The transmitter is expected to be controlled by the UART's RTS pin.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
drivers/tty/serial/imx.c | 107 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 95 insertions(+), 12 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 95bd0a5ae0d1..0d870477d80d 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -365,8 +365,23 @@ static void imx_stop_tx(struct uart_port *port)
if (sport->dma_is_enabled && sport->dma_is_txing)
return;
- temp = readl(sport->port.membase + UCR1);
- writel(temp & ~UCR1_TXMPTYEN, sport->port.membase + UCR1);
+ temp = readl(port->membase + UCR1);
+ writel(temp & ~UCR1_TXMPTYEN, port->membase + UCR1);
+
+ /* in rs485 mode disable transmitter if shifter is empty */
+ if (port->rs485.flags & SER_RS485_ENABLED &&
+ readl(port->membase + USR2) & USR2_TXDC) {
+ temp = readl(port->membase + UCR2);
+ if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
+ temp &= ~UCR2_CTS;
+ else
+ temp |= UCR2_CTS;
+ writel(temp, port->membase + UCR2);
+
+ temp = readl(port->membase + UCR4);
+ temp &= ~UCR4_TCEN;
+ writel(temp, port->membase + UCR4);
+ }
}
/*
@@ -560,6 +575,20 @@ static void imx_start_tx(struct uart_port *port)
struct imx_port *sport = (struct imx_port *)port;
unsigned long temp;
+ if (port->rs485.flags & SER_RS485_ENABLED) {
+ /* enable transmitter and shifter empty irq */
+ temp = readl(port->membase + UCR2);
+ if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
+ temp &= ~UCR2_CTS;
+ else
+ temp |= UCR2_CTS;
+ writel(temp, port->membase + UCR2);
+
+ temp = readl(port->membase + UCR4);
+ temp |= UCR4_TCEN;
+ writel(temp, port->membase + UCR4);
+ }
+
if (!sport->dma_is_enabled) {
temp = readl(sport->port.membase + UCR1);
writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);
@@ -715,6 +744,7 @@ static irqreturn_t imx_int(int irq, void *dev_id)
unsigned int sts2;
sts = readl(sport->port.membase + USR1);
+ sts2 = readl(sport->port.membase + USR2);
if (sts & USR1_RRDY) {
if (sport->dma_is_enabled)
@@ -723,8 +753,10 @@ static irqreturn_t imx_int(int irq, void *dev_id)
imx_rxint(irq, dev_id);
}
- if (sts & USR1_TRDY &&
- readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN)
+ if ((sts & USR1_TRDY &&
+ readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN) ||
+ (sts2 & USR2_TXDC &&
+ readl(sport->port.membase + UCR4) & UCR4_TCEN))
imx_txint(irq, dev_id);
if (sts & USR1_RTSD)
@@ -733,7 +765,6 @@ static irqreturn_t imx_int(int irq, void *dev_id)
if (sts & USR1_AWAKE)
writel(USR1_AWAKE, sport->port.membase + USR1);
- sts2 = readl(sport->port.membase + USR2);
if (sts2 & USR2_ORE) {
dev_err(sport->port.dev, "Rx FIFO overrun\n");
sport->port.icount.overrun++;
@@ -785,11 +816,13 @@ static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
struct imx_port *sport = (struct imx_port *)port;
unsigned long temp;
- temp = readl(sport->port.membase + UCR2) & ~(UCR2_CTS | UCR2_CTSC);
- if (mctrl & TIOCM_RTS)
- temp |= UCR2_CTS | UCR2_CTSC;
-
- writel(temp, sport->port.membase + UCR2);
+ if (!(port->rs485.flags & SER_RS485_ENABLED)) {
+ temp = readl(sport->port.membase + UCR2);
+ temp &= ~(UCR2_CTS | UCR2_CTSC);
+ if (mctrl & TIOCM_RTS)
+ temp |= UCR2_CTS | UCR2_CTSC;
+ writel(temp, sport->port.membase + UCR2);
+ }
temp = readl(sport->port.membase + uts_reg(sport)) & ~UTS_LOOP;
if (mctrl & TIOCM_LOOP)
@@ -1266,11 +1299,26 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
if (termios->c_cflag & CRTSCTS) {
if (sport->have_rtscts) {
ucr2 &= ~UCR2_IRTS;
- ucr2 |= UCR2_CTSC;
+
+ if (port->rs485.flags & SER_RS485_ENABLED)
+ /*
+ * RTS is mandatory for rs485 operation, so keep
+ * it under manual control and keep transmitter
+ * disabled.
+ */
+ if (!(port->rs485.flags &
+ SER_RS485_RTS_AFTER_SEND))
+ ucr2 |= UCR2_CTS;
+ else
+ ucr2 |= UCR2_CTSC;
+
} else {
termios->c_cflag &= ~CRTSCTS;
}
- }
+ } else if (port->rs485.flags & SER_RS485_ENABLED)
+ /* disable transmitter */
+ if (!(port->rs485.flags & SER_RS485_RTS_AFTER_SEND))
+ ucr2 |= UCR2_CTS;
if (termios->c_cflag & CSTOPB)
ucr2 |= UCR2_STPB;
@@ -1492,6 +1540,38 @@ static void imx_poll_put_char(struct uart_port *port, unsigned char c)
}
#endif
+static int imx_rs485_config(struct uart_port *port,
+ struct serial_rs485 *rs485conf)
+{
+ struct imx_port *sport = (struct imx_port *)port;
+
+ /* unimplemented */
+ rs485conf->delay_rts_before_send = 0;
+ rs485conf->delay_rts_after_send = 0;
+ rs485conf->flags |= SER_RS485_RX_DURING_TX;
+
+ /* RTS is required to control the transmitter */
+ if (!sport->have_rtscts)
+ rs485conf->flags &= ~SER_RS485_ENABLED;
+
+ if (rs485conf->flags & SER_RS485_ENABLED) {
+ unsigned long temp;
+
+ /* disable transmitter */
+ temp = readl(sport->port.membase + UCR2);
+ temp &= ~UCR2_CTSC;
+ if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND)
+ temp &= ~UCR2_CTS;
+ else
+ temp |= UCR2_CTS;
+ writel(temp, sport->port.membase + UCR2);
+ }
+
+ port->rs485 = *rs485conf;
+
+ return 0;
+}
+
static struct uart_ops imx_pops = {
.tx_empty = imx_tx_empty,
.set_mctrl = imx_set_mctrl,
@@ -1849,6 +1929,9 @@ static int serial_imx_probe(struct platform_device *pdev)
sport->port.irq = rxirq;
sport->port.fifosize = 32;
sport->port.ops = &imx_pops;
+ sport->port.rs485_config = imx_rs485_config;
+ sport->port.rs485.flags =
+ SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX;
sport->port.flags = UPF_BOOT_AUTOCONF;
init_timer(&sport->timer);
sport->timer.function = imx_timeout;
--
2.1.4
--
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