linux-kernel - [PATCH 7/8] serial: xilinx_uartps: get clock rate info from dts

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Message-Id: <23a299ee5e89cfd17bb9affd8fbb9f41b79cfd46.1351721190.git.josh.cartwright@ni.com>
Date:	Wed, 31 Oct 2012 13:28:49 -0600
From:	Josh Cartwright <josh.cartwright@...com>
To:	Grant Likely <grant.likely@...retlab.ca>,
	Rob Herring <rob.herring@...xeda.com>,
	Russell King <linux@....linux.org.uk>,
	Mike Turquette <mturquette@...com>,
	John Stultz <johnstul@...ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Alan Cox <alan@...ux.intel.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	John Linn <John.Linn@...inx.com>,
	Michal Simek <michal.simek@...inx.com>
Cc:	devicetree-discuss@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-serial@...r.kernel.org,
	Michal Simek <monstr@...str.eu>
Subject: [PATCH 7/8] serial: xilinx_uartps: get clock rate info from dts

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@...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..5fb763f 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@...01000 {
 			compatible = "xlnx,xuartps";
 			reg = <0xE0001000 0x1000>;
 			interrupts = <0 50 4>;
-			clock = <50000000>;
+			clocks = <&uart_clk 0>;
 		};
 
 		slcr: slcr@...00000 {
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


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