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>

1 files changed, 122 insertions, 3 deletions

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 43ca659c1d4b..3fceae099c44 100644
--- 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
@@ -1591,6 +1684,13 @@ static int atmel_startup(struct uart_port *port)
         }
 
         /*
+         * Get the GPIO lines IRQ
+         */
+        retval = atmel_request_gpio_irq(port);
+        if (retval)
+                goto free_irq;
+
+        /*
          * Initialize DMA (if necessary)
          */
         atmel_init_property(atmel_port, pdev);
@@ -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;
 }