2 files changed, 42 insertions, 2 deletions

diff --git a/arch/arm/mach-ep93xx/clock.c b/arch/arm/mach-ep93xx/clock.c
index f174d1a3b11c..9d7515c36bff 100644
--- a/arch/arm/mach-ep93xx/clock.c
+++ b/arch/arm/mach-ep93xx/clock.c
@@ -27,6 +27,10 @@ struct clk {
         u32             enable_mask;
 };
 
+static struct clk clk_uart = {
+        .name           = "UARTCLK",
+        .rate           = 14745600,
+};
 static struct clk clk_pll1 = {
         .name           = "pll1",
 };
@@ -50,6 +54,7 @@ static struct clk clk_usb_host = {
 
 
 static struct clk *clocks[] = {
+        &clk_uart,
         &clk_pll1,
         &clk_f,
         &clk_h,
diff --git a/drivers/serial/amba-pl010.c b/drivers/serial/amba-pl010.c
index ea49aafd66bf..1a9a24b82636 100644
--- a/drivers/serial/amba-pl010.c
+++ b/drivers/serial/amba-pl010.c
@@ -48,6 +48,7 @@
 #include <linux/serial.h>
 #include <linux/amba/bus.h>
 #include <linux/amba/serial.h>
+#include <linux/clk.h>
 
 #include <asm/io.h>
 
@@ -70,6 +71,7 @@
  */
 struct uart_amba_port {
         struct uart_port        port;
+        struct clk              *clk;
         struct amba_device      *dev;
         struct amba_pl010_data  *data;
         unsigned int            old_status;
@@ -313,11 +315,20 @@ static int pl010_startup(struct uart_port *port)
         int retval;
 
         /*
+         * Try to enable the clock producer.
+         */
+        retval = clk_enable(uap->clk);
+        if (retval)
+                goto out;
+
+        uap->port.uartclk = clk_get_rate(uap->clk);
+
+        /*
          * Allocate the IRQ
          */
         retval = request_irq(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
         if (retval)
-                return retval;
+                goto clk_dis;
 
         /*
          * initialise the old status of the modem signals
@@ -331,6 +342,11 @@ static int pl010_startup(struct uart_port *port)
                uap->port.membase + UART010_CR);
 
         return 0;
+
+ clk_dis:
+        clk_disable(uap->clk);
+ out:
+        return retval;
 }
 
 static void pl010_shutdown(struct uart_port *port)
@@ -351,6 +367,11 @@ static void pl010_shutdown(struct uart_port *port)
         writel(readb(uap->port.membase + UART010_LCRH) &
                 ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
                uap->port.membase + UART010_LCRH);
+
+        /*
+         * Shut down the clock producer
+         */
+        clk_disable(uap->clk);
 }
 
 static void
@@ -540,6 +561,8 @@ pl010_console_write(struct console *co, const char *s, unsigned int count)
         struct uart_amba_port *uap = amba_ports[co->index];
         unsigned int status, old_cr;
 
+        clk_enable(uap->clk);
+
         /*
          *      First save the CR then disable the interrupts
          */
@@ -557,6 +580,8 @@ pl010_console_write(struct console *co, const char *s, unsigned int count)
                 barrier();
         } while (status & UART01x_FR_BUSY);
         writel(old_cr, uap->port.membase + UART010_CR);
+
+        clk_disable(uap->clk);
 }
 
 static void __init
@@ -605,6 +630,8 @@ static int __init pl010_console_setup(struct console *co, char *options)
         if (!uap)
                 return -ENODEV;
 
+        uap->port.uartclk = clk_get_rate(uap->clk);
+
         if (options)
                 uart_parse_options(options, &baud, &parity, &bits, &flow);
         else
@@ -666,12 +693,17 @@ static int pl010_probe(struct amba_device *dev, void *id)
                 goto free;
         }
 
+        uap->clk = clk_get(&dev->dev, "UARTCLK");
+        if (IS_ERR(uap->clk)) {
+                ret = PTR_ERR(uap->clk);
+                goto unmap;
+        }
+
         uap->port.dev = &dev->dev;
         uap->port.mapbase = dev->res.start;
         uap->port.membase = base;
         uap->port.iotype = UPIO_MEM;
         uap->port.irq = dev->irq[0];
-        uap->port.uartclk = 14745600;
         uap->port.fifosize = 16;
         uap->port.ops = &amba_pl010_pops;
         uap->port.flags = UPF_BOOT_AUTOCONF;
@@ -686,6 +718,8 @@ static int pl010_probe(struct amba_device *dev, void *id)
         if (ret) {
                 amba_set_drvdata(dev, NULL);
                 amba_ports[i] = NULL;
+                clk_put(uap->clk);
+ unmap:
                 iounmap(base);
  free:
                 kfree(uap);
@@ -708,6 +742,7 @@ static int pl010_remove(struct amba_device *dev)
                         amba_ports[i] = NULL;
 
         iounmap(uap->port.membase);
+        clk_put(uap->clk);
         kfree(uap);
         return 0;
 }