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@xxxxxxxxxxxxxxxx>
> [moved to use added UART_CAP_TEMT]
> Signed-off-by: Heiko Stuebner <heiko.stuebner@xxxxxxxxxxxxxxxxxxxxx>
> [moved to use added UART_CAP_NOTEMT, improve timeout]
> Signed-off-by: Eric Tremblay <etremblay@xxxxxxxxxxxxxxxxxxxx>
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
