openwrt/target/linux/bcm27xx/patches-6.6/950-0475-serial-sc16is7xx-Read-modem-line-state-at-startup.patch

From 3a49598d7be0e3085f3229723e278fe3a6992f59 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Tue, 13 Jun 2023 16:12:54 +0100
Subject: [PATCH 0475/1085] serial: sc16is7xx: Read modem line state at startup

This patch sets the driver modem line state to the actual line state
at driver startup.

See: https://github.com/raspberrypi/linux/issues/5501

Signed-off-by: Earl Schmidt <schmidt.earl.f@gmail.com>
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
 drivers/tty/serial/sc16is7xx.c | 3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1210,6 +1210,9 @@ static int sc16is7xx_startup(struct uart
 	      SC16IS7XX_IER_MSI_BIT;
 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
 
+	/* Initialize the Modem Control signals to current status */
+	one->old_mctrl = sc16is7xx_get_hwmctrl(port);
+
 	/* Enable modem status polling */
 	uart_port_lock_irqsave(port, &flags);
 	sc16is7xx_enable_ms(port);