Revert "Revert "serial: Deassert Transmit Enable on probe in driver-s…

…pecific way"" This reverts commit 9ce2640. This re-introduces the upstream linux-stable changes and makes future upgrades/merges easier. Work has been scheduled to fix the affected RS-485 serial ATS tests which incorrectly configured the RS-485 flags and caused the failures that prompted the original revert. Signed-off-by: Gratian Crisan <[email protected]>
alynch-ni · Jan 11, 2023 · fdca62b · fdca62b
1 parent 9423c38
commit fdca62b
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Showing 6 changed files with 33 additions and 40 deletions.
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
@@ -345,6 +345,9 @@ static void omap8250_restore_regs(struct uart_8250_port *up)
 	omap8250_update_mdr1(up, priv);
 
 	__omap8250_set_mctrl(&up->port, up->port.mctrl);
+
+	if (up->port.rs485.flags & SER_RS485_ENABLED)
+		serial8250_em485_stop_tx(up);
 }
 
 /*

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
@@ -1739,7 +1739,6 @@ static int pci_fintek_init(struct pci_dev *dev)
 	resource_size_t bar_data[3];
 	u8 config_base;
 	struct serial_private *priv = pci_get_drvdata(dev);
-	struct uart_8250_port *port;
 
 	if (!(pci_resource_flags(dev, 5) & IORESOURCE_IO) ||
 			!(pci_resource_flags(dev, 4) & IORESOURCE_IO) ||
@@ -1786,13 +1785,7 @@ static int pci_fintek_init(struct pci_dev *dev)
 
 		pci_write_config_byte(dev, config_base + 0x06, dev->irq);
 
-		if (priv) {
-			/* re-apply RS232/485 mode when
-			 * pciserial_resume_ports()
-			 */
-			port = serial8250_get_port(priv->line[i]);
-			pci_fintek_rs485_config(&port->port, NULL);
-		} else {
+		if (!priv) {
 			/* First init without port data
 			 * force init to RS232 Mode
 			 */

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
@@ -614,7 +614,7 @@ EXPORT_SYMBOL_GPL(serial8250_rpm_put);
 static int serial8250_em485_init(struct uart_8250_port *p)
 {
 	if (p->em485)
-		return 0;
+		goto deassert_rts;
 
 	p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC);
 	if (!p->em485)
@@ -630,7 +630,9 @@ static int serial8250_em485_init(struct uart_8250_port *p)
 	p->em485->active_timer = NULL;
 	p->em485->tx_stopped = true;
 
-	p->rs485_stop_tx(p);
+deassert_rts:
+	if (p->em485->tx_stopped)
+		p->rs485_stop_tx(p);
 
 	return 0;
 }
@@ -2051,6 +2053,9 @@ EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl);
 
 static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
+	if (port->rs485.flags & SER_RS485_ENABLED)
+		return;
+
 	if (port->set_mctrl)
 		port->set_mctrl(port, mctrl);
 	else
@@ -3201,9 +3206,6 @@ static void serial8250_config_port(struct uart_port *port, int flags)
 	if (flags & UART_CONFIG_TYPE)
 		autoconfig(up);
 
-	if (port->rs485.flags & SER_RS485_ENABLED)
-		port->rs485_config(port, &port->rs485);
-
 	/* if access method is AU, it is a 16550 with a quirk */
 	if (port->type == PORT_16550A && port->iotype == UPIO_AU)
 		up->bugs |= UART_BUG_NOMSR;

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
@@ -2761,10 +2761,6 @@ static int lpuart_probe(struct platform_device *pdev)
 	if (ret)
 		goto failed_reset;
 
-	ret = uart_add_one_port(&lpuart_reg, &sport->port);
-	if (ret)
-		goto failed_attach_port;
-
 	ret = uart_get_rs485_mode(&sport->port);
 	if (ret)
 		goto failed_get_rs485;
@@ -2776,7 +2772,9 @@ static int lpuart_probe(struct platform_device *pdev)
 	    sport->port.rs485.delay_rts_after_send)
 		dev_err(&pdev->dev, "driver doesn't support RTS delays\n");
 
-	sport->port.rs485_config(&sport->port, &sport->port.rs485);
+	ret = uart_add_one_port(&lpuart_reg, &sport->port);
+	if (ret)
+		goto failed_attach_port;
 
 	ret = devm_request_irq(&pdev->dev, sport->port.irq, handler, 0,
 				DRIVER_NAME, sport);

