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| author | Crescent Hsieh <crescentcy.hsieh@moxa.com> | 2026-07-31 15:48:10 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-08-03 16:51:57 +0200 |
| commit | 55edf8511f4728a79757ab64ae9126e2ea59e310 (patch) | |
| tree | b8d55c66e366fe41152ce5a9b049aaff3a06e633 /drivers | |
| parent | 0a53c72969e72041476a5ae3fe8381fc7e2c13dd (diff) | |
| download | linux-55edf8511f4728a79757ab64ae9126e2ea59e310.tar.gz linux-55edf8511f4728a79757ab64ae9126e2ea59e310.zip | |
serial: 8250_mxpcie: enable automatic RTS/CTS flow control
The MUEx50 UART supports automatic RTS/CTS flow control via the enhanced
feature register.
Implement a mxpcie-specific set_termios() callback that enables MUEx50
auto-RTS/auto-CTS when CRTSCTS is requested and disables it otherwise.
Keep the 8250 port status flags in sync with the hardware configuration.
Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com>
Link: https://patch.msgid.link/20260731074820.735619-5-crescentcy.hsieh@moxa.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/8250/8250_mxpcie.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_mxpcie.c b/drivers/tty/serial/8250/8250_mxpcie.c index e1d607b607e8..25ca43225e7a 100644 --- a/drivers/tty/serial/8250/8250_mxpcie.c +++ b/drivers/tty/serial/8250/8250_mxpcie.c @@ -58,6 +58,10 @@ /* Enhanced Function Register (EFR) */ #define MOXA_PUART_EFR 0x0A #define MOXA_PUART_EFR_ENHANCED BIT(4) +#define MOXA_PUART_EFR_AUTO_RTS BIT(6) +#define MOXA_PUART_EFR_AUTO_CTS BIT(7) +#define MOXA_PUART_EFR_RX_FLOW_MASK GENMASK(1, 0) +#define MOXA_PUART_EFR_TX_FLOW_MASK GENMASK(3, 2) #define MOXA_PUART_TTL 0x10 /* Tx Interrupt Trigger Level */ #define MOXA_PUART_RTL 0x11 /* Rx Interrupt Trigger Level */ @@ -148,6 +152,29 @@ static void mxpcie8250_set_interface(struct mxpcie8250 *priv, iowrite8(cval, uir_addr); } +static void mxpcie8250_set_termios(struct uart_port *port, + struct ktermios *new, + const struct ktermios *old) +{ + struct uart_8250_port *up = up_to_u8250p(port); + struct tty_struct *tty = port->state->port.tty; + unsigned int cflag = tty->termios.c_cflag; + u8 efr; + + serial8250_do_set_termios(port, new, old); + + up->port.status &= ~(UPSTAT_AUTORTS | UPSTAT_AUTOCTS); + + efr = serial_in(up, MOXA_PUART_EFR); + efr &= ~(MOXA_PUART_EFR_AUTO_RTS | MOXA_PUART_EFR_AUTO_CTS); + + if (cflag & CRTSCTS) { + efr |= (MOXA_PUART_EFR_AUTO_RTS | MOXA_PUART_EFR_AUTO_CTS); + up->port.status |= (UPSTAT_AUTORTS | UPSTAT_AUTOCTS); + } + serial_out(up, MOXA_PUART_EFR, efr); +} + static int mxpcie8250_startup(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); @@ -285,6 +312,7 @@ static int mxpcie8250_probe(struct pci_dev *pdev, const struct pci_device_id *id up.port.iobase = 0; up.port.regshift = 0; + up.port.set_termios = mxpcie8250_set_termios; up.port.startup = mxpcie8250_startup; up.port.shutdown = mxpcie8250_shutdown; |