second patch utilize it with ioctl command "TIOCSRS485" to
switch serial interfaces.

Crescent CY Hsieh (2):
  tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by
    default
  tty: serial: 8250: Add support for MOXA PCIe boards to switch
    interface

 drivers/tty/serial/8250/8250_pci.c | 102 ++++++++++++++++++++++++++++-
 drivers/tty/serial/serial_core.c   |  21 +++++-
 include/uapi/linux/serial.h        |   4 ++
 3 files changed, 123 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH 1/2] tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by default

[Crescent CY Hsieh]

MOXA PCIe RS422/RS485 boards will not function by default because of the
initial default serial interface of all MOXA PCIe boards is set to
RS232.

This patch fixes the problem above by setting the initial default serial
interface to RS422 for those MOXA RS422/RS485 PCIe boards.

Signed-off-by: Crescent CY Hsieh <crescentcy.hsieh@moxa.com>
---
 drivers/tty/serial/8250/8250_pci.c | 58 +++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index b2be3783f..66a2450da 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -19,6 +19,7 @@
 #include <linux/serial_core.h>
 #include <linux/8250_pci.h>
 #include <linux/bitops.h>
+#include <linux/bitfield.h>
 
 #include <asm/byteorder.h>
 #include <asm/io.h>
@@ -1968,6 +1969,20 @@ pci_sunix_setup(struct serial_private *priv,
 
 #define MOXA_GPIO_PIN2	BIT(2)
 
+#define MOXA_RS232	0x00
+#define MOXA_RS422	0x01
+#define MOXA_RS485_4W	0x0B
+#define MOXA_RS485_2W	0x0F
+#define MOXA_UIR_OFFSET	0x04
+#define MOXA_EVEN_RS_MASK	GENMASK(3, 0)
+#define MOXA_ODD_RS_MASK	GENMASK(7, 4)
+
+enum {
+	MOXA_SUPP_RS232 = BIT(0),
+	MOXA_SUPP_RS422 = BIT(1),
+	MOXA_SUPP_RS485 = BIT(2),
+};
+
 static bool pci_moxa_is_mini_pcie(unsigned short device)
 {
 	if (device == PCI_DEVICE_ID_MOXA_CP102N	||
@@ -1981,13 +1996,54 @@ static bool pci_moxa_is_mini_pcie(unsigned short device)
 	return false;
 }
 
+u32 pci_moxa_supported_rs(struct pci_dev *dev)
+{
+	switch (dev->device & 0x0F00) {
+	case 0x0000:
+	case 0x0600:
+		return MOXA_SUPP_RS232;
+	case 0x0100:
+		return MOXA_SUPP_RS232 | MOXA_SUPP_RS422 | MOXA_SUPP_RS485;
+	case 0x0300:
+		return MOXA_SUPP_RS422 | MOXA_SUPP_RS485;
+	}
+	return 0;
+}
+
+static int pci_moxa_set_interface(const struct pci_dev *dev,
+				  unsigned int port_idx,
+				  u8 mode)
+{
+	resource_size_t iobar_addr = pci_resource_start(dev, 2);
+	resource_size_t UIR_addr = iobar_addr + MOXA_UIR_OFFSET + port_idx / 2;
+	u8 val;
+
+	val = inb(UIR_addr);
+
+	if (port_idx % 2) {
+		val &= ~MOXA_ODD_RS_MASK;
+		val |= FIELD_PREP(MOXA_ODD_RS_MASK, mode);
+	} else {
+		val &= ~MOXA_EVEN_RS_MASK;
+		val |= FIELD_PREP(MOXA_EVEN_RS_MASK, mode);
+	}
+	outb(val, UIR_addr);
+
+	return 0;
+}
+
 static int pci_moxa_init(struct pci_dev *dev)
 {
 	unsigned short device = dev->device;
 	resource_size_t iobar_addr = pci_resource_start(dev, 2);
-	unsigned int num_ports = (device & 0x00F0) >> 4;
+	unsigned int num_ports = (device & 0x00F0) >> 4, i;
 	u8 val;
 
+	if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232)) {
+		for (i = 0; i < num_ports; ++i)
+			pci_moxa_set_interface(dev, i, MOXA_RS422);
+	}
+
 	/*
 	 * Enable hardware buffer to prevent break signal output when system boots up.
 	 * This hardware buffer is only supported on Mini PCIe series.
-- 
2.34.1

[PATCH 2/2] tty: serial: 8250: Add support for MOXA PCIe boards to switch interface

[Crescent CY Hsieh]

MOXA PCIe boards have 4 serial interfaces and don't require additional
stuff to switch between interfaces:

- RS232
- RS422
- RS485_2W (half-duplex)
- RS485_4W (full-duplex)

By using ioctl command "TIOCRS485", it can switch between default
interface and RS485 if supported.

