lkml.org 
[lkml]   [2011]   [Jan]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/2] serial: Provide capability to disable modem status interrupts in 8250 driver
Date
Certain SOC platforms utilize the 8250 serial UART core that do not provide
valid modem control lines (in particular, CTS). A mechanism is needed to
allow platforms to configure the 8250 driver to disable modem status interrupts.
Add a new UPF_NO_MSR flag and use it to check for the condition.

This patch was tested using a MityDSP-L138F platform having a UART CTS pin
connected to a clock signal (and configured, via pinmux, as a clock input
for another peripheral function).

Signed-off-by: Michael Williamson <michael.williamson@criticallink.com>
---
Tested against linux-davinci tree.
Checked that patch against davinci-next was successful.
drivers/serial/8250.c | 3 ++-
include/linux/serial_core.h | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 09a5508..5b9e9f3 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2613,7 +2613,8 @@ static void serial8250_config_port(struct uart_port *port, int flags)
autoconfig(up, probeflags);

/* if access method is AU, it is a 16550 with a quirk */
- if (up->port.type == PORT_16550A && up->port.iotype == UPIO_AU)
+ if ((up->port.type == PORT_16550A && up->port.iotype == UPIO_AU) ||
+ up->port.flags & UPF_NO_MSR)
up->bugs |= UART_BUG_NOMSR;

if (up->port.type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 212eb4c..e76064e 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -339,6 +339,7 @@ struct uart_port {
#define UPF_BUGGY_UART ((__force upf_t) (1 << 14))
#define UPF_NO_TXEN_TEST ((__force upf_t) (1 << 15))
#define UPF_MAGIC_MULTIPLIER ((__force upf_t) (1 << 16))
+#define UPF_NO_MSR ((__force upf_t) (1 << 17))
#define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
#define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
/* The exact UART type is known and should not be probed. */
@@ -348,7 +349,7 @@ struct uart_port {
#define UPF_DEAD ((__force upf_t) (1 << 30))
#define UPF_IOREMAP ((__force upf_t) (1 << 31))

-#define UPF_CHANGE_MASK ((__force upf_t) (0x17fff))
+#define UPF_CHANGE_MASK ((__force upf_t) (0x37fff))
#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))

unsigned int mctrl; /* current modem ctrl settings */
--
1.7.0.4


\
 
 \ /
  Last update: 2011-01-04 14:51    [W:0.042 / U:0.512 seconds]
©2003-2014 Jasper Spaans. Advertise on this site