# SPDX-License-Identifier: GPL-2.0
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#
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# The 8250/16550 serial drivers. You shouldn't be in this list unless
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# you somehow have an implicit or explicit dependency on SERIAL_8250.
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#
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config SERIAL_8250
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tristate "8250/16550 and compatible serial support"
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depends on !S390
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select SERIAL_CORE
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select SERIAL_MCTRL_GPIO if GPIOLIB
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help
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This selects whether you want to include the driver for the standard
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serial ports. The standard answer is Y. People who might say N
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here are those that are setting up dedicated Ethernet WWW/FTP
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servers, or users that have one of the various bus mice instead of a
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serial mouse and don't intend to use their machine's standard serial
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port for anything. (Note that the Cyclades multi serial port driver
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does not need this driver built in for it to work.)
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To compile this driver as a module, choose M here: the
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module will be called 8250.
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[WARNING: Do not compile this driver as a module if you are using
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non-standard serial ports, since the configuration information will
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be lost when the driver is unloaded. This limitation may be lifted
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in the future.]
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BTW1: If you have a mouseman serial mouse which is not recognized by
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the X window system, try running gpm first.
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BTW2: If you intend to use a software modem (also called Winmodem)
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under Linux, forget it. These modems are crippled and require
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proprietary drivers which are only available under Windows.
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Most people will say Y or M here, so that they can use serial mice,
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modems and similar devices connecting to the standard serial ports.
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config SERIAL_8250_DEPRECATED_OPTIONS
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bool "Support 8250_core.* kernel options (DEPRECATED)"
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depends on SERIAL_8250
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default y
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help
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In 3.7 we renamed 8250 to 8250_core by mistake, so now we have to
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accept kernel parameters in both forms like 8250_core.nr_uarts=4 and
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8250.nr_uarts=4. We now renamed the module back to 8250, but if
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anybody noticed in 3.7 and changed their userspace we still have to
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keep the 8250_core.* options around until they revert the changes
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they already did.
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If 8250 is built as a module, this adds 8250_core alias instead.
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If you did not notice yet and/or you have userspace from pre-3.7, it
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is safe (and recommended) to say N here.
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config SERIAL_8250_PNP
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bool "8250/16550 PNP device support" if EXPERT
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depends on SERIAL_8250 && PNP
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default y
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help
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This builds standard PNP serial support. You may be able to
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disable this feature if you only need legacy serial support.
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config SERIAL_8250_16550A_VARIANTS
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bool "Support for variants of the 16550A serial port"
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depends on SERIAL_8250
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default !X86
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help
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The 8250 driver can probe for many variants of the venerable 16550A
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serial port. Doing so takes additional time at boot.
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On modern systems, especially those using serial only for a simple
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console, you can say N here.
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config SERIAL_8250_FINTEK
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bool "Support for Fintek F81216A LPC to 4 UART RS485 API"
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depends on SERIAL_8250
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help
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Selecting this option will add support for the RS485 capabilities
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of the Fintek F81216A LPC to 4 UART.
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If this option is not selected the device will be configured as a
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standard 16550A serial port.
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If unsure, say N.
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config SERIAL_8250_CONSOLE
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bool "Console on 8250/16550 and compatible serial port"
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depends on SERIAL_8250=y
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select SERIAL_CORE_CONSOLE
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select SERIAL_EARLYCON
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help
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If you say Y here, it will be possible to use a serial port as the
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system console (the system console is the device which receives all
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kernel messages and warnings and which allows logins in single user
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mode). This could be useful if some terminal or printer is connected
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to that serial port.
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Even if you say Y here, the currently visible virtual console
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(/dev/tty0) will still be used as the system console by default, but
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you can alter that using a kernel command line option such as
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"console=ttyS1". (Try "man bootparam" or see the documentation of
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your boot loader (grub or lilo or loadlin) about how to pass options
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to the kernel at boot time.)
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If you don't have a VGA card installed and you say Y here, the
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kernel will automatically use the first serial line, /dev/ttyS0, as
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system console.
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You can set that using a kernel command line option such as
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"console=uart8250,io,0x3f8,9600n8"
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"console=uart8250,mmio,0xff5e0000,115200n8".
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and it will switch to normal serial console when the corresponding
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port is ready.
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"earlycon=uart8250,io,0x3f8,9600n8"
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"earlycon=uart8250,mmio,0xff5e0000,115200n8".
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it will not only setup early console.
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If unsure, say N.
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config SERIAL_8250_GSC
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tristate
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depends on SERIAL_8250 && PARISC
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default SERIAL_8250
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config SERIAL_8250_DMA
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bool "DMA support for 16550 compatible UART controllers" if EXPERT
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depends on SERIAL_8250 && DMADEVICES=y
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default SERIAL_8250
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help
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This builds DMA support that can be used with 8250/16650
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compatible UART controllers that support DMA signaling.
