[ PATCH V9 0/2] serial/uart/8250: Introduce tunable RX trigger I/F

[Yoshihiro YUNOMAE]

Hi Greg,

This patch set introduces tunable RX interrupt trigger I/F for 8250 serials.
I used Greg's patch(*1) as 1st patch in this version, and applied 2nd patch
of previous version.

Would you review this patch set?

Thanks!

Note:
I cleaned up Greg's patch as follows:
 - Delete extra line break
 - Use kcalloc instead of kmalloc
 - sizeof(struct attribute_group *) => sizeof(**uport->tty_groups)

*1: https://lkml.org/lkml/2014/7/12/177

<Change log>

Changes in V9:
 [2/2]
 -  Use attr_group instead of dev_spec_attr_group of uart_port structure

Changes in V8:
 - Split V7's patch up into 2 patches

Changes in V7:
 - Add Documentation
 - Change I/F name from rx_int_trig to rx_trig_bytes because the name
   rx_int_trig is hard to understand how users specify the value

Changes in V6:
 - Move FCR_RX_TRIG_* definition in 8250.h to include/uapi/linux/serial_reg.h,
   rename those to UART_FCR_R_TRIG_*, and use UART_FCR_TRIGGER_MASK to
   UART_FCR_R_TRIG_BITS()
 - Change following function names:
    convert_fcr2val() => fcr_get_rxtrig_bytes()
    convert_val2rxtrig() => bytes_to_fcr_rxtrig()
 - Fix typo in serial8250_do_set_termios()
 - Delete the verbose error message pr_info() in bytes_to_fcr_rxtrig()
 - Rename *rx_int_trig/rx_trig* to *rxtrig* for several functions or variables
   (but UI remains rx_int_trig)
 - Change the meaningless variable name 'val' to 'bytes' following functions:
    fcr_get_rxtrig_bytes(), bytes_to_fcr_rxtrig(), do_set_rxtrig(),
    do_serial8250_set_rxtrig(), and serial8250_set_attr_rxtrig()
 - Use up->fcr in order to get rxtrig_bytes instead of rx_trig_raw in
   fcr_get_rxtrig_bytes()
 - Use conf_type->rxtrig_bytes[0] instead of switch statement for support check
   in register_dev_spec_attr_grp()
 - Delete the checking whether a user changed FCR or not when minimum buffer
   is needed in serial8250_do_set_termios()

Changes in V5.1:
 - Fix FCR_RX_TRIG_MAX_STATE definition

Changes in V5:
 - Support Tegra, 16650V2, 16654, and 16750
 - Store default FCR value to up->fcr when the port is first created
 - Add rx_trig_byte[] in uart_config[] for each device and use rx_trig_byte[]
   in convert_fcr2val() and convert_val2rxtrig()

Changes in V4:
 - Introduce fifo_bug flag in uart_8250_port structure
   This is enabled only when parity is enabled and UART_BUG_PARITY is enabled
   for up->bugs. If this flag is enabled, user cannot set RX trigger.
 - Return -EOPNOTSUPP when it does not support device at convert_fcr2val() and
   at convert_val2rxtrig()
 - Set the nearest lower RX trigger when users input a meaningless value at
   convert_val2rxtrig()
 - Check whether p->fcr is existing at serial8250_clear_and_reinit_fifos()
 - Set fcr = up->fcr in the begging of serial8250_do_set_termios()

Changes in V3:
 - Change I/F from ioctl(2) to sysfs(rx_int_trig)

Changed in V2:
 - Use _IOW for TIOCSFIFORTRIG definition
 - Pass the interrupt trigger value itself

---

Greg Kroah-Hartman (1):
      Serial: allow port drivers to have a default attribute group

Yoshihiro YUNOMAE (1):
      serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers


 Documentation/ABI/testing/sysfs-tty |   16 +++
 drivers/tty/serial/8250/8250.h      |    2 
 drivers/tty/serial/8250/8250_core.c |  173 ++++++++++++++++++++++++++++++++---
 drivers/tty/serial/serial_core.c    |   24 +++--
 include/linux/serial_8250.h         |    2 
 include/linux/serial_core.h         |    2 
 include/uapi/linux/serial_reg.h     |    5 +
 7 files changed, 202 insertions(+), 22 deletions(-)

-- 
Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: yoshihiro.yunomae.ez@xxxxxxxxxxx
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