Merge tag 'tty-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty and serial driver updates from Greg KH:
 "Here is the big set of tty and serial driver updates for 5.13-rc1.

  Actually busy this release, with a number of cleanups happening:

   - much needed core tty cleanups by Jiri Slaby

   - removal of unused and orphaned old-style serial drivers. If anyone
     shows up with this hardware, it is trivial to restore these but we
     really do not think they are in use anymore.

   - fixes and cleanups from Johan Hovold on a number of termios setting
     corner cases that loads of drivers got wrong as well as removing
     unneeded code due to tty core changes from long ago that were never
     propagated out to the drivers

   - loads of platform-specific serial port driver updates and fixes

   - coding style cleanups and other small fixes and updates all over
     the tty/serial tree.

  All of these have been in linux-next for a while now with no reported
  issues"

* tag 'tty-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (186 commits)
  serial: extend compile-test coverage
  serial: stm32: add FIFO threshold configuration
  dt-bindings: serial: 8250: update TX FIFO trigger level
  dt-bindings: serial: stm32: override FIFO threshold properties
  dt-bindings: serial: add RX and TX FIFO properties
  serial: xilinx_uartps: drop low-latency workaround
  serial: vt8500: drop low-latency workaround
  serial: timbuart: drop low-latency workaround
  serial: sunsu: drop low-latency workaround
  serial: sifive: drop low-latency workaround
  serial: txx9: drop low-latency workaround
  serial: sa1100: drop low-latency workaround
  serial: rp2: drop low-latency workaround
  serial: rda: drop low-latency workaround
  serial: owl: drop low-latency workaround
  serial: msm_serial: drop low-latency workaround
  serial: mpc52xx_uart: drop low-latency workaround
  serial: meson: drop low-latency workaround
  serial: mcf: drop low-latency workaround
  serial: lpc32xx_hs: drop low-latency workaround
  ...

1 files changed, 28 insertions, 23 deletions

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 76b94d0ff586..84e8158088cd 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -159,6 +159,8 @@ struct uart_omap_port {
 	u32			calc_latency;
 	struct work_struct	qos_work;
 	bool			is_suspending;
+
+	unsigned int		rs485_tx_filter_count;
 };
 
 #define to_uart_omap_port(p) ((container_of((p), struct uart_omap_port, port)))
@@ -302,7 +304,8 @@ static void serial_omap_stop_tx(struct uart_port *port)
 			serial_out(up, UART_OMAP_SCR, up->scr);
 			res = (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) ?
 				1 : 0;
-			if (gpiod_get_value(up->rts_gpiod) != res) {
+			if (up->rts_gpiod &&
+			    gpiod_get_value(up->rts_gpiod) != res) {
 				if (port->rs485.delay_rts_after_send > 0)
 					mdelay(
 					port->rs485.delay_rts_after_send);
@@ -328,19 +331,6 @@ static void serial_omap_stop_tx(struct uart_port *port)
 		serial_out(up, UART_IER, up->ier);
 	}
 
-	if ((port->rs485.flags & SER_RS485_ENABLED) &&
-	    !(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
-		/*
-		 * Empty the RX FIFO, we are not interested in anything
-		 * received during the half-duplex transmission.
-		 */
-		serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_RCVR);
-		/* Re-enable RX interrupts */
-		up->ier |= UART_IER_RLSI | UART_IER_RDI;
-		up->port.read_status_mask |= UART_LSR_DR;
-		serial_out(up, UART_IER, up->ier);
-	}
-
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
 }
@@ -366,6 +356,10 @@ static void transmit_chars(struct uart_omap_port *up, unsigned int lsr)
 		serial_out(up, UART_TX, up->port.x_char);
 		up->port.icount.tx++;
 		up->port.x_char = 0;
+		if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
+		    !(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
+			up->rs485_tx_filter_count++;
+
 		return;
 	}
 	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
@@ -377,6 +371,10 @@ static void transmit_chars(struct uart_omap_port *up, unsigned int lsr)
 		serial_out(up, UART_TX, xmit->buf[xmit->tail]);
 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 		up->port.icount.tx++;
+		if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
+		    !(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
+			up->rs485_tx_filter_count++;
+
 		if (uart_circ_empty(xmit))
 			break;
 	} while (--count > 0);
@@ -411,7 +409,7 @@ static void serial_omap_start_tx(struct uart_port *port)
 
 		/* if rts not already enabled */
 		res = (port->rs485.flags & SER_RS485_RTS_ON_SEND) ? 1 : 0;
-		if (gpiod_get_value(up->rts_gpiod) != res) {
+		if (up->rts_gpiod && gpiod_get_value(up->rts_gpiod) != res) {
 			gpiod_set_value(up->rts_gpiod, res);
 			if (port->rs485.delay_rts_before_send > 0)
 				mdelay(port->rs485.delay_rts_before_send);
@@ -420,7 +418,7 @@ static void serial_omap_start_tx(struct uart_port *port)
 
 	if ((port->rs485.flags & SER_RS485_ENABLED) &&
 	    !(port->rs485.flags & SER_RS485_RX_DURING_TX))
-		serial_omap_stop_rx(port);
+		up->rs485_tx_filter_count = 0;
 
 	serial_omap_enable_ier_thri(up);
 	pm_runtime_mark_last_busy(up->dev);
@@ -491,8 +489,13 @@ static void serial_omap_rlsi(struct uart_omap_port *up, unsigned int lsr)
 	 * Read one data character out to avoid stalling the receiver according
 	 * to the table 23-246 of the omap4 TRM.
 	 */
-	if (likely(lsr & UART_LSR_DR))
+	if (likely(lsr & UART_LSR_DR)) {
 		serial_in(up, UART_RX);
+		if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
+		    !(up->port.rs485.flags & SER_RS485_RX_DURING_TX) &&
+		    up->rs485_tx_filter_count)
+			up->rs485_tx_filter_count--;
+	}
 
 	up->port.icount.rx++;
 	flag = TTY_NORMAL;
@@ -543,6 +546,13 @@ static void serial_omap_rdi(struct uart_omap_port *up, unsigned int lsr)
 		return;
 
 	ch = serial_in(up, UART_RX);
+	if ((up->port.rs485.flags & SER_RS485_ENABLED) &&
+	    !(up->port.rs485.flags & SER_RS485_RX_DURING_TX) &&
+	    up->rs485_tx_filter_count) {
+		up->rs485_tx_filter_count--;
+		return;
+	}
+
 	flag = TTY_NORMAL;
 	up->port.icount.rx++;
 
@@ -1407,18 +1417,13 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485)
 	/* store new config */
 	port->rs485 = *rs485;
 
-	/*
-	 * Just as a precaution, only allow rs485
-	 * to be enabled if the gpio pin is valid
-	 */
 	if (up->rts_gpiod) {
 		/* enable / disable rts */
 		val = (port->rs485.flags & SER_RS485_ENABLED) ?
 			SER_RS485_RTS_AFTER_SEND : SER_RS485_RTS_ON_SEND;
 		val = (port->rs485.flags & val) ? 1 : 0;
 		gpiod_set_value(up->rts_gpiod, val);
-	} else
-		port->rs485.flags &= ~SER_RS485_ENABLED;
+	}
 
 	/* Enable interrupts */
 	up->ier = mode;