That means, for RS422/RS485 board, it can switch between RS422 and
RS485 by setting the flags within struct serial_rs485.

However, for the RS232/RS422/RS485 board, it can only switch between
RS232 and RS485, there's no flag for switching interface into RS422.

This patch adds a flag call "SER_RS422_ENALBED" in serial.h and modifies
serial_core.c to make it possible to switch interface between RS232,
RS422 and RS485.

Signed-off-by: Crescent CY Hsieh <crescentcy.hsieh@moxa.com>
---
 drivers/tty/serial/8250/8250_pci.c | 44 ++++++++++++++++++++++++++++++
 drivers/tty/serial/serial_core.c   | 21 ++++++++++++--
 include/uapi/linux/serial.h        |  4 +++
 3 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 66a2450da..6eabf6bf5 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1983,6 +1983,10 @@ enum {
 	MOXA_SUPP_RS485 = BIT(2),
 };
 
+static const struct serial_rs485 pci_moxa_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX | SER_RS422_ENABLED,
+};
+
 static bool pci_moxa_is_mini_pcie(unsigned short device)
 {
 	if (device == PCI_DEVICE_ID_MOXA_CP102N	||
@@ -2032,6 +2036,37 @@ static int pci_moxa_set_interface(const struct pci_dev *dev,
 	return 0;
 }
 
+/*
+ * MOXA PCIe boards support switching the serial interface using the ioctl
+ * command "TIOCSRS485".
+ *
+ *	RS232			= (no flags are set)
+ *	RS422			= SER_RS422_ENABLED
+ *	RS485_2W (half-duplex)	= SER_RS485_ENABLED
+ *	RS485_4W (full-duplex)	= SER_RS485_ENABLED | SER_RS485_RX_DURING_TX
+ */
+static int pci_moxa_rs485_config(struct uart_port *port,
+				 struct ktermios *termios,
+				 struct serial_rs485 *rs485)
+{
+	struct pci_dev *dev = to_pci_dev(port->dev);
+	u8 mode = MOXA_RS232;
+
+	if (rs485->flags & SER_RS485_ENABLED) {
+		if (rs485->flags & SER_RS485_RX_DURING_TX)
+			mode = MOXA_RS485_4W;
+		else
+			mode = MOXA_RS485_2W;
+	} else if (rs485->flags & SER_RS422_ENABLED) {
+		mode = MOXA_RS422;
+	} else {
+		if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232))
+			return -ENODEV;
+	}
+
+	return pci_moxa_set_interface(dev, port->port_id, mode);
+}
+
 static int pci_moxa_init(struct pci_dev *dev)
 {
 	unsigned short device = dev->device;
@@ -2067,9 +2102,18 @@ pci_moxa_setup(struct serial_private *priv,
 		const struct pciserial_board *board,
 		struct uart_8250_port *port, int idx)
 {
+	struct pci_dev *dev = priv->dev;
 	unsigned int bar = FL_GET_BASE(board->flags);
 	int offset;
 
+	if (pci_moxa_supported_rs(dev) & MOXA_SUPP_RS485) {
+		port->port.rs485_config = pci_moxa_rs485_config;
+		port->port.rs485_supported = pci_moxa_rs485_supported;
+
+		if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232))
+			port->port.rs485.flags = SER_RS422_ENABLED;
+	}
+
 	if (board->num_ports == 4 && idx == 3)
 		offset = 7 * board->uart_offset;
 	else
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 831d03361..e4ea0e428 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1305,7 +1305,7 @@ static int uart_get_icount(struct tty_struct *tty,
 
 #define SER_RS485_LEGACY_FLAGS	(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
 				 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
-				 SER_RS485_TERMINATE_BUS)
+				 SER_RS485_TERMINATE_BUS | SER_RS422_ENABLED)
 
 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
 {
@@ -1371,11 +1371,26 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
 {
 	u32 supported_flags = port->rs485_supported.flags;
 
