[PATCH v2 6/7] serial: imx: set_mctrl(): correctly restore autoRTS state
From: Sergey Organov <hidden>
Date: 2019-06-26 14:16:24
Also in:
linux-serial
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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 <s.hauer@pengutronix.de> Tested-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Sergey Organov <redacted> --- drivers/tty/serial/imx.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 4867f80..171347d 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c@@ -970,10 +970,19 @@ 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 (UCR2_CTSC) if RTS is lowered and restore + * autoRTS setting if RTS is raised. Inverted UCR2_IRTS is set + * if and only if CRTSCTS bit is set for the port, so we use it + * to get the state to restore to. + */ 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; + if (!(ucr2 & UCR2_IRTS)) + ucr2 |= UCR2_CTSC; + } imx_uart_writel(sport, ucr2, UCR2); }
--
2.10.0.1.g57b01a3
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