serial: imx: implement handshaking using gpios with the mctrl_gpio helper

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 70 insertions, 20 deletions

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 0bdf4d5c7c65..d27a0c62a75f 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -576,6 +576,7 @@ config SERIAL_IMX
         depends on ARCH_MXC || COMPILE_TEST
         select SERIAL_CORE
         select RATIONAL
+        select SERIAL_MCTRL_GPIO if GPIOLIB
         help
           If you have a machine based on a Motorola IMX CPU you
           can enable its onboard serial port by enabling this option.
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 591f1c26e3e9..9362f54c816c 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -44,6 +44,8 @@
 #include <linux/platform_data/serial-imx.h>
 #include <linux/platform_data/dma-imx.h>
 
+#include "serial_mctrl_gpio.h"
+
 /* Register definitions */
 #define URXD0 0x0  /* Receiver Register */
 #define URTX0 0x40 /* Transmitter Register */
@@ -209,6 +211,8 @@ struct imx_port {
         struct clk              *clk_per;
         const struct imx_uart_data *devdata;
 
+        struct mctrl_gpios *gpios;
+
         /* DMA fields */
         unsigned int            dma_is_inited:1;
         unsigned int            dma_is_enabled:1;
@@ -311,6 +315,26 @@ static void imx_port_ucrs_restore(struct uart_port *port,
 }
 #endif
 
+static void imx_port_rts_active(struct imx_port *sport, unsigned long *ucr2)
+{
+        *ucr2 &= ~UCR2_CTSC;
+        *ucr2 |= UCR2_CTS;
+
+        mctrl_gpio_set(sport->gpios, sport->port.mctrl | TIOCM_RTS);
+}
+
+static void imx_port_rts_inactive(struct imx_port *sport, unsigned long *ucr2)
+{
+        *ucr2 &= ~(UCR2_CTSC | UCR2_CTS);
+
+        mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS);
+}
+
+static void imx_port_rts_auto(struct imx_port *sport, unsigned long *ucr2)
+{
+        *ucr2 |= UCR2_CTSC;
+}
+
 /*
  * interrupts disabled on entry
  */
@@ -334,9 +358,9 @@ static void imx_stop_tx(struct uart_port *port)
             readl(port->membase + USR2) & USR2_TXDC) {
                 temp = readl(port->membase + UCR2);
                 if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
-                        temp &= ~UCR2_CTS;
+                        imx_port_rts_inactive(sport, &temp);
                 else
-                        temp |= UCR2_CTS;
+                        imx_port_rts_active(sport, &temp);
                 writel(temp, port->membase + UCR2);
 
                 temp = readl(port->membase + UCR4);
@@ -378,6 +402,8 @@ static void imx_enable_ms(struct uart_port *port)
         struct imx_port *sport = (struct imx_port *)port;
 
         mod_timer(&sport->timer, jiffies);
+
+        mctrl_gpio_enable_ms(sport->gpios);
 }
 
 static void imx_dma_tx(struct imx_port *sport);
@@ -537,14 +563,14 @@ static void imx_start_tx(struct uart_port *port)
         unsigned long temp;
 
         if (port->rs485.flags & SER_RS485_ENABLED) {
-                /* enable transmitter and shifter empty irq */
                 temp = readl(port->membase + UCR2);
                 if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
-                        temp &= ~UCR2_CTS;
+                        imx_port_rts_inactive(sport, &temp);
                 else
-                        temp |= UCR2_CTS;
+                        imx_port_rts_active(sport, &temp);
                 writel(temp, port->membase + UCR2);
 
+                /* enable transmitter and shifter empty irq */
                 temp = readl(port->membase + UCR4);
                 temp |= UCR4_TCEN;
                 writel(temp, port->membase + UCR4);
@@ -759,9 +785,8 @@ static unsigned int imx_tx_empty(struct uart_port *port)
 /*
  * We have a modem side uart, so the meanings of RTS and CTS are inverted.
  */
-static unsigned int imx_get_mctrl(struct uart_port *port)
+static unsigned int imx_get_hwmctrl(struct imx_port *sport)
 {
-        struct imx_port *sport = (struct imx_port *)port;
         unsigned int tmp = TIOCM_DSR;
         unsigned usr1 = readl(sport->port.membase + USR1);
 
