serial: 8250_dw: Enable runtime PM

This allows ACPI to put the device to D3 when it's not used.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_dw.c

@@ -27,6 +27,7 @@
 #include <linux/slab.h>
 #include <linux/acpi.h>
 #include <linux/clk.h>
+#include <linux/pm_runtime.h>
 
 #include "8250.h"
 
@@ -115,6 +116,18 @@ static int dw8250_handle_irq(struct uart_port *p)
 	return 0;
 }
 
+static void
+dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
+{
+	if (!state)
+		pm_runtime_get_sync(port->dev);
+
+	serial8250_do_pm(port, state, old);
+
+	if (state)
+		pm_runtime_put_sync_suspend(port->dev);
+}
+
 static int dw8250_probe_of(struct uart_port *p)
 {
 	struct device_node	*np = p->dev->of_node;
@@ -293,6 +306,7 @@ static int dw8250_probe(struct platform_device *pdev)
 	uart.port.mapbase = regs->start;
 	uart.port.irq = irq->start;
 	uart.port.handle_irq = dw8250_handle_irq;
+	uart.port.pm = dw8250_do_pm;
 	uart.port.type = PORT_8250;
 	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
 	uart.port.dev = &pdev->dev;
@@ -336,6 +350,9 @@ static int dw8250_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, data);
 
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
 	return 0;
 }
 
@@ -343,37 +360,64 @@ static int dw8250_remove(struct platform_device *pdev)
 {
 	struct dw8250_data *data = platform_get_drvdata(pdev);
 
+	pm_runtime_get_sync(&pdev->dev);
+
 	serial8250_unregister_port(data->line);
 
 	if (!IS_ERR(data->clk))
 		clk_disable_unprepare(data->clk);
 
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
 	return 0;
 }
 
 #ifdef CONFIG_PM
-static int dw8250_suspend(struct platform_device *pdev, pm_message_t state)
+static int dw8250_suspend(struct device *dev)
 {
-	struct dw8250_data *data = platform_get_drvdata(pdev);
+	struct dw8250_data *data = dev_get_drvdata(dev);
 
 	serial8250_suspend_port(data->line);
 
 	return 0;
 }
 
-static int dw8250_resume(struct platform_device *pdev)
+static int dw8250_resume(struct device *dev)
 {
-	struct dw8250_data *data = platform_get_drvdata(pdev);
+	struct dw8250_data *data = dev_get_drvdata(dev);
 
 	serial8250_resume_port(data->line);
 
 	return 0;
 }
-#else
-#define dw8250_suspend NULL
-#define dw8250_resume NULL
 #endif /* CONFIG_PM */
 
+#ifdef CONFIG_PM_RUNTIME
+static int dw8250_runtime_suspend(struct device *dev)
+{
+	struct dw8250_data *data = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(data->clk);
+
+	return 0;
+}
+
+static int dw8250_runtime_resume(struct device *dev)
+{
+	struct dw8250_data *data = dev_get_drvdata(dev);
+
+	clk_prepare_enable(data->clk);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops dw8250_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume)
+	SET_RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL)
+};
+
 static const struct of_device_id dw8250_of_match[] = {
 	{ .compatible = "snps,dw-apb-uart" },
 	{ /* Sentinel */ }
@@ -391,13 +435,12 @@ static struct platform_driver dw8250_platform_driver = {
 	.driver = {
 		.name		= "dw-apb-uart",
 		.owner		= THIS_MODULE,
+		.pm		= &dw8250_pm_ops,
 		.of_match_table	= dw8250_of_match,
 		.acpi_match_table = ACPI_PTR(dw8250_acpi_match),
 	},
 	.probe			= dw8250_probe,
 	.remove			= dw8250_remove,
-	.suspend		= dw8250_suspend,
-	.resume			= dw8250_resume,
 };
 
 module_platform_driver(dw8250_platform_driver);