-	if (!(rs485->flags & SER_RS485_ENABLED)) {
+	if (!(rs485->flags & SER_RS485_ENABLED) && !(rs485->flags & SER_RS422_ENABLED)) {
 		memset(rs485, 0, sizeof(*rs485));
 		return;
 	}
 
+	/* Pick sane setting if the user enables both interfaces */
+	if (rs485->flags & SER_RS485_ENABLED && rs485->flags & SER_RS422_ENABLED) {
+		dev_warn_ratelimited(port->dev,
+			"%s (%d): Invalid serial interface setting, using RS485 instead\n",
+			port->name, port->line);
+		rs485->flags &= ~(SER_RS422_ENABLED);
+	}
+
+	/* Clear other bits and return if enable RS422 */
+	if (rs485->flags & SER_RS422_ENABLED) {
+		memset(rs485, 0, sizeof(*rs485));
+		rs485->flags |= SER_RS422_ENABLED;
+		return;
+	}
+
 	/* Pick sane settings if the user hasn't */
 	if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) &&
 	    !(rs485->flags & SER_RS485_RTS_ON_SEND) ==
@@ -1400,7 +1415,7 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
 static void uart_set_rs485_termination(struct uart_port *port,
 				       const struct serial_rs485 *rs485)
 {
-	if (!(rs485->flags & SER_RS485_ENABLED))
+	if (!(rs485->flags & SER_RS485_ENABLED) && !(rs485->flags & SER_RS422_ENABLED))
 		return;
 
 	gpiod_set_value_cansleep(port->rs485_term_gpio,
diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
index 53bc1af67..427609fd5 100644
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -137,6 +137,8 @@ struct serial_icounter_struct {
  * * %SER_RS485_ADDRB		- Enable RS485 addressing mode.
  * * %SER_RS485_ADDR_RECV - Receive address filter (enables @addr_recv). Requires %SER_RS485_ADDRB.
  * * %SER_RS485_ADDR_DEST - Destination address (enables @addr_dest). Requires %SER_RS485_ADDRB.
+ *
+ * * %SER_RS422_ENABLED		- RS422 enabled.
  */
 struct serial_rs485 {
 	__u32	flags;
@@ -149,6 +151,8 @@ struct serial_rs485 {
 #define SER_RS485_ADDR_RECV		(1 << 7)
 #define SER_RS485_ADDR_DEST		(1 << 8)
 
+#define SER_RS422_ENABLED		(1 << 9)
+
 	__u32	delay_rts_before_send;
 	__u32	delay_rts_after_send;
 
-- 
2.34.1

Re: [PATCH 1/2] tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by default

[Jiri Slaby]

On 27. 10. 23, 8:24, Crescent CY Hsieh wrote:
> MOXA PCIe RS422/RS485 boards will not function by default because of the
> initial default serial interface of all MOXA PCIe boards is set to
> RS232.
> 
> This patch fixes the problem above by setting the initial default serial
> interface to RS422 for those MOXA RS422/RS485 PCIe boards.
> 
> Signed-off-by: Crescent CY Hsieh <crescentcy.hsieh@moxa.com>

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>

thanks,
-- 
js
suse labs

Re: [PATCH 2/2] tty: serial: 8250: Add support for MOXA PCIe boards to switch interface

[Jiri Slaby]

On 27. 10. 23, 8:24, Crescent CY Hsieh wrote:
> MOXA PCIe boards have 4 serial interfaces and don't require additional
> stuff to switch between interfaces:
> 
> - RS232
> - RS422
> - RS485_2W (half-duplex)
> - RS485_4W (full-duplex)
> 
> By using ioctl command "TIOCRS485", it can switch between default
> interface and RS485 if supported.
> 
> That means, for RS422/RS485 board, it can switch between RS422 and
> RS485 by setting the flags within struct serial_rs485.
> 
> However, for the RS232/RS422/RS485 board, it can only switch between
> RS232 and RS485, there's no flag for switching interface into RS422.
> 
> This patch adds a flag call "SER_RS422_ENALBED" in serial.h and modifies

It's not "ENALBED".

Anyway, I am afraid you have to split the patch into two:
1) add the flag and core support (but wait a bit for others if they 
agree with this approach)
2) add the support for moxa.

