[PATCH v2 4/5] serial: xilinx_uartps: get clock rate info from dts

Josh Cartwright
2012-11-08T19:54:17Z

Add support for specifying clock information for the uart clk via the
device tree. This eliminates the need to hardcode rates in the device
tree.

Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
---
arch/arm/boot/dts/zynq-7000.dtsi | 4 ++--
drivers/tty/serial/xilinx_uartps.c | 30 +++++++++++++++++-------------
2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi
index bb3085c..c975c2d 100644
--- a/arch/arm/boot/dts/zynq-7000.dtsi
+++ b/arch/arm/boot/dts/zynq-7000.dtsi
@@ -44,14 +44,14 @@
compatible = "xlnx,xuartps";
reg = <0xE0000000 0x1000>;
interrupts = <0 27 4>;
- clock = <50000000>;
+ clocks = <&uart_clk 0>;
};

uart1: uart@e0001000 {
compatible = "xlnx,xuartps";
reg = <0xE0001000 0x1000>;
interrupts = <0 50 4>;
- clock = <50000000>;
+ clocks = <&uart_clk 1>;
};

slcr: slcr@f8000000 {
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 23efe17..adfecbc 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -17,6 +17,7 @@
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/console.h>
+#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/of.h>
@@ -944,18 +945,20 @@ static int __devinit xuartps_probe(struct platform_device *pdev)
int rc;
struct uart_port *port;
struct resource *res, *res2;
- int clk = 0;
+ struct clk *clk;

- const unsigned int *prop;
-
- prop = of_get_property(pdev->dev.of_node, "clock", NULL);
- if (prop)
- clk = be32_to_cpup(prop);
+ clk = of_clk_get(pdev->dev.of_node, 0);
if (!clk) {
dev_err(&pdev->dev, "no clock specified\n");
return -ENODEV;
}

+ rc = clk_prepare_enable(clk);
+ if (rc) {
+ dev_err(&pdev->dev, "could not enable clock\n");
+ return -EBUSY;
+ }
+
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
@@ -978,7 +981,8 @@ static int __devinit xuartps_probe(struct platform_device *pdev)
port->mapbase = res->start;
port->irq = res2->start;
port->dev = &pdev->dev;
- port->uartclk = clk;
+ port->uartclk = clk_get_rate(clk);
+ port->private_data = clk;
dev_set_drvdata(&pdev->dev, port);
rc = uart_add_one_port(&xuartps_uart_driver, port);
if (rc) {
@@ -1000,14 +1004,14 @@ static int __devinit xuartps_probe(struct platform_device *pdev)
static int __devexit xuartps_remove(struct platform_device *pdev)
{
struct uart_port *port = dev_get_drvdata(&pdev->dev);
- int rc = 0;
+ struct clk *clk = port->private_data;
+ int rc;

/* Remove the xuartps port from the serial core */
- if (port) {
- rc = uart_remove_one_port(&xuartps_uart_driver, port);
- dev_set_drvdata(&pdev->dev, NULL);
- port->mapbase = 0;
- }
+ rc = uart_remove_one_port(&xuartps_uart_driver, port);
+ dev_set_drvdata(&pdev->dev, NULL);
+ port->mapbase = 0;
+ clk_disable_unprepare(clk);
return rc;
}

--
1.8.0