Dear Gregory CLEMENT, On Fri, 25 Apr 2014 16:07:00 +0200, Gregory CLEMENT wrote: > Some platform (such as the Armada 38x ones) can gate the clock of > their USB controller. This patch add the support for the clock, by > enabling them during probe and disabling them on remove. > > As not all platforms have clock support then enabling and disabling > the clocks have been placed in separate functions. Then if the clocks > are not supported we still can use the same calls, and there is no > > Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx> > --- > drivers/usb/host/xhci-plat.c | 52 ++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 50 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c > index f5351af4b2c5..bb5d563f729c 100644 > --- a/drivers/usb/host/xhci-plat.c > +++ b/drivers/usb/host/xhci-plat.c > @@ -11,6 +11,7 @@ > * version 2 as published by the Free Software Foundation. > */ > > +#include <linux/clk.h> > #include <linux/dma-mapping.h> > #include <linux/module.h> > #include <linux/of.h> > @@ -85,6 +86,42 @@ static const struct hc_driver xhci_plat_xhci_driver = { > .bus_resume = xhci_bus_resume, > }; > > +#if defined(CONFIG_HAVE_CLK) > +static int try_enable_clk(struct platform_device *pdev) > +{ > + struct clk *clk = devm_clk_get(&pdev->dev, NULL); > + > + /* Not all platforms have a clk so it is not an error if the clock > + does not exists. */ > + if (!IS_ERR(clk)) Instead, do: if (IS_ERR(clk)) return 0; return clk_prepare_enable(clk); > + if (clk_prepare_enable(clk)) > + return -ENODEV; > + return 0; > +} > + > +static int try_disable_clk(struct platform_device *pdev) > +{ > + struct clk *clk = devm_clk_get(&pdev->dev, NULL); No, this isn't correct: you shouldn't be getting the clock to disable/unprepare it, otherwise you have an unbalanced number of get()/put() calls on the clocks. Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html