USB: host: ehci-atmel: Add suspend/resume support

This patch add suspend/resume support for Atmel EHCI, mostly
about disabling and unpreparing clocks so USB PLL is stopped
before entering sleep state.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/ehci-atmel.c b/drivers/usb/host/ehci-atmel.c
index 56a88506febe7992eff94df50e4c7c84dc071d9e..5a15e3dd006b98e4c26ea7b6c850952fef1a05da 100644 (file)
--- a/drivers/usb/host/ehci-atmel.c
+++ b/drivers/usb/host/ehci-atmel.c
@@ -37,6 +37,8 @@ static int clocked;
 
 static void atmel_start_clock(void)
 {
+       if (clocked)
+               return;
        if (IS_ENABLED(CONFIG_COMMON_CLK)) {
                clk_set_rate(uclk, 48000000);
                clk_prepare_enable(uclk);
@@ -48,6 +50,8 @@ static void atmel_start_clock(void)
 
 static void atmel_stop_clock(void)
 {
+       if (!clocked)
+               return;
        clk_disable_unprepare(fclk);
        clk_disable_unprepare(iclk);
        if (IS_ENABLED(CONFIG_COMMON_CLK))
@@ -174,6 +178,29 @@ static int ehci_atmel_drv_remove(struct platform_device *pdev)
        return 0;
 }
 
+#ifdef CONFIG_PM
+static int ehci_atmel_drv_suspend(struct device *dev)
+{
+       struct usb_hcd *hcd = dev_get_drvdata(dev);
+       int ret;
+
+       ret = ehci_suspend(hcd, false);
+       if (ret)
+               return ret;
+
+       atmel_stop_clock();
+       return 0;
+}
+
+static int ehci_atmel_drv_resume(struct device *dev)
+{
+       struct usb_hcd *hcd = dev_get_drvdata(dev);
+
+       atmel_start_clock();
+       return ehci_resume(hcd, false);
+}
+#endif
+
 #ifdef CONFIG_OF
 static const struct of_device_id atmel_ehci_dt_ids[] = {
        { .compatible = "atmel,at91sam9g45-ehci" },
@@ -183,12 +210,16 @@ static const struct of_device_id atmel_ehci_dt_ids[] = {
 MODULE_DEVICE_TABLE(of, atmel_ehci_dt_ids);
 #endif
 
+static SIMPLE_DEV_PM_OPS(ehci_atmel_pm_ops, ehci_atmel_drv_suspend,
+                                       ehci_atmel_drv_resume);
+
 static struct platform_driver ehci_atmel_driver = {
        .probe          = ehci_atmel_drv_probe,
        .remove         = ehci_atmel_drv_remove,
        .shutdown       = usb_hcd_platform_shutdown,
        .driver         = {
                .name   = "atmel-ehci",
+               .pm     = &ehci_atmel_pm_ops,
                .of_match_table = of_match_ptr(atmel_ehci_dt_ids),
        },
 };