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
@@ -380,8 +380,7 @@ static void imx_uart_rts_active(struct imx_port *sport, u32 *ucr2)
 {
 	*ucr2 &= ~(UCR2_CTSC | UCR2_CTS);
 
-	sport->port.mctrl |= TIOCM_RTS;
-	mctrl_gpio_set(sport->gpios, sport->port.mctrl);
+	mctrl_gpio_set(sport->gpios, sport->port.mctrl | TIOCM_RTS);
 }
 
 /* called with port.lock taken and irqs caller dependent */
@@ -390,8 +389,7 @@ static void imx_uart_rts_inactive(struct imx_port *sport, u32 *ucr2)
 	*ucr2 &= ~UCR2_CTSC;
 	*ucr2 |= UCR2_CTS;
 
-	sport->port.mctrl &= ~TIOCM_RTS;
-	mctrl_gpio_set(sport->gpios, sport->port.mctrl);
+	mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS);
 }
 
 static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
@@ -2318,8 +2316,6 @@ static int imx_uart_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev,
 			"low-active RTS not possible when receiver is off, enabling receiver\n");
 
-	imx_uart_rs485_config(&sport->port, &sport->port.rs485);
-
 	/* Disable interrupts before requesting them */
 	ucr1 = imx_uart_readl(sport, UCR1);
 	ucr1 &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN | UCR1_RTSDEN);

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
@@ -149,15 +149,10 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
 	unsigned long flags;
 	unsigned int old;
 
-	if (port->rs485.flags & SER_RS485_ENABLED) {
-		set &= ~TIOCM_RTS;
-		clear &= ~TIOCM_RTS;
-	}
-
 	spin_lock_irqsave(&port->lock, flags);
 	old = port->mctrl;
 	port->mctrl = (old & ~clear) | set;
-	if (old != port->mctrl)
+	if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
 		port->ops->set_mctrl(port, port->mctrl);
 	spin_unlock_irqrestore(&port->lock, flags);
 }
@@ -1336,8 +1331,13 @@ static int uart_set_rs485_config(struct uart_port *port,
 
 	spin_lock_irqsave(&port->lock, flags);
 	ret = port->rs485_config(port, &rs485);
-	if (!ret)
+	if (!ret) {
 		port->rs485 = rs485;
+
+		/* Reset RTS and other mctrl lines when disabling RS485 */
+		if (!(rs485.flags & SER_RS485_ENABLED))
+			port->ops->set_mctrl(port, port->mctrl);
+	}
 	spin_unlock_irqrestore(&port->lock, flags);
 	if (ret)
 		return ret;
@@ -2314,7 +2314,8 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
 
 		uart_change_pm(state, UART_PM_STATE_ON);
 		spin_lock_irq(&uport->lock);
-		ops->set_mctrl(uport, 0);
+		if (!(uport->rs485.flags & SER_RS485_ENABLED))
+			ops->set_mctrl(uport, 0);
 		spin_unlock_irq(&uport->lock);
 		if (console_suspend_enabled || !uart_console(uport)) {
 			/* Protected by port mutex for now */
@@ -2325,10 +2326,10 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
 				if (tty)
 					uart_change_speed(tty, state, NULL);
 				spin_lock_irq(&uport->lock);
-				if (uport->rs485_config)
-					uport->rs485_config(uport,
-							    &uport->rs485);
-				ops->set_mctrl(uport, uport->mctrl);
+				if (!(uport->rs485.flags & SER_RS485_ENABLED))
+					ops->set_mctrl(uport, uport->mctrl);
+				else
+					uport->rs485_config(uport, &uport->rs485);
 				ops->start_tx(uport);
 				spin_unlock_irq(&uport->lock);
 				tty_port_set_initialized(port, 1);
@@ -2434,10 +2435,10 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 		 */
 		spin_lock_irqsave(&port->lock, flags);
 		port->mctrl &= TIOCM_DTR;
-		if (port->rs485.flags & SER_RS485_ENABLED &&
-		    !(port->rs485.flags & SER_RS485_RTS_AFTER_SEND))
-			port->mctrl |= TIOCM_RTS;
-		port->ops->set_mctrl(port, port->mctrl);
+		if (!(port->rs485.flags & SER_RS485_ENABLED))
+			port->ops->set_mctrl(port, port->mctrl);
+		else
+			port->rs485_config(port, &port->rs485);
 		spin_unlock_irqrestore(&port->lock, flags);
 
 		/*