Re: [PATCH v6 2/3] serial: imx: set_mctrl(): correctly restore autoRTS state
From: Uwe Kleine-König <hidden>
Date: 2019-07-22 20:24:20
Also in:
linux-serial
On Mon, Jul 22, 2019 at 10:22:10PM +0300, Sergey Organov wrote:
quoted hunk ↗ jump to hunk
imx_uart_set_mctrl() happened to set UCR2_CTSC bit whenever TIOCM_RTS was set, no matter if RTS/CTS handshake is enabled or not. Now fixed by turning handshake on only when CRTSCTS bit for the port is set. Acked-by: Uwe Kleine-König <redacted> Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de> Tested-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Sergey Organov <redacted> --- drivers/tty/serial/imx.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 32f36d8..059ba35 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c@@ -974,10 +974,22 @@ static void imx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) if (!(port->rs485.flags & SER_RS485_ENABLED)) { u32 ucr2; + /* + * Turn off autoRTS if RTS is lowered and restore autoRTS + * setting if RTS is raised.
"lower" and "raising" are misleading here. I recommend sticking to "active" and "inactive".
+ */
ucr2 = imx_uart_readl(sport, UCR2);
ucr2 &= ~(UCR2_CTS | UCR2_CTSC);
- if (mctrl & TIOCM_RTS)
- ucr2 |= UCR2_CTS | UCR2_CTSC;
+ if (mctrl & TIOCM_RTS) {
+ ucr2 |= UCR2_CTS;
+ /*
+ * UCR2_IRTS is unset if and only if the port is
+ * configured for CRTSCTS, so we use inverted UCR2_IRTS
+ * to get the state to restore to.
+ */
+ if (!(ucr2 & UCR2_IRTS))
+ ucr2 |= UCR2_CTSC;
+ }If you teach imx_uart_rts_auto about IRTS this function could be reused here I think. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel