From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
This patch permits the usage fo GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI
signals.
Signed-off-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/serial/8250.txt | 21 +++++++++++++++++++++
drivers/tty/serial/8250/8250.h | 2 ++
drivers/tty/serial/8250/8250_core.c | 5 +++++
drivers/tty/serial/8250/8250_port.c | 11 ++++++++++-
drivers/tty/serial/8250/Kconfig | 1 +
include/linux/serial_8250.h | 1 +
6 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
index 936ab5b..277e0ee 100644
--- a/Documentation/devicetree/bindings/serial/8250.txt
+++ b/Documentation/devicetree/bindings/serial/8250.txt
@@ -42,6 +42,9 @@ Optional properties:
- auto-flow-control: one way to enable automatic flow control support. The
driver is allowed to detect support for the capability even without this
property.
+- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD
+ line respectively. It will use specified GPIO instead of the peripheral
+ function pin for the UART feature. If unsure, don't specify this property.
Note:
* fsl,ns16550:
@@ -63,3 +66,21 @@ Example:
interrupts = <10>;
reg-shift = <2>;
};
+
+Example for OMAP UART using GPIO-based modem control signals:
+
+ uart4: serial@49042000 {
+ compatible = "ti,omap3-uart";
+ reg = <0x49042000 0x400>;
+ interrupts = <80>;
+ dmas = <&sdma 81 &sdma 82>;
+ dma-names = "tx", "rx";
+ ti,hwmods = "uart4";
+ clock-frequency = <48000000>;
+ cts-gpios = <&gpio3 5 GPIO_ACTIVE_LOW>;
+ rts-gpios = <&gpio3 6 GPIO_ACTIVE_LOW>;
+ dtr-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>;
+ dsr-gpios = <&gpio1 13 GPIO_ACTIVE_LOW>;
+ dcd-gpios = <&gpio1 14 GPIO_ACTIVE_LOW>;
+ rng-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>;
+ };
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index d54dcd8..98ee73c 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -15,6 +15,8 @@
#include <linux/serial_reg.h>
#include <linux/dmaengine.h>
+#include "../serial_mctrl_gpio.h"
+
struct uart_8250_dma {
int (*tx_dma)(struct uart_8250_port *p);
int (*rx_dma)(struct uart_8250_port *p, unsigned int iir);
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index c9720a9..cadcaa5 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1004,6 +1004,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
if (up->port.flags & UPF_FIXED_TYPE)
uart->port.type = up->port.type;
+ uart->gpios = mctrl_gpio_init(&uart->port, 0);
+ if (IS_ERR(uart->gpios))
+ return PTR_ERR(uart->gpios);
+
serial8250_set_defaults(uart);
/* Possibly override default I/O functions. */
@@ -1049,6 +1053,7 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
ret = 0;
}
+
}
mutex_unlock(&serial_mutex);
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 8d262bc..e7bfeef 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1393,6 +1393,8 @@ static void serial8250_disable_ms(struct uart_port *port)
if (up->bugs & UART_BUG_NOMSR)
return;
+ mctrl_gpio_disable_ms(up->gpios);
+
up->ier &= ~UART_IER_MSI;
serial_port_out(port, UART_IER, up->ier);
}
@@ -1405,6 +1407,8 @@ static void serial8250_enable_ms(struct uart_port *port)
if (up->bugs & UART_BUG_NOMSR)
return;
+ mctrl_gpio_enable_ms(up->gpios);
+
up->ier |= UART_IER_MSI;
serial8250_rpm_get(up);
@@ -1680,7 +1684,8 @@ static unsigned int serial8250_get_mctrl(struct uart_port *port)
ret |= TIOCM_DSR;
if (status & UART_MSR_CTS)
ret |= TIOCM_CTS;
- return ret;
+
+ return mctrl_gpio_get(up->gpios, &ret);
}
void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -1707,10 +1712,14 @@ EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl);
static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
+ struct uart_8250_port *up = up_to_u8250p(port);
+
if (port->set_mctrl)
port->set_mctrl(port, mctrl);
else
serial8250_do_set_mctrl(port, mctrl);
+
+ mctrl_gpio_set(up->gpios, mctrl);
}
static void serial8250_break_ctl(struct uart_port *port, int break_state)
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index b03cb517..997e9a8 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -6,6 +6,7 @@
config SERIAL_8250
tristate "8250/16550 and compatible serial support"
select SERIAL_CORE
+ select SERIAL_MCTRL_GPIO if GPIOLIB
---help---
This selects whether you want to include the driver for the standard
serial ports. The standard answer is Y. People who might say N
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index faa0e03..86a3ef4 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -104,6 +104,7 @@ struct uart_8250_port {
* if no_console_suspend
*/
unsigned char probe;
+ struct mctrl_gpios *gpios;
#define UART_PROBE_RSA (1 << 0)
/*
--
2.1.4
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