On Wed, 18 Mar 2015, Jakub Kicinski wrote:
> From: Jakub Kicinski <kubakici@xxxxx>
>
> Users of RS-485 can request via ioctl that RTS signals should
> be activated selected number of milliseconds before the actual
> data transmission or stay active after the transmission is
> finished. In sc16is7xx, however, RTS signalling is handled by
> the hardware and driver has no way of providing this feature.
>
> Note: this change will make the driver return -EINVAL when the
> feature is requested (.delay_rts_*_send are set).
Makes sense. I removed the use of .delay_rts_before_send that my user app
was setting and tested it and you are correct it.
>
> Signed-off-by: Jakub Kicinski <kubakici@xxxxx>
Signed-off-by: Jon Ringle <jringle@xxxxxxxxxxxxx>
> ---
> drivers/tty/serial/sc16is7xx.c | 26 +++++---------------------
> 1 file changed, 5 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index 20573d72715d..25c27c09b0d0 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -651,21 +651,6 @@ static void sc16is7xx_wq_proc(struct work_struct *ws)
>
> static void sc16is7xx_stop_tx(struct uart_port* port)
> {
> - struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
> - struct circ_buf *xmit = &one->port.state->xmit;
> -
> - /* handle rs485 */
> - if (port->rs485.flags & SER_RS485_ENABLED) {
> - /* do nothing if current tx not yet completed */
> - int lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
> - if (!(lsr & SC16IS7XX_LSR_TEMT_BIT))
> - return;
> -
> - if (uart_circ_empty(xmit) &&
> - (port->rs485.delay_rts_after_send > 0))
> - mdelay(port->rs485.delay_rts_after_send);
> - }
> -
> sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
> SC16IS7XX_IER_THRI_BIT,
> 0);
> @@ -685,12 +670,6 @@ static void sc16is7xx_start_tx(struct uart_port *port)
> {
> struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
>
> - /* handle rs485 */
> - if ((port->rs485.flags & SER_RS485_ENABLED) &&
> - (port->rs485.delay_rts_before_send > 0)) {
> - mdelay(port->rs485.delay_rts_before_send);
> - }
> -
> if (!work_pending(&one->tx_work))
> schedule_work(&one->tx_work);
> }
> @@ -849,6 +828,11 @@ static int sc16is7xx_config_rs485(struct uart_port *port,
> efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT;
> else
> return -EINVAL;
> +
> + /* RTS signal is handled by HW, timing can't be influenced */
> + if (rs485->delay_rts_after_send ||
> + rs485->delay_rts_before_send)
> + return -EINVAL;
> }
>
> sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
> --
> 2.1.0
>
>
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