Re: [PATCH] mfd: omap-usb-tll: check clk_prepare return code
From: Andreas Kemnade
Date: Tue Nov 19 2024 - 09:09:06 EST
Am Tue, 19 Nov 2024 15:10:23 +0200
schrieb Roger Quadros <rogerq@xxxxxxxxxx>:
> Hi,
>
> On 13/11/2024 23:16, Karol Przybylski wrote:
> > clk_prepare() is called in usbtll_omap_probe to fill clk array.
> > Return code is not checked, leaving possible error condition unhandled.
> >
> > Added variable to hold return value from clk_prepare() and dev_dbg statement
> > when it's not successful.
> >
> > Found in coverity scan, CID 1594680
> >
> > Signed-off-by: Karol Przybylski <karprzy7@xxxxxxxxx>
> > ---
> > drivers/mfd/omap-usb-tll.c | 11 +++++++----
> > 1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c
> > index 0f7fdb99c809..2e9319ee1b74 100644
> > --- a/drivers/mfd/omap-usb-tll.c
> > +++ b/drivers/mfd/omap-usb-tll.c
> > @@ -202,7 +202,7 @@ static int usbtll_omap_probe(struct platform_device *pdev)
> > struct device *dev = &pdev->dev;
> > struct usbtll_omap *tll;
> > void __iomem *base;
> > - int i, nch, ver;
> > + int i, nch, ver, err;
> >
> > dev_dbg(dev, "starting TI HSUSB TLL Controller\n");
> >
> > @@ -248,10 +248,13 @@ static int usbtll_omap_probe(struct platform_device *pdev)
> > "usb_tll_hs_usb_ch%d_clk", i);
> > tll->ch_clk[i] = clk_get(dev, clkname);
> >
> > - if (IS_ERR(tll->ch_clk[i]))
> > + if (IS_ERR(tll->ch_clk[i])) {
> > dev_dbg(dev, "can't get clock : %s\n", clkname);
if you want dev_err() later, then why not here?
> > - else
> > - clk_prepare(tll->ch_clk[i]);
> > + } else {
> > + err = clk_prepare(tll->ch_clk[i]);
> > + if (err)
> > + dev_dbg(dev, "clock prepare error for: %s\n", clkname);
>
> dev_err()?
>
So why do you want a different return handling here? (I doubt there is
any clock having a real prepare() involved here)
As said in an earlier incarnation of this patch, the real question is
whether having partial clocks available is a valid operating scenario.
If yes, then the error should be ignored. If no, then bailing out early
is a good idea.
clk_prepare() errors are catched by failing clk_enable() later,
ch_clk[i] is checked later, too.
> I think we should return the error in this case.
> (after unpreparing the prepared clocks and clk_put())
>
and pm_runtime_put_sync(dev)
Regards,
Andreas