[ARM] Convert AMBA PL010 driver to use the clk infrastructure
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>
diff --git a/arch/arm/mach-ep93xx/clock.c b/arch/arm/mach-ep93xx/clock.c
index f174d1a..9d7515c 100644
--- a/arch/arm/mach-ep93xx/clock.c
+++ b/arch/arm/mach-ep93xx/clock.c
@@ -27,6 +27,10 @@
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 *clocks[] = {
+ &clk_uart,
&clk_pll1,
&clk_f,
&clk_h,
diff --git a/drivers/serial/amba-pl010.c b/drivers/serial/amba-pl010.c
index ea49aaf..1a9a24b 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
amba_ports[i] = NULL;
iounmap(uap->port.membase);
+ clk_put(uap->clk);
kfree(uap);
return 0;
}