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    SubjectRe: [PATCH v2 6/6] usb: host: ohci-exynos: Use devm_ioremap_resource instead of devm_ioremap
    From
    Hi,


    On Sat, May 10, 2014 at 5:30 PM, Vivek Gautam <gautam.vivek@samsung.com> wrote:
    > Using devm_ioremap_resource() API should actually be preferred over
    > devm_ioremap(), since the former request the mem region first and then
    > gives back the ioremap'ed memory pointer.
    > devm_ioremap_resource() calls request_mem_region(), therby preventing
    > other drivers to make any overlapping call to the same region.
    >
    > Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>

    Although this patch and rest in the series are merged.
    But i have got a doubt, so making this thread alive.

    > ---
    > drivers/usb/host/ohci-exynos.c | 7 +++----
    > 1 file changed, 3 insertions(+), 4 deletions(-)
    >
    > diff --git a/drivers/usb/host/ohci-exynos.c b/drivers/usb/host/ohci-exynos.c
    > index 9cf80cb..dec691d 100644
    > --- a/drivers/usb/host/ohci-exynos.c
    > +++ b/drivers/usb/host/ohci-exynos.c
    > @@ -120,10 +120,9 @@ skip_phy:
    >
    > hcd->rsrc_start = res->start;
    > hcd->rsrc_len = resource_size(res);
    > - hcd->regs = devm_ioremap(&pdev->dev, res->start, hcd->rsrc_len);
    > - if (!hcd->regs) {
    > - dev_err(&pdev->dev, "Failed to remap I/O memory\n");
    > - err = -ENOMEM;
    > + hcd->regs = devm_ioremap_resource(&pdev->dev, res);

    Here, we replaced devm_ioremap() call with devm_ioremap_resource(),
    which internally
    requests the memory region and then does a "devm_ioremap()" or
    "devm_ioremap_nocache()"
    based on the check for IORESOURCE_CACHEABLE flag.

    But this flag is not set for the resource of this device.
    So should we be explicitly setting the flag in driver ?

    The query goes for other patches too in this series, wherein
    devm_ioremap() call is replaced with devm_ioremap_resource().

    [snip]


    --
    Best Regards
    Vivek Gautam
    Samsung R&D Institute, Bangalore
    India


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