linux-kernel - [PATCH] serial: 8250: Do XR17V35X specific wakeup in serial8250_do

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Message-Id: <1437035353-13708-1-git-send-email-joro@8bytes.org>
Date:	Thu, 16 Jul 2015 10:29:13 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.cz>
Cc:	Peter Hurley <peter@...leysoftware.com>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Tony Lindgren <tony@...mide.com>,
	Alan Cox <alan@...ux.intel.com>, linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>,
	Michael Welling <mwelling@...e.org>,
	Joe Schultz <jschultz@...-inc.com>
Subject: [PATCH] serial: 8250: Do XR17V35X specific wakeup in serial8250_do_startup

From: Joerg Roedel <jroedel@...e.de>

The XR17V35X UART needs the ECB bit set in its XR_EFR
register to enable access to IER [7:5], ISR [5:4], FCR[5:4],
MCR[7:5], and MSR [7:0].

Also reset the IER register to mask interrupts after access
to all bits of this register has been enabled.

This makes my 8-port XR17V35X working with the in-kernel
serial driver.

Cc: Peter Hurley <peter@...leysoftware.com>
Cc: Michael Welling <mwelling@...e.org>
Cc: Joe Schultz <jschultz@...-inc.com>
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 drivers/tty/serial/8250/8250_core.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 37fff12..4124a91 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2164,6 +2164,21 @@ int serial8250_do_startup(struct uart_port *port)
 	 */
 	enable_rsa(up);
 #endif
+
+	if (port->type == PORT_XR17V35X) {
+		/*
+		 * First enable access to IER [7:5], ISR [5:4], FCR [5:4],
+		 * MCR [7:5] and MSR [7:0]
+		 */
+		serial_port_out(port, UART_XR_EFR, UART_EFR_ECB);
+
+		/*
+		 * Make sure all interrups are masked until initialization is
+		 * complete and the FIFOs are cleared
+		 */
+		serial_port_out(port, UART_IER, 0);
+	}
+
 	/*
 	 * Clear the FIFO buffers and disable them.
 	 * (they will be reenabled in set_termios())
-- 
1.9.1

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