Commit d56e57ca authored Mar 08, 2018 by Yoshihiro Shimoda Committed by Greg Kroah-Hartman Mar 09, 2018

usb: host: xhci-plat: revert "usb: host: xhci-plat: enable clk in resume timing"



This patch reverts the commit 835e4241 ("usb: host: xhci-plat:
enable clk in resume timing") because this driver also has runtime PM
and the commit 56086910 ("clk: renesas: cpg-mssr: Restore module
clocks during resume") will restore the clock on R-Car H3 environment.

If the xhci_plat_suspend() disables the clk, the system cannot enable
the clk in resume like the following behavior:

< In resume >
 - genpd_resume_noirq() runs and enable the clk (enable_count = 1)
 - cpg_mssr_resume_noirq() restores the clk register.
  -- Since the clk was disabled in suspend, cpg_mssr_resume_noirq()
     will disable the clk and keep the enable_count.
 - Even if xhci_plat_resume() calls clk_prepare_enable(), since
   the enable_count is 1, the clk will be not enabled.

After this patch is applied, the cpg-mssr driver will save the clk
as enable, so the clk will be enabled in resume.

Fixes: 835e4241 ("usb: host: xhci-plat: enable clk in resume timing")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent a5f59683

drivers/usb/host/xhci-plat.c

+1 −10

Original line number	Diff line number	Diff line
		@@ -360,7 +360,6 @@ static int __maybe_unused xhci_plat_suspend(struct device *dev)
		{
		struct usb_hcd *hcd = dev_get_drvdata(dev);
		struct xhci_hcd *xhci = hcd_to_xhci(hcd);
		int ret;

		/*
		* xhci_suspend() needs `do_wakeup` to know whether host is allowed
		@@ -370,12 +369,7 @@ static int __maybe_unused xhci_plat_suspend(struct device *dev)
		* reconsider this when xhci_plat_suspend enlarges its scope, e.g.,
		* also applies to runtime suspend.
		*/
		ret = xhci_suspend(xhci, device_may_wakeup(dev));

		if (!device_may_wakeup(dev) && !IS_ERR(xhci->clk))
		clk_disable_unprepare(xhci->clk);

		return ret;
		return xhci_suspend(xhci, device_may_wakeup(dev));
		}

		static int __maybe_unused xhci_plat_resume(struct device *dev)
		@@ -384,9 +378,6 @@ static int __maybe_unused xhci_plat_resume(struct device *dev)
		struct xhci_hcd *xhci = hcd_to_xhci(hcd);
		int ret;

		if (!device_may_wakeup(dev) && !IS_ERR(xhci->clk))
		clk_prepare_enable(xhci->clk);

		ret = xhci_priv_resume_quirk(hcd);
		if (ret)
		return ret;