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/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 135f836..bf3780a 100644
--- 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 @@
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 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 @@
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 @@
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 @@
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 @@
.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 @@
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);