Commit bc2be239 authored Jan 30, 2017 by Fabio Estevam Committed by Greg Kroah-Hartman Jan 31, 2017

serial: imx: Fix the CTS_B polarity in RS485 mode

When userspace passes the SER_RS485_RTS_ON_SEND flag it means that the
CTS_B pin should go to logic level high before the transmission begins.

CTS_B goes to logic level high when both CTSC and CTS bits are cleared.

When userspace passes the SER_RS485_RTS_AFTER_SEND flag it means that the
CTS_B pin should go to logic level low after the transmission finishes.

CTS_B goes to logic level low when CTSC bit is cleared and CTS bit is set.

So fix the CTS_B polarity logic.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 1a613626

drivers/tty/serial/imx.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -336,15 +336,15 @@ static void imx_port_ucrs_restore(struct uart_port *port,

		static void imx_port_rts_active(struct imx_port sport, unsigned long ucr2)
		{
		*ucr2 &= ~UCR2_CTSC;
		*ucr2 \|= UCR2_CTS;
		*ucr2 &= ~(UCR2_CTSC \| UCR2_CTS);

		mctrl_gpio_set(sport->gpios, sport->port.mctrl \| TIOCM_RTS);
		}

		static void imx_port_rts_inactive(struct imx_port sport, unsigned long ucr2)
		{
		*ucr2 &= ~(UCR2_CTSC \| UCR2_CTS);
		*ucr2 &= ~UCR2_CTSC;
		*ucr2 \|= UCR2_CTS;

		mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS);
		}