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[0/3] Handle UART without interrupt on TEMT using em485

Message ID 20210128233629.4164-1-etremblay@distech-controls.com
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Series Handle UART without interrupt on TEMT using em485 | expand

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Eric Tremblay Jan. 28, 2021, 11:36 p.m. UTC 
The series is mainly about the support of 8250 UART without TEMT
interrupt. I saw that there was some development in the past but
it was never merged. Since the last discussion were quite some
time ago, I was not sure if I should post a v4 over the
last v3 or start from scratch so I decided to post a new patch. Please
advice if I should have done the reverse.

The approach is a little different from the last proposed patch which was
doing using a polling at 100us. I tought that it could be really long on 
some fast baudrate and really not that long on slow baudrate. The current
approach is to calculate the time of a bytes when the settings are changed.
When we get the interrupt for the empty FIFO, it's the longer it can take
to empty the shift register.

The other two patches are to use that features with the PORT_16550A_FSL64
found on some chip like the LS1043A.

Thanks

Eric Tremblay (3):
  serial: 8250: Handle UART without interrupt on TEMT using em485
  serial: 8250: add compatible for fsl,16550-FIFO64
  serial: 8250: remove UART_CAP_TEMT on PORT_16550A_FSL64

 drivers/tty/serial/8250/8250.h            |  1 +
 drivers/tty/serial/8250/8250_bcm2835aux.c |  2 +-
 drivers/tty/serial/8250/8250_of.c         |  5 ++
 drivers/tty/serial/8250/8250_omap.c       |  2 +-
 drivers/tty/serial/8250/8250_port.c       | 89 ++++++++++++++++++++++-
 include/linux/serial_8250.h               |  2 +
 6 files changed, 98 insertions(+), 3 deletions(-)