tty: serial: tegra: Add runtime PM support

Add runtime PM support for tegra uart high speed driver.

Bug 887359
Reviewed-on: http://git-master/r/76805

Change-Id: I3439435eb40d36d66182a19011791399b6e65655
Signed-off-by: Pradeep Kumar <pgoudagunta@nvidia.com>
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Reviewed-on: http://git-master/r/78713
Reviewed-by: Rohan Somvanshi <rsomvanshi@nvidia.com>
Tested-by: Rohan Somvanshi <rsomvanshi@nvidia.com>

1 files changed, 39 insertions, 7 deletions

diff --git a/drivers/tty/serial/tegra_hsuart.c b/drivers/tty/serial/tegra_hsuart.c
index 04d007a03eb7..0d5d855f97a0 100644
--- a/drivers/tty/serial/tegra_hsuart.c
+++ b/drivers/tty/serial/tegra_hsuart.c
@@ -42,6 +42,7 @@
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/tegra_uart.h>
+#include <linux/pm_runtime.h>
 
 #include <mach/dma.h>
 #include <mach/clk.h>
@@ -635,10 +636,12 @@ static void tegra_uart_hw_deinit(struct tegra_uart_port *t)
 	unsigned char lsr;
 	unsigned char msr;
 	unsigned char mcr;
+	struct uart_port *u;
 
 	/* Disable interrupts */
 	uart_writeb(t, 0, UART_IER);
 
+	u = &t->uport;
 	lsr = uart_readb(t, UART_LSR);
 	if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
 		msr = uart_readb(t, UART_MSR);
@@ -676,7 +679,7 @@ static void tegra_uart_hw_deinit(struct tegra_uart_port *t)
 
 	spin_unlock_irqrestore(&t->uport.lock, flags);
 
-	clk_disable(t->clk);
+	pm_runtime_put_sync(u->dev);
 }
 
 static void tegra_uart_free_rx_dma_buffer(struct tegra_uart_port *t)
@@ -701,6 +704,7 @@ static void tegra_uart_free_rx_dma(struct tegra_uart_port *t)
 static int tegra_uart_hw_init(struct tegra_uart_port *t)
 {
 	unsigned char ier;
+	struct uart_port *u;
 
 	dev_vdbg(t->uport.dev, "+tegra_uart_hw_init\n");
 
@@ -709,8 +713,9 @@ static int tegra_uart_hw_init(struct tegra_uart_port *t)
 	t->lcr_shadow = 0;
 	t->ier_shadow = 0;
 	t->baud = 0;
+	u = &t->uport;
 
-	clk_enable(t->clk);
+	pm_runtime_get_sync(u->dev);
 
 	/* Reset the UART controller to clear all previous status.*/
 	tegra_periph_reset_assert(t->clk);
@@ -1394,13 +1399,39 @@ static int __devexit tegra_uart_remove(struct platform_device *pdev);
 static int tegra_uart_suspend(struct platform_device *pdev, pm_message_t state);
 static int tegra_uart_resume(struct platform_device *pdev);
 
+#if defined(CONFIG_PM_RUNTIME)
+static int tegra_uart_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct tegra_uart_port *t = platform_get_drvdata(pdev);
+	clk_disable(t->clk);
+	return 0;
+}
+
+static int tegra_uart_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct tegra_uart_port *t = platform_get_drvdata(pdev);
+	clk_enable(t->clk);
+	return 0;
+}
+
+static const struct dev_pm_ops tegra_uart_pm_ops  = {
+	.runtime_suspend = tegra_uart_runtime_suspend,
+	.runtime_resume = tegra_uart_runtime_resume,
+};
+#endif
+
 static struct platform_driver tegra_uart_platform_driver = {
 	.remove		= tegra_uart_remove,
 	.probe		= tegra_uart_probe,
 	.suspend	= tegra_uart_suspend,
 	.resume		= tegra_uart_resume,
 	.driver		= {
-		.name	= "tegra_uart"
+		.name	= "tegra_uart",
+#if defined(CONFIG_PM_RUNTIME)
+		.pm 	= &tegra_uart_pm_ops
+#endif
 	}
 };
 
@@ -1427,7 +1458,7 @@ static int tegra_uart_suspend(struct platform_device *pdev, pm_message_t state)
 	/* enable clock before calling suspend so that controller
 	   register can be accessible */
 	if (t->uart_state == TEGRA_UART_CLOCK_OFF) {
-		clk_enable(t->clk);
+		pm_runtime_get_sync(u->dev);
 		t->uart_state = TEGRA_UART_OPENED;
 	}
 
@@ -1465,6 +1496,7 @@ static int __devexit tegra_uart_remove(struct platform_device *pdev)
 		pr_err("Invalid Uart instance (%d)\n", pdev->id);
 
 	u = &t->uport;
+	pm_runtime_disable(u->dev);
 	uart_remove_one_port(&tegra_uart_driver, u);
 
 	tegra_uart_free_rx_dma_buffer(t);
@@ -1551,8 +1583,8 @@ static int tegra_uart_probe(struct platform_device *pdev)
 			goto rx_dma_buff_fail;
 		}
 	}
+	pm_runtime_enable(u->dev);
 	return ret;
-
 rx_dma_buff_fail:
 	uart_remove_one_port(&tegra_uart_driver, u);
 fail:
@@ -1584,7 +1616,7 @@ void tegra_uart_request_clock_off(struct uart_port *uport)
 	spin_unlock_irqrestore(&uport->lock, flags);
 
 	if (is_clk_disable)
-		clk_disable(t->clk);
+		pm_runtime_put_sync(uport->dev);
 
 	return;
 }
@@ -1608,7 +1640,7 @@ void tegra_uart_request_clock_on(struct uart_port *uport)
 	spin_unlock_irqrestore(&uport->lock, flags);
 
 	if (is_clk_enable)
-		clk_enable(t->clk);
+		pm_runtime_get_sync(uport->dev);
 
 	return;
 }