OMAP/serial: Add support for driving a GPIO as DTR.

OMAP hardware doesn't provide a phyisical DTR line, but
some configurations may need a DTR line which tracks whether
the device is open or not.

So allow a gpio to be configured as the DTR line.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 44 insertions, 1 deletions

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index c1b93c752d70..25d53b2800c1 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -304,6 +304,9 @@ void __init omap_serial_init_port(struct omap_board_data *bdata,
         omap_up.dma_rx_timeout = info->dma_rx_timeout;
         omap_up.dma_rx_poll_rate = info->dma_rx_poll_rate;
         omap_up.autosuspend_timeout = info->autosuspend_timeout;
+        omap_up.DTR_gpio = info->DTR_gpio;
+        omap_up.DTR_inverted = info->DTR_inverted;
+        omap_up.DTR_present = info->DTR_present;
 
         pdata = &omap_up;
         pdata_size = sizeof(struct omap_uart_port_info);
diff --git a/arch/arm/plat-omap/include/plat/omap-serial.h b/arch/arm/plat-omap/include/plat/omap-serial.h
index 1a52725ffcf2..52d3de45745f 100644
--- a/arch/arm/plat-omap/include/plat/omap-serial.h
+++ b/arch/arm/plat-omap/include/plat/omap-serial.h
@@ -69,6 +69,9 @@ struct omap_uart_port_info {
         unsigned int            dma_rx_timeout;
         unsigned int            autosuspend_timeout;
         unsigned int            dma_rx_poll_rate;
+        int                     DTR_gpio;
+        int                     DTR_inverted;
+        int                     DTR_present;
 
         int (*get_context_loss_count)(struct device *);
         void (*set_forceidle)(struct platform_device *);
@@ -131,6 +134,10 @@ struct uart_omap_port {
         u32                     errata;
         u8                      wakeups_enabled;
 
+        int                     DTR_gpio;
+        int                     DTR_inverted;
+        int                     DTR_active;
+
         struct pm_qos_request   pm_qos_request;
         u32                     latency;
         u32                     calc_latency;
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index d3cda0cb2df0..aa603f221c6a 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -39,6 +39,7 @@
 #include <linux/irq.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
+#include <linux/gpio.h>
 
 #include <plat/dma.h>
 #include <plat/dmtimer.h>
@@ -507,6 +508,16 @@ static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
         up->mcr |= mcr;
         serial_out(up, UART_MCR, up->mcr);
         pm_runtime_put(&up->pdev->dev);
+
+        if (gpio_is_valid(up->DTR_gpio) &&
+            !!(mctrl & TIOCM_DTR) != up->DTR_active) {
+                up->DTR_active = !up->DTR_active;
+                if (gpio_cansleep(up->DTR_gpio))
+                        schedule_work(&up->qos_work);
+                else
+                        gpio_set_value(up->DTR_gpio,
+                                       up->DTR_active != up->DTR_inverted);
+        }
 }
 
 static void serial_omap_break_ctl(struct uart_port *port, int break_state)
@@ -715,6 +726,9 @@ static void serial_omap_uart_qos_work(struct work_struct *work)
                                                 qos_work);
 
         pm_qos_update_request(&up->pm_qos_request, up->latency);
+        if (gpio_is_valid(up->DTR_gpio))
+                gpio_set_value_cansleep(up->DTR_gpio,
+                                        up->DTR_active != up->DTR_inverted);
 }
 
 static void
@@ -1435,7 +1449,7 @@ static int serial_omap_probe(struct platform_device *pdev)
         struct uart_omap_port   *up;
         struct resource         *mem, *irq, *dma_tx, *dma_rx;
         struct omap_uart_port_info *omap_up_info = pdev->dev.platform_data;
-        int ret = -ENOSPC;
+        int ret;
 
         if (pdev->dev.of_node)
                 omap_up_info = of_get_uart_port_info(&pdev->dev);
@@ -1466,10 +1480,29 @@ static int serial_omap_probe(struct platform_device *pdev)
         if (!dma_tx)
                 return -ENXIO;
 
+        if (gpio_is_valid(omap_up_info->DTR_gpio) &&
+            omap_up_info->DTR_present) {
+                ret = gpio_request(omap_up_info->DTR_gpio, "omap-serial");
+                if (ret < 0)
+                        return ret;
+                ret = gpio_direction_output(omap_up_info->DTR_gpio,
+                                            omap_up_info->DTR_inverted);
+                if (ret < 0)
+                        return ret;
+        }
+
         up = devm_kzalloc(&pdev->dev, sizeof(*up), GFP_KERNEL);
         if (!up)
                 return -ENOMEM;
 
+        if (gpio_is_valid(omap_up_info->DTR_gpio) &&
+            omap_up_info->DTR_present) {
+                up->DTR_gpio = omap_up_info->DTR_gpio;
+                up->DTR_inverted = omap_up_info->DTR_inverted;
+        } else
+                up->DTR_gpio = -EINVAL;
+        up->DTR_active = 0;
+
         up->pdev = pdev;
         up->port.dev = &pdev->dev;
         up->port.type = PORT_OMAP;