> serial_core.c to make it possible to switch interface between RS232,
> RS422 and RS485.
...
> --- a/drivers/tty/serial/8250/8250_pci.c
> +++ b/drivers/tty/serial/8250/8250_pci.c

> @@ -2032,6 +2036,37 @@ static int pci_moxa_set_interface(const struct pci_dev *dev,
>   	return 0;
>   }
>   
> +/*
> + * MOXA PCIe boards support switching the serial interface using the ioctl
> + * command "TIOCSRS485".
> + *
> + *	RS232			= (no flags are set)
> + *	RS422			= SER_RS422_ENABLED
> + *	RS485_2W (half-duplex)	= SER_RS485_ENABLED
> + *	RS485_4W (full-duplex)	= SER_RS485_ENABLED | SER_RS485_RX_DURING_TX
> + */
> +static int pci_moxa_rs485_config(struct uart_port *port,
> +				 struct ktermios *termios,
> +				 struct serial_rs485 *rs485)
> +{
> +	struct pci_dev *dev = to_pci_dev(port->dev);
> +	u8 mode = MOXA_RS232;
> +
> +	if (rs485->flags & SER_RS485_ENABLED) {
> +		if (rs485->flags & SER_RS485_RX_DURING_TX)
> +			mode = MOXA_RS485_4W;
> +		else
> +			mode = MOXA_RS485_2W;
> +	} else if (rs485->flags & SER_RS422_ENABLED) {
> +		mode = MOXA_RS422;
> +	} else {
> +		if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232))
> +			return -ENODEV;
> +	}
> +
> +	return pci_moxa_set_interface(dev, port->port_id, mode);

Looks good to me now.

> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1305,7 +1305,7 @@ static int uart_get_icount(struct tty_struct *tty,
>   
>   #define SER_RS485_LEGACY_FLAGS	(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
>   				 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
> -				 SER_RS485_TERMINATE_BUS)
> +				 SER_RS485_TERMINATE_BUS | SER_RS422_ENABLED)
>   
>   static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
>   {
> @@ -1371,11 +1371,26 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
>   {
>   	u32 supported_flags = port->rs485_supported.flags;
>   
> -	if (!(rs485->flags & SER_RS485_ENABLED)) {
> +	if (!(rs485->flags & SER_RS485_ENABLED) && !(rs485->flags & SER_RS422_ENABLED)) {

maybe easier:
   if (!(rs485->flags & (SER_RS485_ENABLED | SER_RS422_ENABLED))) {
?

>   		memset(rs485, 0, sizeof(*rs485));
>   		return;
>   	}
>   
> +	/* Pick sane setting if the user enables both interfaces */
> +	if (rs485->flags & SER_RS485_ENABLED && rs485->flags & SER_RS422_ENABLED) {
> +		dev_warn_ratelimited(port->dev,
> +			"%s (%d): Invalid serial interface setting, using RS485 instead\n",
> +			port->name, port->line);
> +		rs485->flags &= ~(SER_RS422_ENABLED);

No need for parens.

> +	}
> +
> +	/* Clear other bits and return if enable RS422 */

"if RS422 is enabled"
or
"if enabling RS422"

> +	if (rs485->flags & SER_RS422_ENABLED) {
> +		memset(rs485, 0, sizeof(*rs485));
> +		rs485->flags |= SER_RS422_ENABLED;
> +		return;
> +	}
> +
>   	/* Pick sane settings if the user hasn't */
>   	if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) &&
>   	    !(rs485->flags & SER_RS485_RTS_ON_SEND) ==
> @@ -1400,7 +1415,7 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
>   static void uart_set_rs485_termination(struct uart_port *port,
>   				       const struct serial_rs485 *rs485)
>   {
> -	if (!(rs485->flags & SER_RS485_ENABLED))
> +	if (!(rs485->flags & SER_RS485_ENABLED) && !(rs485->flags & SER_RS422_ENABLED))

if (!(rs485->flags & (SER_RS485_ENABLED | SER_RS422_ENABLED))) {

thanks,
-- 
js
suse labs

Re: [PATCH 1/2] tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by default

[kernel test robot]

