Commit ecba98f9 authored by Sherry Sun's avatar Sherry Sun Committed by Greg Kroah-Hartman
Browse files

tty: serial: fsl_lpuart: set RTS watermark for lpuart 



Add RTS watermark support for LPUART. The RX RTS_B output negates when
the number of empty words in the receive FIFO is greater or equal to
RTSWATER. Here set the RTSWATER to half of the rxfifo_size.

Signed-off-by: default avatarSherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-6-sherry.sun@nxp.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 96f54fd4

drivers/tty/serial/fsl_lpuart.c

+8 −0
Original line number Diff line number Diff line
@@ -201,6 +201,7 @@ 
#define UARTDATA_MASK		0x3ff



#define UARTMODIR_IREN		0x00020000

#define UARTMODIR_RTSWATER	GENMASK(10, 8)

#define UARTMODIR_TXCTSSRC	0x00000020

#define UARTMODIR_TXCTSC	0x00000010

#define UARTMODIR_RXRTSE	0x00000008
@@ -1573,6 +1574,13 @@ static void lpuart32_setup_watermark(struct lpuart_port *sport) 
	      (0x0 << UARTWATER_TXWATER_OFF);

	lpuart32_write(&sport->port, val, UARTWATER);



	/* set RTS watermark */

	if (!uart_console(&sport->port)) {

		val = lpuart32_read(&sport->port, UARTMODIR);

		val |= FIELD_PREP(UARTMODIR_RTSWATER, sport->rxfifo_size >> 1);

		lpuart32_write(&sport->port, val, UARTMODIR);

	}



	/* Restore cr2 */

	lpuart32_write(&sport->port, ctrl_saved, UARTCTRL);

}