@@ -779,6 +804,16 @@ static unsigned int imx_get_mctrl(struct uart_port *port)
         return tmp;
 }
 
+static unsigned int imx_get_mctrl(struct uart_port *port)
+{
+        struct imx_port *sport = (struct imx_port *)port;
+        unsigned int ret = imx_get_hwmctrl(sport);
+
+        mctrl_gpio_get(sport->gpios, &ret);
+
+        return ret;
+}
+
 static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
         struct imx_port *sport = (struct imx_port *)port;
@@ -801,6 +836,8 @@ static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
         if (mctrl & TIOCM_LOOP)
                 temp |= UTS_LOOP;
         writel(temp, sport->port.membase + uts_reg(sport));
+
+        mctrl_gpio_set(sport->gpios, mctrl);
 }
 
 /*
@@ -830,7 +867,7 @@ static void imx_mctrl_check(struct imx_port *sport)
 {
         unsigned int status, changed;
 
-        status = imx_get_mctrl(&sport->port);
+        status = imx_get_hwmctrl(sport);
         changed = status ^ sport->old_status;
 
         if (changed == 0)
@@ -1218,6 +1255,8 @@ static void imx_shutdown(struct uart_port *port)
                 imx_uart_dma_exit(sport);
         }
 
+        mctrl_gpio_disable_ms(sport->gpios);
+
         spin_lock_irqsave(&sport->port.lock, flags);
         temp = readl(sport->port.membase + UCR2);
         temp &= ~(UCR2_TXEN);
@@ -1295,9 +1334,10 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
 {
         struct imx_port *sport = (struct imx_port *)port;
         unsigned long flags;
-        unsigned int ucr2, old_ucr1, old_ucr2, baud, quot;
+        unsigned long ucr2, old_ucr1, old_ucr2;
+        unsigned int baud, quot;
         unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
-        unsigned int div, ufcr;
+        unsigned long div, ufcr;
         unsigned long num, denom;
         uint64_t tdiv64;
 
@@ -1326,19 +1366,25 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
                                  * it under manual control and keep transmitter
                                  * disabled.
                                  */
-                                if (!(port->rs485.flags &
-                                      SER_RS485_RTS_AFTER_SEND))
-                                        ucr2 |= UCR2_CTS;
+                                if (port->rs485.flags &
+                                    SER_RS485_RTS_AFTER_SEND)
+                                        imx_port_rts_inactive(sport, &ucr2);
+                                else
+                                        imx_port_rts_active(sport, &ucr2);
                         } else {
-                                ucr2 |= UCR2_CTSC;
+                                imx_port_rts_auto(sport, &ucr2);
                         }
                 } else {
                         termios->c_cflag &= ~CRTSCTS;
                 }
-        } else if (port->rs485.flags & SER_RS485_ENABLED)
+        } else if (port->rs485.flags & SER_RS485_ENABLED) {
                 /* disable transmitter */
-                if (!(port->rs485.flags & SER_RS485_RTS_AFTER_SEND))
-                        ucr2 |= UCR2_CTS;
+                if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
+                        imx_port_rts_inactive(sport, &ucr2);
+                else
+                        imx_port_rts_active(sport, &ucr2);
+        }
+
 
         if (termios->c_cflag & CSTOPB)
                 ucr2 |= UCR2_STPB;
@@ -1579,11 +1625,10 @@ static int imx_rs485_config(struct uart_port *port,
 
                 /* disable transmitter */
                 temp = readl(sport->port.membase + UCR2);
-                temp &= ~UCR2_CTSC;
                 if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND)
-                        temp &= ~UCR2_CTS;
+                        imx_port_rts_inactive(sport, &temp);
                 else
-                        temp |= UCR2_CTS;
+                        imx_port_rts_active(sport, &temp);
                 writel(temp, sport->port.membase + UCR2);
         }
 
@@ -1956,6 +2001,10 @@ static int serial_imx_probe(struct platform_device *pdev)
         sport->timer.function = imx_timeout;
         sport->timer.data     = (unsigned long)sport;
 
+        sport->gpios = mctrl_gpio_init(&sport->port, 0);
+        if (IS_ERR(sport->gpios))
+                return PTR_ERR(sport->gpios);
+
         sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
         if (IS_ERR(sport->clk_ipg)) {
                 ret = PTR_ERR(sport->clk_ipg);