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config SERIAL_8250_PCI
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tristate "8250/16550 PCI device support"
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depends on SERIAL_8250 && PCI
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default SERIAL_8250
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help
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This builds standard PCI serial support. You may be able to
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disable this feature if you only need legacy serial support.
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Saves about 9K.
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Note that serial ports on NetMos 9835 Multi-I/O cards are handled
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by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
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config SERIAL_8250_EXAR
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tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
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depends on SERIAL_8250_PCI
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default SERIAL_8250
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help
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This builds support for XR17C1xx, XR17V3xx and some Commtech
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422x PCIe serial cards that are not covered by the more generic
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SERIAL_8250_PCI option.
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config SERIAL_8250_HP300
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tristate
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depends on SERIAL_8250 && HP300
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default SERIAL_8250
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config SERIAL_8250_CS
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tristate "8250/16550 PCMCIA device support"
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depends on PCMCIA && SERIAL_8250
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help
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Say Y here to enable support for 16-bit PCMCIA serial devices,
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including serial port cards, modems, and the modem functions of
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multi-function Ethernet/modem cards. (PCMCIA- or PC-cards are
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credit-card size devices often used with laptops.)
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To compile this driver as a module, choose M here: the
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module will be called serial_cs.
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If unsure, say N.
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config SERIAL_8250_MEN_MCB
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tristate "MEN MCB UART device support"
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depends on MCB && SERIAL_8250
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help
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This enables support for FPGA based UARTs found on many MEN
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boards. This driver enables support for the 16z025, 16z057
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and 16z125 UARTs.
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To compile this driver as a module, chose M here: the
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module will be called 8250_men_mcb.
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config SERIAL_8250_NR_UARTS
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int "Maximum number of 8250/16550 serial ports"
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depends on SERIAL_8250
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default "4"
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help
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Set this to the number of serial ports you want the driver
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to support. This includes any ports discovered via ACPI or
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PCI enumeration and any ports that may be added at run-time
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via hot-plug, or any ISA multi-port serial cards.
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config SERIAL_8250_RUNTIME_UARTS
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int "Number of 8250/16550 serial ports to register at runtime"
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depends on SERIAL_8250
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range 0 SERIAL_8250_NR_UARTS
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default "4"
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help
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Set this to the maximum number of serial ports you want
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the kernel to register at boot time. This can be overridden
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with the module parameter "nr_uarts", or boot-time parameter
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8250.nr_uarts
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config SERIAL_8250_EXTENDED
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bool "Extended 8250/16550 serial driver options"
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depends on SERIAL_8250
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help
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If you wish to use any non-standard features of the standard "dumb"
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driver, say Y here. This includes HUB6 support, shared serial
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interrupts, special multiport support, support for more than the
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four COM 1/2/3/4 boards, etc.
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Note that the answer to this question won't directly affect the
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kernel: saying N will just cause the configurator to skip all
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the questions about serial driver options. If unsure, say N.
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config SERIAL_8250_MANY_PORTS
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bool "Support more than 4 legacy serial ports"
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depends on SERIAL_8250_EXTENDED && !IA64
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help
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Say Y here if you have dumb serial boards other than the four
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standard COM 1/2/3/4 ports. This may happen if you have an AST
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FourPort, Accent Async, Boca (read the Boca mini-HOWTO, available
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from <https://www.tldp.org/docs.html#howto>), or other custom
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serial port hardware which acts similar to standard serial port
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hardware. If you only use the standard COM 1/2/3/4 ports, you can
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say N here to save some memory. You can also say Y if you have an
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"intelligent" multiport card such as Cyclades, Digiboards, etc.
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#
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# Multi-port serial cards
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#
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config SERIAL_8250_FOURPORT
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tristate "Support Fourport cards"
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depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
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help
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Say Y here if you have an AST FourPort serial board.
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To compile this driver as a module, choose M here: the module
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will be called 8250_fourport.
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config SERIAL_8250_ACCENT
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tristate "Support Accent cards"
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depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
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help
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Say Y here if you have an Accent Async serial board.
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To compile this driver as a module, choose M here: the module
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will be called 8250_accent.
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config SERIAL_8250_ASPEED_VUART
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tristate "Aspeed Virtual UART"
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depends on SERIAL_8250
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depends on OF
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depends on MFD_SYSCON
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depends on ARCH_ASPEED || COMPILE_TEST
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select REGMAP
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help
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If you want to use the virtual UART (VUART) device on Aspeed
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BMC platforms, enable this option. This enables the 16550A-
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compatible device on the local LPC bus, giving a UART device
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with no physical RS232 connections.
