On 05/29/2015 03:48 PM, Jakub Kici?ski wrote:

On Fri, 29 May 2015 13:35:54 +0530, Bhuvanchandra DV wrote:

quoted

Enable Vybrid's build-in support for RS-485 auto RTS for
controlling line direction of RS-485 transceiver driver.

Signed-off-by: Bhuvanchandra DV <redacted>
---
  drivers/tty/serial/fsl_lpuart.c | 60 +++++++++++++++++++++++++++++++++++++++++
  1 file changed, 60 insertions(+)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 357f623..c553b14 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c

@@ -820,6 +820,50 @@ static unsigned int lpuart32_tx_empty(struct uart_port *port)
  		TIOCSER_TEMT : 0;
  }

+static int lpuart_config_rs485(struct uart_port *port,
+			struct serial_rs485 *rs485)
+{
+	struct lpuart_port *sport = container_of(port,
+			struct lpuart_port, port);
+	u8 modem = readb(sport->port.membase + UARTMODEM) &
+		~(UARTMODEM_TXRTSPOL | UARTMODEM_TXRTSE);

Please put empty line between variables and code.

Ok

quoted

+	writeb(modem, sport->port.membase + UARTMODEM);
+
+	if (rs485->flags & SER_RS485_ENABLED) {
+		/* Enable auto RS-485 RTS mode */
+		modem |= UARTMODEM_TXRTSE;
+
+		/*
+		* RTS needs to be logic HIGH either during transer _or_ after
+		* transfer, other variants are not supported by the hardware.
+		*/

Indentation is off here.  '*' should be aligned.

Ok

quoted

+		if (!(rs485->flags & (SER_RS485_RTS_ON_SEND |
+				SER_RS485_RTS_AFTER_SEND)))

and here - things should be aligned on the containing bracket (SER_
under SER_ here).

Ok

quoted

+			rs485->flags |= SER_RS485_RTS_ON_SEND;
+
+		if (rs485->flags & SER_RS485_RTS_ON_SEND &&
+				rs485->flags & SER_RS485_RTS_AFTER_SEND)

and here - same bracket rule (rs485-> under rs485->)

Ok

quoted

+			rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
+
+		/*
+		* The hardware defaults to RTS logic HIGH while transfer.
+		* Switch polarity in case RTS shall be logic HIGH
+		* after transfer.
+		* Note: UART is assumed to be active high.
+		*/
+		if (rs485->flags & SER_RS485_RTS_ON_SEND)
+			modem &= ~UARTMODEM_TXRTSPOL;

UARTMODEM_TXRTSPOL was already clear when you read modem.

Ok

quoted

+		else if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
+			modem |= UARTMODEM_TXRTSPOL;
+	}
+
+	/* Store the new configuration */
+	sport->port.rs485 = *rs485;
+
+	writeb(modem, sport->port.membase + UARTMODEM);
+	return 0;
+}
+
  static unsigned int lpuart_get_mctrl(struct uart_port *port)
  {
  	return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR;

[...]

quoted

@@ -1802,6 +1854,14 @@ static int lpuart_probe(struct platform_device *pdev)
  		dev_info(sport->port.dev, "DMA rx channel request failed, "
  				"operating without rx DMA\n");

+	if (of_property_read_bool(np, "linux,rs485-enabled-at-boot-time")) {
+		sport->port.rs485.flags |= SER_RS485_ENABLED;
+		sport->port.rs485.flags |= SER_RS485_RTS_ON_SEND;
+		writeb(UARTMODEM_TXRTSE, sport->port.membase + UARTMODEM);
+	} else {
+		sport->port.rs485.flags &= ~SER_RS485_ENABLED;

Why the need to clear the flag?  sport was kzalloc'ed.

Will remove it.

Best Regards,
Bhuvan