tty/serial/8250: use mctrl_gpio helpers

This patch permits the usage for GPIOs to control
the CTS/RTS/DTR/DSR/DCD/RI signals.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
index 936ab5b..f5561ac 100644 (file)
--- 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 +66,19 @@ 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>;
+               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 1a16fea..122e0e4 100644 (file)
--- 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);
@@ -131,12 +133,43 @@ void serial8250_em485_destroy(struct uart_8250_port *p);
 
 static inline void serial8250_out_MCR(struct uart_8250_port *up, int value)
 {
+       int mctrl_gpio = 0;
+
        serial_out(up, UART_MCR, value);
+
+       if (value & UART_MCR_RTS)
+               mctrl_gpio |= TIOCM_RTS;
+       if (value & UART_MCR_DTR)
+               mctrl_gpio |= TIOCM_DTR;
+
+       mctrl_gpio_set(up->gpios, mctrl_gpio);
 }
 
 static inline int serial8250_in_MCR(struct uart_8250_port *up)
 {
-       return serial_in(up, UART_MCR);
+       int mctrl, mctrl_gpio = 0;
+
+       mctrl = serial_in(up, UART_MCR);
+
+       /* save current MCR values */
+       if (mctrl & UART_MCR_RTS)
+               mctrl_gpio |= TIOCM_RTS;
+       if (mctrl & UART_MCR_DTR)
+               mctrl_gpio |= TIOCM_DTR;
+
+       mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio);
+
+       if (mctrl_gpio & TIOCM_RTS)
+               mctrl |= UART_MCR_RTS;
+       else
+               mctrl &= ~UART_MCR_RTS;
+
+       if (mctrl_gpio & TIOCM_DTR)
+               mctrl |= UART_MCR_DTR;
+       else
+               mctrl &= ~UART_MCR_DTR;
+
+       return mctrl;
 }
 
 #if defined(__alpha__) && !defined(CONFIG_PCI)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index dcf43f6..13ad5c3 100644 (file)
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -974,6 +974,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
 
        uart = serial8250_find_match_or_unused(&up->port);
        if (uart && uart->port.type != PORT_8250_CIR) {
+               struct mctrl_gpios *gpios;
+
                if (uart->port.dev)
                        uart_remove_one_port(&serial8250_reg, &uart->port);
 
@@ -1011,6 +1013,13 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
                if (up->port.flags & UPF_FIXED_TYPE)
                        uart->port.type = up->port.type;
 
+               gpios = mctrl_gpio_init(&uart->port, 0);
+               if (IS_ERR(gpios)) {
+                       if (PTR_ERR(gpios) != -ENOSYS)
+                               return PTR_ERR(gpios);
+               } else
+                       uart->gpios = gpios;
+
                serial8250_set_defaults(uart);
 
                /* Possibly override default I/O functions.  */

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 61ad6c3..e14982f 100644 (file)
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -134,18 +134,21 @@ static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
 
        serial8250_do_set_mctrl(port, mctrl);
 
-       /*
-        * Turn off autoRTS if RTS is lowered and restore autoRTS setting
-        * if RTS is raised
-        */
-       lcr = serial_in(up, UART_LCR);
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-       if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
-               priv->efr |= UART_EFR_RTS;
-       else
-               priv->efr &= ~UART_EFR_RTS;
-       serial_out(up, UART_EFR, priv->efr);
-       serial_out(up, UART_LCR, lcr);
+       if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios,
+                                               UART_GPIO_RTS))) {
+               /*
+                * Turn off autoRTS if RTS is lowered and restore autoRTS
+                * setting if RTS is raised
+                */
+               lcr = serial_in(up, UART_LCR);
+               serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+               if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
+                       priv->efr |= UART_EFR_RTS;
+               else
+                       priv->efr &= ~UART_EFR_RTS;
+               serial_out(up, UART_EFR, priv->efr);
+               serial_out(up, UART_LCR, lcr);
+       }
 }
 
 /*
@@ -446,7 +449,9 @@ static void omap_8250_set_termios(struct uart_port *port,
        priv->efr = 0;
        up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
 
-       if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
+       if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW
+               && IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios,
+                                                       UART_GPIO_RTS))) {
                /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
                up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
                priv->efr |= UART_EFR_CTS;

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index bdfa659..7481b95 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1618,6 +1618,8 @@ 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);
 }
@@ -1630,6 +1632,8 @@ 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);
@@ -1913,7 +1917,8 @@ unsigned int serial8250_do_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);
 }
 EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl);
 

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index b5a0f2e..b1c73de 100644 (file)
--- 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 48ec765..923266c 100644 (file)
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -111,6 +111,7 @@ struct uart_8250_port {
                                                 *   if no_console_suspend
                                                 */
        unsigned char           probe;
+       struct mctrl_gpios      *gpios;
 #define UART_PROBE_RSA (1 << 0)
 
        /*