From 44b374622a3f93f2f9ce0a782f3fedb7cd758b6b Mon Sep 17 00:00:00 2001 From: Hugo Villeneuve Date: Thu, 21 May 2026 14:16:53 -0400 Subject: [PATCH] serial: core: add new I/O type for SPI and I2C bus devices I2C/SPI serial drivers don't use the following struct uart_port variables: port->membase port->mapbase port->iobase However, they are forced to set membase to a non-zero value so that uart_configure_port() will succeed because of the following check: /* If there isn't a port here, don't do anything further. */ if (!port->iobase && !port->mapbase && !port->membase) return; Add a new I/O type for SPI and I2C bus devices to remove the need to implement the kind of above-mentioned ambiguous workarounds to make them work. Now that UART report functions are using uart_iotype_*() functions, no more irrelevant I/O information are being printed for UPIO_BUS iotypes. Signed-off-by: Hugo Villeneuve Link: https://patch.msgid.link/20260521-tty-upio-v3-7-bf74567994a0@dimonoff.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 11 ++++++----- include/linux/serial_core.h | 1 + include/uapi/linux/serial.h | 1 + 3 files changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 9b16480b374a..06d7f44643d6 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2542,11 +2542,10 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, { unsigned int flags; - /* - * If there isn't a port here, don't do anything further. - */ - if (!port->iobase && !port->mapbase && !port->membase) - return; + /* If there isn't a port here, don't do anything further. */ + if (uart_iotype_mmio(port->iotype) || uart_iotype_io(port->iotype)) + if (!port->iobase && !port->mapbase && !port->membase) + return; /* * Now do the auto configuration stuff. Note that config_port @@ -3249,6 +3248,8 @@ bool uart_match_port(const struct uart_port *port1, return hub6_match_port(port1, port2); else if (uart_iotype_mmio(port1->iotype)) return port1->mapbase == port2->mapbase; + else if (port1->iotype == UPIO_BUS) + return true; else return false; } diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 66b1459d53fc..c4cc4f66af4b 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -437,6 +437,7 @@ enum uart_iotype { UPIO_TSI = SERIAL_IO_TSI, /* Tsi108/109 type IO */ UPIO_MEM32BE = SERIAL_IO_MEM32BE, /* 32b big endian */ UPIO_MEM16 = SERIAL_IO_MEM16, /* 16b little endian */ + UPIO_BUS = SERIAL_IO_BUS, /* Serial bus I/O access (ex: SPI, I2C) */ }; struct uart_port { diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h index de9b4733607e..e6f61538fc28 100644 --- a/include/uapi/linux/serial.h +++ b/include/uapi/linux/serial.h @@ -72,6 +72,7 @@ struct serial_struct { #define SERIAL_IO_TSI 5 #define SERIAL_IO_MEM32BE 6 #define SERIAL_IO_MEM16 7 +#define SERIAL_IO_BUS 8 #define UART_CLEAR_FIFO 0x01 #define UART_USE_FIFO 0x02