[PATCH] serial: 8250: Do XR17V35X specific wakeup in serial8250_do_startup

Joerg Roedel
2015-07-16T08:29:24Z

From: Joerg Roedel <jroedel@suse.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@hurleysoftware.com>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Joe Schultz <jschultz@xes-inc.com>
Signed-off-by: Joerg Roedel <jroedel@suse.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