Messages in this thread | | | Date | Fri, 1 Oct 2021 14:48:42 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH v2 1/3] serial: 8250: Handle UART without interrupt on TEMT using em485 |
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On Thu, Feb 04, 2021 at 11:11:56AM -0500, Eric Tremblay wrote: > The patch introduce the UART_CAP_NOTEMT capability. The capability
s/The patch//
> indicate that the UART doesn't have an interrupt available on TEMT.
indicates
> In the case where the device does not support it, we calculate the > maximum time it could take for the transmitter to empty the > shift register. When we get in the situation where we get the > THRE interrupt, we check if the TEMT bit is set. If it's not, we start > the a timer and recall __stop_tx() after the delay. > > The transmit sequence is a bit modified when the capability is set. The > new timer is used between the last interrupt(THRE) and a potential > stop_tx timer.
> Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> > [moved to use added UART_CAP_TEMT] > Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com> > [moved to use added UART_CAP_NOTEMT, improve timeout] > Signed-off-by: Eric Tremblay <etremblay@distech-controls.com>
Does it need Co-developed-by tag(s)?
...
> +#define UART_CAP_NOTEMT (1 << 18) /* UART without interrupt on TEMT available*/
Missed space in the comment .
...
> +static inline void serial8250_em485_update_temt_delay(struct uart_8250_port *p, > + unsigned int cflag, unsigned int baud) > +{ > + unsigned int bits; > + > + if (!p->em485) > + return; > + > + bits = uart_get_byte_size(cflag);
Should be rebased. We have tty_get_frame_size() for a while.
> + p->em485->no_temt_delay = bits * NSEC_PER_SEC / baud; > +}
-- With Best Regards, Andy Shevchenko
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