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

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