usb: musb: da8xx: Add support of suspend / resume

Implement PM methods specifics for da8xx glue.
The only thing to do is to power off the phy.
As the registers are in retention during suspend,
there is no need to save them.
Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/da8xx.c

@@ -573,6 +573,34 @@ static int da8xx_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int da8xx_suspend(struct device *dev)
+{
+	int ret;
+	struct da8xx_glue *glue = dev_get_drvdata(dev);
+
+	ret = phy_power_off(glue->phy);
+	if (ret)
+		return ret;
+	clk_disable_unprepare(glue->clk);
+
+	return 0;
+}
+
+static int da8xx_resume(struct device *dev)
+{
+	int ret;
+	struct da8xx_glue *glue = dev_get_drvdata(dev);
+
+	ret = clk_prepare_enable(glue->clk);
+	if (ret)
+		return ret;
+	return phy_power_on(glue->phy);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(da8xx_pm_ops, da8xx_suspend, da8xx_resume);
+
 #ifdef CONFIG_OF
 static const struct of_device_id da8xx_id_table[] = {
 	{
@@ -588,6 +616,7 @@ static struct platform_driver da8xx_driver = {
 	.remove		= da8xx_remove,
 	.driver		= {
 		.name	= "musb-da8xx",
+		.pm = &da8xx_pm_ops,
 		.of_match_table = of_match_ptr(da8xx_id_table),
 	},
 };