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config SERIAL_8250_BOCA
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tristate "Support Boca cards"
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depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
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help
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Say Y here if you have a Boca serial board. Please read the Boca
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mini-HOWTO, available from <https://www.tldp.org/docs.html#howto>
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To compile this driver as a module, choose M here: the module
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will be called 8250_boca.
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config SERIAL_8250_EXAR_ST16C554
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tristate "Support Exar ST16C554/554D Quad UART"
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depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
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help
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The Uplogix Envoy TU301 uses this Exar Quad UART. If you are
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tinkering with your Envoy TU301, or have a machine with this UART,
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say Y here.
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To compile this driver as a module, choose M here: the module
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will be called 8250_exar_st16c554.
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config SERIAL_8250_HUB6
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tristate "Support Hub6 cards"
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depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
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help
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Say Y here if you have a HUB6 serial board.
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To compile this driver as a module, choose M here: the module
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will be called 8250_hub6.
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#
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# Misc. options/drivers.
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#
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config SERIAL_8250_SHARE_IRQ
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bool "Support for sharing serial interrupts"
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depends on SERIAL_8250_EXTENDED
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help
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Some serial boards have hardware support which allows multiple dumb
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serial ports on the same board to share a single IRQ. To enable
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support for this in the serial driver, say Y here.
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config SERIAL_8250_DETECT_IRQ
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bool "Autodetect IRQ on standard ports (unsafe)"
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depends on SERIAL_8250_EXTENDED
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help
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Say Y here if you want the kernel to try to guess which IRQ
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to use for your serial port.
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This is considered unsafe; it is far better to configure the IRQ in
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a boot script using the setserial command.
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If unsure, say N.
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config SERIAL_8250_RSA
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bool "Support RSA serial ports"
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depends on SERIAL_8250_EXTENDED
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help
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Say Y here if you have a IODATA RSA-DV II/S ISA card and
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would like to use its >115kbps speeds.
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You will need to provide module parameter "probe_rsa", or boot-time
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parameter 8250.probe_rsa with I/O addresses of this card then.
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If you don't have such card, or if unsure, say N.
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config SERIAL_8250_DWLIB
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bool
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config SERIAL_8250_ACORN
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tristate "Acorn expansion card serial port support"
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depends on ARCH_ACORN && SERIAL_8250
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help
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If you have an Atomwide Serial card or Serial Port card for an Acorn
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system, say Y to this option. The driver can handle 1, 2, or 3 port
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cards. If unsure, say N.
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config SERIAL_8250_BCM2835AUX
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tristate "BCM2835 auxiliar mini UART support"
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depends on ARCH_BCM2835 || COMPILE_TEST
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depends on SERIAL_8250 && SERIAL_8250_SHARE_IRQ
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help
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Support for the BCM2835 auxiliar mini UART.
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Features and limitations of the UART are
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Registers are similar to 16650 registers,
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set bits in the control registers that are unsupported
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are ignored and read back as 0
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7/8 bit operation with 1 start and 1 stop bit
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8 symbols deep fifo for rx and tx
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SW controlled RTS and SW readable CTS
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Clock rate derived from system clock
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Uses 8 times oversampling (compared to 16 times for 16650)
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Missing break detection (but break generation)
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Missing framing error detection
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Missing parity bit
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Missing receive time-out interrupt
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Missing DCD, DSR, DTR and RI signals
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If unsure, say N.
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config SERIAL_8250_FSL
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bool
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depends on SERIAL_8250_CONSOLE
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default PPC || ARM || ARM64
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config SERIAL_8250_DW
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tristate "Support for Synopsys DesignWare 8250 quirks"
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depends on SERIAL_8250
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select SERIAL_8250_DWLIB
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help
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Selecting this option will enable handling of the extra features
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present in the Synopsys DesignWare APB UART.
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config SERIAL_8250_EM
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tristate "Support for Emma Mobile integrated serial port"
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depends on SERIAL_8250 && ARM && HAVE_CLK
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help
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Selecting this option will add support for the integrated serial
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port hardware found on the Emma Mobile line of processors.
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If unsure, say N.
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config SERIAL_8250_IOC3
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tristate "SGI IOC3 8250 UART support"
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depends on SGI_MFD_IOC3 && SERIAL_8250
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select SERIAL_8250_EXTENDED
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select SERIAL_8250_SHARE_IRQ
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help
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Enable this if you have a SGI Origin or Octane machine. This module
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provides basic serial support by directly driving the UART chip
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behind the IOC3 device on those systems. Maximum baud speed is
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38400bps using this driver.
