atmel_serial: keep clock off when it's not needed

[linux-2.6-omap-h63xx.git] / drivers / serial / atmel_serial.c

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 3a6da80b081c14405ecfdd60660470928843e84c..d5efd6c77904aef0dbb74641820b8937890f4ae5 100644 (file)
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -131,7 +131,8 @@ struct atmel_uart_char {
 struct atmel_uart_port {
        struct uart_port        uart;           /* uart */
        struct clk              *clk;           /* uart clock */
-       unsigned short          suspended;      /* is port suspended? */
+       int                     may_wakeup;     /* cached value of device_may_wakeup for times we need to disable it */
+       u32                     backup_imr;     /* IMR saved during suspend */
        int                     break_active;   /* break being received */
 
        short                   use_dma_rx;     /* enable PDC receiver */
@@ -984,8 +985,15 @@ static void atmel_serial_pm(struct uart_port *port, unsigned int state,
                 * This is called on uart_open() or a resume event.
                 */
                clk_enable(atmel_port->clk);
+
+               /* re-enable interrupts if we disabled some on suspend */
+               UART_PUT_IER(port, atmel_port->backup_imr);
                break;
        case 3:
+               /* Back up the interrupt mask and disable all interrupts */
+               atmel_port->backup_imr = UART_GET_IMR(port);
+               UART_PUT_IDR(port, -1);
+
                /*
                 * Disable the peripheral clock for this serial port.
                 * This is called on uart_close() or a suspend event.
@@ -1250,6 +1258,8 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
                atmel_port->clk = clk_get(&pdev->dev, "usart");
                clk_enable(atmel_port->clk);
                port->uartclk = clk_get_rate(atmel_port->clk);
+               clk_disable(atmel_port->clk);
+               /* only enable clock when USART is in use */
        }
 
        atmel_port->use_dma_rx = data->use_dma_rx;
@@ -1371,6 +1381,8 @@ static int __init atmel_console_setup(struct console *co, char *options)
                return -ENODEV;
        }
 
+       clk_enable(atmel_ports[co->index].clk);
+
        UART_PUT_IDR(port, -1);
        UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
        UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);
@@ -1395,7 +1407,7 @@ static struct console atmel_console = {
        .data           = &atmel_uart,
 };
 
-#define ATMEL_CONSOLE_DEVICE   &atmel_console
+#define ATMEL_CONSOLE_DEVICE   (&atmel_console)
 
 /*
  * Early console initialization (before VM subsystem initialized).
@@ -1475,13 +1487,12 @@ static int atmel_serial_suspend(struct platform_device *pdev,
                        cpu_relax();
        }
 
-       if (device_may_wakeup(&pdev->dev)
-           && !atmel_serial_clk_will_stop())
-               enable_irq_wake(port->irq);
-       else {
-               uart_suspend_port(&atmel_uart, port);
-               atmel_port->suspended = 1;
-       }
+       /* we can not wake up if we're running on slow clock */
+       atmel_port->may_wakeup = device_may_wakeup(&pdev->dev);
+       if (atmel_serial_clk_will_stop())
+               device_set_wakeup_enable(&pdev->dev, 0);
+
+       uart_suspend_port(&atmel_uart, port);
 
        return 0;
 }
@@ -1491,11 +1502,8 @@ static int atmel_serial_resume(struct platform_device *pdev)
        struct uart_port *port = platform_get_drvdata(pdev);
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-       if (atmel_port->suspended) {
-               uart_resume_port(&atmel_uart, port);
-               atmel_port->suspended = 0;
-       } else
-               disable_irq_wake(port->irq);
+       uart_resume_port(&atmel_uart, port);
+       device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup);
 
        return 0;
 }
@@ -1513,6 +1521,8 @@ static int __devinit atmel_serial_probe(struct platform_device *pdev)
        BUILD_BUG_ON(!is_power_of_2(ATMEL_SERIAL_RINGSIZE));
 
        port = &atmel_ports[pdev->id];
+       port->backup_imr = 0;
+
        atmel_init_port(port, pdev);
 
        if (!atmel_use_dma_rx(&port->uart)) {
@@ -1528,6 +1538,15 @@ static int __devinit atmel_serial_probe(struct platform_device *pdev)
        if (ret)
                goto err_add_port;
 
+       if (atmel_is_console_port(&port->uart)
+                       && ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {
+               /*
+                * The serial core enabled the clock for us, so undo
+                * the clk_enable() in atmel_console_setup()
+                */
+               clk_disable(port->clk);
+       }
+
        device_init_wakeup(&pdev->dev, 1);
        platform_set_drvdata(pdev, port);
 
@@ -1538,7 +1557,6 @@ err_add_port:
        port->rx_ring.buf = NULL;
 err_alloc_ring:
        if (!atmel_is_console_port(&port->uart)) {
-               clk_disable(port->clk);
                clk_put(port->clk);
                port->clk = NULL;
        }
@@ -1562,7 +1580,6 @@ static int __devexit atmel_serial_remove(struct platform_device *pdev)
 
        /* "port" is allocated statically, so we shouldn't free it */
 
-       clk_disable(atmel_port->clk);
        clk_put(atmel_port->clk);
 
        return ret;