tty: sdio_uart: add modem functionality

Add the POSIX block for carrier

Linux TIOCMIWAIT functionality is still lacking from the driver.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 32 insertions, 1 deletions

diff --git a/drivers/mmc/card/sdio_uart.c b/drivers/mmc/card/sdio_uart.c
index b999972eaf28..2a13db54ffc4 100644
--- a/drivers/mmc/card/sdio_uart.c
+++ b/drivers/mmc/card/sdio_uart.c
@@ -29,6 +29,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/sched.h>
 #include <linux/mutex.h>
 #include <linux/seq_file.h>
 #include <linux/serial_reg.h>
@@ -86,6 +87,7 @@ struct sdio_uart_port {
         struct uart_icount      icount;
         unsigned int            uartclk;
         unsigned int            mctrl;
+        unsigned int            rx_mctrl;
         unsigned int            read_status_mask;
         unsigned int            ignore_status_mask;
         unsigned char           x_char;
@@ -220,6 +222,8 @@ static unsigned int sdio_uart_get_mctrl(struct sdio_uart_port *port)
         unsigned char status;
         unsigned int ret;
 
+        /* FIXME: What stops this losing the delta bits and breaking
+           sdio_uart_check_modem_status ? */
         status = sdio_in(port, UART_MSR);
 
         ret = 0;
@@ -503,8 +507,20 @@ static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
                 port->icount.rng++;
         if (status & UART_MSR_DDSR)
                 port->icount.dsr++;
-        if (status & UART_MSR_DDCD)
+        if (status & UART_MSR_DDCD) {
                 port->icount.dcd++;
+                /* DCD raise - wake for open */
+                if (status & UART_MSR_DCD)
+                        wake_up_interruptible(&port->port.open_wait);
+                else {
+                        /* DCD drop - hang up if tty attached */
+                        tty = tty_port_tty_get(&port->port);
+                        if (tty) {
+                                tty_hangup(tty);
+                                tty_kref_put(tty);
+                        }
+                }
+        }
         if (status & UART_MSR_DCTS) {
                 port->icount.cts++;
                 tty = tty_port_tty_get(&port->port);
@@ -560,6 +576,20 @@ static void sdio_uart_irq(struct sdio_func *func)
         port->in_sdio_uart_irq = NULL;
 }
 
+static int uart_carrier_raised(struct tty_port *tport)
+{
+        struct sdio_uart_port *port =
+                        container_of(tport, struct sdio_uart_port, port);
+        unsigned int ret = sdio_uart_claim_func(port);
+        if (ret)        /* Missing hardware shoudn't block for carrier */
+                return 1;
+        ret = sdio_uart_get_mctrl(port);
+        sdio_uart_release_func(port);
+        if (ret & TIOCM_CAR)
+                return 1;
+        return 0;
+}
+
 /**
  *      uart_dtr_rts            -        port helper to set uart signals
  *      @tport: tty port to be updated
@@ -1044,6 +1074,7 @@ static const struct file_operations sdio_uart_proc_fops = {
 
 static const struct tty_port_operations sdio_uart_port_ops = {
         .dtr_rts = uart_dtr_rts,
+        .carrier_raised = uart_carrier_raised,
         .shutdown = sdio_uart_shutdown,
         .activate = sdio_uart_activate,
 };