[PATCH 1/2] serial: Provide capability to disable modem status interrupts in 8250 driver
From: Michael Williamson <hidden>
Date: 2011-01-04 13:48:55
Also in:
linux-serial, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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 <redacted> --- 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