Hi Crescent,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tty/tty-testing]
[also build test WARNING on tty/tty-next next-20231026]
[cannot apply to tty/tty-linus usb/usb-testing usb/usb-next usb/usb-linus linus/master v6.6-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Crescent-CY-Hsieh/tty-serial-8250-Fix-MOXA-RS422-RS485-PCIe-boards-not-work-by-default/20231027-142745
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
patch link:    https://lore.kernel.org/r/20231027062440.7749-2-crescentcy.hsieh%40moxa.com
patch subject: [PATCH 1/2] tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by default
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20231027/202310271618.QBCWA4yo-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231027/202310271618.QBCWA4yo-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310271618.QBCWA4yo-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/tty/serial/8250/8250_pci.c:2001:5: warning: no previous prototype for 'pci_moxa_supported_rs' [-Wmissing-prototypes]
    2001 | u32 pci_moxa_supported_rs(struct pci_dev *dev)
         |     ^~~~~~~~~~~~~~~~~~~~~


vim +/pci_moxa_supported_rs +2001 drivers/tty/serial/8250/8250_pci.c

  2000	
> 2001	u32 pci_moxa_supported_rs(struct pci_dev *dev)
  2002	{
  2003		switch (dev->device & 0x0F00) {
  2004		case 0x0000:
  2005		case 0x0600:
  2006			return MOXA_SUPP_RS232;
  2007		case 0x0100:
  2008			return MOXA_SUPP_RS232 | MOXA_SUPP_RS422 | MOXA_SUPP_RS485;
  2009		case 0x0300:
  2010			return MOXA_SUPP_RS422 | MOXA_SUPP_RS485;
  2011		}
  2012		return 0;
  2013	}
  2014	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/2] tty: serial: 8250: Add support for MOXA PCIe boards to switch interface

[Crescent CY Hsieh]

On Fri, Oct 27, 2023 at 10:29:38AM +0200, Jiri Slaby wrote:
> On 27. 10. 23, 8:24, Crescent CY Hsieh wrote:
> > MOXA PCIe boards have 4 serial interfaces and don't require additional
> > stuff to switch between interfaces:
> > 
> > - RS232
> > - RS422
> > - RS485_2W (half-duplex)
> > - RS485_4W (full-duplex)
> > 
> > By using ioctl command "TIOCRS485", it can switch between default
> > interface and RS485 if supported.
> > 
> > That means, for RS422/RS485 board, it can switch between RS422 and
> > RS485 by setting the flags within struct serial_rs485.
> > 
> > However, for the RS232/RS422/RS485 board, it can only switch between
> > RS232 and RS485, there's no flag for switching interface into RS422.
> > 
> > This patch adds a flag call "SER_RS422_ENALBED" in serial.h and modifies
> 
> It's not "ENALBED".
> 
> Anyway, I am afraid you have to split the patch into two:
> 1) add the flag and core support (but wait a bit for others if they agree
> with this approach)
> 2) add the support for moxa.

Agree, I will split this patch into two separate patches and only send
the patch for adding the flag and core support first.

---
Sincerely,
Crescent CY Hsieh

Re: [PATCH 1/2] tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by default

[kernel test robot]

Hi Crescent,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tty/tty-testing]
[also build test WARNING on tty/tty-next next-20231027]
[cannot apply to tty/tty-linus usb/usb-testing usb/usb-next usb/usb-linus linus/master v6.6-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Crescent-CY-Hsieh/tty-serial-8250-Fix-MOXA-RS422-RS485-PCIe-boards-not-work-by-default/20231027-142745
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
patch link:    https://lore.kernel.org/r/20231027062440.7749-2-crescentcy.hsieh%40moxa.com
patch subject: [PATCH 1/2] tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by default
config: i386-randconfig-002-20231028 (https://download.01.org/0day-ci/archive/20231028/202310281723.0DAslF1o-lkp@intel.com/config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231028/202310281723.0DAslF1o-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310281723.0DAslF1o-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/tty/serial/8250/8250_pci.c:2001:5: warning: no previous declaration for 'pci_moxa_supported_rs' [-Wmissing-declarations]
    u32 pci_moxa_supported_rs(struct pci_dev *dev)
        ^~~~~~~~~~~~~~~~~~~~~


vim +/pci_moxa_supported_rs +2001 drivers/tty/serial/8250/8250_pci.c

  2000	
> 2001	u32 pci_moxa_supported_rs(struct pci_dev *dev)
  2002	{
  2003		switch (dev->device & 0x0F00) {
  2004		case 0x0000:
  2005		case 0x0600:
  2006			return MOXA_SUPP_RS232;
  2007		case 0x0100:
  2008			return MOXA_SUPP_RS232 | MOXA_SUPP_RS422 | MOXA_SUPP_RS485;
  2009		case 0x0300:
  2010			return MOXA_SUPP_RS422 | MOXA_SUPP_RS485;
  2011		}
  2012		return 0;
  2013	}
  2014	

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