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config SERIAL_8250_RT288X
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bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
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depends on SERIAL_8250
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default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620
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help
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Selecting this option will add support for the alternate register
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layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others.
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If unsure, say N.
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config SERIAL_8250_OMAP
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tristate "Support for OMAP internal UART (8250 based driver)"
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depends on SERIAL_8250 && (ARCH_OMAP2PLUS || ARCH_K3)
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help
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If you have a machine based on an Texas Instruments OMAP CPU you
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can enable its onboard serial ports by enabling this option.
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This driver uses ttyS instead of ttyO.
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config SERIAL_8250_OMAP_TTYO_FIXUP
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bool "Replace ttyO with ttyS"
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depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE
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default y
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help
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This option replaces the "console=ttyO" argument with the matching
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ttyS argument if the user did not specified it on the command line.
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This ensures that the user can see the kernel output during boot
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which he wouldn't see otherwise. The getty has still to be configured
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for ttyS instead of ttyO regardless of this option.
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This option is intended for people who "automatically" enable this
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driver without knowing that this driver requires a different console=
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argument. If you read this, please keep this option disabled and
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instead update your kernel command line. If you prepare a kernel for a
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distribution or other kind of larger user base then you probably want
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to keep this option enabled. Otherwise people might complain about a
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not booting kernel because the serial console remains silent in case
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they forgot to update the command line.
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config SERIAL_8250_LPC18XX
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tristate "NXP LPC18xx/43xx serial port support"
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depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST)
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default ARCH_LPC18XX
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help
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If you have a LPC18xx/43xx based board and want to use the
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serial port, say Y to this option. If unsure, say Y.
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config SERIAL_8250_MT6577
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tristate "Mediatek serial port support"
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depends on SERIAL_8250 && ARCH_MEDIATEK
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help
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If you have a Mediatek based board and want to use the
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serial port, say Y to this option. If unsure, say N.
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config SERIAL_8250_UNIPHIER
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tristate "Support for UniPhier on-chip UART"
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depends on SERIAL_8250
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depends on ARCH_UNIPHIER || COMPILE_TEST
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help
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If you have a UniPhier based board and want to use the on-chip
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serial ports, say Y to this option. If unsure, say N.
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config SERIAL_8250_INGENIC
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tristate "Support for Ingenic SoC serial ports"
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depends on SERIAL_8250
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depends on OF_FLATTREE
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depends on MIPS || COMPILE_TEST
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help
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If you have a system using an Ingenic SoC and wish to make use of
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its UARTs, say Y to this option. If unsure, say N.
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config SERIAL_8250_LPSS
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tristate "Support for serial ports on Intel LPSS platforms"
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default SERIAL_8250
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depends on SERIAL_8250 && PCI
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depends on X86 || COMPILE_TEST
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select SERIAL_8250_DWLIB
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select DW_DMAC_CORE if SERIAL_8250_DMA
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select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS)
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select RATIONAL
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help
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Selecting this option will enable handling of the extra features
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present on the UART found on various Intel platforms such as:
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- Intel Baytrail SoC
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- Intel Braswell SoC
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- Intel Quark X1000 SoC
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config SERIAL_8250_MID
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tristate "Support for serial ports on Intel MID platforms"
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default SERIAL_8250
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depends on SERIAL_8250 && PCI
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depends on X86 || COMPILE_TEST
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select HSU_DMA if SERIAL_8250_DMA
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select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID)
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select RATIONAL
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help
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Selecting this option will enable handling of the extra features
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present on the UART found on Intel Medfield SOC and various other
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Intel platforms.
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config SERIAL_8250_PXA
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tristate "PXA serial port support"
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depends on SERIAL_8250
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depends on ARCH_PXA || ARCH_MMP
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help
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If you have a machine based on an Intel XScale PXA2xx CPU you can
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enable its onboard serial ports by enabling this option. The option is
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applicable to both devicetree and legacy boards, and early console is
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part of its support.
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config SERIAL_8250_TEGRA
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tristate "8250 support for Tegra serial ports"
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default SERIAL_8250
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depends on SERIAL_8250
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depends on ARCH_TEGRA || COMPILE_TEST
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help
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Select this option if you have machine with an NVIDIA Tegra SoC and
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wish to enable 8250 serial driver for the Tegra serial interfaces.
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config SERIAL_OF_PLATFORM
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tristate "Devicetree based probing for 8250 ports"
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depends on SERIAL_8250 && OF
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help
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This option is used for all 8250 compatible serial ports that
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are probed through devicetree, including Open Firmware based
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PowerPC systems and embedded systems on architectures using the
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flattened device tree format.
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