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Message-ID: <92aed0d9-791f-4708-8a73-4c78457a710e@kernel.org>
Date: Mon, 2 Oct 2023 09:19:26 +0200
From: Jiri Slaby <jirislaby@...nel.org>
To: Crescent CY Hsieh <crescentcy.hsieh@...a.com>,
gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org
Subject: Re: [PATCH 4/4] tty: serial: 8250: Add support for MOXA PCIe boards
to switch interface between RS422/RS485
On 02. 10. 23, 3:57, 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
Hopefully not SER_RS422_ENALBED.
> serial_core.c to make it possible to switch interface between RS232,
> RS422 and RS485.
>
> Signed-off-by: Crescent CY Hsieh <crescentcy.hsieh@...a.com>
> ---
> drivers/tty/serial/8250/8250_pci.c | 41 ++++++++++++++++++++++++++++++
> drivers/tty/serial/serial_core.c | 20 ++++++++++++---
> include/uapi/linux/serial.h | 4 +++
> 3 files changed, 61 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
> index 31bfe5381000..86dce37f08c0 100644
> --- a/drivers/tty/serial/8250/8250_pci.c
> +++ b/drivers/tty/serial/8250/8250_pci.c
> @@ -1898,6 +1898,10 @@ pci_sunix_setup(struct serial_private *priv,
>
> #define MOXA_GPIO_SET_ALL_OUTPUT 0x0F
>
> +static const struct serial_rs485 pci_moxa_rs485_supported = {
> + .flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | SER_RS422_ENABLED,
> +};
> +
> static int pci_moxa_set_interface(struct pci_dev *dev,
> unsigned int port_idx,
> unsigned char mode)
> @@ -1921,6 +1925,30 @@ static int pci_moxa_set_interface(struct pci_dev *dev,
> return 0;
> }
>
> +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);
> + unsigned short device = dev->device;
> + unsigned char mode = MOXA_RS232;
u8
> +
> + 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 ((device & 0x0F00) == 0x0300) {
This is the second time you test this. Introduce a function.
> + pci_warn(dev, "RS232 interface is not supported.");
Don't spam the logs.
> + return -EINVAL;
> + }
> + }
add \n here
> + return pci_moxa_set_interface(dev, port->line, mode);
> +}
> +
> static int pci_moxa_init(struct pci_dev *dev)
> {
> unsigned short device = dev->device;
> @@ -1965,9 +1993,22 @@ static int pci_moxa_setup(struct serial_private *priv,
> struct uart_8250_port *port,
> int idx)
> {
> + struct pci_dev *dev = priv->dev;
> + unsigned short device = dev->device;
> unsigned int bar = FL_GET_BASE(board->flags);
> int offset;
>
> + /*
> + * For the device IDs of MOXA PCIe boards match the pattern 0x*3** and 0x*1**,
> + * these boards support switching interface between RS422/RS485 using TIOCSRS485.
> + */
> + if ((device & 0x0F00) == 0x0100 || (device & 0x0F00) == 0x0300) {
Use helpers.
> + port->port.rs485_config = pci_moxa_rs485_config;
> + port->port.rs485_supported = pci_moxa_rs485_supported;
> +
> + if ((device & 0x0F00) == 0x0300)
> + port->port.rs485.flags = SER_RE422_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 7bdc21d5e13b..f316d9705809 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1299,7 +1299,7 @@ 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_ENALBED)
So have you tested this at all?
> @@ -1365,11 +1365,23 @@ 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);
No need for parens.
> + }
> + /* Clear other bits and return if enalbe RS422 */
enable
> + 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) ==
> @@ -1394,7 +1406,7 @@ 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 53bc1af67a41..427609fd52cb 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;
>
thanks,
--
js
suse labs
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