On Wed, 2022-07-06 at 16:21 +0200, Marco Felsch wrote: > Currently we enable the clock immediately after requesting it and > leave > it on the whole time. Afterwards if the phy request is failing we > leave > the usb-controller <-> usb-phy connection in a partly initialized > state. > At least on i.MX8M SoCs this can cause strange system hangs during > boot. > > The (more) correct way would be to have the whole power-domain > framework > and the blk-ctrl driver support within barebox. So we can leave the > power-domain in a known good state for linux. Since this is not the > case > we can move the clk_enable() call so it gets called after we know > that > all ressources are available. So the probability to leave the system > in > a partly initialized state is lesser. > > Drop the !IS_ERR() since NULL and errors are handled in clk_enable() > as > well. > > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> > --- > drivers/usb/imx/chipidea-imx.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/imx/chipidea-imx.c > b/drivers/usb/imx/chipidea-imx.c > index bf8b6f1eb8..f71cf80b7d 100644 > --- a/drivers/usb/imx/chipidea-imx.c > +++ b/drivers/usb/imx/chipidea-imx.c > @@ -260,8 +260,6 @@ static int imx_chipidea_probe(struct device_d > *dev) > * devices which have only one. > */ > ci->clk = clk_get(dev, NULL); > - if (!IS_ERR(ci->clk)) > - clk_enable(ci->clk); > > /* Device trees are using both "phys" and "fsl,usbphy". > Prefer the > * more modern former one but fall back to the old one. > @@ -302,6 +300,14 @@ static int imx_chipidea_probe(struct device_d > *dev) > ci->data.drvdata = ci; > ci->data.usbphy = ci->usbphy; > > + /* > + * Enable the clock after we ensured that all resources are > available. > + * This is crucial since the phy can be missing which and so > the > + * usb-controller <-> usb-phy communication is only partly > initialized. > + * This can trigger strange system hangs at least on i.MX8M > SoCs. > + */ > + clk_enable(ci->clk); > + > if ((ci->flags & MXC_EHCI_PORTSC_MASK) == MXC_EHCI_MODE_HSIC) > imx_chipidea_port_init(ci); > Tested-by: Johannes Zink <j.zink@xxxxxxxxxxxxxx> # i.MX7
