On 05/29/2015 03:48 PM, Jakub Kiciński wrote:
On Fri, 29 May 2015 13:35:54 +0530, Bhuvanchandra DV wrote:
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 <bhuvanchandra.dv@xxxxxxxxxxx>
---
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
+ 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
+ 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
+ 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
+ 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
+ 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;
[...]
@@ -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
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