serial: sh-sci: Add support for GPIO-controlled modem lines

Enhance the Renesas SCI UART driver to add support for GPIO-controlled
modem lines (CTS, DSR, DCD, RNG, RTS, DTR), using the serial_mctrl_gpio
helpers.

GPIO-controlled modem lines can be used when dedicated modem lines are
not available. Invalid configurations specifying both GPIO RTS/CTS and
dedicated RTS/CTS are rejected.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 7e3a58c..b5c8ad1 100644 (file)
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -736,6 +736,7 @@ config SERIAL_SH_SCI
        tristate "SuperH SCI(F) serial port support"
        depends on SUPERH || ARCH_RENESAS || H8300 || COMPILE_TEST
        select SERIAL_CORE
+       select SERIAL_MCTRL_GPIO if GPIOLIB
 
 config SERIAL_SH_SCI_NR_UARTS
        int "Maximum number of SCI(F) serial ports"

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 135f836..bf3780a 100644 (file)
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -57,6 +57,7 @@
 #include <asm/sh_bios.h>
 #endif
 
+#include "serial_mctrl_gpio.h"
 #include "sh-sci.h"
 
 /* Offsets into the sci_port->irqs array */
@@ -111,6 +112,7 @@ struct sci_port {
        unsigned int            error_clear;
        unsigned int            sampling_rate_mask;
        resource_size_t         reg_size;
+       struct mctrl_gpios      *gpios;
 
        /* Break timer */
        struct timer_list       break_timer;
@@ -1817,6 +1819,8 @@ static unsigned int sci_tx_empty(struct uart_port *port)
  */
 static void sci_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
+       struct sci_port *s = to_sci_port(port);
+
        if (mctrl & TIOCM_LOOP) {
                const struct plat_sci_reg *reg;
 
@@ -1829,15 +1833,35 @@ static void sci_set_mctrl(struct uart_port *port, unsigned int mctrl)
                                        serial_port_in(port, SCFCR) |
                                        SCFCR_LOOP);
        }
+
+       mctrl_gpio_set(s->gpios, mctrl);
 }
 
 static unsigned int sci_get_mctrl(struct uart_port *port)
 {
+       struct sci_port *s = to_sci_port(port);
+       struct mctrl_gpios *gpios = s->gpios;
+       unsigned int mctrl = 0;
+
+       mctrl_gpio_get(gpios, &mctrl);
+
        /*
         * CTS/RTS is handled in hardware when supported, while nothing
         * else is wired up. Keep it simple and simply assert CTS/DSR/CAR.
         */
-       return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+       if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(gpios, UART_GPIO_CTS)))
+               mctrl |= TIOCM_CTS;
+       if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(gpios, UART_GPIO_DSR)))
+               mctrl |= TIOCM_DSR;
+       if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(gpios, UART_GPIO_DCD)))
+               mctrl |= TIOCM_CAR;
+
+       return mctrl;
+}
+
+static void sci_enable_ms(struct uart_port *port)
+{
+       mctrl_gpio_enable_ms(to_sci_port(port)->gpios);
 }
 
 static void sci_break_ctl(struct uart_port *port, int break_state)
@@ -1899,6 +1923,8 @@ static void sci_shutdown(struct uart_port *port)
 
        dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
 
+       mctrl_gpio_disable_ms(to_sci_port(port)->gpios);
+
        spin_lock_irqsave(&port->lock, flags);
        sci_stop_rx(port);
        sci_stop_tx(port);
@@ -2300,6 +2326,9 @@ done:
                sci_start_rx(port);
 
        sci_port_disable(s);
+
+       if (UART_ENABLE_MS(port, termios->c_cflag))
+               sci_enable_ms(port);
 }
 
 static void sci_pm(struct uart_port *port, unsigned int state,
@@ -2425,6 +2454,7 @@ static struct uart_ops sci_uart_ops = {
        .start_tx       = sci_start_tx,
        .stop_tx        = sci_stop_tx,
        .stop_rx        = sci_stop_rx,
+       .enable_ms      = sci_enable_ms,
        .break_ctl      = sci_break_ctl,
        .startup        = sci_startup,
        .shutdown       = sci_shutdown,
@@ -2912,6 +2942,20 @@ static int sci_probe_single(struct platform_device *dev,
        if (ret)
                return ret;
 
+       sciport->gpios = mctrl_gpio_init(&sciport->port, 0);
+       if (IS_ERR(sciport->gpios) && PTR_ERR(sciport->gpios) != -ENOSYS)
+               return PTR_ERR(sciport->gpios);
+
+       if (p->capabilities & SCIx_HAVE_RTSCTS) {
+               if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(sciport->gpios,
+                                                       UART_GPIO_CTS)) ||
+                   !IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(sciport->gpios,
+                                                       UART_GPIO_RTS))) {
+                       dev_err(&dev->dev, "Conflicting RTS/CTS config\n");
+                       return -EINVAL;
+               }
+       }
+
        ret = uart_add_one_port(&sci_uart_driver, &sciport->port);
        if (ret) {
                sci_cleanup_single(sciport);