[PATCH 4.14 063/165] usb: host: xhci-plat: revert "usb: host: xhci-plat: enable clk in resume timing"

From: Greg Kroah-Hartman
Date: Thu May 24 2018 - 06:21:59 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>

[ Upstream commit d56e57ca030c8b4296944a2ae61ac167bf979c07 ]

This patch reverts the commit 835e4241e714 ("usb: host: xhci-plat:
enable clk in resume timing") because this driver also has runtime PM
and the commit 560869100b99 ("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: 835e4241e714 ("usb: host: xhci-plat: enable clk in resume timing")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-plat.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)

--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -355,7 +355,6 @@ static int __maybe_unused xhci_plat_susp
{
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
@@ -365,12 +364,7 @@ static int __maybe_unused xhci_plat_susp
* 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)
@@ -379,9 +373,6 @@ static int __maybe_unused xhci_plat_resu
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;