From 197540dc8301a296e8ae7aa062f9f61f047eea05 Mon Sep 17 00:00:00 2001 From: Sergey Organov Date: Fri, 26 Jul 2019 21:52:40 +0300 Subject: [PATCH] serial: imx: set_mctrl(): correctly restore autoRTS state 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. Reviewed-by: Sascha Hauer Tested-by: Sascha Hauer Signed-off-by: Sergey Organov Link: https://lore.kernel.org/r/1564167161-3972-3-git-send-email-sorganov@gmail.com Signed-off-by: Greg Kroah-Hartman --- 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. + */ 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; + } imx_uart_writel(sport, ucr2, UCR2); } -- 2.7.4