[ARM] Convert AMBA PL010 driver to use the clk infrastructure
authorRussell King <rmk@dyn-67.arm.linux.org.uk>
Sun, 22 Apr 2007 11:30:41 +0000 (12:30 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Sun, 22 Apr 2007 11:30:41 +0000 (12:30 +0100)
Convert the AMBA PL010 serial driver to use the clock infrastructure
to allow EP93xx platforms to properly gate the clock to the UARTs.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/mach-ep93xx/clock.c
drivers/serial/amba-pl010.c

index f174d1a3b11c7333d18a19f3524e39256af05add..9d7515c36bffa84e08c5c065fc5abfb008b58652 100644 (file)
@@ -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,
index ea49aafd66bfe72f5b068237ba5410480fb541f9..1a9a24b82636e42704ae910f97e46d212800ebd4 100644 (file)
@@ -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;
@@ -312,12 +314,21 @@ static int pl010_startup(struct uart_port *port)
        struct uart_amba_port *uap = (struct uart_amba_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;
 }