[v9,0/6] Add RS485 9th bit addressing mode support to DW UART

This patchset adds RS-485 9th bit addressing mode support to the DW
UART driver and the necessary serial core bits to handle it. The
addressing mode is configured through ->rs485_config() as was requested
during the review of the earlier versions. The line configuration
related ADDRB is still kept in ktermios->c_cflag to be able to take
account the extra addressing bit while calculating timing, etc. but it
is set/cleared by ->rs485_config().

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org

v8 -> v9:
- Tweak comments (struct fields info & one callback style correction)
- Add struct layout checks as static_asserts

v7 -> v8:
- Use anonymous union/struct in serial_rs485 to create "v2" of it
- Remove a stray newline change
- Reorder local var declarations
- Put ktermios param before serial_rs485 for rs485_config

v6 -> v7:
- Fixed typos in documentation & comment
- Changes lsr typing from unsigned int to u16

v5 -> v6:
- Reorder remaining patches
- LSR changes are simpler due to helper added by LSR fix series
- Depend on rs485_struct sanitization on catching much of invalid config
- In order to be able to alter ADDRB in termios .c_cflag within
  .rs485_config(), take termios_rwsem and pass ktermios to it.
- Moved addressing mode setup entirely into .rs485_config()
- Use ndelay() instead of udelay() (uart_port->frame_time is in nsecs)


Ilpo Järvinen (6):
  serial: 8250: make saved LSR larger
  serial: 8250: create lsr_save_mask
  serial: 8250_lpss: Use 32-bit reads
  serial: take termios_rwsem for ->rs485_config() & pass termios as
    param
  serial: Support for RS-485 multipoint addresses
  serial: 8250_dwlib: Support for 9th bit multipoint addressing

 Documentation/driver-api/serial/driver.rst    |   2 +
 .../driver-api/serial/serial-rs485.rst        |  26 ++++-
 drivers/tty/serial/8250/8250.h                |   9 +-
 drivers/tty/serial/8250/8250_core.c           |   4 +
 drivers/tty/serial/8250/8250_dw.c             |   2 +-
 drivers/tty/serial/8250/8250_dwlib.c          | 105 +++++++++++++++++-
 drivers/tty/serial/8250/8250_exar.c           |  11 +-
 drivers/tty/serial/8250/8250_fintek.c         |   2 +-
 drivers/tty/serial/8250/8250_fsl.c            |   2 +-
 drivers/tty/serial/8250/8250_ingenic.c        |   2 +-
 drivers/tty/serial/8250/8250_lpc18xx.c        |   2 +-
 drivers/tty/serial/8250/8250_lpss.c           |   2 +-
 drivers/tty/serial/8250/8250_omap.c           |   7 +-
 drivers/tty/serial/8250/8250_pci.c            |   2 +-
 drivers/tty/serial/8250/8250_port.c           |  20 ++--
 drivers/tty/serial/amba-pl011.c               |   2 +-
 drivers/tty/serial/ar933x_uart.c              |   2 +-
 drivers/tty/serial/atmel_serial.c             |   2 +-
 drivers/tty/serial/fsl_lpuart.c               |   4 +-
 drivers/tty/serial/imx.c                      |   2 +-
 drivers/tty/serial/max310x.c                  |   2 +-
 drivers/tty/serial/mcf.c                      |   3 +-
 drivers/tty/serial/omap-serial.c              |   3 +-
 drivers/tty/serial/sc16is7xx.c                |   2 +-
 drivers/tty/serial/serial_core.c              |  36 +++++-
 drivers/tty/serial/stm32-usart.c              |   2 +-
 drivers/tty/tty_ioctl.c                       |   4 +
 include/linux/serial_8250.h                   |   7 +-
 include/linux/serial_core.h                   |   1 +
 include/uapi/asm-generic/termbits-common.h    |   1 +
 include/uapi/linux/serial.h                   |  20 +++-
 31 files changed, 238 insertions(+), 53 deletions(-)