tty/serial: at91: add interrupts for modem control lines

Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 43ca659c1d4b898f9b826210810a30fc055050d4..3fceae099c4497060d1314c1a1065e97967557db 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -45,6 +45,7 @@
 #include <linux/gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/err.h>
+#include <linux/irq.h>
 
 #include <asm/io.h>
 #include <asm/ioctls.h>
@@ -167,7 +168,9 @@ struct atmel_uart_port {
 
        struct serial_rs485     rs485;          /* rs485 settings */
        struct mctrl_gpios      *gpios;
+       int                     gpio_irq[UART_GPIO_MAX];
        unsigned int            tx_done_mask;
+       bool                    ms_irq_enabled;
        bool                    is_usart;       /* usart or uart */
        struct timer_list       uart_timer;     /* uart timer */
        int (*prepare_rx)(struct uart_port *port);
@@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
  */
 static void atmel_enable_ms(struct uart_port *port)
 {
-       UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
-                       | ATMEL_US_DCDIC | ATMEL_US_CTSIC);
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+       uint32_t ier = 0;
+
+       /*
+        * Interrupt should not be enabled twice
+        */
+       if (atmel_port->ms_irq_enabled)
+               return;
+
+       atmel_port->ms_irq_enabled = true;
+
+       if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
+               enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
+       else
+               ier |= ATMEL_US_CTSIC;
+
+       if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
+               enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
+       else
+               ier |= ATMEL_US_DSRIC;
+
+       if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
+               enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
+       else
+               ier |= ATMEL_US_RIIC;
+
+       if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
+               enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
+       else
+               ier |= ATMEL_US_DCDIC;
+
+       UART_PUT_IER(port, ier);
 }
 
 /*
@@ -1079,11 +1112,31 @@ atmel_handle_status(struct uart_port *port, unsigned int pending,
 static irqreturn_t atmel_interrupt(int irq, void *dev_id)
 {
        struct uart_port *port = dev_id;
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
        unsigned int status, pending, pass_counter = 0;
+       bool gpio_handled = false;
 
        do {
                status = atmel_get_lines_status(port);
                pending = status & UART_GET_IMR(port);
+               if (!gpio_handled) {
+                       /*
+                        * Dealing with GPIO interrupt
+                        */
+                       if (irq == atmel_port->gpio_irq[UART_GPIO_CTS])
+                               pending |= ATMEL_US_CTSIC;
+
+                       if (irq == atmel_port->gpio_irq[UART_GPIO_DSR])
+                               pending |= ATMEL_US_DSRIC;
+
+                       if (irq == atmel_port->gpio_irq[UART_GPIO_RI])
+                               pending |= ATMEL_US_RIIC;
+
+                       if (irq == atmel_port->gpio_irq[UART_GPIO_DCD])
+                               pending |= ATMEL_US_DCDIC;
+
+                       gpio_handled = true;
+               }
                if (!pending)
                        break;
 
@@ -1563,6 +1616,45 @@ static void atmel_get_ip_name(struct uart_port *port)
        }
 }
 
+static void atmel_free_gpio_irq(struct uart_port *port)
+{
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+       enum mctrl_gpio_idx i;
+
+       for (i = 0; i < UART_GPIO_MAX; i++)
+               if (atmel_port->gpio_irq[i] >= 0)
+                       free_irq(atmel_port->gpio_irq[i], port);
+}
+
+static int atmel_request_gpio_irq(struct uart_port *port)
+{
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+       int *irq = atmel_port->gpio_irq;
+       enum mctrl_gpio_idx i;
+       int err = 0;
+
+       for (i = 0; (i < UART_GPIO_MAX) && !err; i++) {
+               if (irq[i] < 0)
+                       continue;
+
+               irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
+               err = request_irq(irq[i], atmel_interrupt, IRQ_TYPE_EDGE_BOTH,
+                                 "atmel_serial", port);
+               if (err)
+                       dev_err(port->dev, "atmel_startup - Can't get %d irq\n",
+                               irq[i]);
+       }
+
+       /*
+        * If something went wrong, rollback.
+        */
+       while (err && (--i >= 0))
+               if (irq[i] >= 0)
+                       free_irq(irq[i], port);
+
+       return err;
+}
+
 /*
  * Perform initialization and enable port for reception
  */
@@ -1579,6 +1671,7 @@ static int atmel_startup(struct uart_port *port)
         * handle an unexpected interrupt
         */
        UART_PUT_IDR(port, -1);
+       atmel_port->ms_irq_enabled = false;
 
        /*
         * Allocate the IRQ
@@ -1590,6 +1683,13 @@ static int atmel_startup(struct uart_port *port)
                return retval;
        }
 
+       /*
+        * Get the GPIO lines IRQ
+        */
+       retval = atmel_request_gpio_irq(port);
+       if (retval)
+               goto free_irq;
+
        /*
         * Initialize DMA (if necessary)
         */
@@ -1654,6 +1754,11 @@ static int atmel_startup(struct uart_port *port)
        }
 
        return 0;
+
+free_irq:
+       free_irq(port->irq, port);
+
+       return retval;
 }
 
 /*
@@ -1701,9 +1806,12 @@ static void atmel_shutdown(struct uart_port *port)
        atmel_port->rx_ring.tail = 0;
 
        /*
-        * Free the interrupt
+        * Free the interrupts
         */
        free_irq(port->irq, port);
+       atmel_free_gpio_irq(port);
+
+       atmel_port->ms_irq_enabled = false;
 }
 
 /*
@@ -2366,10 +2474,21 @@ static int atmel_serial_resume(struct platform_device *pdev)
 
 static int atmel_init_gpios(struct atmel_uart_port *p, struct device *dev)
 {
+       enum mctrl_gpio_idx i;
+       struct gpio_desc *gpiod;
+
        p->gpios = mctrl_gpio_init(dev, 0);
        if (IS_ERR_OR_NULL(p->gpios))
                return -1;
 
+       for (i = 0; i < UART_GPIO_MAX; i++) {
+               gpiod = mctrl_gpio_to_gpiod(p->gpios, i);
+               if (gpiod && (gpiod_get_direction(gpiod) == GPIOF_DIR_IN))
+                       p->gpio_irq[i] = gpiod_to_irq(gpiod);
+               else
+                       p->gpio_irq[i] = -EINVAL;
+       }
+
        return 0;
 }