Hi
On Fri, 2024-01-05 at 20:11 +0100, Uwe Kleine-König wrote:
> On Fri, Jan 05, 2024 at 06:22:18PM +0100, Philipp Stanner wrote:
> > Some drivers want to use (request) a region exclusively but
> > nevertheless
> > create several mappings within that region.
> >
> > Currently, there is no managed devres function to request a region
> > without mapping it.
> >
> > Add the function devm_platform_get_resource()
> >
> > Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
> > ---
> > drivers/base/platform.c | 37
> > +++++++++++++++++++++++++++++++++
> > include/linux/platform_device.h | 2 ++
> > 2 files changed, 39 insertions(+)
> >
> > diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> > index 10c577963418..243b9ec54d04 100644
> > --- a/drivers/base/platform.c
> > +++ b/drivers/base/platform.c
> > @@ -82,6 +82,43 @@ struct resource *platform_get_mem_or_io(struct
> > platform_device *dev,
> > }
> > EXPORT_SYMBOL_GPL(platform_get_mem_or_io);
> >
> > +/**
> > + * devm_platform_get_and_resource - get and request a resource
>
> This function name is wrong.
>
> > + *
> > + * @pdev: the platform device to get the resource from
> > + * @type: resource type (either IORESOURCE_MEM or IORESOURCE_IO)
> > + * @num: resource index
> > + * @name: name to be associated with the request
> > + *
> > + * Return: a pointer to the resource on success, an ERR_PTR on
> > failure.
> > + *
> > + * Gets a resource and requests it. Use this instead of
> > + * devm_platform_ioremap_resource() only if you have to create
> > several single
> > + * mappings with devm_ioremap().
> > + */
> > +struct resource *devm_platform_get_resource(struct platform_device
> > *pdev,
> > + unsigned int type, unsigned int num, const char
> > *name)
> > +{
> > + struct resource *res;
> > +
> > + res = platform_get_resource(pdev, type, num);
> > + if (!res)
> > + return ERR_PTR(-EINVAL);
>
> From devm_platform_get_resource I'd expect that it only does
> platform_get_resource() + register a cleanup function to undo it.
>
> > + if (type & IORESOURCE_MEM)
> > + res = devm_request_mem_region(&pdev->dev, res-
> > >start, res->end, name);
> > + else if (type & IORESOURCE_IO)
> > + res = devm_request_region(&pdev->dev, res->start,
> > res->end, name);
> > + else
> > + return ERR_PTR(-EINVAL);
>
> So this part is surprising. IMHO your function's name should include
> "request".
Yes, that sounds very correct to me. I'll address that in v2
Thx for the feedback,
P.
>
> > + if (!res)
> > + return ERR_PTR(-EBUSY);
> > +
> > + return res;
> > +}
> > +EXPORT_SYMBOL_GPL(devm_platform_get_resource);
> > +
> > #ifdef CONFIG_HAS_IOMEM
> > /**
> > * devm_platform_get_and_ioremap_resource - call
> > devm_ioremap_resource() for a
>
> Best regards
> Uwe
>
